using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Drawing;
using System.Globalization;
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)
{
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
alphaValue = (int)(decimal.Parse(values[3]) * 255);
}
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 + "'");
}
}
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);
}
}
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 ColorTranslator.ToHtml(colour);
}
return base.ConvertTo(context, culture, value, destinationType);
}
}
}