mcs/class/System.Drawing/Test/System.Drawing.Drawing2D/LinearGradientBrushTest.cs

   1 //
   2 // System.Drawing.Drawing2D.LinearGradientBrush unit tests
   3 //
   4 // Authors:
   5 //      Sebastien Pouliot  <sebastien@ximian.com>
   6 //
   7 // Copyright (C) 2006, 2008 Novell, Inc (http://www.novell.com)
   8 //
   9 // Permission is hereby granted, free of charge, to any person obtaining
  10 // a copy of this software and associated documentation files (the
  11 // "Software"), to deal in the Software without restriction, including
  12 // without limitation the rights to use, copy, modify, merge, publish,
  13 // distribute, sublicense, and/or sell copies of the Software, and to
  14 // permit persons to whom the Software is furnished to do so, subject to
  15 // the following conditions:
  16 //
  17 // The above copyright notice and this permission notice shall be
  18 // included in all copies or substantial portions of the Software.
  19 //
  20 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27 //
  28
  29 using System;
  30 using System.ComponentModel;
  31 using System.Drawing;
  32 using System.Drawing.Drawing2D;
  33 using System.Security.Permissions;
  34 using NUnit.Framework;
  35
  36 namespace MonoTests.System.Drawing.Drawing2D {
  37
  38         [TestFixture]
  39         [SecurityPermission (SecurityAction.Deny, UnmanagedCode = true)]
  40         public class LinearGradientBrushTest {
  41
  42                 private Point pt1;
  43                 private Point pt2;
  44                 private Color c1;
  45                 private Color c2;
  46                 private LinearGradientBrush default_brush;
  47                 private Matrix empty_matrix;
  48                 private RectangleF rect;
  49
  50                 [TestFixtureSetUp]
  51                 public void FixtureSetUp ()
  52                 {
  53                         pt1 = new Point (0, 0);
  54                         pt2 = new Point (32, 32);
  55                         c1 = Color.Blue;
  56                         c2 = Color.Red;
  57                         default_brush = new LinearGradientBrush (pt1, pt2, c1, c2);
  58                         empty_matrix = new Matrix ();
  59                         rect = new RectangleF (0, 0, 32, 32);
  60                 }
  61
  62                 private void CheckDefaultRectangle (string msg, RectangleF rect)
  63                 {
  64                         Assert.AreEqual (pt1.X, rect.X, msg + ".Rectangle.X");
  65                         Assert.AreEqual (pt1.Y, rect.Y, msg + ".Rectangle.Y");
  66                         Assert.AreEqual (pt2.X, rect.Width, msg + ".Rectangle.Width");
  67                         Assert.AreEqual (pt2.Y, rect.Height, msg + ".Rectangle.Height");
  68                 }
  69
  70                 private void CheckDefaultMatrix (Matrix matrix)
  71                 {
  72                         float[] elements = matrix.Elements;
  73                         Assert.AreEqual (1.0f, elements[0], 0.1, "matrix.0");
  74                         Assert.AreEqual (1.0f, elements[1], 0.1, "matrix.1");
  75                         Assert.AreEqual (-1.0f, elements[2], 0.1, "matrix.2");
  76                         Assert.AreEqual (1.0f, elements[3], 0.1, "matrix.3");
  77                         Assert.AreEqual (16.0f, elements[4], 0.1, "matrix.4");
  78                         Assert.AreEqual (-16.0f, elements[5], 0.1, "matrix.5");
  79                 }
  80
  81                 private void CheckBrushAt45 (LinearGradientBrush lgb)
  82                 {
  83                         CheckDefaultRectangle ("4", lgb.Rectangle);
  84                         Assert.AreEqual (1, lgb.Blend.Factors.Length, "Blend.Factors");
  85                         Assert.AreEqual (1, lgb.Blend.Factors[0], "Blend.Factors [0]");
  86                         Assert.AreEqual (1, lgb.Blend.Positions.Length, "Blend.Positions");
  87                         // lgb.Blend.Positions [0] is always small (e-39) but never quite the same
  88                         Assert.IsFalse (lgb.GammaCorrection, "GammaCorrection");
  89                         Assert.AreEqual (2, lgb.LinearColors.Length, "LinearColors");
  90                         Assert.IsNotNull (lgb.Transform, "Transform");
  91                         CheckDefaultMatrix (lgb.Transform);
  92                 }
  93
  94                 private void CheckMatrixAndRect (PointF pt1, PointF pt2, float[] testVals)
  95                 {
  96                         Matrix m;
  97                         RectangleF rect;
  98
  99                         using (LinearGradientBrush b = new LinearGradientBrush (pt1, pt2, Color.Black, Color.White)) {
 100                                 m = b.Transform;
 101                                 rect = b.Rectangle;
 102                         }
 103
 104                         Assert.AreEqual (testVals[0], m.Elements[0], 0.0001, "matrix.0");
 105                         Assert.AreEqual (testVals[1], m.Elements[1], 0.0001, "matrix.1");
 106                         Assert.AreEqual (testVals[2], m.Elements[2], 0.0001, "matrix.2");
 107                         Assert.AreEqual (testVals[3], m.Elements[3], 0.0001, "matrix.3");
 108                         Assert.AreEqual (testVals[4], m.Elements[4], 0.0001, "matrix.4");
 109                         Assert.AreEqual (testVals[5], m.Elements[5], 0.0001, "matrix.5");
 110
 111                         Assert.AreEqual (testVals[6], rect.X, 0.0001, "rect.X");
 112                         Assert.AreEqual (testVals[7], rect.Y, 0.0001, "rect.Y");
 113                         Assert.AreEqual (testVals[8], rect.Width, 0.0001, "rect.Width");
 114                         Assert.AreEqual (testVals[9], rect.Height, 0.0001, "rect.Height");
 115                 }
 116
 117                 private void CheckMatrixForScalableAngle (RectangleF rect, float angle, float[] testVals)
 118                 {
 119                         Matrix m;
 120
 121                         using (LinearGradientBrush b = new LinearGradientBrush (rect, Color.Firebrick, Color.Lavender, angle, true)) {
 122                                 m = b.Transform;
 123                         }
 124
 125                         Assert.AreEqual (testVals[0], m.Elements[0], 0.0001, "matrix.0");
 126                         Assert.AreEqual (testVals[1], m.Elements[1], 0.0001, "matrix.1");
