mcs/class/Managed.Windows.Forms/System.Windows.Forms/TextControl.cs

   1 // Permission is hereby granted, free of charge, to any person obtaining
   2 // a copy of this software and associated documentation files (the
   3 // "Software"), to deal in the Software without restriction, including
   4 // without limitation the rights to use, copy, modify, merge, publish,
   5 // distribute, sublicense, and/or sell copies of the Software, and to
   6 // permit persons to whom the Software is furnished to do so, subject to
   7 // the following conditions:
   8 //
   9 // The above copyright notice and this permission notice shall be
  10 // included in all copies or substantial portions of the Software.
  11 //
  12 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  13 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  14 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  15 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  16 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  17 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  18 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  19 //
  20 // Copyright (c) 2004-2006 Novell, Inc. (http://www.novell.com)
  21 //
  22 // Authors:
  23 //      Peter Bartok    pbartok@novell.com
  24 //
  25 //
  26
  27 // NOT COMPLETE
  28
  29 // There's still plenty of things missing, I've got most of it planned, just hadn't had
  30 // the time to write it all yet.
  31 // Stuff missing (in no particular order):
  32 // - Align text after RecalculateLine
  33 // - Implement tag types for hotlinks, etc.
  34 // - Implement CaretPgUp/PgDown
  35
  36 // NOTE:
  37 // selection_start.pos and selection_end.pos are 0-based
  38 // selection_start.pos = first selected char
  39 // selection_end.pos = first NOT-selected char
  40 //
  41 // FormatText methods are 1-based (as are all tags, LineTag.Start is 1 for
  42 // the first character on a line; the reason is that 0 is the position
  43 // *before* the first character on a line
  44
  45
  46 #undef Debug
  47
  48 using System;
  49 using System.Collections;
  50 using System.Drawing;
  51 using System.Drawing.Text;
  52 using System.Text;
  53 using RTF=System.Windows.Forms.RTF;
  54
  55 namespace System.Windows.Forms {
  56         internal enum LineColor {
  57                 Red     = 0,
  58                 Black   = 1
  59         }
  60
  61         internal enum CaretSelection {
  62                 Position,       // Selection=Caret
  63                 Word,           // Selection=Word under caret
  64                 Line            // Selection=Line under caret
  65         }
  66
  67         [Flags]
  68         internal enum FormatSpecified {
  69                 None,
  70
  71                 BackColor = 2,
  72                 Font = 4,
  73                 Color = 8,
  74         }
  75
  76         internal enum CaretDirection {
  77                 CharForward,    // Move a char to the right
  78                 CharBack,       // Move a char to the left
  79                 LineUp,         // Move a line up
  80                 LineDown,       // Move a line down
  81                 Home,           // Move to the beginning of the line
  82                 End,            // Move to the end of the line
  83                 PgUp,           // Move one page up
  84                 PgDn,           // Move one page down
  85                 CtrlPgUp,       // Move caret to the first visible char in the viewport
  86                 CtrlPgDn,       // Move caret to the last visible char in the viewport
  87                 CtrlHome,       // Move to the beginning of the document
  88                 CtrlEnd,        // Move to the end of the document
  89                 WordBack,       // Move to the beginning of the previous word (or beginning of line)
  90                 WordForward,    // Move to the beginning of the next word (or end of line)
  91                 SelectionStart, // Move to the beginning of the current selection
  92                 SelectionEnd,   // Move to the end of the current selection
  93                 CharForwardNoWrap,   // Move a char forward, but don't wrap onto the next line
  94                 CharBackNoWrap      // Move a char backward, but don't wrap onto the previous line
  95         }
  96
  97         internal enum LineEnding {
  98                 Wrap = 1,    // line wraps to the next line
  99                 Limp = 2,    // \r
 100                 Hard = 4,    // \r\n
 101                 Soft = 8,    // \r\r\n
 102                 Rich = 16,    // \n
 103
 104                 None = 0
 105         }
 106
 107         internal class Document : ICloneable, IEnumerable {
 108                 #region Structures
 109                 // FIXME - go through code and check for places where
 110                 // we do explicit comparisons instead of using the compare overloads
 111                 internal struct Marker {
 112                         internal Line           line;
 113                         internal LineTag        tag;
 114                         internal int            pos;
 115                         internal int            height;
 116
 117                         public static bool operator<(Marker lhs, Marker rhs) {
 118                                 if (lhs.line.line_no < rhs.line.line_no) {
 119                                         return true;
 120                                 }
 121
 122                                 if (lhs.line.line_no == rhs.line.line_no) {
 123                                         if (lhs.pos < rhs.pos) {
 124                                                 return true;
 125                                         }
 126                                 }
 127                                 return false;
 128                         }
 129
 130                         public static bool operator>(Marker lhs, Marker rhs) {
 131                                 if (lhs.line.line_no > rhs.line.line_no) {
 132                                         return true;
 133                                 }
 134
 135                                 if (lhs.line.line_no == rhs.line.line_no) {
 136                                         if (lhs.pos > rhs.pos) {
 137                                                 return true;
 138                                         }
 139                                 }
 140                                 return false;
 141                         }
 142
 143                         public static bool operator==(Marker lhs, Marker rhs) {
 144                                 if ((lhs.line.line_no == rhs.line.line_no) && (lhs.pos == rhs.pos)) {
 145                                         return true;
 146                                 }
 147                                 return false;
 148                         }
 149
 150                         public static bool operator!=(Marker lhs, Marker rhs) {
 151                                 if ((lhs.line.line_no != rhs.line.line_no) || (lhs.pos != rhs.pos)) {
 152                                         return true;
 153                                 }
 154                                 return false;
 155                         }
 156
 157                         public void Combine(Line move_to_line, int move_to_line_length) {
 158                                 line = move_to_line;
 159                                 pos += move_to_line_length;
 160                                 tag = LineTag.FindTag(line, pos);
 161                         }
 162
 163                         // This is for future use, right now Document.Split does it by hand, with some added shortcut logic
 164                         public void Split(Line move_to_line, int split_at) {
 165                                 line = move_to_line;
 166                                 pos -= split_at;
 167                                 tag = LineTag.FindTag(line, pos);
 168                         }
 169
 170                         public override bool Equals(object obj) {
 171                                    return this==(Marker)obj;
 172                         }
 173
 174                         public override int GetHashCode() {
 175                                 return base.GetHashCode ();
 176                         }
 177
 178                         public override string ToString() {
 179                                 return "Marker Line " + line + ", Position " + pos;
 180                         }
 181
 182                 }
 183                 #endregion Structures
 184
 185                 #region Local Variables
 186                 private Line            document;
 187                 private int             lines;
 188                 private Line            sentinel;
 189                 private int             document_id;
 190                 private Random          random = new Random();
 191                 internal string         password_char;
 192                 private StringBuilder   password_cache;
 193                 private bool            calc_pass;
 194                 private int             char_count;
 195                 private bool            enable_links;
 196
 197                 // For calculating widths/heights
 198                 public static readonly StringFormat string_format = new StringFormat (StringFormat.GenericTypographic);
 199
 200                 private int             recalc_suspended;
 201                 private bool            recalc_pending;
 202                 private int             recalc_start = 1;   // This starts at one, since lines are 1 based
 203                 private int             recalc_end;
 204                 private bool            recalc_optimize;
 205
 206                 private int             update_suspended;
 207                 private bool update_pending;
 208                 private int update_start = 1;
 209
 210                 internal bool           multiline;
 211                 internal HorizontalAlignment alignment;
 212                 internal bool           wrap;
 213
 214                 internal UndoManager    undo;
 215
 216                 internal Marker         caret;
 217                 internal Marker         selection_start;
 218                 internal Marker         selection_end;
 219                 internal bool           selection_visible;
 220                 internal Marker         selection_anchor;
 221                 internal Marker         selection_prev;
 222                 internal bool           selection_end_anchor;
 223
 224                 internal int            viewport_x;
 225                 internal int            viewport_y;             // The visible area of the document
 226                 internal int            offset_x;
 227                 internal int            offset_y;
 228                 internal int            viewport_width;
 229                 internal int            viewport_height;
 230
 231                 internal int            document_x;             // Width of the document
 232                 internal int            document_y;             // Height of the document
 233
 234                 internal int            crlf_size;              // 1 or 2, depending on whether we use \r\n or just \n
 235
 236                 internal TextBoxBase    owner;                  // Who's owning us?
 237                 static internal int     caret_width = 1;
 238                 static internal int     caret_shift = 1;
 239
 240                 internal int left_margin = 2;  // A left margin for all lines
 241                 internal int top_margin = 2;
 242                 internal int right_margin = 2;
 243                 #endregion      // Local Variables
 244
 245                 #region Constructors
 246                 internal Document (TextBoxBase owner)
 247                 {
 248                         lines = 0;
 249
 250                         this.owner = owner;
 251
 252                         multiline = true;
 253                         password_char = "";
 254                         calc_pass = false;
 255                         recalc_pending = false;
 256
 257                         // Tree related stuff
 258                         sentinel = new Line (this, LineEnding.None);
 259                         sentinel.color = LineColor.Black;
 260
 261                         document = sentinel;
 262
 263                         // We always have a blank line
 264                         owner.HandleCreated += new EventHandler(owner_HandleCreated);
 265                         owner.VisibleChanged += new EventHandler(owner_VisibleChanged);
 266
 267                         Add (1, String.Empty, owner.Font, owner.ForeColor, LineEnding.None);
 268
 269                         undo = new UndoManager (this);
 270
 271                         selection_visible = false;
 272                         selection_start.line = this.document;
 273                         selection_start.pos = 0;
 274                         selection_start.tag = selection_start.line.tags;
 275                         selection_end.line = this.document;
 276                         selection_end.pos = 0;
 277                         selection_end.tag = selection_end.line.tags;
 278                         selection_anchor.line = this.document;
 279                         selection_anchor.pos = 0;
 280                         selection_anchor.tag = selection_anchor.line.tags;
 281                         caret.line = this.document;
 282                         caret.pos = 0;
 283                         caret.tag = caret.line.tags;
 284
 285                         viewport_x = 0;
 286                         viewport_y = 0;
 287
 288                         offset_x = 0;
 289                         offset_y = 0;
 290
 291                         crlf_size = 2;
 292
 293                         // Default selection is empty
 294
 295                         document_id = random.Next();
 296
 297                         string_format.Trimming = StringTrimming.None;
 298                         string_format.FormatFlags = StringFormatFlags.DisplayFormatControl;
 299
 300                         UpdateMargins ();
 301                 }
 302                 #endregion
 303
 304                 #region Internal Properties
 305                 internal Line Root {
 306                         get {
 307                                 return document;
 308                         }
 309
 310                         set {
 311                                 document = value;
 312                         }
 313                 }
 314
 315                 // UIA: Method used via reflection in TextRangeProvider
 316                 internal int Lines {
 317                         get {
 318                                 return lines;
 319                         }
 320                 }
 321
 322                 internal Line CaretLine {
 323                         get {
 324                                 return caret.line;
 325                         }
 326                 }
 327
 328                 internal int CaretPosition {
 329                         get {
 330                                 return caret.pos;
 331                         }
 332                 }
 333
 334                 internal Point Caret {
 335                         get {
 336                                 return new Point((int)caret.tag.Line.widths[caret.pos] + caret.line.X, caret.line.Y);
 337                         }
 338                 }
 339
 340                 internal LineTag CaretTag {
 341                         get {
 342                                 return caret.tag;
 343                         }
 344
 345                         set {
 346                                 caret.tag = value;
 347                         }
 348                 }
 349
 350                 internal int CRLFSize {
 351                         get {
 352                                 return crlf_size;
 353                         }
 354
 355                         set {
 356                                 crlf_size = value;
 357                         }
 358                 }
 359
 360                 /// <summary>
 361                 ///  Whether text is scanned for links
 362                 /// </summary>
 363                 internal bool EnableLinks {
 364                         get { return enable_links; }
 365                         set { enable_links = value; }
 366                 }
 367
 368                 internal string PasswordChar {
 369                         get {
 370                                 return password_char;
 371                         }
 372
 373                         set {
 374                                 password_char = value;
 375                                 PasswordCache.Length = 0;
 376                                 if ((password_char.Length != 0) && (password_char[0] != '\0')) {
 377                                         calc_pass = true;
 378                                 } else {
 379                                         calc_pass = false;
 380                                 }
 381                         }
 382                 }
 383
 384                 private StringBuilder PasswordCache {
 385                         get {
 386                                 if (password_cache == null)
 387                                           password_cache = new StringBuilder();
 388                                 return password_cache;
 389                         }
 390                 }
 391
 392                 internal int ViewPortX {
 393                         get {
 394                                 return viewport_x;
 395                         }
 396
 397                         set {
 398                                 viewport_x = value;
 399                         }
 400                 }
 401
 402                 internal int Length {
 403                         get {
 404                                 return char_count + lines - 1;  // Add \n for each line but the last
 405                         }
 406                 }
 407
 408                 private int CharCount {
 409                         get {
 410                                 return char_count;
 411                         }
 412
 413                         set {
 414                                 char_count = value;
 415
 416                                 if (LengthChanged != null) {
 417                                         LengthChanged(this, EventArgs.Empty);
 418                                 }
 419                         }
 420                 }
 421
 422                 internal int ViewPortY {
 423                         get {
 424                                 return viewport_y;
 425                         }
 426
 427                         set {
 428                                 viewport_y = value;
 429                         }
 430                 }
 431
 432                 internal int OffsetX
 433                 {
 434                         get
 435                         {
 436                                 return offset_x;
 437                         }
 438
 439                         set
 440                         {
 441                                 offset_x = value;
 442                         }
 443                 }
 444
 445                 internal int OffsetY
 446                 {
 447                         get
 448                         {
 449                                 return offset_y;
 450                         }
 451
 452                         set
 453                         {
 454                                 offset_y = value;
 455                         }
 456                 }
 457
 458                 internal int ViewPortWidth {
 459                         get {
 460                                 return viewport_width;
 461                         }
 462
 463                         set {
 464                                 viewport_width = value;
 465                         }
 466                 }
 467
 468                 internal int ViewPortHeight {
 469                         get {
 470                                 return viewport_height;
 471                         }
 472
 473                         set {
 474                                 viewport_height = value;
 475                         }
 476                 }
 477
 478
 479                 internal int Width {
 480                         get {
 481                                 return this.document_x;
 482                         }
 483                 }
 484
 485                 internal int Height {
 486                         get {
 487                                 return this.document_y;
 488                         }
 489                 }
 490
 491                 internal bool SelectionVisible {
 492                         get {
 493                                 return selection_visible;
 494                         }
 495                 }
 496
 497                 internal bool Wrap {
 498                         get {
 499                                 return wrap;
 500                         }
 501
 502                         set {
 503                                 wrap = value;
 504                         }
 505                 }
 506
 507                 #endregion      // Internal Properties
 508
 509                 #region Private Methods
 510
 511                 internal void UpdateMargins ()
 512                 {
 513                         switch (owner.actual_border_style) {
 514                                 case BorderStyle.None:
 515                                         left_margin = 0;
 516                                         top_margin = 0;
 517                                         right_margin = 1;
 518                                         break;
 519                                 case BorderStyle.FixedSingle:
 520                                         left_margin = 2;
 521                                         top_margin = 2;
 522                                         right_margin = 3;
 523                                         break;
 524                                 case BorderStyle.Fixed3D:
 525                                         left_margin = 1;
 526                                         top_margin = 1;
 527                                         right_margin = 2;
 528                                         break;
 529                         }
 530                 }
 531
 532                 internal void SuspendRecalc ()
 533                 {
 534                         if (recalc_suspended == 0) {
 535                                 recalc_start = int.MaxValue;
 536                                 recalc_end = int.MinValue;
 537                         }
 538
 539                         recalc_suspended++;
 540                 }
 541
 542                 internal void ResumeRecalc (bool immediate_update)
 543                 {
 544                         if (recalc_suspended > 0)
 545                                 recalc_suspended--;
 546
 547                         if (recalc_suspended == 0 && (immediate_update || recalc_pending) && !(recalc_start == int.MaxValue && recalc_end == int.MinValue)) {
 548                                 RecalculateDocument (owner.CreateGraphicsInternal (), recalc_start, recalc_end, recalc_optimize);
 549                                 recalc_pending = false;
 550                         }
 551                 }
 552
 553                 internal void SuspendUpdate ()
 554                 {
 555                         update_suspended++;
 556                 }
 557
 558                 internal void ResumeUpdate (bool immediate_update)
 559                 {
 560                         if (update_suspended > 0)
 561                                 update_suspended--;
 562
 563                         if (immediate_update && update_suspended == 0 && update_pending) {
 564                                 UpdateView (GetLine (update_start), 0);
 565                                 update_pending = false;
 566                         }
 567                 }
 568
 569                 // For debugging
 570                 internal int DumpTree(Line line, bool with_tags) {
 571                         int     total;
 572
 573                         total = 1;
 574
 575                         Console.Write("Line {0} [# {1}], Y: {2}, ending style: {3},  Text: '{4}'",
 576                                         line.line_no, line.GetHashCode(), line.Y, line.ending,
 577                                         line.text != null ? line.text.ToString() : "undefined");
 578
 579                         if (line.left == sentinel) {
 580                                 Console.Write(", left = sentinel");
 581                         } else if (line.left == null) {
 582                                 Console.Write(", left = NULL");
 583                         }
 584
 585                         if (line.right == sentinel) {
 586                                 Console.Write(", right = sentinel");
 587                         } else if (line.right == null) {
 588                                 Console.Write(", right = NULL");
 589                         }
 590
 591                         Console.WriteLine("");
 592
 593                         if (with_tags) {
 594                                 LineTag tag;
 595                                 int     count;
 596                                 int     length;
 597
 598                                 tag = line.tags;
 599                                 count = 1;
 600                                 length = 0;
 601                                 Console.Write("   Tags: ");
 602                                 while (tag != null) {
 603                                         Console.Write("{0} <{1}>-<{2}>", count++, tag.Start, tag.End
 604                                                         /*line.text.ToString (tag.start - 1, tag.length)*/);
 605                                         length += tag.Length;
 606
 607                                         if (tag.Line != line) {
 608                                                 Console.Write("BAD line link");
 609                                                 throw new Exception("Bad line link in tree");
 610                                         }
 611                                         tag = tag.Next;
 612                                         if (tag != null) {
 613                                                 Console.Write(", ");
 614                                         }
 615                                 }
 616                                 if (length > line.text.Length) {
 617                                         throw new Exception(String.Format("Length of tags more than length of text on line (expected {0} calculated {1})", line.text.Length, length));
 618                                 } else if (length < line.text.Length) {
 619                                         throw new Exception(String.Format("Length of tags less than length of text on line (expected {0} calculated {1})", line.text.Length, length));
 620                                 }
 621                                 Console.WriteLine("");
 622                         }
 623                         if (line.left != null) {
 624                                 if (line.left != sentinel) {
 625                                         total += DumpTree(line.left, with_tags);
 626                                 }
 627                         } else {
 628                                 if (line != sentinel) {
 629                                         throw new Exception("Left should not be NULL");
 630                                 }
 631                         }
 632
 633                         if (line.right != null) {
 634                                 if (line.right != sentinel) {
 635                                         total += DumpTree(line.right, with_tags);
 636                                 }
 637                         } else {
 638                                 if (line != sentinel) {
 639                                         throw new Exception("Right should not be NULL");
 640                                 }
 641                         }
 642
 643                         for (int i = 1; i <= this.lines; i++) {
 644                                 if (GetLine(i) == null) {
 645                                         throw new Exception(String.Format("Hole in line order, missing {0}", i));
 646                                 }
 647                         }
 648
 649                         if (line == this.Root) {
 650                                 if (total < this.lines) {
 651                                         throw new Exception(String.Format("Not enough nodes in tree, found {0}, expected {1}", total, this.lines));
 652                                 } else if (total > this.lines) {
 653                                         throw new Exception(String.Format("Too many nodes in tree, found {0}, expected {1}", total, this.lines));
 654                                 }
 655                         }
 656
 657                         return total;
 658                 }
 659
 660                 private void SetSelectionVisible (bool value)
 661                 {
 662                         selection_visible = value;
 663
 664                         // cursor and selection are enemies, we can't have both in the same room at the same time
 665                         if (owner.IsHandleCreated && !owner.show_caret_w_selection)
 666                                 XplatUI.CaretVisible (owner.Handle, !selection_visible);
 667                 }
 668
 669                 private void DecrementLines(int line_no) {
