using System;
using System.Collections.Generic;
using System.Drawing;
using System.Globalization;
using System.Linq;
using System.Text;
using System.Threading;
namespace Svg
{
///
/// Converts string representations of colours into objects.
///
public class SvgColourConverter : System.Drawing.ColorConverter
{
///
/// Converts the given object to the converter's native type.
///
/// A that provides a format context. You can use this object to get additional information about the environment from which this converter is being invoked.
/// A that specifies the culture to represent the color.
/// The object to convert.
///
/// An representing the converted value.
///
/// The conversion cannot be performed.
///
///
///
public override object ConvertFrom(System.ComponentModel.ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value)
{
string colour = value as string;
if (colour != null)
{
var oldCulture = Thread.CurrentThread.CurrentCulture;
try {
Thread.CurrentThread.CurrentCulture = System.Globalization.CultureInfo.InvariantCulture;
colour = colour.Trim();
if (colour.StartsWith("rgb"))
{
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);
//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("%"))
{
colorpart = System.Drawing.Color.FromArgb(alphaValue, (int)(255 * float.Parse(values[0].Trim().TrimEnd('%')) / 100f),
(int)(255 * float.Parse(values[1].Trim().TrimEnd('%')) / 100f),
(int)(255 * float.Parse(values[2].Trim().TrimEnd('%')) / 100f));
}
else
{
colorpart = System.Drawing.Color.FromArgb(alphaValue, int.Parse(values[0]), int.Parse(values[1]), int.Parse(values[2]));
}
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
{
throw new SvgException("Colour is in an invalid format: '" + colour + "'");
}
}
else if (colour.StartsWith("#") && colour.Length == 4)
{
colour = string.Format(culture, "#{0}{0}{1}{1}{2}{2}", colour[1], colour[2], colour[3]);
return base.ConvertFrom(context, culture, colour);
}
switch (colour.ToLowerInvariant())
{
case "activeborder": return SystemColors.ActiveBorder;
case "activecaption": return SystemColors.ActiveCaption;
case "appworkspace": return SystemColors.AppWorkspace;
case "background": return SystemColors.Desktop;
case "buttonface": return SystemColors.Control;
case "buttonhighlight": return SystemColors.ControlLightLight;
case "buttonshadow": return SystemColors.ControlDark;
case "buttontext": return SystemColors.ControlText;
case "captiontext": return SystemColors.ActiveCaptionText;
case "graytext": return SystemColors.GrayText;
case "highlight": return SystemColors.Highlight;
case "highlighttext": return SystemColors.HighlightText;
case "inactiveborder": return SystemColors.InactiveBorder;
case "inactivecaption": return SystemColors.InactiveCaption;
case "inactivecaptiontext": return SystemColors.InactiveCaptionText;
case "infobackground": return SystemColors.Info;
case "infotext": return SystemColors.InfoText;
case "menu": return SystemColors.Menu;
case "menutext": return SystemColors.MenuText;
case "scrollbar": return SystemColors.ScrollBar;
case "threeddarkshadow": return SystemColors.ControlDarkDark;
case "threedface": return SystemColors.Control;
case "threedhighlight": return SystemColors.ControlLight;
case "threedlightshadow": return SystemColors.ControlLightLight;
case "window": return SystemColors.Window;
case "windowframe": return SystemColors.WindowFrame;
case "windowtext": return SystemColors.WindowText;
}
}
finally
{
// Make sure to set back the old culture even an error occurred.
Thread.CurrentThread.CurrentCulture = oldCulture;
}
}
return base.ConvertFrom(context, culture, value);
}
public override bool CanConvertFrom(System.ComponentModel.ITypeDescriptorContext context, Type sourceType)
{
if (sourceType == typeof(string))
{
return true;
}
return base.CanConvertFrom(context, sourceType);
}
public override bool CanConvertTo(System.ComponentModel.ITypeDescriptorContext context, Type destinationType)
{
if (destinationType == typeof(string))
{
return true;
}
return base.CanConvertTo(context, destinationType);
}
public override object ConvertTo(System.ComponentModel.ITypeDescriptorContext context, System.Globalization.CultureInfo culture, object value, Type destinationType)
{
if (destinationType == typeof(string))
{
var colour = (Color)value;
return "#" + colour.R.ToString("X2", null) + colour.G.ToString("X2", null) + colour.B.ToString("X2", null);
}
return base.ConvertTo(context, culture, value, destinationType);
}
///
/// Converts HSL color (with HSL specified from 0 to 1) to RGB color.
/// Taken from http://www.geekymonkey.com/Programming/CSharp/RGB2HSL_HSL2RGB.htm
///
///
///
///
///
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;
}
}
}