private Bitmap DecodeImage(IProgressContext progress = null)
{
if (_decodedImage != null)
{
return(_decodedImage);
}
Func <Bitmap> decodeImageAction;
if (IsIndexed)
{
var transcoder = CreateImageConfiguration(ImageFormat, PaletteFormat)
.Transcode.With(_encodingDefinition.GetIndexEncoding(ImageFormat).IndexEncoding)
.TranscodePalette.With(_encodingDefinition.GetPaletteEncoding(PaletteFormat))
.Build();
decodeImageAction = () => transcoder.Decode(ImageInfo.ImageData, ImageInfo.PaletteData, ImageInfo.ImageSize, progress);
}
else
{
var transcoder = CreateImageConfiguration(ImageFormat, PaletteFormat)
.Transcode.With(_encodingDefinition.GetColorEncoding(ImageFormat))
.Build();
decodeImageAction = () => transcoder.Decode(ImageInfo.ImageData, ImageInfo.ImageSize, progress);
}
ExecuteActionWithProgress(() => _decodedImage = decodeImageAction(), progress);
_bestImage ??= _decodedImage;
return(_decodedImage);
}
private void AssertPaletteFormatExists(int paletteFormat)
{
if (EncodingDefinition.GetPaletteEncoding(paletteFormat) == null)
{
throw new InvalidOperationException($"The palette format '{paletteFormat}' is not supported by the plugin.");
}
}
/// <summary>
/// Decode given palette data without buffering.
/// </summary>
/// <param name="paletteData">Palette data to decode.</param>
/// <param name="context"></param>
/// <returns>Decoded palette.</returns>
private IList <Color> DecodePalette(byte[] paletteData, IProgressContext context = null)
{
var paletteEncoding = EncodingDefinition.GetPaletteEncoding(PaletteFormat);
return(paletteEncoding
.Load(paletteData, new EncodingLoadContext(new Size(1, paletteData.Length * 8 / paletteEncoding.BitsPerValue), TaskCount))
.ToArray());
}
private (IList <byte[]> imageData, byte[] paletteData) EncodeImage(Bitmap image, int imageFormat, int paletteFormat = -1,
IProgressContext progress = null)
{
// Create transcoder
IImageTranscoder transcoder;
if (IsIndexEncoding(imageFormat))
{
var indexEncoding = EncodingDefinition.GetIndexEncoding(imageFormat).IndexEncoding;
transcoder = CreateImageConfiguration(ImageFormat, PaletteFormat)
.ConfigureQuantization(options => options.WithColorCount(indexEncoding.MaxColors))
.Transcode.With(indexEncoding)
.TranscodePalette.With(EncodingDefinition.GetPaletteEncoding(paletteFormat))
.Build();
}
else
{
transcoder = CreateImageConfiguration(ImageFormat, PaletteFormat)
.Transcode.With(EncodingDefinition.GetColorEncoding(imageFormat))
.Build();
}
byte[] mainImageData = null;
byte[] mainPaletteData = null;
ExecuteActionWithProgress(() => (mainImageData, mainPaletteData) = transcoder.Encode(image, progress), progress);
var imageData = new byte[ImageInfo.MipMapCount + 1][];
imageData[0] = mainImageData;
// Decode palette if present, only when mip maps are needed
IList <Color> decodedPalette = null;
if (mainPaletteData != null && ImageInfo.MipMapCount > 0)
{
decodedPalette = DecodePalette(mainPaletteData);
}
// Encode mip maps
var(width, height) = (image.Width / 2, image.Height / 2);
for (var i = 0; i < ImageInfo.MipMapCount; i++)
{
imageData[i + 1] = EncodeMipMap(ResizeImage(image, width, height), imageFormat, decodedPalette);
width /= 2;
height /= 2;
}
return(imageData, mainPaletteData);
}
private byte[] EncodePalette(IList <Color> palette, int paletteFormat)
{
return(EncodingDefinition.GetPaletteEncoding(paletteFormat)
.Save(palette, new EncodingSaveContext(new Size(1, palette.Count), TaskCount)));
}