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Commit e84cc9ea authored by Alec Mouri's avatar Alec Mouri
Browse files

Correctly render ISO gainmapped images 

* Apply the gainmap in reverse when using an HDR base image
* Support alternative primaries
* Nudge the guards that optimize away applying the gainmap shader

Bug: 349357636
Flag: com.android.graphics.hwui.flags.iso_gainmap_apis
Test: GainmapTests
Change-Id: I230a765feddb306330e643e6ead8e62719f49ee5
parent 06af5c8f

libs/hwui/SkiaCanvas.cpp

+7 −12
Original line number Diff line number Diff line
@@ -622,18 +622,13 @@ bool SkiaCanvas::useGainmapShader(Bitmap& bitmap) { 
    auto colorSpace = info.colorSpace();

    // If we don't have a colorspace, we can't apply a gainmap

    if (!colorSpace) return false;

    skcms_TransferFunction tfn;

    colorSpace->transferFn(&tfn);



    auto transferType = skcms_TransferFunction_getType(&tfn);

    switch (transferType) {

        case skcms_TFType_HLGish:

        case skcms_TFType_HLGinvish:

        case skcms_TFType_PQish:

            return true;

        case skcms_TFType_Invalid:

        case skcms_TFType_sRGBish:

            return false;



    const float targetRatio = uirenderer::getTargetHdrSdrRatio(colorSpace);



    if (bitmap.gainmap()->info.fBaseImageType == SkGainmapInfo::BaseImageType::kHDR) {

        return targetRatio < bitmap.gainmap()->info.fDisplayRatioHdr;

    } else {

        return targetRatio > bitmap.gainmap()->info.fDisplayRatioSdr;

    }

}

libs/hwui/effects/GainmapRenderer.cpp

+12 −3
Original line number Diff line number Diff line
@@ -73,7 +73,9 @@ void DrawGainmapBitmap(SkCanvas* c, const sk_sp<const SkImage>& image, const SkR 
#ifdef __ANDROID__

    auto destColorspace = c->imageInfo().refColorSpace();

    float targetSdrHdrRatio = getTargetHdrSdrRatio(destColorspace.get());

    if (targetSdrHdrRatio > 1.f && gainmapImage) {

    const bool baseImageHdr = gainmapInfo.fBaseImageType == SkGainmapInfo::BaseImageType::kHDR;

    if (gainmapImage && ((baseImageHdr && targetSdrHdrRatio < gainmapInfo.fDisplayRatioHdr) ||

                         (!baseImageHdr && targetSdrHdrRatio > gainmapInfo.fDisplayRatioSdr))) {

        SkPaint gainmapPaint = *paint;

        float sX = gainmapImage->width() / (float)image->width();

        float sY = gainmapImage->height() / (float)image->height();
@@ -183,7 +185,10 @@ private: 
                baseImage->colorSpace() ? baseImage->refColorSpace() : SkColorSpace::MakeSRGB();



        // Determine the color space in which the gainmap math is to be applied.

        sk_sp<SkColorSpace> gainmapMathColorSpace = baseColorSpace->makeLinearGamma();

        sk_sp<SkColorSpace> gainmapMathColorSpace =

                mGainmapInfo.fGainmapMathColorSpace

                        ? mGainmapInfo.fGainmapMathColorSpace->makeLinearGamma()

                        : baseColorSpace->makeLinearGamma();



        // Create a color filter to transform from the base image's color space to the color space

        // in which the gainmap is to be applied.
@@ -266,6 +271,10 @@ private: 
                    W = 1.f;

                }

            }



            if (mGainmapInfo.fBaseImageType == SkGainmapInfo::BaseImageType::kHDR) {

                W -= 1.f;

            }

            mBuilder.uniform("W") = W;

            uniforms = mBuilder.uniforms();

        }