 127                         Assert.AreEqual (testVals[2], m.Elements[2], 0.0001, "matrix.2");
 128                         Assert.AreEqual (testVals[3], m.Elements[3], 0.0001, "matrix.3");
 129                         Assert.AreEqual (testVals[4], m.Elements[4], 0.0001, "matrix.4");
 130                         Assert.AreEqual (testVals[5], m.Elements[5], 0.0001, "matrix.5");
 131                 }
 132
 133                 [Test]
 134                 public void Constructor_Point_Point_Color_Color ()
 135                 {
 136                         LinearGradientBrush lgb = new LinearGradientBrush (pt1, pt2, c1, c2);
 137                         CheckBrushAt45 (lgb);
 138
 139                         Assert.AreEqual (WrapMode.Tile, lgb.WrapMode, "WrapMode.Tile");
 140                         lgb.WrapMode = WrapMode.TileFlipX;
 141                         Assert.AreEqual (WrapMode.TileFlipX, lgb.WrapMode, "WrapMode.TileFlipX");
 142                         lgb.WrapMode = WrapMode.TileFlipY;
 143                         Assert.AreEqual (WrapMode.TileFlipY, lgb.WrapMode, "WrapMode.TileFlipY");
 144                         lgb.WrapMode = WrapMode.TileFlipXY;
 145                         Assert.AreEqual (WrapMode.TileFlipXY, lgb.WrapMode, "WrapMode.TileFlipXY");
 146                         // can't set WrapMode.Clamp
 147                 }
 148
 149                 [Test]
 150                 public void Constructor_Point_Point_Color_Color_1 ()
 151                 {
 152                         PointF pt1 = new Point (100, 200);
 153                         PointF pt2 = new Point (200, 200);
 154                         CheckMatrixAndRect (pt1, pt2, new float[] { 1, 0, 0, 1, 0, 0, 100, 150, 100, 100 });
 155
 156                         pt1 = new Point (100, 200);
 157                         pt2 = new Point (0, 200);
 158                         CheckMatrixAndRect (pt1, pt2, new float[] { -1, 0, 0, -1, 100, 400, 0, 150, 100, 100 });
 159
 160                         pt1 = new Point (100, 200);
 161                         pt2 = new Point (100, 300);
 162                         CheckMatrixAndRect (pt1, pt2, new float[] { 0, 1, -1, 0, 350, 150, 50, 200, 100, 100  });
 163
 164                         pt1 = new Point (100, 200);
 165                         pt2 = new Point (100, 100);
 166                         CheckMatrixAndRect (pt1, pt2, new float[] { 0, -1, 1, 0, -50, 250, 50, 100, 100, 100 });
 167
 168                         pt1 = new Point (100, 100);
 169                         pt2 = new Point (150, 225);
 170                         CheckMatrixAndRect (pt1, pt2, new float[] { 1, 2.5f, -0.6896552f, 0.2758622f, 112.069f, -194.8276f, 100, 100, 50, 125 });
 171
 172                         pt1 = new Point (100, 100);
 173                         pt2 = new Point (55, 200);
 174                         CheckMatrixAndRect (pt1, pt2, new float[] { -1, 2.222222f, -0.7484408f, -0.3367983f, 267.2661f, 28.29753f, 55, 100, 45, 100 });
 175
 176                         pt1 = new Point (100, 100);
 177                         pt2 = new Point (150, 60);
 178                         CheckMatrixAndRect (pt1, pt2, new float[] { 1, -0.8000001f, 0.9756095f, 1.219512f, -78.04876f, 82.43903f, 100, 60, 50, 40 });
 179
 180                         pt1 = new Point (100, 100);
 181                         pt2 = new Point (27, 59);
 182                         CheckMatrixAndRect (pt1, pt2, new float[] { -1, -0.5616435f, 0.8539224f, -1.520399f, 59.11317f, 236.0361f, 27, 59, 73, 41 });
 183                 }
 184
 185                 [Test]
 186                 public void Constructor_RectangleF_Color_Color_Single_0 ()
 187                 {
 188                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 0f);
 189                         CheckDefaultRectangle ("Original", lgb.Rectangle);
 190                         Assert.AreEqual (1, lgb.Blend.Factors.Length, "Blend.Factors");
 191                         Assert.AreEqual (1, lgb.Blend.Factors[0], "Blend.Factors[0]");
 192                         Assert.AreEqual (1, lgb.Blend.Positions.Length, "Blend.Positions");
 193                         // lgb.Blend.Positions [0] is always small (e-39) but never quite the same
 194                         Assert.IsFalse (lgb.GammaCorrection, "GammaCorrection");
 195                         Assert.AreEqual (c1.ToArgb (), lgb.LinearColors[0].ToArgb (), "LinearColors[0]");
 196                         Assert.AreEqual (c2.ToArgb (), lgb.LinearColors[1].ToArgb (), "LinearColors[1]");
 197                         Assert.AreEqual (rect, lgb.Rectangle, "Rectangle");
 198                         Assert.IsTrue (lgb.Transform.IsIdentity, "Transform.IsIdentity");
 199                         Assert.AreEqual (WrapMode.Tile, lgb.WrapMode, "WrapMode");
 200
 201                         Matrix matrix = new Matrix (2, -1, 1, 2, 10, 10);
 202                         lgb.Transform = matrix;
 203                         Assert.AreEqual (matrix, lgb.Transform, "Transform");
 204                 }
 205
 206                 [Test]
 207                 public void Constructor_RectangleF_Color_Color_Single_22_5 ()
 208                 {
 209                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 22.5f);
 210                         CheckDefaultRectangle ("Original", lgb.Rectangle);
 211                         float[] elements = lgb.Transform.Elements;
 212                         Assert.AreEqual (1.207107, elements[0], 0.0001, "matrix.0");
 213                         Assert.AreEqual (0.5, elements[1], 0.0001, "matrix.1");
 214                         Assert.AreEqual (-0.5, elements[2], 0.0001, "matrix.2");
 215                         Assert.AreEqual (1.207107, elements[3], 0.0001, "matrix.3");
 216                         Assert.AreEqual (4.686291, elements[4], 0.0001, "matrix.4");
 217                         Assert.AreEqual (-11.313709, elements[5], 0.0001, "matrix.5");
 218                 }
 219
 220                 [Test]
 221                 public void Constructor_RectangleF_Color_Color_Single_45 ()
 222                 {
 223                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 45f);
 224                         CheckBrushAt45 (lgb);
 225                 }
 226
 227                 [Test]
 228                 public void Constructor_RectangleF_Color_Color_Single_90 ()
