/// <summary>
/// Merge two color using the Alpha channel value as multiplier
/// </summary>
/// <param name="colorPrecision1">The first color to merge</param>
/// <param name="colorPrecision2">The second color to merge</param>
/// <returns>The merge color (averaging based on the alpha channel)</returns>
// @ review : assume not premultiply ?
// @ review : Use Extended or regular value ?
// @ review : if both color are opaque should be just add them (instead of averaging them) ?
// ...Might help some customer but would be inconstient (not done for now)
public static ColorDouble operator +(ColorDouble colorPrecision1, ColorDouble colorPrecision2)
{
ColorDouble retVal = new ColorDouble();
if (colorPrecision1.IsEmpty == false && colorPrecision2.IsEmpty == false)
{
double dividend = ColorDouble._maxChannelValue * 2 - ColorDouble._minChannelValue;
retVal.ExtendedAlpha = Math.Max(colorPrecision1.ExtendedAlpha, colorPrecision2.ExtendedAlpha);
retVal.ExtendedRed = (colorPrecision1.ExtendedRed * colorPrecision1.ExtendedAlpha + colorPrecision2.ExtendedRed * colorPrecision2.ExtendedAlpha) / dividend;
retVal.ExtendedGreen = (colorPrecision1.ExtendedGreen * colorPrecision1.ExtendedAlpha + colorPrecision2.ExtendedGreen * colorPrecision2.ExtendedAlpha) / dividend;
retVal.ExtendedBlue = (colorPrecision1.ExtendedBlue * colorPrecision1.ExtendedAlpha + colorPrecision2.ExtendedBlue * colorPrecision2.ExtendedAlpha) / dividend;
retVal._isDefined = true;
}
else
{
if (colorPrecision1.IsEmpty)
{
retVal = (ColorDouble)colorPrecision2.Clone();
}
else
{
retVal = (ColorDouble)colorPrecision1.Clone();
}
}
return(retVal);
}
/// <summary>
/// Negate a color without affecting the alpha channel.
/// </summary>
/// <param name="colorPrecision">The color to negate</param>
/// <returns>The negated color</returns>
// @ review : IGNORE alpha ? (we are right now)
// @review : Should we Use ExtendedAlpha here ? Does not make much sense for Negating a color
public static ColorDouble operator !(ColorDouble colorPrecision)
{
ColorDouble retVal = new ColorDouble();
if (colorPrecision.IsEmpty)
{
return(retVal);
}
retVal.ExtendedAlpha = colorPrecision.ExtendedAlpha;
retVal.ExtendedRed = ColorDouble._maxChannelValue - colorPrecision.ExtendedRed;
retVal.ExtendedGreen = ColorDouble._maxChannelValue - colorPrecision.ExtendedGreen;
retVal.ExtendedBlue = ColorDouble._maxChannelValue - colorPrecision.ExtendedBlue;
retVal._isDefined = true;
return(retVal);
}
/// <summary>
/// Un-Merge two color using the Alpha channel value as multiplier
/// </summary>
/// <param name="colorPrecision1">The resulting color</param>
/// <param name="colorPrecision2">The color to remove from the resulting image</param>
/// <returns>The merging color (color that would lead to color one perform "thisColor + color2")</returns>
// @ review : assume not premultiply ?
// @ review : Use Extended or regular value ?
// @ review : if both color are opaque should be just subtract them (instead of un-averaging them) ?
// ...Might help some customer but would be inconstient (not done for now)
public static ColorDouble operator -(ColorDouble colorPrecision1, ColorDouble colorPrecision2)
{
ColorDouble retVal = new ColorDouble();
if (colorPrecision1.IsEmpty == false || colorPrecision2.IsEmpty == false)
{
double dividend = ColorDouble._maxChannelValue;
retVal.ExtendedAlpha = Math.Max(colorPrecision1.ExtendedAlpha, colorPrecision2.ExtendedAlpha);
retVal.ExtendedRed = (colorPrecision1.ExtendedRed * colorPrecision1.ExtendedAlpha * 2 - colorPrecision2.ExtendedRed * colorPrecision2.ExtendedAlpha) / dividend;
retVal.ExtendedGreen = (colorPrecision1.ExtendedGreen * colorPrecision1.ExtendedAlpha * 2 - colorPrecision2.ExtendedGreen * colorPrecision2.ExtendedAlpha) / dividend;
retVal.ExtendedBlue = (colorPrecision1.ExtendedBlue * colorPrecision1.ExtendedAlpha * 2 - colorPrecision2.ExtendedBlue * colorPrecision2.ExtendedAlpha) / dividend;
retVal._isDefined = true;
}
return(retVal);
}
