mcs/class/System.Drawing/System.Drawing/ColorConverter.cs

   1 //
   2 // System.Drawing.ColorConverter
   3 //
   4 // Authors:
   5 //      Gonzalo Paniagua Javier (gonzalo@ximian.com)
   6 //      Ravindra (rkumar@novell.com)
   7 //
   8 // Copyright (C) 2002 Ximian, Inc.  http://www.ximian.com
   9 // Copyright (C) 2004,2006 Novell, Inc (http://www.novell.com)
  10 //
  11 // Permission is hereby granted, free of charge, to any person obtaining
  12 // a copy of this software and associated documentation files (the
  13 // "Software"), to deal in the Software without restriction, including
  14 // without limitation the rights to use, copy, modify, merge, publish,
  15 // distribute, sublicense, and/or sell copies of the Software, and to
  16 // permit persons to whom the Software is furnished to do so, subject to
  17 // the following conditions:
  18 //
  19 // The above copyright notice and this permission notice shall be
  20 // included in all copies or substantial portions of the Software.
  21 //
  22 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  23 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  24 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  25 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  26 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  27 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  28 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  29 //
  30
  31 using System.Collections;
  32 using System.ComponentModel;
  33 using System.Globalization;
  34 using System.Text;
  35 using System.ComponentModel.Design.Serialization;
  36 using System.Reflection;
  37
  38 namespace System.Drawing
  39 {
  40         public class ColorConverter : TypeConverter
  41         {
  42                 static StandardValuesCollection cached;
  43                 static object creatingCached = new object ();
  44
  45                 public ColorConverter () { }
  46
  47                 public override bool CanConvertFrom (ITypeDescriptorContext context, Type sourceType)
  48                 {
  49                         if (sourceType == typeof (string))
  50                                 return true;
  51
  52                         return base.CanConvertFrom (context, sourceType);
  53                 }
  54
  55                 public override bool CanConvertTo (ITypeDescriptorContext context, Type destinationType)
  56                 {
  57                         if (destinationType == typeof (InstanceDescriptor))
  58                                 return true;
  59
  60                         return base.CanConvertTo (context, destinationType);
  61                 }
  62
  63                 public override object ConvertFrom (ITypeDescriptorContext context,
  64                                                     CultureInfo culture,
  65                                                     object value)
  66                 {
  67                         string s = value as string;
  68                         if (s == null)
  69                                 return base.ConvertFrom (context, culture, value);
  70
  71                         s = s.Trim ();
  72
  73                         if (s.Length == 0) {
  74                                 return Color.Empty;
  75                         }
  76
  77                         object named = Color.NamedColors [s];
  78                         if (named != null)
  79                                 return (Color) named;
  80
  81                         named = Color.SystemColors [s];
  82                         if (named != null)
  83                                 return (Color) named;
  84
  85                         String numSeparator = culture.TextInfo.ListSeparator;
  86
  87                         Int32Converter converter = new Int32Converter ();
  88
  89                         object result = null;
  90
  91                         if (s.IndexOf (numSeparator) == -1) {
  92                                 if ((s.Length == 8 && (s.StartsWith ("0x") || s.StartsWith ("0X")))
  93                                         || (s.Length == 7 && s.StartsWith ("#"))) {
  94                                         result = Color.FromArgb (-16777216 | (int) converter.