 670                         int     current;
 671
 672                         current = line_no;
 673                         while (current <= lines) {
 674                                 GetLine(current).line_no--;
 675                                 current++;
 676                         }
 677                         return;
 678                 }
 679
 680                 private void IncrementLines(int line_no) {
 681                         int     current;
 682
 683                         current = this.lines;
 684                         while (current >= line_no) {
 685                                 GetLine(current).line_no++;
 686                                 current--;
 687                         }
 688                         return;
 689                 }
 690
 691                 private void RebalanceAfterAdd(Line line1) {
 692                         Line    line2;
 693
 694                         while ((line1 != document) && (line1.parent.color == LineColor.Red)) {
 695                                 if (line1.parent == line1.parent.parent.left) {
 696                                         line2 = line1.parent.parent.right;
 697
 698                                         if ((line2 != null) && (line2.color == LineColor.Red)) {
 699                                                 line1.parent.color = LineColor.Black;
 700                                                 line2.color = LineColor.Black;
 701                                                 line1.parent.parent.color = LineColor.Red;
 702                                                 line1 = line1.parent.parent;
 703                                         } else {
 704                                                 if (line1 == line1.parent.right) {
 705                                                         line1 = line1.parent;
 706                                                         RotateLeft(line1);
 707                                                 }
 708
 709                                                 line1.parent.color = LineColor.Black;
 710                                                 line1.parent.parent.color = LineColor.Red;
 711
 712                                                 RotateRight(line1.parent.parent);
 713                                         }
 714                                 } else {
 715                                         line2 = line1.parent.parent.left;
 716
 717                                         if ((line2 != null) && (line2.color == LineColor.Red)) {
 718                                                 line1.parent.color = LineColor.Black;
 719                                                 line2.color = LineColor.Black;
 720                                                 line1.parent.parent.color = LineColor.Red;
 721                                                 line1 = line1.parent.parent;
 722                                         } else {
 723                                                 if (line1 == line1.parent.left) {
 724                                                         line1 = line1.parent;
 725                                                         RotateRight(line1);
 726                                                 }
 727
 728                                                 line1.parent.color = LineColor.Black;
 729                                                 line1.parent.parent.color = LineColor.Red;
 730                                                 RotateLeft(line1.parent.parent);
 731                                         }
 732                                 }
 733                         }
 734                         document.color = LineColor.Black;
 735                 }
 736
 737                 private void RebalanceAfterDelete(Line line1) {
 738                         Line line2;
 739
 740                         while ((line1 != document) && (line1.color == LineColor.Black)) {
 741                                 if (line1 == line1.parent.left) {
 742                                         line2 = line1.parent.right;
 743                                         if (line2.color == LineColor.Red) {
 744                                                 line2.color = LineColor.Black;
 745                                                 line1.parent.color = LineColor.Red;
 746                                                 RotateLeft(line1.parent);
 747                                                 line2 = line1.parent.right;
 748                                         }
 749                                         if ((line2.left.color == LineColor.Black) && (line2.right.color == LineColor.Black)) {
 750                                                 line2.color = LineColor.Red;
 751                                                 line1 = line1.parent;
 752                                         } else {
 753                                                 if (line2.right.color == LineColor.Black) {
 754                                                         line2.left.color = LineColor.Black;
 755                                                         line2.color = LineColor.Red;
 756                                                         RotateRight(line2);
 757                                                         line2 = line1.parent.right;
 758                                                 }
 759                                                 line2.color = line1.parent.color;
 760                                                 line1.parent.color = LineColor.Black;
 761                                                 line2.right.color = LineColor.Black;
 762                                                 RotateLeft(line1.parent);
 763                                                 line1 = document;
 764                                         }
 765                                 } else {
 766                                         line2 = line1.parent.left;
 767                                         if (line2.color == LineColor.Red) {
 768                                                 line2.color = LineColor.Black;
 769                                                 line1.parent.color = LineColor.Red;
 770                                                 RotateRight(line1.parent);
 771                                                 line2 = line1.parent.left;
 772                                         }
 773                                         if ((line2.right.color == LineColor.Black) && (line2.left.color == LineColor.Black)) {
 774                                                 line2.color = LineColor.Red;
 775                                                 line1 = line1.parent;
 776                                         } else {
 777                                                 if (line2.left.color == LineColor.Black) {
 778                                                         line2.right.color = LineColor.Black;
 779                                                         line2.color = LineColor.Red;
 780                                                         RotateLeft(line2);
 781                                                         line2 = line1.parent.left;
 782                                                 }
 783                                                 line2.color = line1.parent.color;
 784                                                 line1.parent.color = LineColor.Black;
 785                                                 line2.left.color = LineColor.Black;
 786                                                 RotateRight(line1.parent);
 787                                                 line1 = document;
 788                                         }
 789                                 }
 790                         }
 791                         line1.color = LineColor.Black;
 792                 }
 793
 794                 private void RotateLeft(Line line1) {
 795                         Line    line2 = line1.right;
 796
 797                         line1.right = line2.left;
 798
 799                         if (line2.left != sentinel) {
 800                                 line2.left.parent = line1;
 801                         }
 802
 803                         if (line2 != sentinel) {
 804                                 line2.parent = line1.parent;
 805                         }
 806
 807                         if (line1.parent != null) {
 808                                 if (line1 == line1.parent.left) {
 809                                         line1.parent.left = line2;
 810                                 } else {
 811                                         line1.parent.right = line2;
 812                                 }
 813                         } else {
 814                                 document = line2;
 815                         }
 816
 817                         line2.left = line1;
 818                         if (line1 != sentinel) {
 819                                 line1.parent = line2;
 820                         }
 821                 }
 822
 823                 private void RotateRight(Line line1) {
 824                         Line line2 = line1.left;
 825
 826                         line1.left = line2.right;
 827
 828                         if (line2.right != sentinel) {
 829                                 line2.right.parent = line1;
 830                         }
 831
 832                         if (line2 != sentinel) {
 833                                 line2.parent = line1.parent;
 834                         }
 835
 836                         if (line1.parent != null) {
 837                                 if (line1 == line1.parent.right) {
 838                                         line1.parent.right = line2;
 839                                 } else {
 840                                         line1.parent.left = line2;
 841                                 }
 842                         } else {
 843                                 document = line2;
 844                         }
 845
 846                         line2.right = line1;
 847                         if (line1 != sentinel) {
 848                                 line1.parent = line2;
 849                         }
 850                 }
 851
 852
 853                 internal void UpdateView(Line line, int pos) {
 854                         if (!owner.IsHandleCreated) {
 855                                 return;
 856                         }
 857
 858                         if (update_suspended > 0) {
 859                                 update_start = Math.Min (update_start, line.line_no);
 860                                 // update_end = Math.Max (update_end, line.line_no);
 861                                 // recalc_optimize = true;
 862                                 update_pending = true;
 863                                 return;
 864                         }
 865
 866                         // Optimize invalidation based on Line alignment
 867                         if (RecalculateDocument(owner.CreateGraphicsInternal(), line.line_no, line.line_no, true)) {
 868                                 // Lineheight changed, invalidate the rest of the document
 869                                 if ((line.Y - viewport_y) >=0 ) {
 870                                         // We formatted something that's in view, only draw parts of the screen
 871                                         owner.Invalidate(new Rectangle(
 872                                                 offset_x,
 873                                                 line.Y - viewport_y + offset_y,
 874                                                 viewport_width,
 875                                                 owner.Height - (line.Y - viewport_y)));
 876                                 } else {
 877                                         // The tag was above the visible area, draw everything
 878                                         owner.Invalidate();
 879                                 }
 880                         } else {
 881                                 switch(line.alignment) {
 882                                         case HorizontalAlignment.Left: {
 883                                                 owner.Invalidate(new Rectangle(
 884                                                         line.X + ((int)line.widths[pos] - viewport_x - 1) + offset_x,
 885                                                         line.Y - viewport_y + offset_y,
 886                                                         viewport_width,
 887                                                         line.height + 1));
 888                                                 break;
 889                                         }
 890
 891                                         case HorizontalAlignment.Center: {
 892                                                 owner.Invalidate(new Rectangle(
 893                                                         line.X + offset_x,
 894                                                         line.Y - viewport_y + offset_y,
 895                                                         viewport_width,
 896                                                         line.height + 1));
 897                                                 break;
 898                                         }
 899
 900                                         case HorizontalAlignment.Right: {
 901                                                 owner.Invalidate(new Rectangle(
 902                                                         line.X + offset_x,
 903                                                         line.Y - viewport_y + offset_y,
 904                                                         (int)line.widths[pos + 1] - viewport_x + line.X,
 905                                                         line.height + 1));
 906                                                 break;
 907                                         }
 908                                 }
 909                         }
 910                 }
 911
 912
 913                 // Update display from line, down line_count lines; pos is unused, but required for the signature
 914                 internal void UpdateView(Line line, int line_count, int pos) {
 915                         if (!owner.IsHandleCreated) {
 916                                 return;
 917                         }
 918
 919                         if (recalc_suspended > 0) {
 920                                 recalc_start = Math.Min (recalc_start, line.line_no);
 921                                 recalc_end = Math.Max (recalc_end, line.line_no + line_count);
 922                                 recalc_optimize = true;
 923                                 recalc_pending = true;
 924                                 return;
 925                         }
 926
 927                         int start_line_top = line.Y;
 928
 929                         int end_line_bottom;
 930                         Line end_line;
 931
 932                         end_line = GetLine (line.line_no + line_count);
 933                         if (end_line == null)
 934                                 end_line = GetLine (lines);
 935
 936
 937                         end_line_bottom = end_line.Y + end_line.height;
 938
 939                         if (RecalculateDocument(owner.CreateGraphicsInternal(), line.line_no, line.line_no + line_count, true)) {
 940                                 // Lineheight changed, invalidate the rest of the document
 941                                 if ((line.Y - viewport_y) >=0 ) {
 942                                         // We formatted something that's in view, only draw parts of the screen
 943                                         owner.Invalidate(new Rectangle(
 944                                                 offset_x,
 945                                                 line.Y - viewport_y + offset_y,
 946                                                 viewport_width,
 947                                                 owner.Height - (line.Y - viewport_y)));
 948                                 } else {
 949                                         // The tag was above the visible area, draw everything
 950                                         owner.Invalidate();
 951                                 }
 952                         } else {
 953                                 int x = 0 - viewport_x + offset_x;
 954                                 int w = viewport_width;
 955                                 int y = Math.Min (start_line_top - viewport_y, line.Y - viewport_y) + offset_y;
 956                                 int h = Math.Max (end_line_bottom - y, end_line.Y + end_line.height - y);
 957
 958                                 owner.Invalidate (new Rectangle (x, y, w, h));
 959                         }
 960                 }
 961
 962                 /// <summary>
 963                 ///  Scans the next paragraph for http:/ ftp:/ www. https:/ etc and marks the tags
 964                 ///  as links.
 965                 /// </summary>
 966                 /// <param name="start_line">The line to start on</param>
 967                 /// <param name="link_changed">marks as true if something is changed</param>
 968                 private void ScanForLinks (Line start_line, ref bool link_changed)
 969                 {
 970                         Line current_line = start_line;
 971                         StringBuilder line_no_breaks = new StringBuilder ();
 972                         StringBuilder line_link_record = new StringBuilder ();
 973                         ArrayList cumulative_length_list = new ArrayList ();
 974                         bool update_caret_tag = false;
 975
 976                         cumulative_length_list.Add (0);
 977
 978                         while (current_line != null) {
 979                                 line_no_breaks.Append (current_line.text);
 980
 981                                 if (link_changed == false)
 982                                         current_line.LinkRecord (line_link_record);
 983
 984                                 current_line.ClearLinks ();
 985
 986                                 cumulative_length_list.Add (line_no_breaks.Length);
 987
 988                                 if (current_line.ending == LineEnding.Wrap)
 989                                         current_line = GetLine (current_line.LineNo + 1);
 990                                 else
 991                                         break;
 992                         }
 993
 994                         // search for protocols.. make sure www. is first!
 995                         string [] search_terms = new string [] { "www.", "http:/", "ftp:/", "https:/" };
 996                         int search_found = 0;
 997                         int index_found = 0;
 998                         string line_no_breaks_string = line_no_breaks.ToString ();
 999                         int line_no_breaks_index = 0;
1000                         int link_end = 0;
1001
1002                         while (true) {
1003                                 if (line_no_breaks_index >= line_no_breaks_string.Length)
1004                                         break;
1005
1006                                 index_found = FirstIndexOfAny (line_no_breaks_string, search_terms, line_no_breaks_index, out search_found);
1007
1008                                 //no links found on this line
1009                                 if (index_found == -1)
1010                                         break;
1011
1012                                 if (search_found == 0) {
1013                                         // if we are at the end of the line to analyse and the end of the line
1014                                         // is "www." then there are no links here
1015                                         if (line_no_breaks_string.Length == index_found + search_terms [0].Length)
1016                                                 break;
1017
1018                                         // if after www. we don't have a letter a digit or a @ or - or /
1019                                         // then it is not a web address, we should continue searching
1020                                         if (char.IsLetterOrDigit (line_no_breaks_string [index_found + search_terms [0].Length]) == false &&
1021                                                 "@/~".IndexOf (line_no_breaks_string [index_found + search_terms [0].Length].ToString ()) == -1) {
1022                                                 line_no_breaks_index = index_found + search_terms [0].Length;
1023                                                 continue;
1024                                         }
1025                                 }
1026
1027                                 link_end = line_no_breaks_string.Length - 1;
1028                                 line_no_breaks_index = line_no_breaks_string.Length;
1029
1030                                 // we've found a link, we just need to find where it ends now
1031                                 for (int i = index_found + search_terms [search_found].Length; i < line_no_breaks_string.Length; i++) {
1032                                         if (line_no_breaks_string [i - 1] == '.') {
1033                                                 if (char.IsLetterOrDigit (line_no_breaks_string [i]) == false &&
1034                                                         "@/~".IndexOf (line_no_breaks_string [i].ToString ()) == -1) {
1035                                                         link_end = i - 1;
1036                                                         line_no_breaks_index = i;
1037                                                         break;
1038                                                 }
1039                                         } else {
1040                                                 if (char.IsLetterOrDigit (line_no_breaks_string [i]) == false &&
1041                                                         "@-/:~.?=_&".IndexOf (line_no_breaks_string [i].ToString ()) == -1) {
1042                                                         link_end = i - 1;
1043                                                         line_no_breaks_index = i;
1044                                                         break;
1045                                                 }
1046                                         }
1047                                 }
1048
1049                                 string link_text = line_no_breaks_string.Substring (index_found, link_end - index_found + 1);
1050                                 int current_cumulative = 0;
1051
1052                                 // we've found a link - index_found -> link_end
1053                                 // now we just make all the tags as containing link and
1054                                 // point them to the text for the whole link
1055
1056                                 current_line = start_line;
1057
1058                                 //find the line we start on
1059                                 for (current_cumulative = 1; current_cumulative < cumulative_length_list.Count; current_cumulative++)
1060                                         if ((int)cumulative_length_list [current_cumulative] > index_found)
1061                                                 break;
1062
1063                                 current_line = GetLine (start_line.LineNo + current_cumulative - 1);
1064
1065                                 // find the tag we start on
1066                                 LineTag current_tag = current_line.FindTag (index_found - (int)cumulative_length_list [current_cumulative - 1] + 1);
1067
1068                                 if (current_tag.Start != (index_found - (int)cumulative_length_list [current_cumulative - 1]) + 1) {
1069                                         if (current_tag == CaretTag)
1070                                                 update_caret_tag = true;
1071
1072                                         current_tag = current_tag.Break ((index_found - (int)cumulative_length_list [current_cumulative - 1]) + 1);
1073                                 }
1074
1075                                 // set the tag
1076                                 current_tag.IsLink = true;
1077                                 current_tag.LinkText = link_text;
1078
1079                                 //go through each character
1080                                 // find the tag we are in
1081                                 // skip the number of characters in the tag
1082                                 for (int i = 1; i < link_text.Length; i++) {
1083                                         // on to a new word-wrapped line
1084                                         if ((int)cumulative_length_list [current_cumulative] <= index_found + i) {
1085
1086                                                 current_line = GetLine (start_line.LineNo + current_cumulative++);
1087                                                 current_tag = current_line.FindTag (index_found + i - (int)cumulative_length_list [current_cumulative - 1] + 1);
1088
1089                                                 current_tag.IsLink = true;
1090                                                 current_tag.LinkText = link_text;
1091
1092                                                 continue;
1093                                         }
1094
1095                                         if (current_tag.End < index_found + 1 + i - (int)cumulative_length_list [current_cumulative - 1]) {
1096                                                 // skip empty tags in the middle of the URL
1097                                                 do {
1098                                                         current_tag = current_tag.Next;
1099                                                 } while (current_tag.Length == 0);
1100
1101                                                 current_tag.IsLink = true;
1102                                                 current_tag.LinkText = link_text;
1103                                         }
1104                                 }
1105
1106                                 //if there are characters left in the tag after the link
1107                                 // split the tag
1108                                 // make the second part a non link
1109                                 if (current_tag.End > (index_found + link_text.Length + 1) - (int)cumulative_length_list [current_cumulative - 1]) {
1110                                         if (current_tag == CaretTag)
1111                                                 update_caret_tag = true;
1112
1113                                         current_tag.Break ((index_found + link_text.Length + 1) - (int)cumulative_length_list [current_cumulative - 1]);
1114                                 }
1115                         }
1116
1117                         if (update_caret_tag) {
1118                                 CaretTag = LineTag.FindTag (CaretLine, CaretPosition);
1119                                 link_changed = true;
1120                         } else {
1121                                 if (link_changed == false) {
1122                                         current_line = start_line;
1123                                         StringBuilder new_link_record = new StringBuilder ();
1124
1125                                         while (current_line != null) {
1126                                                 current_line.LinkRecord (new_link_record);
1127
1128                                                 if (current_line.ending == LineEnding.Wrap)
1129                                                         current_line = GetLine (current_line.LineNo + 1);
1130                                                 else
1131                                                         break;
1132                                         }
1133
1134                                         if (new_link_record.Equals (line_link_record) == false)
1135                                                 link_changed = true;
1136                                 }
1137                         }
1138                 }
1139
1140                 private int FirstIndexOfAny (string haystack, string [] needles, int start_index, out int term_found)
1141                 {
1142                         term_found = -1;
1143                         int best_index = -1;
1144
1145                         for (int i = 0; i < needles.Length; i++) {
1146 #if  NET_2_0
1147                                 int index = haystack.IndexOf (needles [i], start_index, StringComparison.InvariantCultureIgnoreCase);
1148 #else
1149                                 int index = haystack.ToLower().IndexOf(needles[i], start_index);
1150 #endif
1151
1152                                 if (index > -1) {
1153                                         if (term_found > -1) {
1154                                                 if (index < best_index) {
1155                                                         best_index = index;
1156                                                         term_found = i;
1157                                                 }
1158                                         } else {
1159                                                 best_index = index;
1160                                                 term_found = i;
1161                                         }
1162                                 }
1163                         }
1164
1165                         return best_index;
1166                 }
1167
1168
1169
1170                 private void InvalidateLinks (Rectangle clip)
