public WicPaletizer(WicTransform prev, uint colors = 256u) : base(prev)
{
var newFormat = Consts.GUID_WICPixelFormat8bppIndexed;
if (!Context.Settings.IndexedColor || Context.PixelFormat.FormatGuid == newFormat || Context.IsGreyscale)
{
return;
}
var conv = AddRef(Wic.CreateFormatConverter());
if (!conv.CanConvert(Context.PixelFormat.FormatGuid, newFormat))
{
throw new NotSupportedException("Can't convert to destination pixel format");
}
var bmp = AddRef(Wic.CreateBitmapFromSource(Source, WICBitmapCreateCacheOption.WICBitmapCacheOnDemand));
var pal = AddRef(Wic.CreatePalette());
pal.InitializeFromBitmap(bmp, colors, false);
Context.DestPalette = pal;
conv.Initialize(bmp, newFormat, WICBitmapDitherType.WICBitmapDitherTypeErrorDiffusion, pal, 10.0, WICBitmapPaletteType.WICBitmapPaletteTypeCustom);
Source = conv;
Context.PixelFormat = PixelFormat.Cache[Source.GetPixelFormat()];
}