public static Picture MakePalette(this IBitmap bitmap, int startIndex, int colourLength)
{
Dictionary <byte, int> colourCount = new Dictionary <byte, int>();
foreach (byte colourIndex in bitmap.Bitmap.ToByteArray())
{
if (bitmap.Palette[colourIndex].A == 0)
{
continue; // Do not count transparent
}
if (colourCount.ContainsKey(colourIndex))
{
colourCount[colourIndex]++;
continue;
}
colourCount.Add(colourIndex, 1);
}
Colour[] colours = colourCount.OrderByDescending(x => x.Value).Select(x => bitmap.Palette[x.Key]).Take(colourLength).ToArray();
Colour[] palette;
if (Settings.GraphicsMode == GraphicsMode.Graphics256)
{
palette = new Colour[256];
palette[0] = Colour.Transparent;
Array.Copy(colours, 0, palette, startIndex, Math.Min(colourLength, colours.Length));
}
else
{
palette = Common.GetPalette16.Entries.ToArray();
}
Bytemap bytemap = bitmap.MatchColours(palette, startIndex, colourLength);
return(new Picture(bytemap, palette));
}