 229                 {
 230                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 90f);
 231                         CheckDefaultRectangle ("Original", lgb.Rectangle);
 232                         float[] elements = lgb.Transform.Elements;
 233                         Assert.AreEqual (0, elements[0], 0.0001, "matrix.0");
 234                         Assert.AreEqual (1, elements[1], 0.0001, "matrix.1");
 235                         Assert.AreEqual (-1, elements[2], 0.0001, "matrix.2");
 236                         Assert.AreEqual (0, elements[3], 0.0001, "matrix.3");
 237                         Assert.AreEqual (32, elements[4], 0.0001, "matrix.4");
 238                         Assert.AreEqual (0, elements[5], 0.0001, "matrix.5");
 239                 }
 240
 241                 [Test]
 242                 public void Constructor_RectangleF_Color_Color_Single_135 ()
 243                 {
 244                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 135f);
 245                         CheckDefaultRectangle ("Original", lgb.Rectangle);
 246                         float[] elements = lgb.Transform.Elements;
 247                         Assert.AreEqual (-1, elements[0], 0.0001, "matrix.0");
 248                         Assert.AreEqual (1, elements[1], 0.0001, "matrix.1");
 249                         Assert.AreEqual (-1, elements[2], 0.0001, "matrix.2");
 250                         Assert.AreEqual (-1, elements[3], 0.0001, "matrix.3");
 251                         Assert.AreEqual (48, elements[4], 0.0001, "matrix.4");
 252                         Assert.AreEqual (16, elements[5], 0.0001, "matrix.5");
 253                 }
 254
 255                 [Test]
 256                 public void Constructor_RectangleF_Color_Color_Single_180 ()
 257                 {
 258                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 180f);
 259                         CheckDefaultRectangle ("Original", lgb.Rectangle);
 260                         float[] elements = lgb.Transform.Elements;
 261                         Assert.AreEqual (-1, elements[0], 0.0001, "matrix.0");
 262                         Assert.AreEqual (0, elements[1], 0.0001, "matrix.1");
 263                         Assert.AreEqual (0, elements[2], 0.0001, "matrix.2");
 264                         Assert.AreEqual (-1, elements[3], 0.0001, "matrix.3");
 265                         Assert.AreEqual (32, elements[4], 0.0001, "matrix.4");
 266                         Assert.AreEqual (32, elements[5], 0.0001, "matrix.5");
 267                 }
 268
 269                 [Test]
 270                 public void Constructor_RectangleF_Color_Color_Single_270 ()
 271                 {
 272                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 270f);
 273                         CheckDefaultRectangle ("Original", lgb.Rectangle);
 274                         float[] elements = lgb.Transform.Elements;
 275                         Assert.AreEqual (0, elements[0], 0.0001, "matrix.0");
 276                         Assert.AreEqual (-1, elements[1], 0.0001, "matrix.1");
 277                         Assert.AreEqual (1, elements[2], 0.0001, "matrix.2");
 278                         Assert.AreEqual (0, elements[3], 0.0001, "matrix.3");
 279                         Assert.AreEqual (0, elements[4], 0.0001, "matrix.4");
 280                         Assert.AreEqual (32, elements[5], 0.0001, "matrix.5");
 281                 }
 282
 283                 [Test]
 284                 public void Constructor_RectangleF_Color_Color_Single_315 ()
 285                 {
 286                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 315f);
 287                         CheckDefaultRectangle ("Original", lgb.Rectangle);
 288                         float[] elements = lgb.Transform.Elements;
 289                         Assert.AreEqual (1, elements[0], 0.0001, "matrix.0");
 290                         Assert.AreEqual (-1, elements[1], 0.0001, "matrix.1");
 291                         Assert.AreEqual (1, elements[2], 0.0001, "matrix.2");
 292                         Assert.AreEqual (1, elements[3], 0.0001, "matrix.3");
 293                         Assert.AreEqual (-16, elements[4], 0.0001, "matrix.4");
 294                         Assert.AreEqual (16, elements[5], 0.0001, "matrix.5");
 295                 }
 296
 297                 [Test]
 298                 public void Constructor_RectangleF_Color_Color_Single_360()
 299                 {
 300                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 360f);
 301                         CheckDefaultRectangle ("Original", lgb.Rectangle);
 302                         float[] elements = lgb.Transform.Elements;
 303                         // just like 0'
 304                         Assert.AreEqual (1, elements[0], 0.0001, "matrix.0");
 305                         Assert.AreEqual (0, elements[1], 0.0001, "matrix.1");
 306                         Assert.AreEqual (0, elements[2], 0.0001, "matrix.2");
 307                         Assert.AreEqual (1, elements[3], 0.0001, "matrix.3");
 308                         Assert.AreEqual (0, elements[4], 0.0001, "matrix.4");
 309                         Assert.AreEqual (0, elements[5], 0.0001, "matrix.5");
 310                 }
 311
 312                 [Test]
 313                 public void Constructor_RectangleF_Color_Color_Single_540 ()
 314                 {
 315                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 540f);
 316                         CheckDefaultRectangle ("Original", lgb.Rectangle);
 317                         float[] elements = lgb.Transform.Elements;
 318                         // just like 180'
 319                         Assert.AreEqual (-1, elements[0], 0.0001, "matrix.0");
 320                         Assert.AreEqual (0, elements[1], 0.0001, "matrix.1");
 321                         Assert.AreEqual (0, elements[2], 0.0001, "matrix.2");
 322                         Assert.AreEqual (-1, elements[3], 0.0001, "matrix.3");
 323                         Assert.AreEqual (32, elements[4], 0.0001, "matrix.4");
 324                         Assert.AreEqual (32, elements[5], 0.0001, "matrix.5");
 325                 }
 326
 327                 [Test]
 328                 public void InterpolationColors_Colors_InvalidBlend ()
 329                 {
 330                         // default Blend doesn't allow getting this property
