SVG/Source/Painting/SvgColourConverter.cs

301 строка
14 KiB
C#

using System;
using System.Drawing;
using System.Globalization;
using System.Text;
namespace Svg
{
/// <summary>
/// Converts string representations of colours into <see cref="Color"/> objects.
/// </summary>
public class SvgColourConverter : ColorConverter
{
/// <summary>
/// Converts the given object to the converter's native type.
/// </summary>
/// <param name="context">A <see cref="T:System.ComponentModel.TypeDescriptor"/> that provides a format context. You can use this object to get additional information about the environment from which this converter is being invoked.</param>
/// <param name="culture">A <see cref="T:System.Globalization.CultureInfo"/> that specifies the culture to represent the color.</param>
/// <param name="value">The object to convert.</param>
/// <returns>
/// An <see cref="T:System.Object"/> representing the converted value.
/// </returns>
/// <exception cref="T:System.ArgumentException">The conversion cannot be performed.</exception>
/// <PermissionSet>
/// <IPermission class="System.Security.Permissions.FileIOPermission, mscorlib, Version=2.0.3600.0, Culture=neutral, PublicKeyToken=b77a5c561934e089" version="1" Unrestricted="true"/>
/// </PermissionSet>
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", StringComparison.InvariantCulture))
{
try
{
int start = colour.IndexOf("(", StringComparison.InvariantCulture) + 1;
//get the values from the RGB string
string[] values = colour.Substring(start, colour.IndexOf(")", StringComparison.InvariantCulture) - 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(".", StringComparison.InvariantCulture))
{
alphastring = "0" + alphastring;
}
var alphaDecimal = decimal.Parse(alphastring, CultureInfo.InvariantCulture);
if (alphaDecimal <= 1)
{
alphaValue = (int)Math.Round(alphaDecimal * 255);
}
else
{
alphaValue = (int)Math.Round(alphaDecimal);
}
}
Color colorpart;
if (values[0].Trim().EndsWith("%", StringComparison.InvariantCulture))
{
colorpart = Color.FromArgb(alphaValue,
(int)Math.Round(255 * float.Parse(values[0].Trim().TrimEnd('%'), NumberStyles.Any, CultureInfo.InvariantCulture) / 100f),
(int)Math.Round(255 * float.Parse(values[1].Trim().TrimEnd('%'), NumberStyles.Any, CultureInfo.InvariantCulture) / 100f),
(int)Math.Round(255 * float.Parse(values[2].Trim().TrimEnd('%'), NumberStyles.Any, CultureInfo.InvariantCulture) / 100f));
}
else
{
colorpart = Color.FromArgb(alphaValue, int.Parse(values[0], CultureInfo.InvariantCulture), int.Parse(values[1], CultureInfo.InvariantCulture), int.Parse(values[2], CultureInfo.InvariantCulture));
}
return colorpart;
}
catch
{
throw new SvgException("Colour is in an invalid format: '" + colour + "'");
}
}
// HSL support
else if (colour.StartsWith("hsl",StringComparison.InvariantCulture))
{
try
{
int start = colour.IndexOf("(", StringComparison.InvariantCulture) + 1;
//get the values from the RGB string
string[] values = colour.Substring(start, colour.IndexOf(")", StringComparison.InvariantCulture) - start).Split(new char[] { ',', ' ' }, StringSplitOptions.RemoveEmptyEntries);
if (values[1].EndsWith("%", StringComparison.InvariantCulture))
{
values[1] = values[1].TrimEnd('%');
}
if (values[2].EndsWith("%", StringComparison.InvariantCulture))
{
values[2] = values[2].TrimEnd('%');
}
// Get the HSL values in a range from 0 to 1.
double h = double.Parse(values[0], CultureInfo.InvariantCulture) / 360.0;
double s = double.Parse(values[1], CultureInfo.InvariantCulture) / 100.0;
double l = double.Parse(values[2], CultureInfo.InvariantCulture) / 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("#", StringComparison.InvariantCulture))
{
if (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);
}
else if (colour.Length != 7)
return SvgPaintServer.NotSet;
}
#if !NO_SDC
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;
}
#endif
int number;
if (Int32.TryParse(colour,NumberStyles.Integer, CultureInfo.InvariantCulture, out number))
{
// numbers are handled as colors by System.Drawing.ColorConverter - we
// have to prevent this and ignore the color instead (see #342)
return SvgPaintServer.NotSet;
}
var index = colour.LastIndexOf("grey", StringComparison.InvariantCultureIgnoreCase);
if (index >= 0 && index + 4 == colour.Length)
value = new StringBuilder(colour).Replace("grey", "gray", index, 4).Replace("Grey", "Gray", index, 4).ToString();
}
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, CultureInfo culture, object value, Type destinationType)
{
if (destinationType == typeof(string))
{
#if !NO_SDC
var colorString = ColorTranslator.ToHtml((Color)value).Replace("LightGrey", "LightGray");
// color names are expected to be lower case in XML
return colorString.StartsWith("#", StringComparison.InvariantCulture) ? colorString : colorString.ToLowerInvariant();
#endif
}
return ToHtml((Color)value);
}
/// <summary>
/// Converts color to html string format.
/// Refer to https://source.dot.net/#System.Drawing.Primitives/System/Drawing/ColorTranslator.cs
/// </summary>
/// <param name="c"></param>
/// <returns></returns>
private static string ToHtml(Color c)
{
var colorString = string.Empty;
if (c.IsEmpty)
return colorString;
if (c.IsNamedColor)
{
colorString = c == Color.LightGray ? "LightGrey" : c.Name;
colorString = colorString.ToLowerInvariant();
}
else
colorString = $"#{c.R:X2}{c.G:X2}{c.B:X2}";
return colorString;
}
/// <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)Math.Round(r * 255.0), (int)Math.Round(g * 255.0), (int)Math.Round(b * 255.0));
return rgb;
}
}
}