  95                                                 ConvertFromString (context, culture, s));
  96                                 }
  97                                 else if ((s.Length == 5 && (s.StartsWith ("0x") || s.StartsWith ("0X")))
  98                                         || (s.Length == 4 && s.StartsWith ("#"))) {
  99                                         int i = (int) converter.ConvertFromString (context, culture, s);
 100                                         i = ((i & 0xf00) << 12) | ((i & 0xf00) << 8) |
 101                                                 ((i & 0xf0) << 8) | ((i & 0xf0) << 4) |
 102                                                 ((i & 0xf) << 4) | (i & 0xf);
 103                                         result = Color.FromArgb ( -16777216 | i );
 104                                 } else if (s.StartsWith ("#") && (s.Length > 9) && !s.StartsWith ("#0x")) {
 105                                         throw new Exception (Locale.GetText ("{0} isn't a valid color (integer too large).", s));
 106                                 }
 107                         }
 108
 109                         if (result == null) {
 110                                 String [] components = s.Split (numSeparator.ToCharArray ());
 111
 112                                 // MS seems to convert the indivual component to int before
 113                                 // checking the number of components
 114                                 int[] numComponents = new int[components.Length];
 115                                 for (int i = 0; i < numComponents.Length; i++) {
 116                                         numComponents[i] = (int) converter.ConvertFrom (context,
 117                                                 culture, components[i]);
 118                                 }
 119
 120                                 switch (components.Length) {
 121                                         case 1:
 122                                                 result = Color.FromArgb (numComponents[0]);
 123                                                 break;
 124                                         case 3:
 125                                                 result = Color.FromArgb (numComponents[0], numComponents[1],
 126                                                         numComponents[2]);
 127                                                 break;
 128                                         case 4:
 129                                                 result = Color.FromArgb (numComponents[0], numComponents[1],
 130                                                         numComponents[2], numComponents[3]);
 131                                                 break;
 132                                         default:
 133                                                 throw new ArgumentException (s + " is not a valid color value.");
 134                                 }
 135                         }
 136
 137                         if (result != null) {
 138                                 Color resultColor = (Color) result;
 139
 140                                 // Look for a named or system color with those values
 141                                 foreach (Color c in Color.NamedColors.Values) {
 142                                         if (c == resultColor)
 143                                                 return c;
 144                                 }
 145
 146                                 foreach (Color c in Color.SystemColors.Values) {
 147                                         if (c == resultColor)
 148                                                 return c;
 149                                 }
 150                         }
 151
 152                         return result;
 153                 }
 154
 155                 public override object ConvertTo (ITypeDescriptorContext context,
 156                                                   CultureInfo culture,
 157                                                   object value,
 158                                                   Type destinationType)
 159                 {
 160                         if ((destinationType == typeof (string)) && (value is Color)) {
 161                                 Color color = (Color) value;
 162
 163                                 if (color == Color.Empty) {
 164                                         return string.Empty;
 165                                 }
 166
 167                                 if (color.IsKnownColor) {
 168                                         return color.Name;
 169                                 }
 170
 171                                 if (color.IsNamedColor)
 172                                         return color.Name;
 173
 174                                 String numSeparator = culture.TextInfo.ListSeparator;
 175
 176                                 StringBuilder sb = new StringBuilder ();
 177                                 if (color.A != 255) {
 178                                         sb.Append (color.A);
 179                                         sb.Append (numSeparator);
 180                                         sb.Append (" ");
 181                                 }
 182                                 sb.Append (color.R);
 183                                 sb.Append (numSeparator);
 184                                 sb.Append (" ");
 185
 186                                 sb.Append (color.G);
 187                                 sb.Append (numSeparator);
 188                                 sb.Append (" ");
 189
 190                                 sb.Append (color.B);
 191                                 return sb.ToString ();
 192                         }
 193
 194                         if (destinationType == typeof (InstanceDescriptor) && value is Color) {
 195                                 Color c = (Color)value;
 196                                 if (c.IsKnownColor){
 197                                         return new InstanceDescriptor (typeof (SystemColors).GetProperty (c.Name), null);
 198                                 } else {
 199                                         MethodInfo met = typeof(Color).GetMethod ("FromArgb", new Type[] { typeof(int), typeof(int), typeof(int), typeof(int) } );
 200                                         return new InstanceDescriptor (met, new object[] {c.A, c.R, c.G, c.B });
 201                                 }
 202                         }
 203
 204                         return base.ConvertTo (context, culture, value, destinationType);
 205                 }
 206
 207                 public override StandardValuesCollection GetStandardValues (ITypeDescriptorContext context)
 208                 {
 209                         lock (creatingCached) {
 210                                 if (cached != null)
 211                                         return cached;
 212
 213                                 ICollection named = (ICollection) Color.NamedColors.Values;
 214                                 ICollection system = (ICollection) Color.SystemColors.Values;
 215                                 Array colors = Array.CreateInstance (typeof (Color), named.Count + system.Count);
 216                                 named.CopyTo (colors, 0);
 217                                 system.CopyTo (colors, named.Count);
 218                                 Array.Sort (colors, 0, colors.Length, new CompareColors ());
 219                                 cached = new StandardValuesCollection (colors);
 220                         }
 221
 222                         return cached;
 223                 }
 224
 225                 public override bool GetStandardValuesSupported (ITypeDescriptorContext context)
 226                 {
 227                         return true;
 228                 }
 229
 230                 class CompareColors : IComparer
 231                 {
 232                         public int Compare (object x, object y)
 233                         {
 234                                 return String.Compare (((Color) x).Name, ((Color) y).Name);
 235                         }
 236                 }
 237         }
 238 }