1171                 {
1172                         for (int i = (owner.list_links.Count - 1); i >= 0; i--) {
1173                                 TextBoxBase.LinkRectangle link = (TextBoxBase.LinkRectangle) owner.list_links [i];
1174
1175                                 if (clip.IntersectsWith (link.LinkAreaRectangle))
1176                                         owner.list_links.RemoveAt (i);
1177                         }
1178                 }
1179                 #endregion      // Private Methods
1180
1181                 #region Internal Methods
1182
1183                 internal void ScanForLinks (int start, int end, ref bool link_changed)
1184                 {
1185                         Line line = null;
1186                         LineEnding lastending = LineEnding.Rich;
1187
1188                         // make sure we start scanning at the real begining of the line
1189                         while (true) {
1190                                 if (start != 1 && GetLine (start - 1).ending == LineEnding.Wrap)
1191                                         start--;
1192                                 else
1193                                         break;
1194                         }
1195
1196                         for (int i = start; i <= end && i <= lines; i++) {
1197                                 line = GetLine (i);
1198
1199                                 if (lastending != LineEnding.Wrap)
1200                                         ScanForLinks (line, ref link_changed);
1201
1202                                 lastending = line.ending;
1203
1204                                 if (lastending == LineEnding.Wrap && (i + 1) <= end)
1205                                         end++;
1206                         }
1207                 }
1208
1209                 // Clear the document and reset state
1210                 internal void Empty() {
1211
1212                         document = sentinel;
1213                         lines = 0;
1214
1215                         // We always have a blank line
1216                         Add (1, String.Empty, owner.Font, owner.ForeColor, LineEnding.None);
1217
1218                         this.RecalculateDocument(owner.CreateGraphicsInternal());
1219                         PositionCaret(0, 0);
1220
1221                         SetSelectionVisible (false);
1222
1223                         selection_start.line = this.document;
1224                         selection_start.pos = 0;
1225                         selection_start.tag = selection_start.line.tags;
1226                         selection_end.line = this.document;
1227                         selection_end.pos = 0;
1228                         selection_end.tag = selection_end.line.tags;
1229                         char_count = 0;
1230
1231                         viewport_x = 0;
1232                         viewport_y = 0;
1233
1234                         document_x = 0;
1235                         document_y = 0;
1236
1237                         if (owner.IsHandleCreated)
1238                                 owner.Invalidate ();
1239                 }
1240
1241                 internal void PositionCaret(Line line, int pos) {
1242                         caret.tag = line.FindTag (pos);
1243
1244                         MoveCaretToTextTag ();
1245
1246                         caret.line = line;
1247                         caret.pos = pos;
1248
1249                         if (owner.IsHandleCreated) {
1250                                 if (owner.Focused) {
1251                                         if (caret.height != caret.tag.Height)
1252                                                 XplatUI.CreateCaret (owner.Handle, caret_width, caret.height);
1253                                         XplatUI.SetCaretPos(owner.Handle,
1254                                                 offset_x + (int)caret.tag.Line.widths[caret.pos] + caret.line.X - viewport_x,
1255                                                 offset_y + caret.line.Y + caret.tag.Shift - viewport_y + caret_shift);
1256                                 }
1257
1258                                 if (CaretMoved != null) CaretMoved(this, EventArgs.Empty);
1259                         }
1260
1261                         // We set this at the end because we use the heights to determine whether or
1262                         // not we need to recreate the caret
1263                         caret.height = caret.tag.Height;
1264
1265                 }
1266
1267                 internal void PositionCaret(int x, int y) {
1268                         if (!owner.IsHandleCreated) {
1269                                 return;
1270                         }
1271
1272                         caret.tag = FindCursor(x, y, out caret.pos);
1273
1274                         MoveCaretToTextTag ();
1275
1276                         caret.line = caret.tag.Line;
1277                         caret.height = caret.tag.Height;
1278
1279                         if (owner.ShowSelection && (!selection_visible || owner.show_caret_w_selection)) {
1280                                 XplatUI.CreateCaret (owner.Handle, caret_width, caret.height);
1281                                 XplatUI.SetCaretPos(owner.Handle,
1282                                         (int)caret.tag.Line.widths[caret.pos] + caret.line.X - viewport_x + offset_x,
1283                                         offset_y + caret.line.Y + caret.tag.Shift - viewport_y + caret_shift);
1284                         }
1285
1286                         if (CaretMoved != null) CaretMoved(this, EventArgs.Empty);
1287                 }
1288
1289                 internal void CaretHasFocus() {
1290                         if ((caret.tag != null) && owner.IsHandleCreated) {
1291                                 XplatUI.CreateCaret(owner.Handle, caret_width, caret.height);
1292                                 XplatUI.SetCaretPos(owner.Handle,
1293                                         offset_x + (int)caret.tag.Line.widths[caret.pos] + caret.line.X - viewport_x,
1294                                         offset_y + caret.line.Y + caret.tag.Shift - viewport_y + caret_shift);
1295
1296                                 DisplayCaret ();
1297                         }
1298
1299                         if (owner.IsHandleCreated && SelectionLength () > 0) {
1300                                 InvalidateSelectionArea ();
1301                         }
1302                 }
1303
1304                 internal void CaretLostFocus() {
1305                         if (!owner.IsHandleCreated) {
1306                                 return;
1307                         }
1308                         XplatUI.DestroyCaret(owner.Handle);
1309                 }
1310
1311                 internal void AlignCaret ()
1312                 {
1313                         AlignCaret (true);
1314                 }
1315
1316                 internal void AlignCaret(bool changeCaretTag) {
1317                         if (!owner.IsHandleCreated) {
1318                                 return;
1319                         }
1320
1321                         if (changeCaretTag) {
1322                                 caret.tag = LineTag.FindTag (caret.line, caret.pos);
1323
1324                                 MoveCaretToTextTag ();
1325                         }
1326
1327                         // if the caret has had SelectionFont changed to a
1328                         // different height, we reflect changes unless the new
1329                         // font is larger than the line (line recalculations
1330                         // ignore empty tags) in which case we make it equal
1331                         // the line height and then when text is entered
1332                         if (caret.tag.Height > caret.tag.Line.Height) {
1333                                 caret.height = caret.line.height;
1334                         } else {
1335                                 caret.height = caret.tag.Height;
1336                         }
1337
1338                         if (owner.Focused) {
1339                                 XplatUI.CreateCaret(owner.Handle, caret_width, caret.height);
1340                                 XplatUI.SetCaretPos (owner.Handle,
1341                                         offset_x + (int) caret.tag.Line.widths [caret.pos] + caret.line.X - viewport_x,
1342                                         offset_y + caret.line.Y + viewport_y + caret_shift);
1343                                 DisplayCaret ();
1344                         }
1345
1346                         if (CaretMoved != null) CaretMoved(this, EventArgs.Empty);
1347                 }
1348
1349                 internal void UpdateCaret() {
1350                         if (!owner.IsHandleCreated || caret.tag == null) {
1351                                 return;
1352                         }
1353
1354                         MoveCaretToTextTag ();
1355
1356                         if (caret.tag.Height != caret.height) {
1357                                 caret.height = caret.tag.Height;
1358                                 if (owner.Focused) {
1359                                         XplatUI.CreateCaret(owner.Handle, caret_width, caret.height);
1360                                 }
1361                         }
1362
1363                         if (owner.Focused) {
1364                                 XplatUI.SetCaretPos(owner.Handle,
1365                                         offset_x + (int)caret.tag.Line.widths[caret.pos] + caret.line.X - viewport_x,
1366                                         offset_y + caret.line.Y + caret.tag.Shift - viewport_y + caret_shift);
1367                                 DisplayCaret ();
1368                         }
1369
1370                         if (CaretMoved != null) CaretMoved(this, EventArgs.Empty);
1371                 }
1372
1373                 internal void DisplayCaret() {
1374                         if (!owner.IsHandleCreated) {
1375                                 return;
1376                         }
1377
1378                         if (owner.ShowSelection && (!selection_visible || owner.show_caret_w_selection)) {
1379                                 XplatUI.CaretVisible(owner.Handle, true);
1380                         }
1381                 }
1382
1383                 internal void HideCaret() {
1384                         if (!owner.IsHandleCreated) {
1385                                 return;
1386                         }
1387
1388                         if (owner.Focused) {
1389                                 XplatUI.CaretVisible(owner.Handle, false);
1390                         }
1391                 }
1392
1393
1394                 internal void MoveCaretToTextTag ()
1395                 {
1396                         if (caret.tag == null || caret.tag.IsTextTag)
1397                                 return;
1398
1399
1400
1401                         if (caret.pos < caret.tag.Start) {
1402                                 caret.tag = caret.tag.Previous;
1403                         } else {
1404                                 caret.tag = caret.tag.Next;
1405                         }
1406                 }
1407
1408                 internal void MoveCaret(CaretDirection direction) {
1409                         // FIXME should we use IsWordSeparator to detect whitespace, instead
1410                         // of looking for actual spaces in the Word move cases?
1411
1412                         bool nowrap = false;
1413                         switch(direction) {
1414                                 case CaretDirection.CharForwardNoWrap:
1415                                         nowrap = true;
1416                                         goto case CaretDirection.CharForward;
1417                                 case CaretDirection.CharForward: {
1418                                         caret.pos++;
1419                                         if (caret.pos > caret.line.TextLengthWithoutEnding ()) {
1420                                                 if (!nowrap) {
1421                                                         // Go into next line
1422                                                         if (caret.line.line_no < this.lines) {
1423                                                                 caret.line = GetLine(caret.line.line_no+1);
1424                                                                 caret.pos = 0;
1425                                                                 caret.tag = caret.line.tags;
1426                                                         } else {
1427                                                                 caret.pos--;
1428                                                         }
1429                                                 } else {
1430                                                         // Single line; we stay where we are
1431                                                         caret.pos--;
1432                                                 }
1433                                         } else {
1434                                                 if ((caret.tag.Start - 1 + caret.tag.Length) < caret.pos) {
1435                                                         caret.tag = caret.tag.Next;
1436                                                 }
1437                                         }
1438                                         UpdateCaret();
1439                                         return;
1440                                 }
1441
1442                                 case CaretDirection.CharBackNoWrap:
1443                                         nowrap = true;
1444                                         goto case CaretDirection.CharBack;
1445                                 case CaretDirection.CharBack: {
1446                                         if (caret.pos > 0) {
1447                                                 // caret.pos--; // folded into the if below
1448
1449                                                 if (--caret.pos > 0) {
1450                                                         if (caret.tag.Start > caret.pos) {
1451                                                                 caret.tag = caret.tag.Previous;
1452                                                         }
1453                                                 }
1454                                         } else {
1455                                                 if (caret.line.line_no > 1 && !nowrap) {
1456                                                         caret.line = GetLine(caret.line.line_no - 1);
1457                                                         caret.pos = caret.line.TextLengthWithoutEnding ();
1458                                                         caret.tag = LineTag.FindTag(caret.line, caret.pos);
1459                                                 }
1460                                         }
1461                                         UpdateCaret();
1462                                         return;
1463                                 }
1464
1465                                 case CaretDirection.WordForward: {
1466                                         int len;
1467
1468                                         len = caret.line.text.Length;
1469                                         if (caret.pos < len) {
1470                                                 while ((caret.pos < len) && (caret.line.text[caret.pos] != ' ')) {
1471                                                         caret.pos++;
1472                                                 }
1473                                                 if (caret.pos < len) {
1474                                                         // Skip any whitespace
1475                                                         while ((caret.pos < len) && (caret.line.text[caret.pos] == ' ')) {
1476                                                                 caret.pos++;
1477                                                         }
1478                                                 }
1479                                                 caret.tag = LineTag.FindTag(caret.line, caret.pos);
1480                                         } else {
1481                                                 if (caret.line.line_no < this.lines) {
1482                                                         caret.line = GetLine(caret.line.line_no + 1);
1483                                                         caret.pos = 0;
1484                                                         caret.tag = caret.line.tags;
1485                                                 }
1486                                         }
1487                                         UpdateCaret();
1488                                         return;
1489                                 }
1490
1491                                 case CaretDirection.WordBack: {
1492                                         if (caret.pos > 0) {
1493                                                 caret.pos--;
1494
1495                                                 while ((caret.pos > 0) && (caret.line.text[caret.pos] == ' ')) {
1496                                                         caret.pos--;
1497                                                 }
1498
1499                                                 while ((caret.pos > 0) && (caret.line.text[caret.pos] != ' ')) {
1500                                                         caret.pos--;
1501                                                 }
1502
1503                                                 if (caret.line.text.ToString(caret.pos, 1) == " ") {
1504                                                         if (caret.pos != 0) {
1505                                                                 caret.pos++;
1506                                                         } else {
1507                                                                 caret.line = GetLine(caret.line.line_no - 1);
1508                                                                 caret.pos = caret.line.text.Length;
1509                                                         }
1510                                                 }
1511                                                 caret.tag = LineTag.FindTag(caret.line, caret.pos);
1512                                         } else {
1513                                                 if (caret.line.line_no > 1) {
1514                                                         caret.line = GetLine(caret.line.line_no - 1);
1515                                                         caret.pos = caret.line.text.Length;
1516                                                         caret.tag = LineTag.FindTag(caret.line, caret.pos);
1517                                                 }
1518                                         }
1519                                         UpdateCaret();
1520                                         return;
1521                                 }
1522
1523                                 case CaretDirection.LineUp: {
1524                                         if (caret.line.line_no > 1) {
1525                                                 int     pixel;
1526
1527                                                 pixel = (int)caret.line.widths[caret.pos];
1528                                                 PositionCaret(pixel, GetLine(caret.line.line_no - 1).Y);
1529
1530                                                 DisplayCaret ();
1531                                         }
1532                                         return;
1533                                 }
1534
1535                                 case CaretDirection.LineDown: {
1536                                         if (caret.line.line_no < lines) {
1537                                                 int     pixel;
1538
1539                                                 pixel = (int)caret.line.widths[caret.pos];
1540                                                 PositionCaret(pixel, GetLine(caret.line.line_no + 1).Y);
1541
1542                                                 DisplayCaret ();
1543                                         }
1544                                         return;
1545                                 }
1546
1547                                 case CaretDirection.Home: {
1548                                         if (caret.pos > 0) {
1549                                                 caret.pos = 0;
1550                                                 caret.tag = caret.line.tags;
1551                                                 UpdateCaret();
1552                                         }
1553                                         return;
1554                                 }
1555
1556                                 case CaretDirection.End: {
1557                                         if (caret.pos < caret.line.TextLengthWithoutEnding ()) {
1558                                                 caret.pos = caret.line.TextLengthWithoutEnding ();
1559                                                 caret.tag = LineTag.FindTag(caret.line, caret.pos);
1560                                                 UpdateCaret();
1561                                         }
1562                                         return;
1563                                 }
1564
1565                                 case CaretDirection.PgUp: {
1566
1567                                         if (caret.line.line_no == 1 && owner.richtext) {
1568                                                 owner.vscroll.Value = 0;
1569                                                 Line line = GetLine (1);
1570                                                 PositionCaret (line, 0);
1571                                         }
1572
1573                                         int y_offset = caret.line.Y + caret.line.height - 1 - viewport_y;
1574                                         int index;
1575                                         LineTag top = FindCursor ((int) caret.line.widths [caret.pos],
1576                                                         viewport_y - viewport_height, out index);
1577
1578                                         owner.vscroll.Value = Math.Min (top.Line.Y, owner.vscroll.Maximum - viewport_height);
1579                                         PositionCaret ((int) caret.line.widths [caret.pos], y_offset + viewport_y);
1580
1581                                         return;
1582                                 }
1583
1584                                 case CaretDirection.PgDn: {
1585
1586                                         if (caret.line.line_no == lines && owner.richtext) {
1587                                                 owner.vscroll.Value = owner.vscroll.Maximum - viewport_height + 1;
1588                                                 Line line = GetLine (lines);
1589                                                 PositionCaret (line, line.TextLengthWithoutEnding());
1590                                         }
1591
1592                                         int y_offset = caret.line.Y - viewport_y;
1593                                         int index;
1594                                         LineTag top = FindCursor ((int) caret.line.widths [caret.pos],
1595                                                         viewport_y + viewport_height, out index);
1596
1597                                         owner.vscroll.Value = Math.Min (top.Line.Y, owner.vscroll.Maximum - viewport_height);
1598                                         PositionCaret ((int) caret.line.widths [caret.pos], y_offset + viewport_y);
1599
1600                                         return;
1601                                 }
1602
1603                                 case CaretDirection.CtrlPgUp: {
1604                                         PositionCaret(0, viewport_y);
1605                                         DisplayCaret ();
1606                                         return;
1607                                 }
1608
1609                                 case CaretDirection.CtrlPgDn: {
1610                                         Line    line;
1611                                         LineTag tag;
1612                                         int     index;
1613
1614                                         tag = FindCursor (0, viewport_y + viewport_height, out index);
1615                                         if (tag.Line.line_no > 1) {
1616                                                 line = GetLine(tag.Line.line_no - 1);
1617                                         } else {
1618                                                 line = tag.Line;
1619                                         }
1620                                         PositionCaret(line, line.Text.Length);
1621                                         DisplayCaret ();
1622                                         return;
1623                                 }
1624
1625                                 case CaretDirection.CtrlHome: {
1626                                         caret.line = GetLine(1);
1627                                         caret.pos = 0;
1628                                         caret.tag = caret.line.tags;
1629
1630                                         UpdateCaret();
1631                                         return;
1632                                 }
1633
1634                                 case CaretDirection.CtrlEnd: {
1635                                         caret.line = GetLine(lines);
1636                                         caret.pos = caret.line.TextLengthWithoutEnding ();
1637                                         caret.tag = LineTag.FindTag(caret.line, caret.pos);
1638
1639                                         UpdateCaret();
1640                                         return;
1641                                 }
1642
1643                                 case CaretDirection.SelectionStart: {
1644                                         caret.line = selection_start.line;
1645                                         caret.pos = selection_start.pos;
1646                                         caret.tag = selection_start.tag;
1647
1648                                         UpdateCaret();
1649                                         return;
1650                                 }
1651
1652                                 case CaretDirection.SelectionEnd: {
1653                                         caret.line = selection_end.line;
1654                                         caret.pos = selection_end.pos;
1655                                         caret.tag = selection_end.tag;
1656
1657                                         UpdateCaret();
1658                                         return;
1659                                 }
1660                         }
1661                 }
1662
1663                 internal void DumpDoc ()
1664                 {
1665                         Console.WriteLine ("<doc lines='{0}'>", lines);
1666                         for (int i = 1; i <= lines ; i++) {
1667                                 Line line = GetLine (i);
1668                                 Console.WriteLine ("<line no='{0}' ending='{1}'>", line.line_no, line.ending);
1669
1670                                 LineTag tag = line.tags;
1671                                 while (tag != null) {
1672                                         Console.Write ("\t<tag type='{0}' span='{1}->{2}' font='{3}' color='{4}'>",
1673                                                         tag.GetType (), tag.Start, tag.Length, tag.Font, tag.Color);
1674                                         Console.Write (tag.Text ());
1675                                         Console.WriteLine ("</tag>");
1676                                         tag = tag.Next;
1677                                 }
1678                                 Console.WriteLine ("</line>");
1679                         }
1680                         Console.WriteLine ("</doc>");
1681                 }
1682
1683                 // UIA: Used via reflection by TextProviderBehavior
1684                 internal void GetVisibleLineIndexes (Rectangle clip, out int start, out int end)
1685                 {
1686                         if (multiline) {
1687                                 start = GetLineByPixel(clip.Top + viewport_y - offset_y, false).line_no;
1688                                 end = GetLineByPixel(clip.Bottom + viewport_y - offset_y, false).line_no;
1689                         } else {
1690                                 start = GetLineByPixel(clip.Left + viewport_x - offset_x, false).line_no;
1691                                 end = GetLineByPixel(clip.Right + viewport_x - offset_x, false).line_no;
1692                         }
1693                 }
1694
1695                 internal void Draw (Graphics g, Rectangle clip)
1696                 {
1697                         Line line;              // Current line being drawn
1698                         LineTag tag;            // Current tag being drawn
1699                         int start;              // First line to draw
1700                         int end;                // Last line to draw
1701                         StringBuilder text;     // String representing the current line
1702                         int line_no;
1703                         Color tag_color;
1704                         Color current_color;
1705
1706                         // First, figure out from what line to what line we need to draw
1707                         GetVisibleLineIndexes (clip, out start, out end);
1708
1709                         // remove links in the list (used for mouse down events) that are within the clip area.
