Function ILAPIENTRY iConvertImage

DevIL/src-IL/src/il_convert.cpp:275–373

Converts an image from one format to another

// Converts an image from one format to another
ILAPI ILimage* ILAPIENTRY iConvertImage(ILimage *Image, ILenum DestFormat, ILenum DestType)
{
	ILimage	*NewImage, *CurImage;
	ILuint	i;
	ILubyte	*NewData;

	CurImage = Image;
	if (Image == NULL) {
		ilSetError(IL_ILLEGAL_OPERATION);
		return IL_FALSE;
	}

	// We don't support 16-bit color indices (or higher).
	if (DestFormat == IL_COLOUR_INDEX && DestType >= IL_SHORT) {
		ilSetError(IL_INVALID_CONVERSION);
		return NULL;
	}

	if (Image->Format == IL_COLOUR_INDEX) {
		NewImage = iConvertPalette(Image, DestFormat);

		//added test 2003-09-01
		if (NewImage == NULL)
			return NULL;

		if (DestType == NewImage->Type)
			return NewImage;

		NewData = (ILubyte*)ilConvertBuffer(NewImage->SizeOfData, NewImage->Format, DestFormat, NewImage->Type, DestType, NULL, NewImage->Data);
		if (NewData == NULL) {
			ifree(NewImage);  // ilCloseImage not needed.
			return NULL;
		}
		ifree(NewImage->Data);
		NewImage->Data = NewData;

		ilCopyImageAttr(NewImage, Image);
		NewImage->Format = DestFormat;
		NewImage->Type = DestType;
		NewImage->Bpc = ilGetBpcType(DestType);
		NewImage->Bpp = ilGetBppFormat(DestFormat);
		NewImage->Bps = NewImage->Bpp * NewImage->Bpc * NewImage->Width;
		NewImage->SizeOfPlane = NewImage->Bps * NewImage->Height;
		NewImage->SizeOfData = NewImage->SizeOfPlane * NewImage->Depth;
	}
	else if (DestFormat == IL_COLOUR_INDEX && Image->Format != IL_LUMINANCE) {
		if (iGetInt(IL_QUANTIZATION_MODE) == IL_NEU_QUANT)
			return iNeuQuant(Image, iGetInt(IL_MAX_QUANT_INDICES));
		else // Assume IL_WU_QUANT otherwise.
			return iQuantizeImage(Image, iGetInt(IL_MAX_QUANT_INDICES));
	}
	else {
		NewImage = (ILimage*)icalloc(1, sizeof(ILimage));  // Much better to have it all set to 0.
		if (NewImage == NULL) {
			return NULL;
		}

		if (ilGetBppFormat(DestFormat) == 0) {