/// <summary>
/// Converts a color from HSL to RGB. </summary>
/// <remarks>Adapted from the algorithm in Foley and Van-Dam.</remarks>
/// <param name="colorToConvert">The HSL value.</param>
/// <returns>A Color structure containing the equivalent RGB values.</returns>
public static GUIColor HSLToRGB(HSL colorToConvert)
{
#if DEBUG
if (colorToConvert == null)
{
throw new ArgumentNullException("colorToConvert");
}
#endif
// ReSharper disable JoinDeclarationAndInitializer
int max, mid, min;
double q;
// ReSharper restore JoinDeclarationAndInitializer
max = Round(colorToConvert.L * 255);
min = Round((1.0 - colorToConvert.S) * (colorToConvert.L / 1.0) * 255);
q = (double)(max - min) / 255;
if (colorToConvert.H >= 0 && colorToConvert.H <= (double)1 / 6)
{
mid = Round((((colorToConvert.H - 0) * q) * 1530) + min);
return(GUIColor.FromARGB(max, mid, min));
}
if (colorToConvert.H <= (double)1 / 3)
{
mid = Round((-((colorToConvert.H - ((double)1 / 6)) * q) * 1530) + max);
return(GUIColor.FromARGB(mid, max, min));
}
if (colorToConvert.H <= 0.5)
{
mid = Round((((colorToConvert.H - ((double)1 / 3)) * q) * 1530) + min);
return(GUIColor.FromARGB(min, max, mid));
}
if (colorToConvert.H <= (double)2 / 3)
{
mid = Round((-((colorToConvert.H - 0.5) * q) * 1530) + max);
return(GUIColor.FromARGB(min, mid, max));
}
if (colorToConvert.H <= (double)5 / 6)
{
mid = Round((((colorToConvert.H - ((double)2 / 3)) * q) * 1530) + min);
return(GUIColor.FromARGB(mid, min, max));
}
if (colorToConvert.H <= 1.0)
{
mid = Round((-((colorToConvert.H - ((double)5 / 6)) * q) * 1530) + max);
return(GUIColor.FromARGB(max, min, mid));
}
return(GUIColor.FromARGB(0, 0, 0));
}
/// <summary>Converts CMYK to RGB.</summary>
/// <param name="colorToConvert">A color to convert.</param>
/// <returns>A Color object.</returns>
public static GUIColor CMYKToRGB(CMYK colorToConvert)
{
#if DEBUG
if (colorToConvert == null)
{
throw new ArgumentNullException("colorToConvert");
}
#endif
int red, green, blue;
red = Round(255 - (255 * colorToConvert.Cyan));
green = Round(255 - (255 * colorToConvert.Magenta));
blue = Round(255 - (255 * colorToConvert.Yellow));
return(GUIColor.FromARGB(red, green, blue));
}
/// <summary>
/// Contrasts the color.
/// </summary>
/// <param name="color">The color.</param>
/// <returns>The contrasted color.</returns>
public static GUIColor ContrastColor(GUIColor color)
{
int d;
// Counting the perceptive luminance - human eye favors green color...
var ar = 0.299 * color.R;
var ag = 0.587 * color.G;
var ab = 0.114 * color.B;
var a = 1 - ((ar + ag + ab) / 255);
if (a < 0.5)
{
d = 0; // bright colors - black font
}
else
{
d = 255; // dark colors - white font
}
return(GUIColor.FromARGB(d, d, d));
}