1710                         InvalidateLinks (clip);
1711
1712                         ///
1713                         /// We draw the single border ourself
1714                         ///
1715                         if (owner.actual_border_style == BorderStyle.FixedSingle) {
1716                                 ControlPaint.DrawBorder (g, owner.ClientRectangle, Color.Black, ButtonBorderStyle.Solid);
1717                         }
1718
1719                         /// Make sure that we aren't drawing one more line then we need to
1720                         line = GetLine (end - 1);
1721                         if (line != null && clip.Bottom == offset_y + line.Y + line.height - viewport_y)
1722                                 end--;
1723
1724                         line_no = start;
1725
1726                         #if Debug
1727                                 DateTime        n = DateTime.Now;
1728                                 Console.WriteLine ("Started drawing: {0}s {1}ms", n.Second, n.Millisecond);
1729                                 Console.WriteLine ("CLIP:  {0}", clip);
1730                                 Console.WriteLine ("S: {0}", GetLine (start).text);
1731                                 Console.WriteLine ("E: {0}", GetLine (end).text);
1732                         #endif
1733
1734                         // Non multiline selection can be handled outside of the loop
1735                         if (!multiline && selection_visible && owner.ShowSelection) {
1736                                 g.FillRectangle (ThemeEngine.Current.ResPool.GetSolidBrush (ThemeEngine.Current.ColorHighlight),
1737                                                 offset_x + selection_start.line.widths [selection_start.pos] +
1738                                                 selection_start.line.X - viewport_x,
1739                                                 offset_y + selection_start.line.Y,
1740                                                 (selection_end.line.X + selection_end.line.widths [selection_end.pos]) -
1741                                                 (selection_start.line.X + selection_start.line.widths [selection_start.pos]),
1742                                                 selection_start.line.height);
1743                         }
1744
1745                         while (line_no <= end) {
1746                                 line = GetLine (line_no);
1747                                 float line_y = line.Y - viewport_y + offset_y;
1748
1749                                 tag = line.tags;
1750                                 if (!calc_pass) {
1751                                         text = line.text;
1752                                 } else {
1753                                         if (PasswordCache.Length < line.text.Length)
1754                                                 PasswordCache.Append(Char.Parse(password_char), line.text.Length - PasswordCache.Length);
1755                                         else if (PasswordCache.Length > line.text.Length)
1756                                                 PasswordCache.Remove(line.text.Length, PasswordCache.Length - line.text.Length);
1757                                         text = PasswordCache;
1758                                 }
1759
1760                                 int line_selection_start = text.Length + 1;
1761                                 int line_selection_end = text.Length + 1;
1762                                 if (selection_visible && owner.ShowSelection &&
1763                                                 (line_no >= selection_start.line.line_no) &&
1764                                                 (line_no <= selection_end.line.line_no)) {
1765
1766                                         if (line_no == selection_start.line.line_no)
1767                                                 line_selection_start = selection_start.pos + 1;
1768                                         else
1769                                                 line_selection_start = 1;
1770
1771                                         if (line_no == selection_end.line.line_no)
1772                                                 line_selection_end = selection_end.pos + 1;
1773                                         else
1774                                                 line_selection_end = text.Length + 1;
1775
1776                                         if (line_selection_end == line_selection_start) {
1777                                                 // There isn't really selection
1778                                                 line_selection_start = text.Length + 1;
1779                                                 line_selection_end = line_selection_start;
1780                                         } else if (multiline) {
1781                                                 // lets draw some selection baby!!  (non multiline selection is drawn outside the loop)
1782                                                 g.FillRectangle (ThemeEngine.Current.ResPool.GetSolidBrush (ThemeEngine.Current.ColorHighlight),
1783                                                                 offset_x + line.widths [line_selection_start - 1] + line.X - viewport_x,
1784                                                                 line_y, line.widths [line_selection_end - 1] - line.widths [line_selection_start - 1],
1785                                                                 line.height);
1786                                         }
1787                                 }
1788
1789                                 current_color = line.tags.ColorToDisplay;
1790                                 while (tag != null) {
1791
1792                                         // Skip empty tags
1793                                         if (tag.Length == 0) {
1794                                                 tag = tag.Next;
1795                                                 continue;
1796                                         }
1797
1798                                         if (((tag.X + tag.Width) < (clip.Left - viewport_x - offset_x)) &&
1799                                              (tag.X > (clip.Right - viewport_x - offset_x))) {
1800                                                 tag = tag.Next;
1801                                                 continue;
1802                                         }
1803
1804                                         if (tag.BackColor != Color.Empty) {
1805                                                 g.FillRectangle (ThemeEngine.Current.ResPool.GetSolidBrush (tag.BackColor),
1806                                                                 offset_x + tag.X + line.X - viewport_x,
1807                                                                 line_y + tag.Shift, tag.Width, line.height);
1808                                         }
1809
1810                                         tag_color = tag.ColorToDisplay;
1811                                         current_color = tag_color;
1812
1813                                         if (!owner.Enabled) {
1814                                                 Color a = tag.Color;
1815                                                 Color b = ThemeEngine.Current.ColorWindowText;
1816
1817                                                 if ((a.R == b.R) && (a.G == b.G) && (a.B == b.B))
1818                                                         tag_color = ThemeEngine.Current.ColorGrayText;
1819
1820                                         }
1821
1822                                         int tag_pos = tag.Start;
1823                                         current_color = tag_color;
1824                                         while (tag_pos < tag.Start + tag.Length) {
1825                                                 int old_tag_pos = tag_pos;
1826
1827                                                 if (tag_pos >= line_selection_start && tag_pos < line_selection_end) {
1828                                                         current_color = ThemeEngine.Current.ColorHighlightText;
1829                                                         tag_pos = Math.Min (tag.End, line_selection_end);
1830                                                 } else if (tag_pos < line_selection_start) {
1831                                                         current_color = tag_color;
1832                                                         tag_pos = Math.Min (tag.End, line_selection_start);
1833                                                 } else {
1834                                                         current_color = tag_color;
1835                                                         tag_pos = tag.End;
1836                                                 }
1837
1838                                                 Rectangle text_size;
1839
1840                                                 tag.Draw (g, current_color,
1841                                                                 offset_x + line.X - viewport_x,
1842                                                                 line_y + tag.Shift,
1843                                                                 old_tag_pos - 1, Math.Min (tag.Start + tag.Length, tag_pos) - 1,
1844                                                                 text.ToString (), out text_size, tag.IsLink);
1845
1846                                                 if (tag.IsLink) {
1847                                                         TextBoxBase.LinkRectangle link = new TextBoxBase.LinkRectangle (text_size);
1848                                                         link.LinkTag = tag;
1849                                                         owner.list_links.Add (link);
1850                                                 }
1851                                         }
1852                                         tag = tag.Next;
1853                                 }
1854
1855                                 line.DrawEnding (g, line_y);
1856                                 line_no++;
1857                         }
1858                 }
1859
1860                 private int GetLineEnding (string line, int start, out LineEnding ending)
1861                 {
1862                         int res;
1863                         int rich_index;
1864
1865                         if (start >= line.Length) {
1866                                 ending = LineEnding.Wrap;
1867                                 return -1;
1868                         }
1869
1870                         res = line.IndexOf ('\r', start);
1871                         rich_index = line.IndexOf ('\n', start);
1872
1873                         // Handle the case where we find both of them, and the \n is before the \r
1874                         if (res != -1 && rich_index != -1)
1875                                 if (rich_index < res) {
1876                                         ending = LineEnding.Rich;
1877                                         return rich_index;
1878                                 }
1879
1880                         if (res != -1) {
1881                                 if (res + 2 < line.Length && line [res + 1] == '\r' && line [res + 2] == '\n') {
1882                                         ending = LineEnding.Soft;
1883                                         return res;
1884                                 }
1885                                 if (res + 1 < line.Length && line [res + 1] == '\n') {
1886                                         ending = LineEnding.Hard;
1887                                         return res;
1888                                 }
1889                                 ending = LineEnding.Limp;
1890                                 return res;
1891                         }
1892
1893                         if (rich_index != -1) {
1894                                 ending = LineEnding.Rich;
1895                                 return rich_index;
1896                         }
1897
1898                         ending = LineEnding.Wrap;
1899                         return line.Length;
1900                 }
1901
1902                 // Get the line ending, but only of the types specified
1903                 private int GetLineEnding (string line, int start, out LineEnding ending, LineEnding type)
1904                 {
1905                         int index = start;
1906                         int last_length = 0;
1907
1908                         do {
1909                                 index = GetLineEnding (line, index + last_length, out ending);
1910                                 last_length = LineEndingLength (ending);
1911                         } while
1912                                 ((ending & type) != ending && index != -1);
1913
1914                         return index == -1 ? line.Length : index;
1915                 }
1916
1917                 internal int LineEndingLength (LineEnding ending)
1918                 {
1919                         switch (ending) {
1920                                 case LineEnding.Limp:
1921                                 case LineEnding.Rich:
1922                                         return 1;
1923                                 case LineEnding.Hard:
1924                                         return 2;
1925                                 case LineEnding.Soft:
1926                                         return 3;
1927                         }
1928
1929                         return 0;
1930                 }
1931
1932                 internal string LineEndingToString (LineEnding ending)
1933                 {
1934                         switch (ending) {
1935                                 case LineEnding.Limp:
1936                                         return "\r";
1937                                 case LineEnding.Hard:
1938                                         return "\r\n";
1939                                 case LineEnding.Soft:
1940                                         return "\r\r\n";
1941                                 case LineEnding.Rich:
1942                                         return "\n";
1943                         }
1944
1945                         return string.Empty;
1946                 }
1947
1948                 internal LineEnding StringToLineEnding (string ending)
1949                 {
1950                         switch (ending) {
1951                                 case "\r":
1952                                         return LineEnding.Limp;
1953                                 case "\r\n":
1954                                         return LineEnding.Hard;
1955                                 case "\r\r\n":
1956                                         return LineEnding.Soft;
1957                                 case "\n":
1958                                         return LineEnding.Rich;
1959                                 default:
1960                                         return LineEnding.None;
1961                         }
1962                 }
1963
1964                 internal void Insert (Line line, int pos, bool update_caret, string s)
1965                 {
1966                         Insert (line, pos, update_caret, s, line.FindTag (pos));
1967                 }
1968
1969                 // Insert text at the given position; use formatting at insertion point for inserted text
1970                 internal void Insert (Line line, int pos, bool update_caret, string s, LineTag tag)
1971                 {
1972                         int break_index;
1973                         int base_line;
1974                         int old_line_count;
1975                         int count = 1;
1976                         LineEnding ending;
1977                         Line split_line;
1978
1979                         // Don't recalculate while we mess around
1980                         SuspendRecalc ();
1981
1982                         base_line = line.line_no;
1983                         old_line_count = lines;
1984
1985                         break_index = GetLineEnding (s, 0, out ending, LineEnding.Hard | LineEnding.Rich);
1986
1987                         // There are no line feeds in our text to be pasted
1988                         if (break_index == s.Length) {
1989                                 line.InsertString (pos, s, tag);
1990                         } else {
1991                                 // Add up to the first line feed to our current position
1992                                 line.InsertString (pos, s.Substring (0, break_index + LineEndingLength (ending)), tag);
1993
1994                                 // Split the rest of the original line to a new line
1995                                 Split (line, pos + (break_index + LineEndingLength (ending)));
1996                                 line.ending = ending;
1997                                 break_index += LineEndingLength (ending);
1998                                 split_line = GetLine (line.line_no + 1);
1999
2000                                 // Insert brand new lines for any more line feeds in the inserted string
2001                                 while (true) {
2002                                         int next_break = GetLineEnding (s, break_index, out ending, LineEnding.Hard | LineEnding.Rich);
2003
2004                                         if (next_break == s.Length)
2005                                                 break;
2006
2007                                         string line_text = s.Substring (break_index, next_break - break_index +
2008                                                         LineEndingLength (ending));
2009
2010                                         Add (base_line + count, line_text, line.alignment, tag.Font, tag.Color, ending);
2011
2012                                         Line last = GetLine (base_line + count);
2013                                         last.ending = ending;
2014
2015                                         count++;
2016                                         break_index = next_break + LineEndingLength (ending);
2017                                 }
2018
2019                                 // Add the remainder of the insert text to the split
2020                                 // part of the original line
2021                                 split_line.InsertString (0, s.Substring (break_index));
2022                         }
2023
2024                         // Allow the document to recalculate things
2025                         ResumeRecalc (false);
2026
2027                         // Update our character count
2028                         CharCount += s.Length;
2029
2030                         UpdateView (line, lines - old_line_count + 1, pos);
2031
2032                         // Move the caret to the end of the inserted text if requested
2033                         if (update_caret) {
2034                                 Line l = GetLine (line.line_no + lines - old_line_count);
2035                                 PositionCaret (l, l.text.Length);
2036                                 DisplayCaret ();
2037                         }
2038                 }
2039
2040                 // Inserts a string at the given position
2041                 internal void InsertString (Line line, int pos, string s)
2042                 {
2043                         // Update our character count
2044                         CharCount += s.Length;
2045
2046                         // Insert the text into the Line
2047                         line.InsertString (pos, s);
2048                 }
2049
2050                 // Inserts a character at the current caret position
2051                 internal void InsertCharAtCaret (char ch, bool move_caret)
2052                 {
2053                         caret.line.InsertString (caret.pos, ch.ToString(), caret.tag);
2054
2055                         // Update our character count
2056                         CharCount++;
2057
2058                         undo.RecordTyping (caret.line, caret.pos, ch);
2059
2060                         UpdateView (caret.line, caret.pos);
2061
2062                         if (move_caret) {
2063                                 caret.pos++;
2064                                 UpdateCaret ();
2065                                 SetSelectionToCaret (true);
2066                         }
2067                 }
2068
2069                 internal void InsertPicture (Line line, int pos, RTF.Picture picture)
2070                 {
2071                         //LineTag next_tag;
2072                         LineTag tag;
2073                         int len;
2074
2075                         len = 1;
2076
2077                         // Just a place holder basically
2078                         line.text.Insert (pos, "I");
2079
2080                         PictureTag picture_tag = new PictureTag (line, pos + 1, picture);
2081
2082                         tag = LineTag.FindTag (line, pos);
2083                         picture_tag.CopyFormattingFrom (tag);
2084                         /*next_tag = */tag.Break (pos + 1);
2085                         picture_tag.Previous = tag;
2086                         picture_tag.Next = tag.Next;
2087                         tag.Next = picture_tag;
2088
2089                         //
2090                         // Picture tags need to be surrounded by text tags
2091                         //
2092                         if (picture_tag.Next == null) {
2093                                 picture_tag.Next = new LineTag (line, pos + 1);
2094                                 picture_tag.Next.CopyFormattingFrom (tag);
2095                                 picture_tag.Next.Previous = picture_tag;
2096                         }
2097
2098                         tag = picture_tag.Next;
2099                         while (tag != null) {
2100                                 tag.Start += len;
2101                                 tag = tag.Next;
2102                         }
2103
2104                         line.Grow (len);
2105                         line.recalc = true;
2106
2107                         UpdateView (line, pos);
2108                 }
2109
2110                 internal void DeleteMultiline (Line start_line, int pos, int length)
2111                 {
2112                         Marker start = new Marker ();
2113                         Marker end = new Marker ();
2114                         int start_index = LineTagToCharIndex (start_line, pos);
2115
2116                         start.line = start_line;
2117                         start.pos = pos;
2118                         start.tag = LineTag.FindTag (start_line, pos);
2119
2120                         CharIndexToLineTag (start_index + length, out end.line,
2121                                         out end.tag, out end.pos);
2122
2123                         SuspendUpdate ();
2124
2125                         if (start.line == end.line) {
2126                                 DeleteChars (start.line, pos, end.pos - pos);
2127                         } else {
2128
2129                                 // Delete first and last lines
2130                                 DeleteChars (start.line, start.pos, start.line.text.Length - start.pos);
2131                                 DeleteChars (end.line, 0, end.pos);
2132
2133                                 int current = start.line.line_no + 1;
2134                                 if (current < end.line.line_no) {
2135                                         for (int i = end.line.line_no - 1; i >= current; i--) {
2136                                                 Delete (i);
2137                                         }
2138                                 }
2139
2140                                 // BIG FAT WARNING - selection_end.line might be stale due
2141                                 // to the above Delete() call. DONT USE IT before hitting the end of this method!
