private static bool CanUseColormap(IMagickImage <QuantumType> image, bool lossless)
{
if (image.ClassType == ClassType.Pseudo)
{
return(true);
}
var histogram = image.Histogram();
if (histogram.Count > 256)
{
return(false);
}
if (!image.HasAlpha)
{
return(true);
}
var max = Quantum.Max;
var min = (QuantumType)(Quantum.Max * 0.125);
if (lossless)
{
min = 0;
}
else
{
max -= min;
}
bool fixAlpha = false;
foreach (var color in histogram.Keys)
{
if (color.A != 0 && color.A != Quantum.Max)
{
fixAlpha = true;
if (color.A > min && color.A < max)
{
return(false);
}
}
}
if (fixAlpha)
{
FixAlpha(image, min, max);
}
return(true);
}
private static (string paletteString, Dictionary <string, int> paletteIndex) GeneratePaletteInfo(
IMagickImage image)
{
var matchedColors = image.Histogram();
var paletteString = string.Empty;
var paletteIndex = new Dictionary <string, int>();
var position = 0;
foreach (var matchedColor in matchedColors)
{
var inGameValue = ColorStrings.Dictionary[matchedColor.Key.ToString()];
paletteString += inGameValue;
paletteIndex[matchedColor.Key.ToString()] = position;
position++;
}
paletteString = paletteString.PadRight(30, '0');
return(paletteString, paletteIndex);
}