 331                         Assert.Throws<ArgumentException> (() => { var x = default_brush.InterpolationColors.Colors; });
 332                 }
 333
 334                 [Test]
 335                 public void InterpolationColors_Positions_InvalidBlend ()
 336                 {
 337                         // default Blend doesn't allow getting this property
 338                         Assert.Throws<ArgumentException> (() => { var x = default_brush.InterpolationColors.Positions; });
 339                 }
 340
 341                 [Test]
 342                 public void LinearColors_Empty ()
 343                 {
 344                         Assert.Throws<IndexOutOfRangeException> (() => default_brush.LinearColors = new Color[0]);
 345                 }
 346
 347                 [Test]
 348                 public void LinearColors_One ()
 349                 {
 350                         Assert.Throws<IndexOutOfRangeException> (() => default_brush.LinearColors = new Color[1]);
 351                 }
 352
 353                 [Test]
 354                 public void LinearColors_Two ()
 355                 {
 356                         Assert.AreEqual (Color.FromArgb (255, 0, 0, 255), default_brush.LinearColors[0], "0");
 357                         Assert.AreEqual (Color.FromArgb (255, 255, 0, 0), default_brush.LinearColors[1], "1");
 358
 359                         LinearGradientBrush lgb = new LinearGradientBrush (pt1, pt2, c1, c2);
 360                         lgb.LinearColors = new Color[2] { Color.Black, Color.White };
 361                         // not the same, the alpha is changed to 255 so they can't compare
 362                         Assert.AreEqual (Color.FromArgb (255, 0, 0, 0), lgb.LinearColors[0], "0");
 363                         Assert.AreEqual (Color.FromArgb (255, 255, 255, 255), lgb.LinearColors[1], "1");
 364                 }
 365
 366                 [Test]
 367                 public void LinearColors_Three ()
 368                 {
 369                         LinearGradientBrush lgb = new LinearGradientBrush (pt1, pt2, c1, c2);
 370                         lgb.LinearColors = new Color[3] { Color.Red, Color.Green, Color.Blue };
 371                         // not the same, the alpha is changed to 255 so they can't compare
 372                         Assert.AreEqual (Color.FromArgb (255, 255, 0, 0), lgb.LinearColors[0], "0");
 373                         Assert.AreEqual (Color.FromArgb (255, 0, 128, 0), lgb.LinearColors[1], "1");
 374                 }
 375
 376                 [Test]
 377                 public void Rectangle ()
 378                 {
 379                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 0f);
 380                         CheckDefaultRectangle ("Original", lgb.Rectangle);
 381                         lgb.MultiplyTransform (new Matrix (2, 0, 0, 2, 2, 2));
 382                         CheckDefaultRectangle ("Multiply", lgb.Rectangle);
 383                         lgb.ResetTransform ();
 384                         CheckDefaultRectangle ("Reset", lgb.Rectangle);
 385                         lgb.RotateTransform (90);
 386                         CheckDefaultRectangle ("Rotate", lgb.Rectangle);
 387                         lgb.ScaleTransform (4, 0.25f);
 388                         CheckDefaultRectangle ("Scale", lgb.Rectangle);
 389                         lgb.TranslateTransform (-10, -20);
 390                         CheckDefaultRectangle ("Translate", lgb.Rectangle);
 391
 392                         lgb.SetBlendTriangularShape (0.5f);
 393                         CheckDefaultRectangle ("SetBlendTriangularShape", lgb.Rectangle);
 394                         lgb.SetSigmaBellShape (0.5f);
 395                         CheckDefaultRectangle ("SetSigmaBellShape", lgb.Rectangle);
 396                 }
 397
 398                 [Test]
 399                 public void Transform_Null ()
 400                 {
 401                         Assert.Throws<ArgumentNullException> (() => default_brush.Transform = null);
 402                 }
 403
 404                 [Test]
 405                 public void Transform_Empty ()
 406                 {
 407                         LinearGradientBrush lgb = new LinearGradientBrush (pt1, pt2, c1, c2);
 408                         lgb.Transform = new Matrix ();
 409                         Assert.IsTrue (lgb.Transform.IsIdentity, "Transform.IsIdentity");
 410                 }
 411
 412                 [Test]
 413                 public void Transform_NonInvertible ()
 414                 {
 415                         Assert.Throws<ArgumentException> (() => default_brush.Transform = new Matrix (123, 24, 82, 16, 47, 30));
 416                 }
 417
 418                 [Test]
 419                 public void WrapMode_AllValid ()
 420                 {
 421                         LinearGradientBrush lgb = new LinearGradientBrush (pt1, pt2, c1, c2);
 422                         lgb.WrapMode = WrapMode.Tile;
 423                         Assert.AreEqual (WrapMode.Tile, lgb.WrapMode, "WrapMode.Tile");
 424                         lgb.WrapMode = WrapMode.TileFlipX;
 425                         Assert.AreEqual (WrapMode.TileFlipX, lgb.WrapMode, "WrapMode.TileFlipX");
 426                         lgb.WrapMode = WrapMode.TileFlipY;
 427                         Assert.AreEqual (WrapMode.TileFlipY, lgb.WrapMode, "WrapMode.TileFlipY");
 428                         lgb.WrapMode = WrapMode.TileFlipXY;
 429                         Assert.AreEqual (WrapMode.TileFlipXY, lgb.WrapMode, "WrapMode.TileFlipXY");
 430                 }
 431
 432                 [Test]
 433                 public void WrapMode_Clamp ()
 434                 {
 435                         Assert.Throws<ArgumentException> (() => default_brush.WrapMode = WrapMode.Clamp);
 436                 }
 437
 438                 [Test]
 439                 public void WrapMode_Invalid ()
 440                 {
 441                         Assert.Throws<InvalidEnumArgumentException> (() => default_brush.WrapMode = (WrapMode) Int32.MinValue);
 442                 }
 443
 444
 445                 [Test]
 446                 public void Clone ()
 447                 {
 448                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 0f);
 449                         LinearGradientBrush clone = (LinearGradientBrush) lgb.Clone ();