2142
2143                                 // Join start and end
2144                                 Combine (start.line.line_no, current);
2145                         }
2146
2147                         ResumeUpdate (true);
2148                 }
2149
2150
2151                 // Deletes n characters at the given position; it will not delete past line limits
2152                 // pos is 0-based
2153                 public void DeleteChars (Line line, int pos, int count)
2154                 {
2155                         // Reduce our character count
2156                         CharCount -= count;
2157
2158                         line.DeleteCharacters (pos, count);
2159
2160                         if (pos >= line.TextLengthWithoutEnding ()) {
2161                                 LineEnding ending = line.ending;
2162                                 GetLineEnding (line.text.ToString (), 0, out ending);
2163
2164                                 if (ending != line.ending) {
2165                                         line.ending = ending;
2166
2167                                         if (!multiline) {
2168                                                 UpdateView (line, lines, pos);
2169                                                 owner.Invalidate ();
2170                                                 return;
2171                                         }
2172                                 }
2173                         }
2174                         if (!multiline) {
2175                                 UpdateView (line, lines, pos);
2176                                 owner.Invalidate ();
2177                         } else
2178                                 UpdateView (line, pos);
2179                 }
2180
2181                 // Deletes a character at or after the given position (depending on forward); it will not delete past line limits
2182                 public void DeleteChar (Line line, int pos, bool forward)
2183                 {
2184                         if ((pos == 0 && forward == false) || (pos == line.text.Length && forward == true))
2185                                 return;
2186
2187                         if (forward)
2188                                 DeleteChars (line, pos, 1);
2189                         else
2190                                 DeleteChars (line, pos - 1, 1);
2191                 }
2192
2193                 // Combine two lines
2194                 internal void Combine(int FirstLine, int SecondLine) {
2195                         Combine(GetLine(FirstLine), GetLine(SecondLine));
2196                 }
2197
2198                 internal void Combine(Line first, Line second) {
2199                         LineTag last;
2200                         int     shift;
2201
2202                         // strip the ending off of the first lines text
2203                         first.text.Length = first.text.Length - LineEndingLength (first.ending);
2204
2205                         // Combine the two tag chains into one
2206                         last = first.tags;
2207
2208                         // Maintain the line ending style
2209                         first.ending = second.ending;
2210
2211                         while (last.Next != null) {
2212                                 last = last.Next;
2213                         }
2214
2215                         // need to get the shift before setting the next tag since that effects length
2216                         shift = last.Start + last.Length - 1;
2217                         last.Next = second.tags;
2218                         last.Next.Previous = last;
2219
2220                         // Fix up references within the chain
2221                         last = last.Next;
2222                         while (last != null) {
2223                                 last.Line = first;
2224                                 last.Start += shift;
2225                                 last = last.Next;
2226                         }
2227
2228                         // Combine both lines' strings
2229                         first.text.Insert(first.text.Length, second.text.ToString());
2230                         first.Grow(first.text.Length);
2231
2232                         // Remove the reference to our (now combined) tags from the doomed line
2233                         second.tags = null;
2234
2235                         // Renumber lines
2236                         DecrementLines(first.line_no + 2);      // first.line_no + 1 will be deleted, so we need to start renumbering one later
2237
2238                         // Mop up
2239                         first.recalc = true;
2240                         first.height = 0;       // This forces RecalcDocument/UpdateView to redraw from this line on
2241                         first.Streamline(lines);
2242
2243                         // Update Caret, Selection, etc
2244                         if (caret.line == second) {
2245                                 caret.Combine(first, shift);
2246                         }
2247                         if (selection_anchor.line == second) {
2248                                 selection_anchor.Combine(first, shift);
2249                         }
2250                         if (selection_start.line == second) {
2251                                 selection_start.Combine(first, shift);
2252                         }
2253                         if (selection_end.line == second) {
2254                                 selection_end.Combine(first, shift);
2255                         }
2256
2257                         #if Debug
2258                                 Line    check_first;
2259                                 Line    check_second;
2260
2261                                 check_first = GetLine(first.line_no);
2262                                 check_second = GetLine(check_first.line_no + 1);
2263
2264                                 Console.WriteLine("Pre-delete: Y of first line: {0}, second line: {1}", check_first.Y, check_second.Y);
2265                         #endif
2266
2267                         this.Delete(second);
2268
2269                         #if Debug
2270                                 check_first = GetLine(first.line_no);
2271                                 check_second = GetLine(check_first.line_no + 1);
2272
2273                                 Console.WriteLine("Post-delete Y of first line: {0}, second line: {1}", check_first.Y, check_second.Y);
2274                         #endif
2275                 }
2276
2277                 // Split the line at the position into two
2278                 internal void Split(int LineNo, int pos) {
2279                         Line    line;
2280                         LineTag tag;
2281
2282                         line = GetLine(LineNo);
2283                         tag = LineTag.FindTag(line, pos);
2284                         Split(line, tag, pos);
2285                 }
2286
2287                 internal void Split(Line line, int pos) {
2288                         LineTag tag;
2289
2290                         tag = LineTag.FindTag(line, pos);
2291                         Split(line, tag, pos);
2292                 }
2293
2294                 ///<summary>Split line at given tag and position into two lines</summary>
2295                 ///if more space becomes available on previous line
2296                 internal void Split(Line line, LineTag tag, int pos) {
2297                         LineTag new_tag;
2298                         Line    new_line;
2299                         bool    move_caret;
2300                         bool    move_sel_start;
2301                         bool    move_sel_end;
2302
2303                         move_caret = false;
2304                         move_sel_start = false;
2305                         move_sel_end = false;
2306
2307 #if DEBUG
2308                         SanityCheck();
2309
2310                         if (tag.End < pos)
2311                                 throw new Exception ("Split called with the wrong tag");
2312 #endif
2313
2314                         // Adjust selection and cursors
2315                         if (caret.line == line && caret.pos >= pos) {
2316                                 move_caret = true;
2317                         }
2318                         if (selection_start.line == line && selection_start.pos > pos) {
2319                                 move_sel_start = true;
2320                         }
2321
2322                         if (selection_end.line == line && selection_end.pos > pos) {
2323                                 move_sel_end = true;
2324                         }
2325
2326                         // cover the easy case first
2327                         if (pos == line.text.Length) {
2328                                 Add (line.line_no + 1, String.Empty, line.alignment, tag.Font, tag.Color, line.ending);
2329
2330                                 new_line = GetLine (line.line_no + 1);
2331
2332                                 if (move_caret) {
2333                                         caret.line = new_line;
2334                                         caret.tag = new_line.tags;
2335                                         caret.pos = 0;
2336
2337                                         if (selection_visible == false) {
2338                                                 SetSelectionToCaret (true);
2339                                         }
2340                                 }
2341
2342                                 if (move_sel_start) {
2343                                         selection_start.line = new_line;
2344                                         selection_start.pos = 0;
2345                                         selection_start.tag = new_line.tags;
2346                                 }
2347
2348                                 if (move_sel_end) {
2349                                         selection_end.line = new_line;
2350                                         selection_end.pos = 0;
2351                                         selection_end.tag = new_line.tags;
2352                                 }
2353
2354 #if DEBUG
2355                                 SanityCheck ();
2356 #endif
2357                                 return;
2358                         }
2359
2360                         // We need to move the rest of the text into the new line
2361                         Add (line.line_no + 1, line.text.ToString (pos, line.text.Length - pos), line.alignment, tag.Font, tag.Color, line.ending);
2362
2363                         // Now transfer our tags from this line to the next
2364                         new_line = GetLine(line.line_no + 1);
2365
2366                         line.recalc = true;
2367                         new_line.recalc = true;
2368
2369                         //make sure that if we are at the end of a tag, we start on the begining
2370                         //of a new one, if one exists... Stops us creating an empty tag and
2371                         //make the operation easier.
2372                         if (tag.Next != null && (tag.Next.Start - 1) == pos)
2373                                 tag = tag.Next;
2374
2375                         if ((tag.Start - 1) == pos) {
2376                                 int     shift;
2377
2378                                 // We can simply break the chain and move the tag into the next line
2379
2380                                 // if the tag we are moving is the first, create an empty tag
2381                                 // for the line we are leaving behind
2382                                 if (tag == line.tags) {
2383                                         new_tag = new LineTag(line, 1);
2384                                         new_tag.CopyFormattingFrom (tag);
2385                                         line.tags = new_tag;
2386                                 }
2387
2388                                 if (tag.Previous != null) {
2389                                         tag.Previous.Next = null;
2390                                 }
2391                                 new_line.tags = tag;
2392                                 tag.Previous = null;
2393                                 tag.Line = new_line;
2394
2395                                 // Walk the list and correct the start location of the tags we just bumped into the next line
2396                                 shift = tag.Start - 1;
2397
2398                                 new_tag = tag;
2399                                 while (new_tag != null) {
2400                                         new_tag.Start -= shift;
2401                                         new_tag.Line = new_line;
2402                                         new_tag = new_tag.Next;
2403                                 }
2404                         } else {
2405                                 int     shift;
2406
2407                                 new_tag = new LineTag (new_line, 1);
2408                                 new_tag.Next = tag.Next;
2409                                 new_tag.CopyFormattingFrom (tag);
2410                                 new_line.tags = new_tag;
2411                                 if (new_tag.Next != null) {
2412                                         new_tag.Next.Previous = new_tag;
2413                                 }
2414                                 tag.Next = null;
2415
2416                                 shift = pos;
2417                                 new_tag = new_tag.Next;
2418                                 while (new_tag != null) {
2419                                         new_tag.Start -= shift;
2420                                         new_tag.Line = new_line;
2421                                         new_tag = new_tag.Next;
2422
2423                                 }
2424                         }
2425
2426                         if (move_caret) {
2427                                 caret.line = new_line;
2428                                 caret.pos = caret.pos - pos;
2429                                 caret.tag = caret.line.FindTag(caret.pos);
2430
2431                                 if (selection_visible == false) {
2432                                         SetSelectionToCaret (true);
2433                                 }
2434                         }
2435
2436                         if (move_sel_start) {
2437                                 selection_start.line = new_line;
2438                                 selection_start.pos = selection_start.pos - pos;
2439                                 if  (selection_start.Equals(selection_end))
2440                                         selection_start.tag = new_line.FindTag(selection_start.pos);
2441                                 else
2442                                         selection_start.tag = new_line.FindTag (selection_start.pos + 1);
2443                         }
2444
2445                         if (move_sel_end) {
2446                                 selection_end.line = new_line;
2447                                 selection_end.pos = selection_end.pos - pos;
2448                                 selection_end.tag = new_line.FindTag(selection_end.pos);
2449                         }
2450
2451                         CharCount -= line.text.Length - pos;
2452                         line.text.Remove(pos, line.text.Length - pos);
2453 #if DEBUG
2454                         SanityCheck ();
2455 #endif
2456                 }
2457
2458 #if DEBUG
2459                 private void SanityCheck () {
2460                         for (int i = 1; i < lines; i++) {
2461                                 LineTag tag = GetLine (i).tags;
2462
2463                                 if (tag.Start != 1)
2464                                         throw new Exception ("Line doesn't start at the begining");
2465
2466                                 int start = 1;
2467                                 tag = tag.Next;
2468
2469                                 while (tag != null) {
2470                                         if (tag.Start == start)
2471                                                 throw new Exception ("Empty tag!");
2472
2473                                         if (tag.Start < start)
2474                                                 throw new Exception ("Insane!!");
2475
2476                                         start = tag.Start;
2477                                         tag = tag.Next;
2478                                 }
2479                         }
2480                 }
2481 #endif
2482
2483                 // Adds a line of text, with given font.
2484                 // Bumps any line at that line number that already exists down
2485                 internal void Add (int LineNo, string Text, Font font, Color color, LineEnding ending)
2486                 {
2487                         Add (LineNo, Text, alignment, font, color, ending);
2488                 }
2489
2490                 internal void Add (int LineNo, string Text, HorizontalAlignment align, Font font, Color color, LineEnding ending)
2491                 {
2492                         Line    add;
2493                         Line    line;
2494                         int     line_no;
2495
2496                         CharCount += Text.Length;
2497
2498                         if (LineNo<1 || Text == null) {
2499                                 if (LineNo<1) {
2500                                         throw new ArgumentNullException("LineNo", "Line numbers must be positive");
2501                                 } else {
2502                                         throw new ArgumentNullException("Text", "Cannot insert NULL line");
2503                                 }
2504                         }
2505
2506                         add = new Line (this, LineNo, Text, align, font, color, ending);
2507
2508                         line = document;
2509                         while (line != sentinel) {
2510                                 add.parent = line;
2511                                 line_no = line.line_no;
2512
2513                                 if (LineNo > line_no) {
2514                                         line = line.right;
2515                                 } else if (LineNo < line_no) {
2516                                         line = line.left;
2517                                 } else {
2518                                         // Bump existing line numbers; walk all nodes to the right of this one and increment line_no
2519                                         IncrementLines(line.line_no);
2520                                         line = line.left;
2521                                 }
2522                         }
2523
2524                         add.left = sentinel;
2525                         add.right = sentinel;
2526
2527                         if (add.parent != null) {
2528                                 if (LineNo > add.parent.line_no) {
2529                                         add.parent.right = add;
2530                                 } else {
2531                                         add.parent.left = add;
2532                                 }
2533                         } else {
2534                                 // Root node
2535                                 document = add;
2536                         }
2537
2538                         RebalanceAfterAdd(add);
2539
2540                         lines++;
2541                 }
2542
2543                 internal virtual void Clear() {
2544                         lines = 0;
2545                         CharCount = 0;
2546                         document = sentinel;
2547                 }
2548
2549                 public virtual object Clone() {
2550                         Document clone;
2551
2552                         clone = new Document(null);
2553
2554                         clone.lines = this.lines;
2555                         clone.document = (Line)document.Clone();
2556
2557                         return clone;
2558                 }
2559
2560                 private void Delete (int LineNo)
2561                 {
2562                         Line    line;
2563
2564                         if (LineNo > lines)
2565                                 return;
2566
2567                         line = GetLine (LineNo);
2568
2569                         CharCount -= line.text.Length;
2570
2571                         DecrementLines (LineNo + 1);
2572                         Delete (line);
2573                 }
2574
2575                 private void Delete(Line line1) {
2576                         Line    line2;// = new Line();
2577                         Line    line3;
2578
2579                         if ((line1.left == sentinel) || (line1.right == sentinel)) {
2580                                 line3 = line1;
2581                         } else {
2582                                 line3 = line1.right;
2583                                 while (line3.left != sentinel) {
2584                                         line3 = line3.left;
2585                                 }
2586                         }
2587
2588                         if (line3.left != sentinel) {
2589                                 line2 = line3.left;
2590                         } else {
2591                                 line2 = line3.right;
2592                         }
2593
2594                         line2.parent = line3.parent;
2595                         if (line3.parent != null) {
2596                                 if(line3 == line3.parent.left) {
2597                                         line3.parent.left = line2;
2598                                 } else {
2599                                         line3.parent.right = line2;
2600                                 }
2601                         } else {
2602                                 document = line2;
2603                         }
2604
2605                         if (line3 != line1) {
2606                                 LineTag tag;
2607
2608                                 if (selection_start.line == line3) {
2609                                         selection_start.line = line1;
2610                                 }
2611
2612                                 if (selection_end.line == line3) {
2613                                         selection_end.line = line1;
2614                                 }
2615
2616                                 if (selection_anchor.line == line3) {
2617                                         selection_anchor.line = line1;
2618                                 }
2619
2620                                 if (caret.line == line3) {
2621                                         caret.line = line1;
2622                                 }
2623
2624
2625                                 line1.alignment = line3.alignment;
2626                                 line1.ascent = line3.ascent;
2627                                 line1.hanging_indent = line3.hanging_indent;
2628                                 line1.height = line3.height;
2629                                 line1.indent = line3.indent;
2630                                 line1.line_no = line3.line_no;
2631                                 line1.recalc = line3.recalc;
2632                                 line1.right_indent = line3.right_indent;
2633                                 line1.ending = line3.ending;
2634                                 line1.space = line3.space;
2635                                 line1.tags = line3.tags;
2636                                 line1.text = line3.text;
2637                                 line1.widths = line3.widths;
2638                                 line1.offset = line3.offset;
2639
2640                                 tag = line1.tags;
2641                                 while (tag != null) {
2642                                         tag.Line = line1;
2643                                         tag = tag.Next;
2644                                 }
2645                         }
2646
2647                         if (line3.color == LineColor.Black)
2648                                 RebalanceAfterDelete(line2);
2649
2650                         this.lines--;
2651                 }
2652
2653                 // Invalidates the start line until the end of the viewstate
2654                 internal void InvalidateLinesAfter (Line start) {
2655                         owner.Invalidate (new Rectangle (0, start.Y - viewport_y, viewport_width, viewport_height - start.Y));
2656                 }
2657
2658                 // Invalidate a section of the document to trigger redraw
2659                 internal void Invalidate(Line start, int start_pos, Line end, int end_pos) {
2660                         Line    l1;
2661                         Line    l2;
2662                         int     p1;
2663                         int     p2;
2664
2665                         if ((start == end) && (start_pos == end_pos)) {
2666                                 return;
2667                         }
2668
2669                         if (end_pos == -1) {
2670                                 end_pos = end.text.Length;
2671                         }
2672
2673                         // figure out what's before what so the logic below is straightforward
2674                         if (start.line_no < end.line_no) {
2675                                 l1 = start;
2676                                 p1 = start_pos;
2677
2678                                 l2 = end;
2679                                 p2 = end_pos;
2680                         } else if (start.line_no > end.line_no) {
2681                                 l1 = end;
2682                                 p1 = end_pos;
2683
2684                                 l2 = start;
2685                                 p2 = start_pos;
2686                         } else {
2687                                 if (start_pos < end_pos) {
2688                                         l1 = start;
2689                                         p1 = start_pos;
2690
2691                                         l2 = end;
2692                                         p2 = end_pos;
2693                                 } else {
2694                                         l1 = end;
2695                                         p1 = end_pos;
2696
2697                                         l2 = start;
2698                                         p2 = start_pos;
2699                                 }
2700
2701                                 int endpoint = (int) l1.widths [p2];
2702                                 if (p2 == l1.text.Length + 1) {
2703                                         endpoint = (int) viewport_width;
2704                                 }
2705
2706                                 #if Debug
2707                                         Console.WriteLine("Invaliding backwards from {0}:{1} to {2}:{3}   {4}",
2708                                                         l1.line_no, p1, l2.line_no, p2,
2709                                                         new Rectangle(
2710                                                                 (int)l1.widths[p1] + l1.X - viewport_x,
2711                                                                 l1.Y - viewport_y,
2712                                                                 (int)l1.widths[p2],
2713                                                                 l1.height
2714                                                                 )
2715                                                 );
2716                                 #endif
2717
2718                                 owner.Invalidate(new Rectangle (
2719                                         offset_x + (int)l1.widths[p1] + l1.X - viewport_x,
2720                                         offset_y + l1.Y - viewport_y,
2721                                         endpoint - (int) l1.widths [p1] + 1,
2722                                         l1.height));
2723                                 return;
2724                         }
2725
2726                         #if Debug
2727                                 Console.WriteLine("Invaliding from {0}:{1} to {2}:{3} Start  => x={4}, y={5}, {6}x{7}", l1.line_no, p1, l2.line_no, p2, (int)l1.widths[p1] + l1.X - viewport_x, l1.Y - viewport_y, viewport_width, l1.height);
2728                                 Console.WriteLine ("invalidate start line:  {0}  position:  {1}", l1.text, p1);
2729                         #endif
2730
2731                         // Three invalidates:
2732                         // First line from start
2733                         owner.Invalidate(new Rectangle(
2734                                 offset_x + (int)l1.widths[p1] + l1.X - viewport_x,
