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Commit 6452f12c authored by Robert Carr's avatar Robert Carr
Browse files

SurfaceFlinger: Inherit Alpha for child surfaces. 

Necessary for various animations to work correctly and
for the general goal of treating child surfaces like
pixels in the parent surface.

Test: Includes new test in SurfaceFlinger_test
Bug: None yet ;)
Change-Id: Ic8309518bd327bbba6ad2f79f265e24cf37898e7
parent 8b71dc3c

services/surfaceflinger/Layer.cpp

+27 −9
Original line number Diff line number Diff line
@@ -595,7 +595,7 @@ void Layer::setGeometry( 
    const State& s(getDrawingState());

#ifdef USE_HWC2

    auto blendMode = HWC2::BlendMode::None;

    if (!isOpaque(s) || s.alpha != 1.0f) {

    if (!isOpaque(s) || getAlpha() != 1.0f) {

        blendMode = mPremultipliedAlpha ?

                HWC2::BlendMode::Premultiplied : HWC2::BlendMode::Coverage;

    }
@@ -604,7 +604,7 @@ void Layer::setGeometry( 
             " %s (%d)", mName.string(), to_string(blendMode).c_str(),

             to_string(error).c_str(), static_cast<int32_t>(error));

#else

    if (!isOpaque(s) || s.alpha != 0xFF) {

    if (!isOpaque(s) || getAlpha() != 0xFF) {

        layer.setBlending(mPremultipliedAlpha ?

                HWC_BLENDING_PREMULT :

                HWC_BLENDING_COVERAGE);
@@ -678,9 +678,10 @@ void Layer::setGeometry( 
        hwcInfo.sourceCrop = sourceCrop;

    }



    error = hwcLayer->setPlaneAlpha(s.alpha);

    float alpha = getAlpha();

    error = hwcLayer->setPlaneAlpha(alpha);

    ALOGE_IF(error != HWC2::Error::None, "[%s] Failed to set plane alpha %.3f: "

            "%s (%d)", mName.string(), s.alpha, to_string(error).c_str(),

            "%s (%d)", mName.string(), alpha, to_string(error).c_str(),

            static_cast<int32_t>(error));



    error = hwcLayer->setZOrder(z);
@@ -698,7 +699,7 @@ void Layer::setGeometry( 
    const Transform& tr(hw->getTransform());

    layer.setFrame(tr.transform(frame));

    layer.setCrop(computeCrop(hw));

    layer.setPlaneAlpha(s.alpha);

    layer.setPlaneAlpha(getAlpha());

#endif



    /*
@@ -1147,7 +1148,7 @@ void Layer::drawWithOpenGL(const sp<const DisplayDevice>& hw, 
    texCoords[3] = vec2(right, 1.0f - top);



    RenderEngine& engine(mFlinger->getRenderEngine());

    engine.setupLayerBlending(mPremultipliedAlpha, isOpaque(s), s.alpha);

    engine.setupLayerBlending(mPremultipliedAlpha, isOpaque(s), getAlpha());

    engine.drawMesh(mMesh);

    engine.disableBlending();

}
@@ -1961,12 +1962,11 @@ bool Layer::isHiddenByPolicy() const { 
}



bool Layer::isVisible() const {

    const Layer::State& s(mDrawingState);

#ifdef USE_HWC2

    return !(isHiddenByPolicy()) && s.alpha > 0.0f

    return !(isHiddenByPolicy()) && getAlpha() > 0.0f

            && (mActiveBuffer != NULL || mSidebandStream != NULL);

#else

    return !(isHiddenByPolicy()) && s.alpha

    return !(isHiddenByPolicy()) && getAlpha()

            && (mActiveBuffer != NULL || mSidebandStream != NULL);

#endif

}
@@ -2523,6 +2523,24 @@ Transform Layer::getTransform() const { 
    return t * getDrawingState().active.transform;

}



#ifdef USE_HWC2

float Layer::getAlpha() const {

    const auto& p = getParent();



    float parentAlpha = (p != nullptr) ? p->getAlpha() : 1.0;

    return parentAlpha * getDrawingState().alpha;

}

#else

uint8_t Layer::getAlpha() const {

    const auto& p = getParent();



    float parentAlpha = (p != nullptr) ? (p->getAlpha() / 255.0f) : 1.0;

    float drawingAlpha = getDrawingState().alpha / 255.0f;

    drawingAlpha = drawingAlpha * parentAlpha;

    return static_cast<uint8_t>(std::round(drawingAlpha * 255));

}

#endif



void Layer::commitChildList() {

    for (size_t i = 0; i < mCurrentChildren.size(); i++) {

        const auto& child = mCurrentChildren[i];

services/surfaceflinger/Layer.h

+9 −0
Original line number Diff line number Diff line
@@ -459,6 +459,15 @@ public: 


    Transform getTransform() const;



    // Returns the Alpha of the Surface, accounting for the Alpha

    // of parent Surfaces in the hierarchy (alpha's will be multiplied

    // down the hierarchy).

#ifdef USE_HWC2

    float getAlpha() const;

#else

    uint8_t getAlpha() const;

#endif



    void traverseInReverseZOrder(const std::function<void(Layer*)>& exec);

    void traverseInZOrder(const std::function<void(Layer*)>& exec);

services/surfaceflinger/tests/Transaction_test.cpp

+39 −0
Original line number Diff line number Diff line
@@ -764,6 +764,45 @@ TEST_F(ChildLayerTest, ChildLayerScaling) { 
    }

}



TEST_F(ChildLayerTest, ChildLayerAlpha) {

    fillSurfaceRGBA8(mBGSurfaceControl, 0, 0, 254);

    fillSurfaceRGBA8(mFGSurfaceControl, 254, 0, 0);

    fillSurfaceRGBA8(mChild, 0, 254, 0);

    waitForPostedBuffers();



    SurfaceComposerClient::openGlobalTransaction();

    mChild->show();

    mChild->setPosition(0, 0);

    mFGSurfaceControl->setPosition(0, 0);

    SurfaceComposerClient::closeGlobalTransaction(true);



    {

        ScreenCapture::captureScreen(&mCapture);

        // Unblended child color

        mCapture->checkPixel(0, 0, 0, 254, 0);

    }



    SurfaceComposerClient::openGlobalTransaction();

    ASSERT_EQ(NO_ERROR, mChild->setAlpha(0.5));

    SurfaceComposerClient::closeGlobalTransaction(true);



    {

        ScreenCapture::captureScreen(&mCapture);

        // Child and BG blended.

        mCapture->checkPixel(0, 0, 127, 127, 0);

    }



    SurfaceComposerClient::openGlobalTransaction();

    ASSERT_EQ(NO_ERROR, mFGSurfaceControl->setAlpha(0.5));

    SurfaceComposerClient::closeGlobalTransaction(true);



    {

        ScreenCapture::captureScreen(&mCapture);

        // Child and BG blended.

        mCapture->checkPixel(0, 0, 95, 64, 95);

    }

}



TEST_F(ChildLayerTest, ReparentChildren) {

    SurfaceComposerClient::openGlobalTransaction();

    mChild->show();