 450                         Assert.AreEqual (lgb.Blend.Factors.Length, clone.Blend.Factors.Length, "Blend.Factors.Length");
 451                         Assert.AreEqual (lgb.Blend.Positions.Length, clone.Blend.Positions.Length, "Blend.Positions.Length");
 452                         Assert.AreEqual (lgb.GammaCorrection, clone.GammaCorrection, "GammaCorrection");
 453                         Assert.AreEqual (lgb.LinearColors.Length, clone.LinearColors.Length, "LinearColors.Length");
 454                         Assert.AreEqual (lgb.LinearColors.Length, clone.LinearColors.Length, "LinearColors.Length");
 455                         Assert.AreEqual (lgb.Rectangle, clone.Rectangle, "Rectangle");
 456                         Assert.AreEqual (lgb.Transform, clone.Transform, "Transform");
 457                         Assert.AreEqual (lgb.WrapMode, clone.WrapMode, "WrapMode");
 458                 }
 459
 460                 [Test]
 461                 public void MultiplyTransform1_Null ()
 462                 {
 463                         Assert.Throws<ArgumentNullException> (() => default_brush.MultiplyTransform (null));
 464                 }
 465
 466                 [Test]
 467                 public void MultiplyTransform2_Null ()
 468                 {
 469                         Assert.Throws<ArgumentNullException> (() => default_brush.MultiplyTransform (null, MatrixOrder.Append));
 470                 }
 471
 472                 [Test]
 473                 public void MultiplyTransform2_Invalid ()
 474                 {
 475                         default_brush.MultiplyTransform (empty_matrix, (MatrixOrder) Int32.MinValue);
 476                 }
 477
 478                 [Test]
 479                 public void MultiplyTransform_NonInvertible ()
 480                 {
 481                         Matrix noninvertible = new Matrix (123, 24, 82, 16, 47, 30);
 482                         Assert.Throws<ArgumentException> (() => default_brush.MultiplyTransform (noninvertible));
 483                 }
 484
 485                 [Test]
 486                 public void ResetTransform ()
 487                 {
 488                         LinearGradientBrush lgb = new LinearGradientBrush (pt1, pt2, c1, c2);
 489                         Assert.IsFalse (lgb.Transform.IsIdentity, "Transform.IsIdentity");
 490                         lgb.ResetTransform ();
 491                         Assert.IsTrue (lgb.Transform.IsIdentity, "Reset.IsIdentity");
 492                 }
 493
 494                 [Test]
 495                 public void RotateTransform ()
 496                 {
 497                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 0f);
 498                         lgb.RotateTransform (90);
 499                         float[] elements = lgb.Transform.Elements;
 500                         Assert.AreEqual (0, elements[0], 0.1, "matrix.0");
 501                         Assert.AreEqual (1, elements[1], 0.1, "matrix.1");
 502                         Assert.AreEqual (-1, elements[2], 0.1, "matrix.2");
 503                         Assert.AreEqual (0, elements[3], 0.1, "matrix.3");
 504                         Assert.AreEqual (0, elements[4], 0.1, "matrix.4");
 505                         Assert.AreEqual (0, elements[5], 0.1, "matrix.5");
 506
 507                         lgb.RotateTransform (270);
 508                         Assert.IsTrue (lgb.Transform.IsIdentity, "Transform.IsIdentity");
 509                 }
 510
 511                 [Test]
 512                 [NUnit.Framework.Category ("NotWorking")]
 513                 public void RotateTransform_Max ()
 514                 {
 515                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 0f);
 516                         lgb.RotateTransform (Single.MaxValue);
 517                         float[] elements = lgb.Transform.Elements;
 518                         Assert.AreEqual (5.93904E+36, elements[0], 1e32, "matrix.0");
 519                         Assert.AreEqual (5.93904E+36, elements[1], 1e32, "matrix.1");
 520                         Assert.AreEqual (-5.93904E+36, elements[2], 1e32, "matrix.2");
 521                         Assert.AreEqual (5.93904E+36, elements[3], 1e32, "matrix.3");
 522                         Assert.AreEqual (0, elements[4], 0.1, "matrix.4");
 523                         Assert.AreEqual (0, elements[5], 0.1, "matrix.5");
 524                 }
 525
 526                 [Test]
 527                 [NUnit.Framework.Category ("NotWorking")]
 528                 public void RotateTransform_Min ()
 529                 {
 530                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 0f);
 531                         lgb.RotateTransform (Single.MinValue);
 532                         float[] elements = lgb.Transform.Elements;
 533                         Assert.AreEqual (-5.93904E+36, elements[0], 1e32, "matrix.0");
 534                         Assert.AreEqual (-5.93904E+36, elements[1], 1e32, "matrix.1");
 535                         Assert.AreEqual (5.93904E+36, elements[2], 1e32, "matrix.2");
 536                         Assert.AreEqual (-5.93904E+36, elements[3], 1e32, "matrix.3");
 537                         Assert.AreEqual (0, elements[4], 0.1, "matrix.4");
 538                         Assert.AreEqual (0, elements[5], 0.1, "matrix.5");
 539                 }
 540
 541                 [Test]
 542                 public void RotateTransform_InvalidOrder ()
 543                 {
 544                         LinearGradientBrush lgb = new LinearGradientBrush (pt1, pt2, c1, c2);
 545                         Assert.Throws<ArgumentException> (() => lgb.RotateTransform (720, (MatrixOrder) Int32.MinValue));
 546                 }
 547
 548                 [Test]
 549                 public void ScaleTransform ()
 550                 {
 551                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 0f);
 552                         lgb.ScaleTransform (2, 4);
 553                         float[] elements = lgb.Transform.Elements;
 554                         Assert.AreEqual (2, elements[0], 0.1, "matrix.0");
 555                         Assert.AreEqual (0, elements[1], 0.1, "matrix.1");
 556                         Assert.AreEqual (0, elements[2], 0.1, "matrix.2");
 557                         Assert.AreEqual (4, elements[3], 0.1, "matrix.3");
 558                         Assert.AreEqual (0, elements[4], 0.1, "matrix.4");