2735                                 offset_y + l1.Y - viewport_y,
2736                                 viewport_width,
2737                                 l1.height));
2738
2739
2740                         // lines inbetween
2741                         if ((l1.line_no + 1) < l2.line_no) {
2742                                 int     y;
2743
2744                                 y = GetLine(l1.line_no + 1).Y;
2745                                 owner.Invalidate(new Rectangle(
2746                                         offset_x,
2747                                         offset_y + y - viewport_y,
2748                                         viewport_width,
2749                                         l2.Y - y));
2750
2751                                 #if Debug
2752                                         Console.WriteLine("Invaliding from {0}:{1} to {2}:{3} Middle => x={4}, y={5}, {6}x{7}", l1.line_no, p1, l2.line_no, p2, 0, y - viewport_y, viewport_width, l2.Y - y);
2753                                 #endif
2754                         }
2755
2756
2757                         // Last line to end
2758                         owner.Invalidate(new Rectangle(
2759                                 offset_x + (int)l2.widths[0] + l2.X - viewport_x,
2760                                 offset_y + l2.Y - viewport_y,
2761                                 (int)l2.widths[p2] + 1,
2762                                 l2.height));
2763
2764                         #if Debug
2765                                 Console.WriteLine("Invaliding from {0}:{1} to {2}:{3} End    => x={4}, y={5}, {6}x{7}", l1.line_no, p1, l2.line_no, p2, (int)l2.widths[0] + l2.X - viewport_x, l2.Y - viewport_y, (int)l2.widths[p2] + 1, l2.height);
2766                         #endif
2767                 }
2768
2769                 /// <summary>Select text around caret</summary>
2770                 internal void ExpandSelection(CaretSelection mode, bool to_caret) {
2771                         if (to_caret) {
2772                                 // We're expanding the selection to the caret position
2773                                 switch(mode) {
2774                                         case CaretSelection.Line: {
2775                                                 // Invalidate the selection delta
2776                                                 if (caret > selection_prev) {
2777                                                         Invalidate(selection_prev.line, 0, caret.line, caret.line.text.Length);
2778                                                 } else {
2779                                                         Invalidate(selection_prev.line, selection_prev.line.text.Length, caret.line, 0);
2780                                                 }
2781
2782                                                 if (caret.line.line_no <= selection_anchor.line.line_no) {
2783                                                         selection_start.line = caret.line;
2784                                                         selection_start.tag = caret.line.tags;
2785                                                         selection_start.pos = 0;
2786
2787                                                         selection_end.line = selection_anchor.line;
2788                                                         selection_end.tag = selection_anchor.tag;
2789                                                         selection_end.pos = selection_anchor.pos;
2790
2791                                                         selection_end_anchor = true;
2792                                                 } else {
2793                                                         selection_start.line = selection_anchor.line;
2794                                                         selection_start.pos = selection_anchor.height;
2795                                                         selection_start.tag = selection_anchor.line.FindTag(selection_anchor.height + 1);
2796
2797                                                         selection_end.line = caret.line;
2798                                                         selection_end.tag = caret.line.tags;
2799                                                         selection_end.pos = caret.line.text.Length;
2800
2801                                                         selection_end_anchor = false;
2802                                                 }
2803                                                 selection_prev.line = caret.line;
2804                                                 selection_prev.tag = caret.tag;
2805                                                 selection_prev.pos = caret.pos;
2806
2807                                                 break;
2808                                         }
2809
2810                                         case CaretSelection.Word: {
2811                                                 int     start_pos;
2812                                                 int     end_pos;
2813
2814                                                 start_pos = FindWordSeparator(caret.line, caret.pos, false);
2815                                                 end_pos = FindWordSeparator(caret.line, caret.pos, true);
2816
2817
2818                                                 // Invalidate the selection delta
2819                                                 if (caret > selection_prev) {
2820                                                         Invalidate(selection_prev.line, selection_prev.pos, caret.line, end_pos);
2821                                                 } else {
2822                                                         Invalidate(selection_prev.line, selection_prev.pos, caret.line, start_pos);
2823                                                 }
2824                                                 if (caret < selection_anchor) {
2825                                                         selection_start.line = caret.line;
2826                                                         selection_start.tag = caret.line.FindTag(start_pos + 1);
2827                                                         selection_start.pos = start_pos;
2828
2829                                                         selection_end.line = selection_anchor.line;
2830                                                         selection_end.tag = selection_anchor.tag;
2831                                                         selection_end.pos = selection_anchor.pos;
2832
2833                                                         selection_prev.line = caret.line;
2834                                                         selection_prev.tag = caret.tag;
2835                                                         selection_prev.pos = start_pos;
2836
2837                                                         selection_end_anchor = true;
2838                                                 } else {
2839                                                         selection_start.line = selection_anchor.line;
2840                                                         selection_start.pos = selection_anchor.height;
2841                                                         selection_start.tag = selection_anchor.line.FindTag(selection_anchor.height + 1);
2842
2843                                                         selection_end.line = caret.line;
2844                                                         selection_end.tag = caret.line.FindTag(end_pos);
2845                                                         selection_end.pos = end_pos;
2846
2847                                                         selection_prev.line = caret.line;
2848                                                         selection_prev.tag = caret.tag;
2849                                                         selection_prev.pos = end_pos;
2850
2851                                                         selection_end_anchor = false;
2852                                                 }
2853                                                 break;
2854                                         }
2855
2856                                         case CaretSelection.Position: {
2857                                                 SetSelectionToCaret(false);
2858                                                 return;
2859                                         }
2860                                 }
2861                         } else {
2862                                 // We're setting the selection 'around' the caret position
2863                                 switch(mode) {
2864                                         case CaretSelection.Line: {
2865                                                 this.Invalidate(caret.line, 0, caret.line, caret.line.text.Length);
2866
2867                                                 selection_start.line = caret.line;
2868                                                 selection_start.tag = caret.line.tags;
2869                                                 selection_start.pos = 0;
2870
2871                                                 selection_end.line = caret.line;
2872                                                 selection_end.pos = caret.line.text.Length;
2873                                                 selection_end.tag = caret.line.FindTag(selection_end.pos);
2874
2875                                                 selection_anchor.line = selection_end.line;
2876                                                 selection_anchor.tag = selection_end.tag;
2877                                                 selection_anchor.pos = selection_end.pos;
2878                                                 selection_anchor.height = 0;
2879
2880                                                 selection_prev.line = caret.line;
2881                                                 selection_prev.tag = caret.tag;
2882                                                 selection_prev.pos = caret.pos;
2883
2884                                                 this.selection_end_anchor = true;
2885
2886                                                 break;
2887                                         }
2888
2889                                         case CaretSelection.Word: {
2890                                                 int     start_pos;
2891                                                 int     end_pos;
2892
2893                                                 start_pos = FindWordSeparator(caret.line, caret.pos, false);
2894                                                 end_pos = FindWordSeparator(caret.line, caret.pos, true);
2895
2896                                                 this.Invalidate(selection_start.line, start_pos, caret.line, end_pos);
2897
2898                                                 selection_start.line = caret.line;
2899                                                 selection_start.tag = caret.line.FindTag(start_pos + 1);
2900                                                 selection_start.pos = start_pos;
2901
2902                                                 selection_end.line = caret.line;
2903                                                 selection_end.tag = caret.line.FindTag(end_pos);
2904                                                 selection_end.pos = end_pos;
2905
2906                                                 selection_anchor.line = selection_end.line;
2907                                                 selection_anchor.tag = selection_end.tag;
2908                                                 selection_anchor.pos = selection_end.pos;
2909                                                 selection_anchor.height = start_pos;
2910
2911                                                 selection_prev.line = caret.line;
2912                                                 selection_prev.tag = caret.tag;
2913                                                 selection_prev.pos = caret.pos;
2914
2915                                                 this.selection_end_anchor = true;
2916
2917                                                 break;
2918                                         }
2919                                 }
2920                         }
2921
2922                         SetSelectionVisible (!(selection_start == selection_end));
2923                 }
2924
2925                 internal void SetSelectionToCaret(bool start) {
2926                         if (start) {
2927                                 // Invalidate old selection; selection is being reset to empty
2928                                 this.Invalidate(selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
2929
2930                                 selection_start.line = caret.line;
2931                                 selection_start.tag = caret.tag;
2932                                 selection_start.pos = caret.pos;
2933
2934                                 // start always also selects end
2935                                 selection_end.line = caret.line;
2936                                 selection_end.tag = caret.tag;
2937                                 selection_end.pos = caret.pos;
2938
2939                                 selection_anchor.line = caret.line;
2940                                 selection_anchor.tag = caret.tag;
2941                                 selection_anchor.pos = caret.pos;
2942                         } else {
2943                                 // Invalidate from previous end to caret (aka new end)
2944                                 if (selection_end_anchor) {
2945                                         if (selection_start != caret) {
2946                                                 this.Invalidate(selection_start.line, selection_start.pos, caret.line, caret.pos);
2947                                         }
2948                                 } else {
2949                                         if (selection_end != caret) {
2950                                                 this.Invalidate(selection_end.line, selection_end.pos, caret.line, caret.pos);
2951                                         }
2952                                 }
2953
2954                                 if (caret < selection_anchor) {
2955                                         selection_start.line = caret.line;
2956                                         selection_start.tag = caret.tag;
2957                                         selection_start.pos = caret.pos;
2958
2959                                         selection_end.line = selection_anchor.line;
2960                                         selection_end.tag = selection_anchor.tag;
2961                                         selection_end.pos = selection_anchor.pos;
2962
2963                                         selection_end_anchor = true;
2964                                 } else {
2965                                         selection_start.line = selection_anchor.line;
2966                                         selection_start.tag = selection_anchor.tag;
2967                                         selection_start.pos = selection_anchor.pos;
2968
2969                                         selection_end.line = caret.line;
2970                                         selection_end.tag = caret.tag;
2971                                         selection_end.pos = caret.pos;
2972
2973                                         selection_end_anchor = false;
2974                                 }
2975                         }
2976
2977                         SetSelectionVisible (!(selection_start == selection_end));
2978                 }
2979
2980                 internal void SetSelection(Line start, int start_pos, Line end, int end_pos) {
2981                         if (selection_visible) {
2982                                 Invalidate(selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
2983                         }
2984
2985                         if ((end.line_no < start.line_no) || ((end == start) && (end_pos <= start_pos))) {
2986                                 selection_start.line = end;
2987                                 selection_start.tag = LineTag.FindTag(end, end_pos);
2988                                 selection_start.pos = end_pos;
2989
2990                                 selection_end.line = start;
2991                                 selection_end.tag = LineTag.FindTag(start, start_pos);
2992                                 selection_end.pos = start_pos;
2993
2994                                 selection_end_anchor = true;
2995                         } else {
2996                                 selection_start.line = start;
2997                                 selection_start.tag = LineTag.FindTag(start, start_pos);
2998                                 selection_start.pos = start_pos;
2999
3000                                 selection_end.line = end;
3001                                 selection_end.tag = LineTag.FindTag(end, end_pos);
3002                                 selection_end.pos = end_pos;
3003
3004                                 selection_end_anchor = false;
3005                         }
3006
3007                         selection_anchor.line = start;
3008                         selection_anchor.tag = selection_start.tag;
3009                         selection_anchor.pos = start_pos;
3010
3011                         if (((start == end) && (start_pos == end_pos)) || start == null || end == null) {
3012                                 SetSelectionVisible (false);
3013                         } else {
3014                                 SetSelectionVisible (true);
3015                                 Invalidate(selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
3016                         }
3017                 }
3018
3019                 internal void SetSelectionStart(Line start, int start_pos, bool invalidate) {
3020                         // Invalidate from the previous to the new start pos
3021                         if (invalidate)
3022                                 Invalidate(selection_start.line, selection_start.pos, start, start_pos);
3023
3024                         selection_start.line = start;
3025                         selection_start.pos = start_pos;
3026                         selection_start.tag = LineTag.FindTag(start, start_pos);
3027
3028                         selection_anchor.line = start;
3029                         selection_anchor.pos = start_pos;
3030                         selection_anchor.tag = selection_start.tag;
3031
3032                         selection_end_anchor = false;
3033
3034
3035                         if ((selection_end.line != selection_start.line) || (selection_end.pos != selection_start.pos)) {
3036                                 SetSelectionVisible (true);
3037                         } else {
3038                                 SetSelectionVisible (false);
3039                         }
3040
3041                         if (invalidate)
3042                                 Invalidate(selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
3043                 }
3044
3045                 internal void SetSelectionStart(int character_index, bool invalidate) {
3046                         Line    line;
3047                         LineTag tag;
3048                         int     pos;
3049
3050                         if (character_index < 0) {
3051                                 return;
3052                         }
3053
3054                         CharIndexToLineTag(character_index, out line, out tag, out pos);
3055                         SetSelectionStart(line, pos, invalidate);
3056                 }
3057
3058                 internal void SetSelectionEnd(Line end, int end_pos, bool invalidate) {
3059
3060                         if (end == selection_end.line && end_pos == selection_start.pos) {
3061                                 selection_anchor.line = selection_start.line;
3062                                 selection_anchor.tag = selection_start.tag;
3063                                 selection_anchor.pos = selection_start.pos;
3064
3065                                 selection_end.line = selection_start.line;
3066                                 selection_end.tag = selection_start.tag;
3067                                 selection_end.pos = selection_start.pos;
3068
3069                                 selection_end_anchor = false;
3070                         } else if ((end.line_no < selection_anchor.line.line_no) || ((end == selection_anchor.line) && (end_pos <= selection_anchor.pos))) {
3071                                 selection_start.line = end;
3072                                 selection_start.tag = LineTag.FindTag(end, end_pos);
3073                                 selection_start.pos = end_pos;
3074
3075                                 selection_end.line = selection_anchor.line;
3076                                 selection_end.tag = selection_anchor.tag;
3077                                 selection_end.pos = selection_anchor.pos;
3078
3079                                 selection_end_anchor = true;
3080                         } else {
3081                                 selection_start.line = selection_anchor.line;
3082                                 selection_start.tag = selection_anchor.tag;
3083                                 selection_start.pos = selection_anchor.pos;
3084
3085                                 selection_end.line = end;
3086                                 selection_end.tag = LineTag.FindTag(end, end_pos);
3087                                 selection_end.pos = end_pos;
3088
3089                                 selection_end_anchor = false;
3090                         }
3091
3092                         if ((selection_end.line != selection_start.line) || (selection_end.pos != selection_start.pos)) {
3093                                 SetSelectionVisible (true);
3094                                 if (invalidate)
3095                                         Invalidate(selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
3096                         } else {
3097                                 SetSelectionVisible (false);
3098                                 // ?? Do I need to invalidate here, tests seem to work without it, but I don't think they should :-s
3099                         }
3100                 }
3101
3102                 internal void SetSelectionEnd(int character_index, bool invalidate) {
3103                         Line    line;
3104                         LineTag tag;
3105                         int     pos;
3106
3107                         if (character_index < 0) {
3108                                 return;
3109                         }
3110
3111                         CharIndexToLineTag(character_index, out line, out tag, out pos);
3112                         SetSelectionEnd(line, pos, invalidate);
3113                 }
3114
3115                 internal void SetSelection(Line start, int start_pos) {
3116                         if (selection_visible) {
3117                                 Invalidate(selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
3118                         }
3119
3120                         selection_start.line = start;
3121                         selection_start.pos = start_pos;
3122                         selection_start.tag = LineTag.FindTag(start, start_pos);
3123
3124                         selection_end.line = start;
3125                         selection_end.tag = selection_start.tag;
3126                         selection_end.pos = start_pos;
3127
3128                         selection_anchor.line = start;
3129                         selection_anchor.tag = selection_start.tag;
3130                         selection_anchor.pos = start_pos;
3131
3132                         selection_end_anchor = false;
3133                         SetSelectionVisible (false);
3134                 }
3135
3136                 internal void InvalidateSelectionArea() {
3137                         Invalidate (selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
3138                 }
3139
3140                 // Return the current selection, as string
3141                 internal string GetSelection() {
3142                         // We return String.Empty if there is no selection
3143                         if ((selection_start.pos == selection_end.pos) && (selection_start.line == selection_end.line)) {
3144                                 return string.Empty;
3145                         }
3146
3147                         if (selection_start.line == selection_end.line) {
3148                                 return selection_start.line.text.ToString (selection_start.pos, selection_end.pos - selection_start.pos);
3149                         } else {
3150                                 StringBuilder   sb;
3151                                 int             i;
3152                                 int             start;
3153                                 int             end;
3154
3155                                 sb = new StringBuilder();
3156                                 start = selection_start.line.line_no;
3157                                 end = selection_end.line.line_no;
3158
3159                                 sb.Append(selection_start.line.text.ToString(selection_start.pos, selection_start.line.text.Length - selection_start.pos));
3160
3161                                 if ((start + 1) < end) {
3162                                         for (i = start + 1; i < end; i++) {
3163                                                 sb.Append(GetLine(i).text.ToString());
3164                                         }
3165                                 }
3166
3167                                 sb.Append(selection_end.line.text.ToString(0, selection_end.pos));
3168
3169                                 return sb.ToString();
3170                         }
3171                 }
3172
3173                 internal void ReplaceSelection(string s, bool select_new) {
3174                         int             i;
3175
3176                         int selection_start_pos = LineTagToCharIndex (selection_start.line, selection_start.pos);
3177                         SuspendRecalc ();
3178
3179                         // First, delete any selected text
3180                         if ((selection_start.pos != selection_end.pos) || (selection_start.line != selection_end.line)) {
3181                                 if (selection_start.line == selection_end.line) {
3182                                         undo.RecordDeleteString (selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
3183
3184                                         DeleteChars (selection_start.line, selection_start.pos, selection_end.pos - selection_start.pos);
3185
3186                                         // The tag might have been removed, we need to recalc it
3187                                         selection_start.tag = selection_start.line.FindTag(selection_start.pos + 1);
3188                                 } else {
3189                                         int             start;
3190                                         int             end;
3191
3192                                         start = selection_start.line.line_no;
3193                                         end = selection_end.line.line_no;
3194
3195                                         undo.RecordDeleteString (selection_start.line, selection_start.pos, selection_end.line, selection_end.pos);
3196
3197                                         InvalidateLinesAfter(selection_start.line);
3198
3199                                         // Delete first line
3200                                         DeleteChars (selection_start.line, selection_start.pos, selection_start.line.text.Length - selection_start.pos);
3201                                         selection_start.line.recalc = true;
3202
3203                                         // Delete last line
3204                                         DeleteChars(selection_end.line, 0, selection_end.pos);
3205
3206                                         start++;
3207                                         if (start < end) {
3208                                                 for (i = end - 1; i >= start; i--) {
3209                                                         Delete(i);
3210                                                 }
3211                                         }
3212
3213                                         // BIG FAT WARNING - selection_end.line might be stale due
3214                                         // to the above Delete() call. DONT USE IT before hitting the end of this method!
