Function ILAPIENTRY iConvertPal

DevIL/src-IL/src/il_pal.cpp:587–840

Converts the palette to the DestFormat format.

// Converts the palette to the DestFormat format.
ILAPI ILpal* ILAPIENTRY iConvertPal(ILpal *Pal, ILenum DestFormat)
{
	ILpal	*NewPal = NULL;
	ILuint	i, j, NewPalSize;

	// Checks to see if the current image is valid and has a palette
	if (Pal == NULL || Pal->PalSize == 0 || Pal->Palette == NULL || Pal->PalType == IL_PAL_NONE) {
		ilSetError(IL_ILLEGAL_OPERATION);
		return NULL;
	}

	/*if (Pal->PalType == DestFormat) {
		return NULL;
	}*/

	NewPal = (ILpal*)ialloc(sizeof(ILpal));
	if (NewPal == NULL) {
		return NULL;
	}
	NewPal->PalSize = Pal->PalSize;
	NewPal->PalType = Pal->PalType;

	switch (DestFormat)
	{
		case IL_PAL_RGB24:
		case IL_PAL_BGR24:
			switch (Pal->PalType)
			{
				case IL_PAL_RGB24:
					NewPal->Palette = (ILubyte*)ialloc(Pal->PalSize);
					if (NewPal->Palette == NULL)
						goto alloc_error;
					if (DestFormat == IL_PAL_BGR24) {
						j = ilGetBppPal(Pal->PalType);
						for (i = 0; i < Pal->PalSize; i += j) {
							NewPal->Palette[i] = Pal->Palette[i+2];
							NewPal->Palette[i+1] = Pal->Palette[i+1];
							NewPal->Palette[i+2] = Pal->Palette[i];
						}
					}
					else {
						memcpy(NewPal->Palette, Pal->Palette, Pal->PalSize);
					}
					NewPal->PalType = DestFormat;
					break;

				case IL_PAL_BGR24:
					NewPal->Palette = (ILubyte*)ialloc(Pal->PalSize);
					if (NewPal->Palette == NULL)
						goto alloc_error;
					if (DestFormat == IL_PAL_RGB24) {
						j = ilGetBppPal(Pal->PalType);
						for (i = 0; i < Pal->PalSize; i += j) {
							NewPal->Palette[i] = Pal->Palette[i+2];
							NewPal->Palette[i+1] = Pal->Palette[i+1];
							NewPal->Palette[i+2] = Pal->Palette[i];
						}
					}