 559                         Assert.AreEqual (0, elements[5], 0.1, "matrix.5");
 560
 561                         lgb.ScaleTransform (0.5f, 0.25f);
 562                         Assert.IsTrue (lgb.Transform.IsIdentity, "Transform.IsIdentity");
 563                 }
 564
 565                 [Test]
 566                 public void ScaleTransform_45 ()
 567                 {
 568                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 45f);
 569                         lgb.ScaleTransform (3, 3);
 570                         float[] elements = lgb.Transform.Elements;
 571                         Assert.AreEqual (3, elements[0], 0.1, "matrix.0");
 572                         Assert.AreEqual (3, elements[1], 0.1, "matrix.1");
 573                         Assert.AreEqual (-3, elements[2], 0.1, "matrix.2");
 574                         Assert.AreEqual (3, elements[3], 0.1, "matrix.3");
 575                         Assert.AreEqual (16, elements[4], 0.1, "matrix.4");
 576                         Assert.AreEqual (-16, elements[5], 0.1, "matrix.5");
 577                 }
 578
 579                 [Test]
 580                 public void ScaleTransform_MaxMin ()
 581                 {
 582                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 0f);
 583                         lgb.ScaleTransform (Single.MaxValue, Single.MinValue);
 584                         float[] elements = lgb.Transform.Elements;
 585                         Assert.AreEqual (Single.MaxValue, elements[0], 1e33, "matrix.0");
 586                         Assert.AreEqual (0, elements[1], 0.1, "matrix.1");
 587                         Assert.AreEqual (0, elements[2], 0.1, "matrix.2");
 588                         Assert.AreEqual (Single.MinValue, elements[3], 1e33, "matrix.3");
 589                         Assert.AreEqual (0, elements[4], 0.1, "matrix.4");
 590                         Assert.AreEqual (0, elements[5], 0.1, "matrix.5");
 591                 }
 592
 593                 [Test]
 594                 public void ScaleTransform_InvalidOrder ()
 595                 {
 596                         LinearGradientBrush lgb = new LinearGradientBrush (pt1, pt2, c1, c2);
 597                         Assert.Throws<ArgumentException> (() => lgb.ScaleTransform (1, 1, (MatrixOrder) Int32.MinValue));
 598                 }
 599
 600                 [Test]
 601                 public void SetBlendTriangularShape_Focus ()
 602                 {
 603                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 0f);
 604                         // max valid
 605                         lgb.SetBlendTriangularShape (1);
 606                         Assert.IsTrue (lgb.Transform.IsIdentity, "Transform.IsIdentity-1");
 607                         // min valid
 608                         lgb.SetBlendTriangularShape (0);
 609                         Assert.IsTrue (lgb.Transform.IsIdentity, "Transform.IsIdentity-1");
 610                         // middle
 611                         lgb.SetBlendTriangularShape (0.5f);
 612                         Assert.IsTrue (lgb.Transform.IsIdentity, "Transform.IsIdentity-1");
 613                         // no impact on matrix
 614                 }
 615
 616                 [Test]
 617                 public void SetBlendTriangularShape_Scale ()
 618                 {
 619                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 0f);
 620                         // max valid
 621                         lgb.SetBlendTriangularShape (0, 1);
 622                         Assert.IsTrue (lgb.Transform.IsIdentity, "Transform.IsIdentity-1");
 623                         // min valid
 624                         lgb.SetBlendTriangularShape (1, 0);
 625                         Assert.IsTrue (lgb.Transform.IsIdentity, "Transform.IsIdentity-1");
 626                         // middle
 627                         lgb.SetBlendTriangularShape (0.5f, 0.5f);
 628                         Assert.IsTrue (lgb.Transform.IsIdentity, "Transform.IsIdentity-1");
 629                         // no impact on matrix
 630                 }
 631
 632                 [Test]
 633                 public void SetBlendTriangularShape_FocusTooSmall ()
 634                 {
 635                         Assert.Throws<ArgumentException> (() => default_brush.SetBlendTriangularShape (-1));
 636                 }
 637
 638                 [Test]
 639                 public void SetBlendTriangularShape_FocusTooBig ()
 640                 {
 641                         Assert.Throws<ArgumentException> (() => default_brush.SetBlendTriangularShape (1.01f));
 642                 }
 643
 644                 [Test]
 645                 public void SetBlendTriangularShape_ScaleTooSmall ()
 646                 {
 647                         Assert.Throws<ArgumentException> (() => default_brush.SetBlendTriangularShape (1, -1));
 648                 }
 649
 650                 [Test]
 651                 public void SetBlendTriangularShape_ScaleTooBig ()
 652                 {
 653                         Assert.Throws<ArgumentException> (() => default_brush.SetBlendTriangularShape (1, 1.01f));
 654                 }
 655
 656                 [Test]
 657                 public void SetSigmaBellShape_Focus ()
 658                 {
 659                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 0f);
 660                         // max valid
 661                         lgb.SetSigmaBellShape (1);
 662                         Assert.IsTrue (lgb.Transform.IsIdentity, "Transform.IsIdentity-1");
 663                         // min valid
 664                         lgb.SetSigmaBellShape (0);
 665                         Assert.IsTrue (lgb.Transform.IsIdentity, "Transform.IsIdentity-1");
 666                         // middle
 667                         lgb.SetSigmaBellShape (0.5f);
 668                         Assert.IsTrue (lgb.Transform.IsIdentity, "Transform.IsIdentity-1");
 669                         // no impact on matrix
 670                 }
 671
 672                 [Test]
 673                 public void SetSigmaBellShape_Scale ()
 674                 {
 675                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 0f);
 676                         // max valid
 677                         lgb.SetSigmaBellShape (0, 1);
 678                         Assert.IsTrue (lgb.Transform.IsIdentity, "Transform.IsIdentity-1");