3215
3216                                         // Join start and end
3217                                         Combine(selection_start.line.line_no, start);
3218                                 }
3219                         }
3220
3221
3222                         Insert(selection_start.line, selection_start.pos, false, s);
3223                         undo.RecordInsertString (selection_start.line, selection_start.pos, s);
3224                         ResumeRecalc (false);
3225
3226                         Line begin_update_line = selection_start.line;
3227                         int begin_update_pos = selection_start.pos;
3228
3229                         if (!select_new) {
3230                                 CharIndexToLineTag(selection_start_pos + s.Length, out selection_start.line,
3231                                                 out selection_start.tag, out selection_start.pos);
3232
3233                                 selection_end.line = selection_start.line;
3234                                 selection_end.pos = selection_start.pos;
3235                                 selection_end.tag = selection_start.tag;
3236                                 selection_anchor.line = selection_start.line;
3237                                 selection_anchor.pos = selection_start.pos;
3238                                 selection_anchor.tag = selection_start.tag;
3239
3240                                 SetSelectionVisible (false);
3241                         } else {
3242                                 CharIndexToLineTag(selection_start_pos, out selection_start.line,
3243                                                 out selection_start.tag, out selection_start.pos);
3244
3245                                 CharIndexToLineTag(selection_start_pos + s.Length, out selection_end.line,
3246                                                 out selection_end.tag, out selection_end.pos);
3247
3248                                 selection_anchor.line = selection_start.line;
3249                                 selection_anchor.pos = selection_start.pos;
3250                                 selection_anchor.tag = selection_start.tag;
3251
3252                                 SetSelectionVisible (true);
3253                         }
3254
3255                         PositionCaret (selection_start.line, selection_start.pos);
3256                         UpdateView (begin_update_line, selection_end.line.line_no - begin_update_line.line_no, begin_update_pos);
3257                 }
3258
3259                 internal void CharIndexToLineTag(int index, out Line line_out, out LineTag tag_out, out int pos) {
3260                         Line    line;
3261                         LineTag tag;
3262                         int     i;
3263                         int     chars;
3264                         int     start;
3265
3266                         chars = 0;
3267
3268                         for (i = 1; i <= lines; i++) {
3269                                 line = GetLine(i);
3270
3271                                 start = chars;
3272                                 chars += line.text.Length;
3273
3274                                 if (index <= chars) {
3275                                         // we found the line
3276                                         tag = line.tags;
3277
3278                                         while (tag != null) {
3279                                                 if (index < (start + tag.Start + tag.Length - 1)) {
3280                                                         line_out = line;
3281                                                         tag_out = LineTag.GetFinalTag (tag);
3282                                                         pos = index - start;
3283                                                         return;
3284                                                 }
3285                                                 if (tag.Next == null) {
3286                                                         Line    next_line;
3287
3288                                                         next_line = GetLine(line.line_no + 1);
3289
3290                                                         if (next_line != null) {
3291                                                                 line_out = next_line;
3292                                                                 tag_out = LineTag.GetFinalTag (next_line.tags);
3293                                                                 pos = 0;
3294                                                                 return;
3295                                                         } else {
3296                                                                 line_out = line;
3297                                                                 tag_out = LineTag.GetFinalTag (tag);
3298                                                                 pos = line_out.text.Length;
3299                                                                 return;
3300                                                         }
3301                                                 }
3302                                                 tag = tag.Next;
3303                                         }
3304                                 }
3305                         }
3306
3307                         line_out = GetLine(lines);
3308                         tag = line_out.tags;
3309                         while (tag.Next != null) {
3310                                 tag = tag.Next;
3311                         }
3312                         tag_out = tag;
3313                         pos = line_out.text.Length;
3314                 }
3315
3316                 internal int LineTagToCharIndex(Line line, int pos) {
3317                         int     i;
3318                         int     length;
3319
3320                         // Count first and last line
3321                         length = 0;
3322
3323                         // Count the lines in the middle
3324
3325                         for (i = 1; i < line.line_no; i++) {
3326                                 length += GetLine(i).text.Length;
3327                         }
3328
3329                         length += pos;
3330
3331                         return length;
3332                 }
3333
3334                 internal int SelectionLength() {
3335                         if ((selection_start.pos == selection_end.pos) && (selection_start.line == selection_end.line)) {
3336                                 return 0;
3337                         }
3338
3339                         if (selection_start.line == selection_end.line) {
3340                                 return selection_end.pos - selection_start.pos;
3341                         } else {
3342                                 int     i;
3343                                 int     start;
3344                                 int     end;
3345                                 int     length;
3346
3347                                 // Count first and last line
3348                                 length = selection_start.line.text.Length - selection_start.pos + selection_end.pos + crlf_size;
3349
3350                                 // Count the lines in the middle
3351                                 start = selection_start.line.line_no + 1;
3352                                 end = selection_end.line.line_no;
3353
3354                                 if (start < end) {
3355                                         for (i = start; i < end; i++) {
3356                                                 Line line = GetLine (i);
3357                                                 length += line.text.Length + LineEndingLength (line.ending);
3358                                         }
3359                                 }
3360
3361                                 return length;
3362                         }
3363
3364
3365                 }
3366
3367
3368                 // UIA: Method used via reflection in TextRangeProvider
3369
3370                 /// <summary>Give it a Line number and it returns the Line object at with that line number</summary>
3371                 internal Line GetLine(int LineNo) {
3372                         Line    line = document;
3373
3374                         while (line != sentinel) {
3375                                 if (LineNo == line.line_no) {
3376                                         return line;
3377                                 } else if (LineNo < line.line_no) {
3378                                         line = line.left;
3379                                 } else {
3380                                         line = line.right;
3381                                 }
3382                         }
3383
3384                         return null;
3385                 }
3386
3387                 /// <summary>Retrieve the previous tag; walks line boundaries</summary>
3388                 internal LineTag PreviousTag(LineTag tag) {
3389                         Line l;
3390
3391                         if (tag.Previous != null) {
3392                                 return tag.Previous;
3393                         }
3394
3395                         // Next line
3396                         if (tag.Line.line_no == 1) {
3397                                 return null;
3398                         }
3399
3400                         l = GetLine(tag.Line.line_no - 1);
3401                         if (l != null) {
3402                                 LineTag t;
3403
3404                                 t = l.tags;
3405                                 while (t.Next != null) {
3406                                         t = t.Next;
3407                                 }
3408                                 return t;
3409                         }
3410
3411                         return null;
3412                 }
3413
3414                 /// <summary>Retrieve the next tag; walks line boundaries</summary>
3415                 internal LineTag NextTag(LineTag tag) {
3416                         Line l;
3417
3418                         if (tag.Next != null) {
3419                                 return tag.Next;
3420                         }
3421
3422                         // Next line
3423                         l = GetLine(tag.Line.line_no + 1);
3424                         if (l != null) {
3425                                 return l.tags;
3426                         }
3427
3428                         return null;
3429                 }
3430
3431                 internal Line ParagraphStart(Line line) {
3432                         Line lastline = line;
3433                         do {
3434                                 if (line.line_no <= 1)
3435                                         break;
3436
3437                                 line = lastline;
3438                                 lastline = GetLine (line.line_no - 1);
3439                         } while (lastline.ending == LineEnding.Wrap);
3440
3441                         return line;
3442                 }
3443
3444                 internal Line ParagraphEnd(Line line) {
3445                         Line    l;
3446
3447                         while (line.ending == LineEnding.Wrap) {
3448                                 l = GetLine(line.line_no + 1);
3449                                 if ((l == null) || (l.ending != LineEnding.Wrap)) {
3450                                         break;
3451                                 }
3452                                 line = l;
3453                         }
3454                         return line;
3455                 }
3456
3457                 /// <summary>Give it a pixel offset coordinate and it returns the Line covering that are (offset
3458                 /// is either X or Y depending on if we are multiline
3459                 /// </summary>
3460                 internal Line GetLineByPixel (int offset, bool exact)
3461                 {
3462                         Line    line = document;
3463                         Line    last = null;
3464
3465                         if (multiline) {
3466                                 while (line != sentinel) {
3467                                         last = line;
3468                                         if ((offset >= line.Y) && (offset < (line.Y+line.height))) {
3469                                                 return line;
3470                                         } else if (offset < line.Y) {
3471                                                 line = line.left;
3472                                         } else {
3473                                                 line = line.right;
3474                                         }
3475                                 }
3476                         } else {
3477                                 while (line != sentinel) {
3478                                         last = line;
3479                                         if ((offset >= line.X) && (offset < (line.X + line.Width)))
3480                                                 return line;
3481                                         else if (offset < line.X)
3482                                                 line = line.left;
3483                                         else
3484                                                 line = line.right;
3485                                 }
3486                         }
3487
3488                         if (exact) {
3489                                 return null;
3490                         }
3491                         return last;
3492                 }
3493
3494                 // UIA: Method used via reflection in TextProviderBehavior
3495
3496                 // Give it x/y pixel coordinates and it returns the Tag at that position
3497                 internal LineTag FindCursor (int x, int y, out int index)
3498                 {
3499                         Line line;
3500
3501                         x -= offset_x;
3502                         y -= offset_y;
3503
3504                         line = GetLineByPixel (multiline ? y : x, false);
3505
3506                         LineTag tag = line.GetTag (x);
3507
3508                         if (tag.Length == 0 && tag.Start == 1)
3509                                 index = 0;
3510                         else
3511                                 index = tag.GetCharIndex (x - line.align_shift);
3512
3513                         return tag;
3514                 }
3515
3516                 /// <summary>Format area of document in specified font and color</summary>
3517                 /// <param name="start_pos">1-based start position on start_line</param>
3518                 /// <param name="end_pos">1-based end position on end_line </param>
3519                 internal void FormatText (Line start_line, int start_pos, Line end_line, int end_pos, Font font,
3520                                 Color color, Color back_color, FormatSpecified specified)
3521                 {
3522                         Line    l;
3523
3524                         // First, format the first line
3525                         if (start_line != end_line) {
3526                                 // First line
3527                                 LineTag.FormatText(start_line, start_pos, start_line.text.Length - start_pos + 1, font, color, back_color, specified);
3528
3529                                 // Format last line
3530                                 LineTag.FormatText(end_line, 1, end_pos, font, color, back_color, specified);
3531
3532                                 // Now all the lines inbetween
3533                                 for (int i = start_line.line_no + 1; i < end_line.line_no; i++) {
3534                                         l = GetLine(i);
3535                                         LineTag.FormatText(l, 1, l.text.Length, font, color, back_color, specified);
3536                                 }
3537                         } else {
3538                                 // Special case, single line
3539                                 LineTag.FormatText(start_line, start_pos, end_pos - start_pos, font, color, back_color, specified);
3540
3541                                 if ((end_pos - start_pos) == 0 && CaretTag.Length != 0)
3542                                         CaretTag = CaretTag.Next;
3543                         }
3544                 }
3545
3546                 internal void RecalculateAlignments ()
3547                 {
3548                         Line    line;
3549                         int     line_no;
3550
3551                         line_no = 1;
3552
3553
3554
3555                         while (line_no <= lines) {
3556                                 line = GetLine(line_no);
3557
3558                                 if (line != null) {
3559                                         switch (line.alignment) {
3560                                         case HorizontalAlignment.Left:
3561                                                 line.align_shift = 0;
3562                                                 break;
3563                                         case HorizontalAlignment.Center:
3564                                                 line.align_shift = (viewport_width - (int)line.widths[line.text.Length]) / 2;
3565                                                 break;
3566                                         case HorizontalAlignment.Right:
3567                                                 line.align_shift = viewport_width - (int)line.widths[line.text.Length] - right_margin;
3568                                                 break;
3569                                         }
3570                                 }
3571
3572                                 line_no++;
3573                         }
3574                         return;
3575                 }
3576
3577                 /// <summary>Calculate formatting for the whole document</summary>
3578                 internal bool RecalculateDocument(Graphics g) {
3579                         return RecalculateDocument(g, 1, this.lines, false);
3580                 }
3581
3582                 /// <summary>Calculate formatting starting at a certain line</summary>
3583                 internal bool RecalculateDocument(Graphics g, int start) {
3584                         return RecalculateDocument(g, start, this.lines, false);
3585                 }
3586
3587                 /// <summary>Calculate formatting within two given line numbers</summary>
3588                 internal bool RecalculateDocument(Graphics g, int start, int end) {
3589                         return RecalculateDocument(g, start, end, false);
3590                 }
3591
3592                 /// <summary>With optimize on, returns true if line heights changed</summary>
3593                 internal bool RecalculateDocument(Graphics g, int start, int end, bool optimize) {
3594                         Line    line;
3595                         int     line_no;
3596                         int     offset;
3597                         int     new_width;
3598                         bool    changed;
3599                         int     shift;
3600
3601                         if (recalc_suspended > 0) {
3602                                 recalc_pending = true;
3603                                 recalc_start = Math.Min (recalc_start, start);
3604                                 recalc_end = Math.Max (recalc_end, end);
3605                                 recalc_optimize = optimize;
3606                                 return false;
3607                         }
3608
3609                         // Fixup the positions, they can go kinda nuts
3610                         // (this is suspend and resume recalc - they set them to 1 and max)
3611                         start = Math.Max (start, 1);
3612                         end = Math.Min (end, lines);
3613
3614                         offset = GetLine(start).offset;
3615                         line_no = start;
3616                         new_width = 0;
3617                         shift = this.lines;
3618                         if (!optimize) {
3619                                 changed = true;         // We always return true if we run non-optimized
3620                         } else {
3621                                 changed = false;
3622                         }
3623
3624                         while (line_no <= (end + this.lines - shift)) {
3625                                 line = GetLine(line_no++);
3626                                 line.offset = offset;
3627
3628                                 // if we are not calculating a password
3629                                 if (!calc_pass) {
3630                                         if (!optimize) {
3631                                                 line.RecalculateLine(g, this);
3632                                         } else {
3633                                                 if (line.recalc && line.RecalculateLine(g, this)) {
3634                                                         changed = true;
3635                                                         // If the height changed, all subsequent lines change
3636                                                         end = this.lines;
3637                                                         shift = this.lines;
3638                                                 }
3639                                         }
3640                                 } else {
3641                                         if (!optimize) {
3642                                                 line.RecalculatePasswordLine(g, this);
3643                                         } else {
3644                                                 if (line.recalc && line.RecalculatePasswordLine(g, this)) {
3645                                                         changed = true;
3646                                                         // If the height changed, all subsequent lines change
3647                                                         end = this.lines;
3648                                                         shift = this.lines;
3649                                                 }
3650                                         }
3651                                 }
3652
3653                                 if (line.widths[line.text.Length] > new_width) {
3654                                         new_width = (int)line.widths[line.text.Length];
3655                                 }
3656
3657                                 // Calculate alignment
3658                                 if (line.alignment != HorizontalAlignment.Left) {
3659                                         if (line.alignment == HorizontalAlignment.Center) {
3660                                                 line.align_shift = (viewport_width - (int)line.widths[line.text.Length]) / 2;
3661                                         } else {
3662                                                 line.align_shift = viewport_width - (int)line.widths[line.text.Length] - 1;
3663                                         }
3664                                 }
3665
3666                                 if (multiline)
3667                                         offset += line.height;
3668                                 else
3669                                         offset += (int) line.widths [line.text.Length];
3670
3671                                 if (line_no > lines) {
3672                                         break;
3673                                 }
3674                         }
3675
3676                         if (document_x != new_width) {
3677                                 document_x = new_width;
3678                                 if (WidthChanged != null) {
3679                                         WidthChanged(this, null);
3680                                 }
3681                         }
3682
3683                         RecalculateAlignments();
3684
3685                         line = GetLine(lines);
3686
3687                         if (document_y != line.Y + line.height) {
3688                                 document_y = line.Y + line.height;
3689                                 if (HeightChanged != null) {
3690                                         HeightChanged(this, null);
3691                                 }
3692                         }
3693
3694                         // scan for links and tell us if its all
3695                         // changed, so we can update everything
3696                         if (EnableLinks)
3697                                 ScanForLinks (start, end, ref changed);
3698
3699                         UpdateCaret();
3700                         return changed;
3701                 }
3702
3703                 internal int Size() {
3704                         return lines;
3705                 }
3706
3707                 private void owner_HandleCreated(object sender, EventArgs e) {
3708                         RecalculateDocument(owner.CreateGraphicsInternal());
3709                         AlignCaret();
3710                 }
3711
3712                 private void owner_VisibleChanged(object sender, EventArgs e) {
3713                         if (owner.Visible) {
3714                                 RecalculateDocument(owner.CreateGraphicsInternal());
3715                         }
3716                 }
3717
3718                 internal static bool IsWordSeparator (char ch)
3719                 {
3720                         switch (ch) {
3721                         case ' ':
3722                         case '\t':
3723                         case '(':
3724                         case ')':
3725                         case '\r':
3726                         case '\n':
3727                                 return true;
3728                         default:
3729                                 return false;
3730                         }
3731                 }
3732
3733                 internal int FindWordSeparator(Line line, int pos, bool forward) {
3734                         int len;
3735
3736                         len = line.text.Length;
3737
3738                         if (forward) {
3739                                 for (int i = pos + 1; i < len; i++) {
3740                                         if (IsWordSeparator(line.Text[i])) {
3741                                                 return i + 1;
3742                                         }
3743                                 }
3744                                 return len;
3745                         } else {
3746                                 for (int i = pos - 1; i > 0; i--) {
3747                                         if (IsWordSeparator(line.Text[i - 1])) {
3748                                                 return i;
3749                                         }
3750                                 }
3751                                 return 0;
3752                         }
3753                 }
3754
3755                 /* Search document for text */
3756                 internal bool FindChars(char[] chars, Marker start, Marker end, out Marker result) {
3757                         Line    line;
3758                         int     line_no;
3759                         int     pos;
3760                         int     line_len;
3761
3762                         // Search for occurence of any char in the chars array
3763                         result = new Marker();
3764
3765                         line = start.line;
3766                         line_no = start.line.line_no;
3767                         pos = start.pos;
3768                         while (line_no <= end.line.line_no) {
3769                                 line_len = line.text.Length;
3770                                 while (pos < line_len) {
3771                                         for (int i = 0; i < chars.Length; i++) {
3772                                                 if (line.text[pos] == chars[i]) {
3773                                                         // Special case
3774                                                         if ((line.line_no == end.line.line_no) && (pos >= end.pos)) {
3775                                                                 return false;
3776                                                         }
3777
3778                                                         result.line = line;
3779                                                         result.pos = pos;
3780                                                         return true;
3781                                                 }
3782                                         }
3783                                         pos++;
3784                                 }
3785
3786                                 pos = 0;
3787                                 line_no++;
3788                                 line = GetLine(line_no);
3789                         }
3790
3791                         return false;
3792                 }
3793
3794                 // This version does not build one big string for searching, instead it handles
3795                 // line-boundaries, which is faster and less memory intensive
3796                 // FIXME - Depending on culture stuff we might have to create a big string and use culturespecific
3797                 // search stuff and change it to accept and return positions instead of Markers (which would match
3798                 // RichTextBox behaviour better but would be inconsistent with the rest of TextControl)
3799                 internal bool Find(string search, Marker start, Marker end, out Marker result, RichTextBoxFinds options) {
3800                         Marker  last;
3801                         string  search_string;
3802                         Line    line;
3803                         int     line_no;
3804                         int     pos;
3805                         int     line_len;
3806                         int     current;
3807                         bool    word;
3808                         bool    word_option;
3809                         bool    ignore_case;
3810                         bool    reverse;
3811                         char    c;
3812
3813                         result = new Marker();
3814                         word_option = ((options & RichTextBoxFinds.WholeWord) != 0);
3815                         ignore_case = ((options & RichTextBoxFinds.MatchCase) == 0);
3816                         reverse = ((options & RichTextBoxFinds.Reverse) != 0);
3817
3818                         line = start.line;
3819                         line_no = start.line.line_no;
3820                         pos = start.pos;
3821                         current = 0;
3822
3823                         // Prep our search string, lowercasing it if we do case-independent matching
3824                         if (ignore_case) {
3825                                 StringBuilder   sb;
3826                                 sb = new StringBuilder(search);
3827                                 for (int i = 0; i < sb.Length; i++) {
3828                                         sb[i] = Char.ToLower(sb[i]);
3829                                 }
3830                                 search_string = sb.ToString();
3831                         } else {
3832                                 search_string = search;
3833                         }
3834
3835                         // We need to check if the character before our start position is a wordbreak
3836                         if (word_option) {
3837                                 if (line_no == 1) {
3838                                         if ((pos == 0) || (IsWordSeparator(line.text[pos - 1]))) {
3839                                                 word = true;
3840                                         } else {
3841                                                 word = false;
3842                                         }
3843                                 } else {
3844                                         if (pos > 0) {
3845                                                 if (IsWordSeparator(line.text[pos - 1])) {
3846                                                         word = true;
3847                                                 } else {
3848                                                         word = false;
3849                                                 }
3850                                         } else {
3851                                                 // Need to check the end of the previous line
3852                                                 Line    prev_line;
3853
3854                                                 prev_line = GetLine(line_no - 1);
3855                                                 if (prev_line.ending == LineEnding.Wrap) {
3856                                                         if (IsWordSeparator(prev_line.text[prev_line.text.Length - 1])) {
3857                                                                 word = true;
3858                                                         } else {
3859                                                                 word = false;
3860                                                         }
3861                                                 } else {
3862                                                         word = true;
3863                                                 }
3864                                         }
3865                                 }
3866                         } else {
3867                                 word = false;
3868                         }
3869
3870                         // To avoid duplication of this loop with reverse logic, we search
3871                         // through the document, remembering the last match and when returning
3872                         // report that last remembered match
3873
3874                         last = new Marker();
3875                         last.height = -1;       // Abused - we use it to track change
3876
3877                         while (line_no <= end.line.line_no) {
3878                                 if (line_no != end.line.line_no) {
3879                                         line_len = line.text.Length;
3880                                 } else {
3881                                         line_len = end.pos;
3882                                 }
3883
3884                                 while (pos < line_len) {
