/// <summary>
/// Builds the color mapping by adding all colors in the given table, and also resolving lookups according to the given alpha map.
/// </summary>
/// <param name="colorTable">The colors that should be added to the current lookup mapping.</param>
/// <param name="alphaMap">The alpha mapping that specifies new ARGB colors that should replace any given RGB colors in the color
/// table.</param>
private void BuildColorMap(ArgbColor[] colorTable, AlphaRemappingTable alphaMap)
{
foreach (ArgbColor sourceArgbColor in colorTable)
if (sourceArgbColor.A == 255)
{
RgbColor sourceRgbColor = (RgbColor)sourceArgbColor;
Color sourceColor = Color.FromArgb(sourceRgbColor.ToArgb());
if (!colorMappingTable.ContainsKey(sourceColor))
{
ArgbColor desiredArgbColor;
if (!alphaMap.TryGetMapping(sourceRgbColor, out desiredArgbColor))
desiredArgbColor = sourceArgbColor;
colorMappingTable.Add(sourceColor, Color.FromArgb(desiredArgbColor.ToArgb()));
}
}
}
/// <summary>
/// Creates a new <see cref="T:DesktopSprites.SpriteManagement.BitmapFrame"/> from the raw buffer, loading extra transparency
/// information and adjusting the colors as required by the transparency.
/// </summary>
/// <param name="buffer">The raw buffer.</param>
/// <param name="palette">The color palette.</param>
/// <param name="transparentIndex">The index of the transparent color.</param>
/// <param name="stride">The stride width of the buffer.</param>
/// <param name="width">The logical width of the buffer.</param>
/// <param name="height">The logical height of the buffer.</param>
/// <param name="depth">The bit depth of the buffer.</param>
/// <param name="hashCode">The hash code of the frame.</param>
/// <param name="fileName">The path to the GIF file being loaded.</param>
/// <returns>A new <see cref="T:DesktopSprites.SpriteManagement.BitmapFrame"/> for the frame held in the raw buffer.</returns>
private BitmapFrame BitmapFrameFromBuffer(byte[] buffer, RgbColor[] palette, int transparentIndex,
int stride, int width, int height, int depth, int hashCode, string fileName)
{
return Disposable.SetupSafely(
BitmapFrame.FromBuffer(buffer, palette, transparentIndex, stride, width, height, depth, hashCode),
frame =>
{
if (IsAlphaBlended)
{
// Check for an alpha remapping table, and apply it if one exists.
string mapFilePath = Path.ChangeExtension(fileName, AlphaRemappingTable.FileExtension);
if (File.Exists(mapFilePath))
{
AlphaRemappingTable map = new AlphaRemappingTable();
map.LoadMap(mapFilePath);
ColorPalette colorPalette = frame.Image.Palette;
for (int i = 0; i < colorPalette.Entries.Length; i++)
{
Color color = colorPalette.Entries[i];
ArgbColor argbColor;
if (map.TryGetMapping(new RgbColor(color.R, color.G, color.B), out argbColor))
colorPalette.Entries[i] = Color.FromArgb(argbColor.ToArgb());
}
frame.Image.Palette = colorPalette;
// We only need to pre-multiply when we add an alpha channel ourselves, as GIFs only support 1 bit transparency.
frame.Image.PreMultiplyAlpha();
}
}
else
{
frame.Image.RemapColors(paletteMapping);
}
});
}
