Method convertToFormatInternalForColorSpace

Engine/ImageConvert.cpp:241–465

template <typename SRCPIX, typename DSTPIX, int srcMaxValue, int dstMaxValue, int srcNComps, int dstNComps,
          bool requiresUnpremult, bool useColorspaces>
void
Image::convertToFormatInternalForColorSpace(const RectI & renderWindow,
                                            const Image & srcImg,
                                            Image & dstImg,
                                            bool copyBitmap,
                                            bool useAlpha0,
                                            ViewerColorSpaceEnum srcColorSpace,
                                            ViewerColorSpaceEnum dstColorSpace,
                                            int channelForAlpha)
{
    /*
     * If channelForAlpha is -1 the user wants to convert using the default
     * If channelForAlpha >= 0 then the user wants a specific channel to convert from. This is used mainly when converting
     * to Alpha images (masks) to know which channel to use for the mask.
     */
    if (channelForAlpha != -1) {
        switch (srcNComps) {
        case 3:
            //invalid value passed by the called
            if (channelForAlpha > 2) {
                channelForAlpha = -1;
            }
            break;
        case 2:
            //invalid value passed by the called
            if (channelForAlpha > 1) {
                channelForAlpha = -1;
            }
        default:
            break;
        }
    } else {
        switch (srcNComps) {
        case 4:
            channelForAlpha = 3;
            break;
        case 3:
        case 1:
        default:
            //no alpha anyway
            break;
        }
    }


    ///special case comp == alpha && channelForAlpha = -1 clear out the mask
    if ( (dstNComps == 1) && (channelForAlpha == -1) ) {
        DSTPIX* dstPixels = (DSTPIX*)dstImg.pixelAt(renderWindow.x1, renderWindow.y1);
        int dstRowSize = dstImg._bounds.width() * dstNComps;
        if (copyBitmap) {
            dstImg.copyBitmapPortion(renderWindow, srcImg);
        }
        for (int y = 0; y < renderWindow.height();
             ++y, dstPixels += dstRowSize) {
            std::fill(dstPixels, dstPixels + renderWindow.width() * dstNComps, 0.);
        }

        return;