3885
3886                                         if (word_option && (current == search_string.Length)) {
3887                                                 if (IsWordSeparator(line.text[pos])) {
3888                                                         if (!reverse) {
3889                                                                 goto FindFound;
3890                                                         } else {
3891                                                                 last = result;
3892                                                                 current = 0;
3893                                                         }
3894                                                 } else {
3895                                                         current = 0;
3896                                                 }
3897                                         }
3898
3899                                         if (ignore_case) {
3900                                                 c = Char.ToLower(line.text[pos]);
3901                                         } else {
3902                                                 c = line.text[pos];
3903                                         }
3904
3905                                         if (c == search_string[current]) {
3906
3907                                                 if (current == 0) {
3908                                                         result.line = line;
3909                                                         result.pos = pos;
3910                                                 }
3911                                                 if (!word_option || (word_option && (word || (current > 0)))) {
3912                                                         current++;
3913                                                 }
3914
3915                                                 if (!word_option && (current == search_string.Length)) {
3916                                                         if (!reverse) {
3917                                                                 goto FindFound;
3918                                                         } else {
3919                                                                 last = result;
3920                                                                 current = 0;
3921                                                         }
3922                                                 }
3923                                         } else {
3924                                                 current = 0;
3925                                         }
3926                                         pos++;
3927
3928                                         if (!word_option) {
3929                                                 continue;
3930                                         }
3931
3932                                         if (IsWordSeparator(c)) {
3933                                                 word = true;
3934                                         } else {
3935                                                 word = false;
3936                                         }
3937                                 }
3938
3939                                 if (word_option) {
3940                                         // Mark that we just saw a word boundary
3941                                         if (line.ending != LineEnding.Wrap || line.line_no == lines - 1) {
3942                                                 word = true;
3943                                         }
3944
3945                                         if (current == search_string.Length) {
3946                                                 if (word) {
3947                                                         if (!reverse) {
3948                                                                 goto FindFound;
3949                                                         } else {
3950                                                                 last = result;
3951                                                                 current = 0;
3952                                                         }
3953                                                 } else {
3954                                                         current = 0;
3955                                                 }
3956                                         }
3957                                 }
3958
3959                                 pos = 0;
3960                                 line_no++;
3961                                 line = GetLine(line_no);
3962                         }
3963
3964                         if (reverse) {
3965                                 if (last.height != -1) {
3966                                         result = last;
3967                                         return true;
3968                                 }
3969                         }
3970
3971                         return false;
3972
3973                         FindFound:
3974                         if (!reverse) {
3975 //                              if ((line.line_no == end.line.line_no) && (pos >= end.pos)) {
3976 //                                      return false;
3977 //                              }
3978                                 return true;
3979                         }
3980
3981                         result = last;
3982                         return true;
3983
3984                 }
3985
3986                 /* Marker stuff */
3987                 internal void GetMarker(out Marker mark, bool start) {
3988                         mark = new Marker();
3989
3990                         if (start) {
3991                                 mark.line = GetLine(1);
3992                                 mark.tag = mark.line.tags;
3993                                 mark.pos = 0;
3994                         } else {
3995                                 mark.line = GetLine(lines);
3996                                 mark.tag = mark.line.tags;
3997                                 while (mark.tag.Next != null) {
3998                                         mark.tag = mark.tag.Next;
3999                                 }
4000                                 mark.pos = mark.line.text.Length;
4001                         }
4002                 }
4003                 #endregion      // Internal Methods
4004
4005                 #region Events
4006                 internal event EventHandler CaretMoved;
4007                 internal event EventHandler WidthChanged;
4008                 internal event EventHandler HeightChanged;
4009                 internal event EventHandler LengthChanged;
4010                 #endregion      // Events
4011
4012                 #region Administrative
4013                 public IEnumerator GetEnumerator() {
4014                         // FIXME
4015                         return null;
4016                 }
4017
4018                 public override bool Equals(object obj) {
4019                         if (obj == null) {
4020                                 return false;
4021                         }
4022
4023                         if (!(obj is Document)) {
4024                                 return false;
4025                         }
4026
4027                         if (obj == this) {
4028                                 return true;
4029                         }
4030
4031                         if (ToString().Equals(((Document)obj).ToString())) {
4032                                 return true;
4033                         }
4034
4035                         return false;
4036                 }
4037
4038                 public override int GetHashCode() {
4039                         return document_id;
4040                 }
4041
4042                 public override string ToString() {
4043                         return "document " + this.document_id;
4044                 }
4045                 #endregion      // Administrative
4046         }
4047
4048         internal class PictureTag : LineTag {
4049
4050                 internal RTF.Picture picture;
4051
4052                 internal PictureTag (Line line, int start, RTF.Picture picture) : base (line, start)
4053                 {
4054                         this.picture = picture;
4055                 }
4056
4057                 public override bool IsTextTag {
4058                         get { return false; }
4059                 }
4060
4061                 public override SizeF SizeOfPosition (Graphics dc, int pos)
4062                 {
4063                         return picture.Size;
4064                 }
4065
4066                 internal override int MaxHeight ()
4067                 {
4068                         return (int) (picture.Height + 0.5F);
4069                 }
4070
4071                 public override void Draw (Graphics dc, Color color, float xoff, float y, int start, int end)
4072                 {
4073                         picture.DrawImage (dc, xoff + Line.widths [start], y, false);
4074                 }
4075
4076                 public override void Draw (Graphics dc, Color color, float xoff, float y, int start, int end, string text)
4077                 {
4078                         picture.DrawImage (dc, xoff + + Line.widths [start], y, false);
4079                 }
4080
4081                 public override string Text ()
4082                 {
4083                         return "I";
4084                 }
4085         }
4086
4087         internal class UndoManager {
4088
4089                 internal enum ActionType {
4090
4091                         Typing,
4092
4093                         // This is basically just cut & paste
4094                         InsertString,
4095                         DeleteString,
4096
4097                         UserActionBegin,
4098                         UserActionEnd
4099                 }
4100
4101                 internal class Action {
4102                         internal ActionType     type;
4103                         internal int            line_no;
4104                         internal int            pos;
4105                         internal object         data;
4106                 }
4107
4108                 #region Local Variables
4109                 private Document        document;
4110                 private Stack           undo_actions;
4111                 private Stack           redo_actions;
4112
4113                 //private int           caret_line;
4114                 //private int           caret_pos;
4115
4116                 // When performing an action, we lock the queue, so that the action can't be undone
4117                 private bool locked;
4118                 #endregion      // Local Variables
4119
4120                 #region Constructors
4121                 internal UndoManager (Document document)
4122                 {
4123                         this.document = document;
4124                         undo_actions = new Stack (50);
4125                         redo_actions = new Stack (50);
4126                 }
4127                 #endregion      // Constructors
4128
4129                 #region Properties
4130                 internal bool CanUndo {
4131                         get { return undo_actions.Count > 0; }
4132                 }
4133
4134                 internal bool CanRedo {
4135                         get { return redo_actions.Count > 0; }
4136                 }
4137
4138                 internal string UndoActionName {
4139                         get {
4140                                 foreach (Action action in undo_actions) {
4141                                         if (action.type == ActionType.UserActionBegin)
4142                                                 return (string) action.data;
4143                                         if (action.type == ActionType.Typing)
4144                                                 return Locale.GetText ("Typing");
4145                                 }
4146                                 return String.Empty;
4147                         }
4148                 }
4149
4150                 internal string RedoActionName {
4151                         get {
4152                                 foreach (Action action in redo_actions) {
4153                                         if (action.type == ActionType.UserActionBegin)
4154                                                 return (string) action.data;
4155                                         if (action.type == ActionType.Typing)
4156                                                 return Locale.GetText ("Typing");
4157                                 }
4158                                 return String.Empty;
4159                         }
4160                 }
4161                 #endregion      // Properties
4162
4163                 #region Internal Methods
4164                 internal void Clear ()
4165                 {
4166                         undo_actions.Clear();
4167                         redo_actions.Clear();
4168                 }
4169
4170                 internal bool Undo ()
4171                 {
4172                         Action action;
4173                         bool user_action_finished = false;
4174
4175                         if (undo_actions.Count == 0)
4176                                 return false;
4177
4178                         locked = true;
4179                         do {
4180                                 Line start;
4181                                 action = (Action) undo_actions.Pop ();
4182
4183                                 // Put onto redo stack
4184                                 redo_actions.Push(action);
4185
4186                                 // Do the thing
4187                                 switch(action.type) {
4188
4189                                 case ActionType.UserActionBegin:
4190                                         user_action_finished = true;
4191                                         break;
4192
4193                                 case ActionType.UserActionEnd:
4194                                         // noop
4195                                         break;
4196
4197                                 case ActionType.InsertString:
4198                                         start = document.GetLine (action.line_no);
4199                                         document.SuspendUpdate ();
4200                                         document.DeleteMultiline (start, action.pos, ((string) action.data).Length + 1);
4201                                         document.PositionCaret (start, action.pos);
4202                                         document.SetSelectionToCaret (true);
4203                                         document.ResumeUpdate (true);
4204                                         break;
4205
4206                                 case ActionType.Typing:
4207                                         start = document.GetLine (action.line_no);
4208                                         document.SuspendUpdate ();
4209                                         document.DeleteMultiline (start, action.pos, ((StringBuilder) action.data).Length);
4210                                         document.PositionCaret (start, action.pos);
4211                                         document.SetSelectionToCaret (true);
4212                                         document.ResumeUpdate (true);
4213
4214                                         // This is an open ended operation, so only a single typing operation can be undone at once
4215                                         user_action_finished = true;
4216                                         break;
4217
4218                                 case ActionType.DeleteString:
4219                                         start = document.GetLine (action.line_no);
4220                                         document.SuspendUpdate ();
4221                                         Insert (start, action.pos, (Line) action.data, true);
4222                                         document.ResumeUpdate (true);
4223                                         break;
4224                                 }
4225                         } while (!user_action_finished && undo_actions.Count > 0);
4226
4227                         locked = false;
4228
4229                         return true;
4230                 }
4231
4232                 internal bool Redo ()
4233                 {
4234                         Action action;
4235                         bool user_action_finished = false;
4236
4237                         if (redo_actions.Count == 0)
4238                                 return false;
4239
4240                         locked = true;
4241                         do {
4242                                 Line start;
4243                                 int start_index;
4244
4245                                 action = (Action) redo_actions.Pop ();
4246                                 undo_actions.Push (action);
4247
4248                                 switch (action.type) {
4249
4250                                 case ActionType.UserActionBegin:
4251                                         //  Noop
4252                                         break;
4253
4254                                 case ActionType.UserActionEnd:
4255                                         user_action_finished = true;
4256                                         break;
4257
4258                                 case ActionType.InsertString:
4259                                         start = document.GetLine (action.line_no);
4260                                         document.SuspendUpdate ();
4261                                         start_index = document.LineTagToCharIndex (start, action.pos);
4262                                         document.InsertString (start, action.pos, (string) action.data);
4263                                         document.CharIndexToLineTag (start_index + ((string) action.data).Length,
4264                                                         out document.caret.line, out document.caret.tag,
4265                                                         out document.caret.pos);
4266                                         document.UpdateCaret ();
4267                                         document.SetSelectionToCaret (true);
4268                                         document.ResumeUpdate (true);
4269                                         break;
4270
4271                                 case ActionType.Typing:
4272                                         start = document.GetLine (action.line_no);
4273                                         document.SuspendUpdate ();
4274                                         start_index = document.LineTagToCharIndex (start, action.pos);
4275                                         document.InsertString (start, action.pos, ((StringBuilder) action.data).ToString ());
4276                                         document.CharIndexToLineTag (start_index + ((StringBuilder) action.data).Length,
4277                                                         out document.caret.line, out document.caret.tag,
4278                                                         out document.caret.pos);
4279                                         document.UpdateCaret ();
4280                                         document.SetSelectionToCaret (true);
4281                                         document.ResumeUpdate (true);
4282
4283                                         // This is an open ended operation, so only a single typing operation can be undone at once
4284                                         user_action_finished = true;
4285                                         break;
4286
4287                                 case ActionType.DeleteString:
4288                                         start = document.GetLine (action.line_no);
4289                                         document.SuspendUpdate ();
4290                                         document.DeleteMultiline (start, action.pos, ((Line) action.data).text.Length);
4291                                         document.PositionCaret (start, action.pos);
4292                                         document.SetSelectionToCaret (true);
4293                                         document.ResumeUpdate (true);
4294
4295                                         break;
4296                                 }
4297                         } while (!user_action_finished && redo_actions.Count > 0);
4298
4299                         locked = false;
4300
4301                         return true;
4302                 }
4303                 #endregion      // Internal Methods
4304
4305                 #region Private Methods
4306
4307                 public void BeginUserAction (string name)
4308                 {
4309                         if (locked)
4310                                 return;
4311
4312                         // Nuke the redo queue
4313                         redo_actions.Clear ();
4314
4315                         Action ua = new Action ();
4316                         ua.type = ActionType.UserActionBegin;
4317                         ua.data = name;
4318
4319                         undo_actions.Push (ua);
4320                 }
4321
4322                 public void EndUserAction ()
4323                 {
4324                         if (locked)
4325                                 return;
4326
4327                         Action ua = new Action ();
4328                         ua.type = ActionType.UserActionEnd;
4329
4330                         undo_actions.Push (ua);
4331                 }
4332
4333                 // start_pos, end_pos = 1 based
4334                 public void RecordDeleteString (Line start_line, int start_pos, Line end_line, int end_pos)
4335                 {
4336                         if (locked)
4337                                 return;
4338
4339                         // Nuke the redo queue
4340                         redo_actions.Clear ();
4341
4342                         Action  a = new Action ();
4343
4344                         // We cant simply store the string, because then formatting would be lost
4345                         a.type = ActionType.DeleteString;
4346                         a.line_no = start_line.line_no;
4347                         a.pos = start_pos;
4348                         a.data = Duplicate (start_line, start_pos, end_line, end_pos);
4349
4350                         undo_actions.Push(a);
4351                 }
4352
4353                 public void RecordInsertString (Line line, int pos, string str)
4354                 {
4355                         if (locked || str.Length == 0)
4356                                 return;
4357
4358                         // Nuke the redo queue
4359                         redo_actions.Clear ();
4360
4361                         Action a = new Action ();
4362
4363                         a.type = ActionType.InsertString;
4364                         a.data = str;
4365                         a.line_no = line.line_no;
4366                         a.pos = pos;
4367
4368                         undo_actions.Push (a);
4369                 }
4370
4371                 public void RecordTyping (Line line, int pos, char ch)
4372                 {
4373                         if (locked)
4374                                 return;
4375
4376                         // Nuke the redo queue
4377                         redo_actions.Clear ();
4378
4379                         Action a = null;
4380
4381                         if (undo_actions.Count > 0)
4382                                 a = (Action) undo_actions.Peek ();
4383
4384                         if (a == null || a.type != ActionType.Typing) {
4385                                 a = new Action ();
4386                                 a.type = ActionType.Typing;
4387                                 a.data = new StringBuilder ();
4388                                 a.line_no = line.line_no;
4389                                 a.pos = pos;
4390
4391                                 undo_actions.Push (a);
4392                         }
4393
4394                         StringBuilder data = (StringBuilder) a.data;
4395                         data.Append (ch);
4396                 }
4397
4398                 // start_pos = 1-based
4399                 // end_pos = 1-based
4400                 public Line Duplicate(Line start_line, int start_pos, Line end_line, int end_pos)
4401                 {
4402                         Line    ret;
4403                         Line    line;
4404                         Line    current;
4405                         LineTag tag;
4406                         LineTag current_tag;
4407                         int     start;
4408                         int     end;
4409                         int     tag_start;
4410
4411                         line = new Line (start_line.document, start_line.ending);
4412                         ret = line;
4413
4414                         for (int i = start_line.line_no; i <= end_line.line_no; i++) {
4415                                 current = document.GetLine(i);
4416
4417                                 if (start_line.line_no == i) {
4418                                         start = start_pos;
4419                                 } else {
4420                                         start = 0;
4421                                 }
4422
4423                                 if (end_line.line_no == i) {
4424                                         end = end_pos;
4425                                 } else {
4426                                         end = current.text.Length;
4427                                 }
4428
4429                                 if (end_pos == 0)
4430                                         continue;
4431
4432                                 // Text for the tag
4433                                 line.text = new StringBuilder (current.text.ToString (start, end - start));
4434
4435                                 // Copy tags from start to start+length onto new line
4436                                 current_tag = current.FindTag (start + 1);
4437                                 while ((current_tag != null) && (current_tag.Start <= end)) {
4438                                         if ((current_tag.Start <= start) && (start < (current_tag.Start + current_tag.Length))) {
4439                                                 // start tag is within this tag
4440                                                 tag_start = start;
4441                                         } else {
4442                                                 tag_start = current_tag.Start;
4443                                         }
4444
4445                                         tag = new LineTag(line, tag_start - start + 1);
4446                                         tag.CopyFormattingFrom (current_tag);
4447
4448                                         current_tag = current_tag.Next;
4449
4450                                         // Add the new tag to the line
4451                                         if (line.tags == null) {
4452                                                 line.tags = tag;
4453                                         } else {
4454                                                 LineTag tail;
4455                                                 tail = line.tags;
4456
4457                                                 while (tail.Next != null) {
4458                                                         tail = tail.Next;
4459                                                 }
4460                                                 tail.Next = tag;
4461                                                 tag.Previous = tail;
4462                                         }
4463                                 }
4464
4465                                 if ((i + 1) <= end_line.line_no) {
4466                                         line.ending = current.ending;
4467
4468                                         // Chain them (we use right/left as next/previous)
4469                                         line.right = new Line (start_line.document, start_line.ending);
4470                                         line.right.left = line;
4471                                         line = line.right;
4472                                 }
4473                         }
4474
4475                         return ret;
4476                 }
4477
4478                 // Insert multi-line text at the given position; use formatting at insertion point for inserted text
4479                 internal void Insert(Line line, int pos, Line insert, bool select)
4480                 {
4481                         Line    current;
4482                         LineTag tag;
4483                         int     offset;
4484                         int     lines;
4485                         Line    first;
4486
4487                         // Handle special case first
4488                         if (insert.right == null) {
4489
4490                                 // Single line insert
4491                                 document.Split(line, pos);
4492
4493                                 if (insert.tags == null) {
4494                                         return; // Blank line
4495                                 }
4496
4497                                 //Insert our tags at the end
4498                                 tag = line.tags;
4499
4500                                 while (tag.Next != null) {
4501                                         tag = tag.Next;
4502                                 }
4503
4504                                 offset = tag.Start + tag.Length - 1;
4505
4506                                 tag.Next = insert.tags;
4507                                 line.text.Insert(offset, insert.text.ToString());
4508
4509                                 // Adjust start locations
4510                                 tag = tag.Next;
4511                                 while (tag != null) {
4512                                         tag.Start += offset;
4513                                         tag.Line = line;
4514                                         tag = tag.Next;
4515                                 }
4516                                 // Put it back together
4517                                 document.Combine(line.line_no, line.line_no + 1);
4518
4519                                 if (select) {
4520                                         document.SetSelectionStart (line, pos, false);
4521                                         document.SetSelectionEnd (line, pos + insert.text.Length, false);
4522                                 }
4523
4524                                 document.UpdateView(line, pos);
4525                                 return;
4526                         }
4527
4528                         first = line;
4529                         lines = 1;
4530                         current = insert;
4531
4532                         while (current != null) {
4533
4534                                 if (current == insert) {
4535                                         // Inserting the first line we split the line (and make space)
4536                                         document.Split(line.line_no, pos);
4537                                         //Insert our tags at the end of the line
4538                                         tag = line.tags;
4539
4540
4541                                         if (tag != null && tag.Length != 0) {
4542                                                 while (tag.Next != null) {
4543                                                         tag = tag.Next;
4544                                                 }
4545                                                 offset = tag.Start + tag.Length - 1;
4546                                                 tag.Next = current.tags;
4547                                                 tag.Next.Previous = tag;
4548
4549                                                 tag = tag.Next;
4550
4551                                         } else {
4552                                                 offset = 0;
4553                                                 line.tags = current.tags;
4554                                                 line.tags.Previous = null;
4555                                                 tag = line.tags;
4556                                         }
4557
4558                                         line.ending = current.ending;
4559                                 } else {
4560                                         document.Split(line.line_no, 0);
4561                                         offset = 0;
4562                                         line.tags = current.tags;
4563                                         line.tags.Previous = null;
4564                                         line.ending = current.ending;
4565                                         tag = line.tags;
4566                                 }
4567
4568                                 // Adjust start locations and line pointers
4569                                 while (tag != null) {
4570                                         tag.Start += offset - 1;
4571                                         tag.Line = line;
4572                                         tag = tag.Next;
4573                                 }
4574
4575                                 line.text.Insert(offset, current.text.ToString());
4576                                 line.Grow(line.text.Length);
4577
4578                                 line.recalc = true;
4579                                 line = document.GetLine(line.line_no + 1);
4580
4581                                 // FIXME? Test undo of line-boundaries
4582                                 if ((current.right == null) && (current.tags.Length != 0)) {
4583                                         document.Combine(line.line_no - 1, line.line_no);
4584                                 }
4585                                 current = current.right;
4586                                 lines++;
4587
4588                         }
4589
4590                         // Recalculate our document
4591                         document.UpdateView(first, lines, pos);
4592                         return;
4593                 }
4594                 #endregion      // Private Methods
4595         }
4596 }