 679                         // min valid
 680                         lgb.SetSigmaBellShape (1, 0);
 681                         Assert.IsTrue (lgb.Transform.IsIdentity, "Transform.IsIdentity-2");
 682                         // middle
 683                         lgb.SetSigmaBellShape (0.5f, 0.5f);
 684                         Assert.IsTrue (lgb.Transform.IsIdentity, "Transform.IsIdentity-3");
 685                         // no impact on matrix
 686                 }
 687
 688                 [Test]
 689                 public void SetSigmaBellShape_FocusTooSmall ()
 690                 {
 691                         Assert.Throws<ArgumentException> (() => default_brush.SetSigmaBellShape (-1));
 692                 }
 693
 694                 [Test]
 695                 public void SetSigmaBellShape_FocusTooBig ()
 696                 {
 697                         Assert.Throws<ArgumentException> (() => default_brush.SetSigmaBellShape (1.01f));
 698                 }
 699
 700                 [Test]
 701                 public void SetSigmaBellShape_ScaleTooSmall ()
 702                 {
 703                         Assert.Throws<ArgumentException> (() => default_brush.SetSigmaBellShape (1, -1));
 704                 }
 705
 706                 [Test]
 707                 public void SetSigmaBellShape_ScaleTooBig ()
 708                 {
 709                         Assert.Throws<ArgumentException> (() => default_brush.SetSigmaBellShape (1, 1.01f));
 710                 }
 711
 712                 [Test]
 713                 public void TranslateTransform ()
 714                 {
 715                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 0f);
 716                         lgb.TranslateTransform (1, 1);
 717                         float[] elements = lgb.Transform.Elements;
 718                         Assert.AreEqual (1, elements[0], 0.1, "matrix.0");
 719                         Assert.AreEqual (0, elements[1], 0.1, "matrix.1");
 720                         Assert.AreEqual (0, elements[2], 0.1, "matrix.2");
 721                         Assert.AreEqual (1, elements[3], 0.1, "matrix.3");
 722                         Assert.AreEqual (1, elements[4], 0.1, "matrix.4");
 723                         Assert.AreEqual (1, elements[5], 0.1, "matrix.5");
 724
 725                         lgb.TranslateTransform (-1, -1);
 726                         // strangely lgb.Transform.IsIdentity is false
 727                         elements = lgb.Transform.Elements;
 728                         Assert.AreEqual (1, elements[0], 0.1, "revert.matrix.0");
 729                         Assert.AreEqual (0, elements[1], 0.1, "revert.matrix.1");
 730                         Assert.AreEqual (0, elements[2], 0.1, "revert.matrix.2");
 731                         Assert.AreEqual (1, elements[3], 0.1, "revert.matrix.3");
 732                         Assert.AreEqual (0, elements[4], 0.1, "revert.matrix.4");
 733                         Assert.AreEqual (0, elements[5], 0.1, "revert.matrix.5");
 734                 }
 735
 736                 [Test]
 737                 public void TranslateTransform_InvalidOrder ()
 738                 {
 739                         LinearGradientBrush lgb = new LinearGradientBrush (pt1, pt2, c1, c2);
 740                         Assert.Throws<ArgumentException> (() => lgb.TranslateTransform (1, 1, (MatrixOrder) Int32.MinValue));
 741                 }
 742
 743                 [Test]
 744                 public void Transform_Operations ()
 745                 {
 746                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 45f);
 747                         Matrix clone = lgb.Transform.Clone ();
 748                         Matrix mul = clone.Clone ();
 749
 750                         clone.Multiply (mul, MatrixOrder.Append);
 751                         lgb.MultiplyTransform (mul, MatrixOrder.Append);
 752                         Assert.AreEqual (lgb.Transform, clone, "Multiply/Append");
 753
 754                         clone.Multiply (mul, MatrixOrder.Prepend);
 755                         lgb.MultiplyTransform (mul, MatrixOrder.Prepend);
 756                         Assert.AreEqual (lgb.Transform, clone, "Multiply/Prepend");
 757
 758                         clone.Rotate (45, MatrixOrder.Append);
 759                         lgb.RotateTransform (45, MatrixOrder.Append);
 760                         Assert.AreEqual (lgb.Transform, clone, "Rotate/Append");
 761
 762                         clone.Rotate (45, MatrixOrder.Prepend);
 763                         lgb.RotateTransform (45, MatrixOrder.Prepend);
 764                         Assert.AreEqual (lgb.Transform, clone, "Rotate/Prepend");
 765
 766                         clone.Scale (0.25f, 2, MatrixOrder.Append);
 767                         lgb.ScaleTransform (0.25f, 2, MatrixOrder.Append);
 768                         Assert.AreEqual (lgb.Transform, clone, "Scale/Append");
 769
 770                         clone.Scale (0.25f, 2, MatrixOrder.Prepend);
 771                         lgb.ScaleTransform (0.25f, 2, MatrixOrder.Prepend);
 772                         Assert.AreEqual (lgb.Transform, clone, "Scale/Prepend");
 773
 774                         clone.Translate (10, 20, MatrixOrder.Append);
 775                         lgb.TranslateTransform (10, 20, MatrixOrder.Append);
 776                         Assert.AreEqual (lgb.Transform, clone, "Translate/Append");
 777
 778                         clone.Translate (30, 40, MatrixOrder.Prepend);
 779                         lgb.TranslateTransform (30, 40, MatrixOrder.Prepend);
 780                         Assert.AreEqual (lgb.Transform, clone, "Translate/Prepend");
 781
 782                         clone.Reset ();
 783                         lgb.ResetTransform ();
 784                         Assert.AreEqual (lgb.Transform, clone, "Reset");
 785                 }
 786
 787                 [Test]
 788                 public void Transform_Operations_OnScalableAngle ()
 789                 {
 790                         LinearGradientBrush lgb = new LinearGradientBrush (rect, c1, c2, 360f, true);
 791                         Matrix clone = lgb.Transform.Clone ();
 792                         Matrix mul = clone.Clone ();
 793                         Matrix m = new Matrix ();
 794                         m.Scale (2, 1);
