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 Novell, Inc.  http://www.novell.com
  10 //
  11
  12 //
  13 // Copyright (C) 2004 Novell, Inc (http://www.novell.com)
  14 //
  15 // Permission is hereby granted, free of charge, to any person obtaining
  16 // a copy of this software and associated documentation files (the
  17 // "Software"), to deal in the Software without restriction, including
  18 // without limitation the rights to use, copy, modify, merge, publish,
  19 // distribute, sublicense, and/or sell copies of the Software, and to
  20 // permit persons to whom the Software is furnished to do so, subject to
  21 // the following conditions:
  22 //
  23 // The above copyright notice and this permission notice shall be
  24 // included in all copies or substantial portions of the Software.
  25 //
  26 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  27 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  28 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  29 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  30 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  31 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  32 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  33 //
  34
  35 using System;
  36 using System.Collections;
  37 using System.ComponentModel;
  38 using System.Globalization;
  39 using System.Text;
  40
  41 namespace System.Drawing
  42 {
  43         public class ColorConverter : TypeConverter
  44         {
  45                 static StandardValuesCollection cached;
  46                 static object creatingCached = new object ();
  47
  48                 public ColorConverter () { }
  49
  50                 public override bool CanConvertFrom (ITypeDescriptorContext context, Type sourceType)
  51                 {
  52                         if (sourceType == typeof (string))
  53                                 return true;
  54
  55                         return base.CanConvertFrom (context, sourceType);
  56                 }
  57
  58                 public override bool CanConvertTo (ITypeDescriptorContext context, Type destinationType)
  59                 {
  60                         if (destinationType == typeof (String))
  61                                 return true;
  62
  63                         return base.CanConvertTo (context, destinationType);
  64                 }
  65
  66                 public override object ConvertFrom (ITypeDescriptorContext context,
  67                                                     CultureInfo culture,
  68                                                     object value)
  69                 {
  70                         string s = value as string;
  71                         if (s == null)
  72                                 return base.ConvertFrom (context, culture, value);
  73
  74                         object named = Color.NamedColors [s];
  75                         if (named != null)
  76                                 return (Color) named;
  77
  78                         named = Color.SystemColors [s];
  79                         if (named != null)
  80                                 return (Color) named;
  81
  82                         String numSeparator = culture.NumberFormat.NumberGroupSeparator;
  83
  84                         int A, R, G, B;
  85                         if (s.IndexOf (numSeparator) > 0) { // "A, R, G, B" format
  86                                 String [] components = s.Split (numSeparator.ToCharArray ());
  87                                 if (components.Length == 3) {
  88                                         A = 255;
  89                                         R = GetNumber (components [0].Trim ());
  90                                         G = GetNumber (components [1].Trim ());
  91                                         B = GetNumber (components [2].Trim ());
  92                                 }
  93                                 else if (components.Length == 4) {
  94                                         A = GetNumber (components [0].Trim ());
  95                                         R = GetNumber (components [1].Trim ());
  96                                         G = GetNumber (components [2].Trim ());
  97                                         B = GetNumber (components [3].Trim ());
  98                                 }
  99                                 else
 100                                         throw new ArgumentException (s + " is not a valid color value.");
 101                         }
 102                         else { // #RRGGBB format
 103                                 int i = GetNumber (s.Trim ());
 104                                 A = (int) (i >> 24) & 0xFF;
 105                                 if (A == 0)
 106                                         A = 255;
 107                                 R = (i >> 16) & 0xFF;
 108                                 G = (i >> 8) & 0xFF;
 109                                 B = i & 0xFF;
 110                         }
 111
 112                         Color result = Color.FromArgb (A, R, G, B);
 113                         // Look for a named or system color with those values
 114                         foreach (Color c in Color.NamedColors.Values) {
 115                                 if (c == result)
 116                                         return c;
 117                         }
 118
 119                         foreach (Color c in Color.SystemColors.Values) {
 120                                 if (c == result)
 121                                         return c;
 122                         }
 123
 124                         return result;
 125                 }
 126
 127                 public override object ConvertTo (ITypeDescriptorContext context,
 128                                                   CultureInfo culture,
 129                                                   object value,
 130                                                   Type destinationType)
 131                 {
 132                         if ((destinationType == typeof (string)) && (value is Color)) {
 133                                 Color color = (Color) value;
 134                                 StringBuilder sb = new StringBuilder ();
 135                                 sb.Append (color.A); sb.Append (", ");
 136                                 sb.Append (color.R); sb.Append (", ");
 137                                 sb.Append (color.G); sb.Append (", ");
 138                                 sb.Append (color.B);
 139                                 return sb.ToString ();
 140                         }
 141
 142                         return base.ConvertTo (context, culture, value, destinationType);
 143                 }
 144
 145                 public override StandardValuesCollection GetStandardValues (ITypeDescriptorContext context)
 146                 {
 147                         if (cached != null)
 148                                 return cached;
 149
 150                         lock (creatingCached)
 151                         {
 152                                 if (cached != null)
 153                                         return cached;
 154
 155                                 ICollection named = (ICollection) Color.NamedColors.Values;
 156                                 ICollection system = (ICollection) Color.SystemColors.Values;
 157                                 Array colors = Array.CreateInstance (typeof (Color), named.Count + system.Count);
 158                                 named.CopyTo (colors, 0);
 159                                 system.CopyTo (colors, named.Count);
 160                                 Array.Sort (colors, 0, colors.Length, new CompareColors ());
 161                                 cached = new StandardValuesCollection (colors);
 162                         }
 163
 164                         return cached;
 165                 }
 166
 167                 public override bool GetStandardValuesSupported (ITypeDescriptorContext context)
 168                 {
 169                         return true;
 170                 }
 171
 172                 private int GetNumber (String str)
 173                 {
 174                         int number;
 175
 176                         if (str.StartsWith ("#0x") || str.StartsWith ("#0X"))
 177                                 // #0xRRGGBB format. Parse hex string.
 178                                 number = Int32.Parse (str.Substring (3), NumberStyles.HexNumber);
 179
 180                         else if (str [0] == '#')
 181                                 // #RRGGBB format. Parse hex string.
 182                                 number = Int32.Parse (str.Substring (1), NumberStyles.HexNumber);
 183
 184                         else if (str.StartsWith ("0x") || str.StartsWith ("0X"))
 185                                 // 0xRRGGBB format. Parse hex string.
 186                                 number = Int32.Parse (str.Substring (2), NumberStyles.HexNumber);
 187
 188                         else    // if (str [0] == '-' || str [0] == '+' || Char.IsDigit (str [0]))
 189                                 // [+/-]RRGGBB format. Parse decimal string.
 190                                 number = Int32.Parse (str, NumberStyles.Integer);
 191
 192                         return number;
 193                 }
 194
 195                 class CompareColors : IComparer
 196                 {
 197                         public int Compare (object x, object y)
 198                         {
 199                                 return String.Compare (((Color) x).Name, ((Color) y).Name);
 200                         }
 201                 }
 202         }
 203 }