CODEWITHSUNDEEP
c++cassemblyrgbcolor-palette
Necrolis
Necrolis

Reputation: 26171

Colorization and Palette Best-Fit Algorithms

Been poking around google and haven't found any like what I'm after. so what is it I'm after? well two things:

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;
}

Upvotes: 3

Views: 1488

Answers (2)

Kornel
Kornel

Reputation: 100110

If you want it faster than linear search, then check out VP-tree or KD-tree.

If you want it perceptually accurate, then do the search in Lab color space.

Upvotes: 0

kbjorklu
kbjorklu

Reputation: 1398

See http://en.wikipedia.org/wiki/Color_difference for how to calculate distances between colors so that human eye sensitivity is taken into account.

Upvotes: 1

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