internal static Image ApplyPalette(this Image image, IList <Color> palette)
{
Image dst = new Image(image.Width, image.Height, 32, image);
int height = image.Height;
int bitsPerPixel = image.BitsPerPixel;
ulong[] srcbits = image.Bits;
ulong[] dstbits = dst.Bits;
int srcstride = image.Stride;
int dststride = dst.Stride;
int srcwidthbits = image.WidthBits;
int srcwidthbits2 = image.WidthBits & ~1;
int srcwidthbits64 = image.WidthBits & ~63;
uint[] colormap = palette.Select(x => x.Argb).ToArray();
for (int iy = 0, yoffsrc = 0, yoffdst = 0; iy < height; iy++, yoffsrc += srcstride, yoffdst += dststride)
{
int xoffsrc = yoffsrc;
int xoffdst = yoffdst;
int ix = 0;
for (; ix < srcwidthbits64; ix += 64, xoffsrc++)
{
ulong bits = srcbits[xoffsrc];
for (int i = 0; i < 64; i += 2 * bitsPerPixel, xoffdst++)
{
dstbits[xoffdst] =
(ulong)colormap[BitUtils.GetBits(bits, i, bitsPerPixel)] |
((ulong)colormap[BitUtils.GetBits(bits, i + bitsPerPixel, bitsPerPixel)] << 32);
}
}
if (ix < srcwidthbits)
{
ulong bits = srcbits[xoffsrc];
for (; ix < srcwidthbits2; ix += 2 * bitsPerPixel, xoffdst++)
{
dstbits[xoffdst] =
(ulong)colormap[BitUtils.GetBits(bits, ix & 63, bitsPerPixel)] |
((ulong)colormap[BitUtils.GetBits(bits, (ix + bitsPerPixel) & 63, bitsPerPixel)] << 32);
}
if (ix < srcwidthbits)
{
dstbits[xoffdst] = (ulong)colormap[BitUtils.GetBits(bits, ix & 63, bitsPerPixel)];
}
}
}
return(dst);
}
public uint GetPixel(int x, int y)
{
this.ValidatePosition(x, y);
int xpos = x * this.BitsPerPixel;
int pos = (y * this.Stride) + (xpos >> 6);
xpos &= 63;
if (this.BitsPerPixel == 24 && xpos + 24 > 64)
{
int rem = 64 - xpos;
return((uint)BitUtils.GetBits(this.Bits[pos], xpos, rem) |
(uint)(BitUtils.GetBits(this.Bits[pos + 1], 0, 24 - rem) << rem));
}
else
{
return((uint)BitUtils.GetBits(this.Bits[pos], xpos, this.BitsPerPixel));
}
}