Been poking around google and haven't found any like what I'm after. so what is it I'm after? well two things:
firstly I'm looking for an algorithm/pseudo-code/white-papers to determine a best-fit color for a give r,g,b tuple from and array of 256 RGB tuples.
Secondly, I'm looking for an algorithm/pseudo-code/white-papers to recolor a 8bit palette image(using the above RGB palette) to either a given Hue/Saturation or by r,g,b channel modification. also would be nice if it was possible to add a fix for gamma and artifacting pixels in the colorization as well.
anyone got any hints/pointers/tips as to where I might find such a thing(I know they must exist, else a few of photoshops functions wouldn't)
UPDATE: here is a basic euclidean distance RGB to palette index finder:
uint_8 __stdcall GFXUTIL_GetNearestPaletteIndex(const uint_8* pPalette, size_t nSize, uint_8 nRed, uint_8 nGreen, uint_8 nBlue)
{
if(pPalette == NULL)
return 0;
int nDistance = -1;
size_t nIndex = 0, nFoundIndex = 0;
while(nIndex < nSize)
{
int nDistRed = pPalette[0] - nRed;
int nDistGreen = pPalette[1] - nGreen;
int nDistBlue = pPalette[2] - nBlue;
int nCurrentDistance = (nDistRed * nDistRed) + (nDistGreen * nDistGreen) + (nDistBlue * nDistBlue);
if(nCurrentDistance < nDistance)
{
nFoundIndex = nIndex;
nDistance = nCurrentDistance;
}
nIndex++;
pPalette += sizeof(uint_32);
}
return nFoundIndex;
}