Method downscaleMipMap

Engine/Image.cpp:2095–2132

code proofread and fixed by @devernay on 8/8/2014

// code proofread and fixed by @devernay on 8/8/2014
void
Image::downscaleMipMap(const RectD& dstRod,
                       const RectI & roi,
                       unsigned int fromLevel,
                       unsigned int toLevel,
                       bool copyBitMap,
                       Image* output) const
{
    assert(getStorageMode() != eStorageModeGLTex);

    ///You should not call this function with a level equal to 0.
    assert(toLevel >  fromLevel);

    assert(_bounds.x1 <= roi.x1 && roi.x2 <= _bounds.x2 &&
           _bounds.y1 <= roi.y1 && roi.y2 <= _bounds.y2);
    double par = getPixelAspectRatio();
//    RectD roiCanonical;
//    roi.toCanonical(fromLevel, par , dstRod, &roiCanonical);
//    RectI dstRoI;
//    roiCanonical.toPixelEnclosing(toLevel, par , &dstRoI);
    unsigned int downscaleLvls = toLevel - fromLevel;

    assert( !copyBitMap || _bitmap.getBitmap() );

    RectI dstRoI  = roi.downscalePowerOfTwoSmallestEnclosing(downscaleLvls);
    ImagePtr tmpImg = std::make_shared<Image>( getComponents(), dstRod, dstRoI, toLevel, par, getBitDepth(), getPremultiplication(), getFieldingOrder(), true);

    buildMipMapLevel( dstRod, roi, downscaleLvls, copyBitMap, tmpImg.get() );

    // check that the downscaled mipmap is inside the output image (it may not be equal to it)
    assert(dstRoI.x1 >= output->_bounds.x1);
    assert(dstRoI.x2 <= output->_bounds.x2);
    assert(dstRoI.y1 >= output->_bounds.y1);
    assert(dstRoI.y2 <= output->_bounds.y2);

    ///Now copy the result of tmpImg into the output image
    output->pasteFrom(*tmpImg, dstRoI, copyBitMap);
}

bool
Image::checkForNaNsAndFix(const RectI& roi)