private Bitmap DecodeIndexInternal(byte[] data, byte[] paletteData, Size imageSize, IProgressContext progress)
{
ContractAssertions.IsTrue(IsIndexed, nameof(IsIndexed));
var progresses = progress?.SplitIntoEvenScopes(2);
// Prepare information and instances
var paddedSize = GetPaddedSize(imageSize);
var swizzle = GetPixelRemapper(_indexEncoding, paddedSize);
var finalSize = GetFinalSize(paddedSize, swizzle);
var colorShader = _shadeColorsFunc?.Invoke();
// Load palette
var paletteColorCount = paletteData.Length * 8 / _paletteEncoding.BitsPerValue * _paletteEncoding.ColorsPerValue;
var setMaxProgress = progresses?[0]?.SetMaxValue(paletteColorCount * _paletteEncoding.ColorsPerValue);
var paletteEnumeration = _paletteEncoding
.Load(paletteData, new EncodingLoadContext(new Size(1, paletteColorCount), _taskCount))
.AttachProgress(setMaxProgress, "Decode palette colors");
// Apply color shader on palette
var palette = colorShader != null?paletteEnumeration.Select(colorShader.Read).ToArray() : paletteEnumeration.ToArray();
// Load indices
setMaxProgress = progresses?[1]?.SetMaxValue(finalSize.Width * finalSize.Height);
var colors = _indexEncoding
.Load(data, palette, new EncodingLoadContext(finalSize, _taskCount))
.AttachProgress(setMaxProgress, "Decode colors");
return(colors.ToBitmap(imageSize, paddedSize, swizzle, _anchor));
}
private Bitmap DecodeColorInternal(byte[] data, Size imageSize, IProgressContext progress)
{
// Prepare information and instances
var paddedSize = GetPaddedSize(imageSize);
var swizzle = GetPixelRemapper(_colorEncoding, paddedSize);
var finalSize = GetFinalSize(paddedSize, swizzle);
var colorShader = _shadeColorsFunc?.Invoke();
// Load colors
var colorCount = data.Length * 8 / _colorEncoding.BitsPerValue * _colorEncoding.ColorsPerValue;
var colorCountBySize = finalSize.Width * finalSize.Height;
// HINT: If the data portion does not fit with the actual image size, it will cause progress irregularities.
// If the given data is shorter than what is needed for the full image, we throw.
// Otherwise enough data is given and the image can be fully decoded, even if excess data is not used.
if (colorCount < colorCountBySize)
{
throw new InvalidOperationException("Given data is too short.");
}
var setMaxProgress = progress?.SetMaxValue(colorCountBySize * _colorEncoding.ColorsPerValue);
var colors = _colorEncoding
.Load(data, new EncodingLoadContext(finalSize, _taskCount))
.AttachProgress(setMaxProgress, "Decode colors");
// Apply color shader
if (colorShader != null)
{
colors = colors.Select(colorShader.Read);
}
// Create image with unpadded dimensions
return(colors.ToBitmap(imageSize, paddedSize, swizzle, _anchor));
}