Added HSL support

Source/Painting/SvgColourConverter.cs

@@ -32,9 +32,9 @@ namespace Svg
 
             if (colour != null)
             {
-            	var oldCulture = Thread.CurrentThread.CurrentCulture;
-            	Thread.CurrentThread.CurrentCulture = System.Globalization.CultureInfo.InvariantCulture;
-            	
+                var oldCulture = Thread.CurrentThread.CurrentCulture;
+                Thread.CurrentThread.CurrentCulture = System.Globalization.CultureInfo.InvariantCulture;
+                
                 colour = colour.Trim();
 
                 if (colour.StartsWith("rgb"))
@@ -43,32 +43,32 @@ namespace Svg
                     {
                         int start = colour.IndexOf("(") + 1;
                         
-						//get the values from the RGB string
-						string[] values = colour.Substring(start, colour.IndexOf(")") - start).Split(new char[]{',', ' '}, StringSplitOptions.RemoveEmptyEntries);
-
-						//determine the alpha value if this is an RGBA (it will be the 4th value if there is one)
-						int alphaValue = 255;
-						if (values.Length > 3)
-						{
-							//the alpha portion of the rgba is not an int 0-255 it is a decimal between 0 and 1
-							//so we have to determine the corosponding byte value
-							var alphastring = values[3];
-							if(alphastring.StartsWith("."))
-							{
-								alphastring = "0" + alphastring;
-							}
-
-							var alphaDecimal = decimal.Parse(alphastring);
-
-							if(alphaDecimal <= 1)
-							{
-								alphaValue = (int)(alphaDecimal * 255);
-							}
-							else
-							{
-								alphaValue = (int)alphaDecimal;
-							}
-						}
+                        //get the values from the RGB string
+                        string[] values = colour.Substring(start, colour.IndexOf(")") - start).Split(new char[]{',', ' '}, StringSplitOptions.RemoveEmptyEntries);
+
+                        //determine the alpha value if this is an RGBA (it will be the 4th value if there is one)
+                        int alphaValue = 255;
+                        if (values.Length > 3)
+                        {
+                            //the alpha portion of the rgba is not an int 0-255 it is a decimal between 0 and 1
+                            //so we have to determine the corosponding byte value
+                            var alphastring = values[3];
+                            if(alphastring.StartsWith("."))
+                            {
+                                alphastring = "0" + alphastring;
+                            }
+
+                            var alphaDecimal = decimal.Parse(alphastring);
+
+                            if(alphaDecimal <= 1)
+                            {
+                                alphaValue = (int)(alphaDecimal * 255);
+                            }
+                            else
+                            {
+                                alphaValue = (int)alphaDecimal;
+                            }
+                        }
 
                         Color colorpart;
                         if (values[0].Trim().EndsWith("%"))
@@ -82,7 +82,36 @@ namespace Svg
                             colorpart = System.Drawing.Color.FromArgb(alphaValue, int.Parse(values[0]), int.Parse(values[1]), int.Parse(values[2]));
                         }
 
-						return colorpart;
+                        return colorpart;
+                    }
+                    catch
+                    {
+                        throw new SvgException("Colour is in an invalid format: '" + colour + "'");
+                    }
+                }
+                // HSL support
+                else if ( colour.StartsWith( "hsl" ) ) {
+                    try
+                    {
+                        int start = colour.IndexOf("(") + 1;
+                        
+                        //get the values from the RGB string
+                        string[] values = colour.Substring(start, colour.IndexOf(")") - start).Split(new char[]{',', ' '}, StringSplitOptions.RemoveEmptyEntries);
+                        if ( values[1].EndsWith( "%" ) )
+                        {
+                            values[1] = values[1].TrimEnd( '%' );
+                        }
+                        if ( values[2].EndsWith( "%" ) ) 
+                        {
+                            values[2] = values[2].TrimEnd( '%' );
+                        }
+                        // Get the HSL values in a range from 0 to 1.
+                        double h = double.Parse( values[0] ) / 360.0;
+                        double s = double.Parse( values[1] ) / 100.0;
+                        double l = double.Parse( values[2] ) / 100.0;
+                        // Convert the HSL color to an RGB color
+                        Color colorpart = Hsl2Rgb( h, s, l );
+                        return colorpart;                    
                     }
                     catch
                     {
@@ -126,7 +155,7 @@ namespace Svg
                     case "windowtext": return SystemColors.WindowText;
                 }
 
-            	Thread.CurrentThread.CurrentCulture = oldCulture;
+                Thread.CurrentThread.CurrentCulture = oldCulture;
             }
 
             return base.ConvertFrom(context, culture, value);
@@ -162,5 +191,72 @@ namespace Svg
 
             return base.ConvertTo(context, culture, value, destinationType);
         }
+
+        /// <summary>
+        /// Converts HSL color (with HSL specified from 0 to 1) to RGB color.
+        /// Taken from http://www.geekymonkey.com/Programming/CSharp/RGB2HSL_HSL2RGB.htm
+        /// </summary>
+        /// <param name="h"></param>
+        /// <param name="sl"></param>
+        /// <param name="l"></param>
+        /// <returns></returns>
+        private static Color Hsl2Rgb( double h, double sl, double l ) {
+            double r = l;   // default to gray
+            double g = l;
+            double b = l;
+            double v = (l <= 0.5) ? (l * (1.0 + sl)) : (l + sl - l * sl);
+            if (v > 0)
+            {
+                  double m;
+                  double sv;
+                  int sextant;
+                  double fract, vsf, mid1, mid2;
+ 
+                  m = l + l - v;
+                  sv = (v - m ) / v;
+                  h *= 6.0;
+                  sextant = (int)h;
+                  fract = h - sextant;
+                  vsf = v * sv * fract;
+                  mid1 = m + vsf;
+                  mid2 = v - vsf;
+                  switch (sextant)
+                  {
+                        case 0:
+                              r = v;
+                              g = mid1;
+                              b = m;
+                              break;
+                        case 1:
+                              r = mid2;
+                              g = v;
+                              b = m;
+                              break;
+                        case 2:
+                              r = m;
+                              g = v;
+                              b = mid1;
+                              break;
+                        case 3:
+                              r = m;
+                              g = mid2;
+                              b = v;
+                              break;
+                        case 4:
+                              r = mid1;
+                              g = m;
+                              b = v;
+                              break;
+                        case 5:
+                              r = v;
+                              g = m;
+                              b = mid2;
+                              break;
+                  }
+            }
+            Color rgb = Color.FromArgb( (int)( r * 255.0 ), (int)( g * 255.0 ), (int)( b * 255.0f ) );
+            return rgb;        
+        }
+
     }
 }
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