Function ILAPIENTRY ilApplyPal

DevIL/src-IL/src/il_pal.cpp:914–1111

ILboolean ILAPIENTRY ilApplyPal(ILconst_string FileName)
{
	ILimage		Image, *CurImage = iCurImage;
	ILubyte		*NewData;
	ILuint		*PalInfo, NumColours, NumPix, MaxDist, DistEntry=0, i, j;
	ILint		Dist1, Dist2, Dist3;
	ILboolean	Same;
	ILenum		Origin;
//	COL_CUBE	*Cubes;

    if( iCurImage == NULL || (iCurImage->Format != IL_BYTE || iCurImage->Format != IL_UNSIGNED_BYTE) ) {
    	ilSetError(IL_ILLEGAL_OPERATION);
        return IL_FALSE;
    }

	NewData = (ILubyte*)ialloc(iCurImage->Width * iCurImage->Height * iCurImage->Depth);
	if (NewData == NULL) {
		return IL_FALSE;
	}

	iCurImage = &Image;
	imemclear(&Image, sizeof(ILimage));
	// IL_PAL_RGB24, because we don't want to make parts transparent that shouldn't be.
	if (!ilLoadPal(FileName) || !ilConvertPal(IL_PAL_RGB24)) {
		ifree(NewData);
		iCurImage = CurImage;
		return IL_FALSE;
	}

	NumColours = Image.Pal.PalSize / 3;  // RGB24 is 3 bytes per entry.
	PalInfo = (ILuint*)ialloc(NumColours * sizeof(ILuint));
	if (PalInfo == NULL) {
		ifree(NewData);
		iCurImage = CurImage;
		return IL_FALSE;
	}

	NumPix = CurImage->SizeOfData / ilGetBppFormat(CurImage->Format);
	switch (CurImage->Format)
	{
		case IL_COLOUR_INDEX:
			iCurImage = CurImage;
			if (!ilConvertPal(IL_PAL_RGB24)) {
				ifree(NewData);
				ifree(PalInfo);
				return IL_FALSE;
			}

			NumPix = iCurImage->Pal.PalSize / ilGetBppPal(iCurImage->Pal.PalType);
			for (i = 0; i < NumPix; i++) {
				for (j = 0; j < Image.Pal.PalSize; j += 3) {
					// No need to perform a sqrt.
					Dist1 = (ILint)iCurImage->Pal.Palette[i] - (ILint)Image.Pal.Palette[j];
					Dist2 = (ILint)iCurImage->Pal.Palette[i+1] - (ILint)Image.Pal.Palette[j+1];
					Dist3 = (ILint)iCurImage->Pal.Palette[i+2] - (ILint)Image.Pal.Palette[j+2];
					PalInfo[j / 3] = Dist1 * Dist1 + Dist2 * Dist2 + Dist3 * Dist3;
				}
				MaxDist = UINT_MAX;