 795                         m.Translate (rect.Width, rect.Height);
 796                         m.Rotate (30f);
 797
 798                         clone.Multiply (mul, MatrixOrder.Append);
 799                         lgb.MultiplyTransform (mul, MatrixOrder.Append);
 800                         Assert.AreEqual (lgb.Transform, clone, "Multiply/Append");
 801
 802                         clone.Multiply (mul, MatrixOrder.Prepend);
 803                         lgb.MultiplyTransform (mul, MatrixOrder.Prepend);
 804                         Assert.AreEqual (lgb.Transform, clone, "Multiply/Prepend");
 805
 806                         clone.Rotate (45, MatrixOrder.Append);
 807                         lgb.RotateTransform (45, MatrixOrder.Append);
 808                         Assert.AreEqual (lgb.Transform, clone, "Rotate/Append");
 809
 810                         clone.Rotate (45, MatrixOrder.Prepend);
 811                         lgb.RotateTransform (45, MatrixOrder.Prepend);
 812                         Assert.AreEqual (lgb.Transform, clone, "Rotate/Prepend");
 813
 814                         clone.Scale (0.25f, 2, MatrixOrder.Append);
 815                         lgb.ScaleTransform (0.25f, 2, MatrixOrder.Append);
 816                         Assert.AreEqual (lgb.Transform, clone, "Scale/Append");
 817
 818                         clone.Scale (0.25f, 2, MatrixOrder.Prepend);
 819                         lgb.ScaleTransform (0.25f, 2, MatrixOrder.Prepend);
 820                         Assert.AreEqual (lgb.Transform, clone, "Scale/Prepend");
 821
 822                         clone.Translate (10, 20, MatrixOrder.Append);
 823                         lgb.TranslateTransform (10, 20, MatrixOrder.Append);
 824                         Assert.AreEqual (lgb.Transform, clone, "Translate/Append");
 825
 826                         clone.Translate (30, 40, MatrixOrder.Prepend);
 827                         lgb.TranslateTransform (30, 40, MatrixOrder.Prepend);
 828                         Assert.AreEqual (lgb.Transform, clone, "Translate/Prepend");
 829
 830                         clone.Reset ();
 831                         lgb.ResetTransform ();
 832                         Assert.AreEqual (lgb.Transform, clone, "Reset");
 833                 }
 834
 835                 [Test]
 836                 public void Constructor_Rectangle_Angle_Scalable ()
 837                 {
 838                         CheckMatrixForScalableAngle (new RectangleF (0, 0, 10, 10), 15, new float[] { 1.183013f, 0.3169873f, -0.3169873f, 1.183012f, 0.6698728f, -2.5f });
 839
 840                         CheckMatrixForScalableAngle (new RectangleF (30, 60, 90, 50), 15, new float[] { 1.183012f, 0.176104f, -0.5705772f, 1.183012f, 34.77311f, -28.76387f });
 841                         CheckMatrixForScalableAngle (new RectangleF (30, 60, 90, 50), 75, new float[] { 0.3169872f, 0.6572293f, -2.129423f, 0.3169873f, 232.2269f, 8.763878f });
 842                         CheckMatrixForScalableAngle (new RectangleF (30, 60, 90, 50), 95, new float[] { -0.09442029f, 0.599571f, -1.942611f, -0.09442017f, 247.2034f, 48.05788f });
 843                         CheckMatrixForScalableAngle (new RectangleF (30, 60, 90, 50), 150, new float[] { -1.183013f, 0.3794515f, -1.229423f, -1.183013f, 268.2269f, 157.0972f });
 844                         CheckMatrixForScalableAngle (new RectangleF (30, 60, 90, 50), 215, new float[] { -1.140856f, -0.4437979f, 1.437905f, -1.140856f, 38.34229f, 215.2576f });
 845                         CheckMatrixForScalableAngle (new RectangleF (30, 60, 90, 50), 300, new float[] { 0.6830127f, -0.6572294f, 2.129422f, 0.6830124f, -157.2269f, 76.23613f });
 846
 847                         CheckMatrixForScalableAngle (new RectangleF (30, 60, 90, 150), 15, new float[] { 1.183012f, 0.5283121f, -0.1901924f, 1.183012f, 11.95002f, -64.33012f });
 848                         CheckMatrixForScalableAngle (new RectangleF (30, 60, 90, 150), 75, new float[] { 0.3169872f, 1.971688f, -0.7098077f, 0.3169872f, 147.05f, -55.66987f });
 849                         CheckMatrixForScalableAngle (new RectangleF (30, 60, 90, 150), 95, new float[] { -0.09442029f, 1.798713f, -0.6475369f, -0.09442022f, 169.499f, 12.84323f });
 850                         CheckMatrixForScalableAngle (new RectangleF (30, 60, 90, 150), 150, new float[] { -1.183013f, 1.138354f, -0.4098077f, -1.183013f, 219.05f, 209.3301f });
 851                         CheckMatrixForScalableAngle (new RectangleF (30, 60, 90, 150), 215, new float[] { -1.140856f, -1.331394f, 0.4793016f, -1.140856f, 95.85849f, 388.8701f });
 852                         CheckMatrixForScalableAngle (new RectangleF (30, 60, 90, 150), 300, new float[] { 0.6830127f, -1.971688f, 0.7098075f, 0.6830125f, -72.04998f, 190.6699f });
 853                 }
 854
 855                 [Test]
 856                 public void LinearColors_Null ()
 857                 {
 858                         Assert.Throws<NullReferenceException> (() => default_brush.LinearColors = null);
 859                 }
 860
 861                 [Test]
 862                 public void InterpolationColors_Null ()
 863                 {
 864                         Assert.Throws<ArgumentException> (() => default_brush.InterpolationColors = null);
 865                 }
 866
 867                 [Test]
 868                 public void Blend_Null ()
 869                 {
 870                         Assert.Throws<NullReferenceException> (() => default_brush.Blend = null);
 871                 }
 872
 873                 [Test]
 874                 public void ZeroWidthRectangle ()
 875                 {
 876                         Rectangle r = new Rectangle (10, 10, 0, 10);
 877                         Assert.AreEqual (0, r.Width, "Width");
 878                         Assert.Throws<ArgumentException> (() => new LinearGradientBrush (r, Color.Red, Color.Blue, LinearGradientMode.Vertical));
 879                 }
 880
 881                 [Test]
 882                 public void ZeroHeightRectangleF ()
 883                 {
 884                         RectangleF r = new RectangleF (10.0f, 10.0f, 10.0f, 0.0f);
 885                         Assert.AreEqual (0.0f, r.Height, "Height");
 886                         Assert.Throws<ArgumentException> (() => new LinearGradientBrush (r, Color.Red, Color.Blue, LinearGradientMode.Vertical));
 887                 }
 888         }
 889 }