libs/hwui/pipeline/skia/RenderNodeDrawable.cpp

/*
 * Copyright (C) 2016 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "RenderNodeDrawable.h"
#include "RenderNode.h"
#include "SkiaDisplayList.h"
#include "SkiaPipeline.h"
#include "utils/TraceUtils.h"
#include <SkPaintFilterCanvas.h>

namespace android {
namespace uirenderer {
namespace skiapipeline {

void RenderNodeDrawable::drawBackwardsProjectedNodes(SkCanvas* canvas, const SkiaDisplayList& displayList,
        int nestLevel) {
    LOG_ALWAYS_FATAL_IF(0 == nestLevel && !displayList.mProjectionReceiver);
    for (auto& child : displayList.mChildNodes) {
        const RenderProperties& childProperties = child.getNodeProperties();

        //immediate children cannot be projected on their parent
        if (childProperties.getProjectBackwards() && nestLevel > 0) {
            SkAutoCanvasRestore acr2(canvas, true);
            //Apply recorded matrix, which is a total matrix saved at recording time to avoid
            //replaying all DL commands.
            canvas->concat(child.getRecordedMatrix());
            child.drawContent(canvas);
        }

        //skip walking sub-nodes if current display list contains a receiver with exception of
        //level 0, which is a known receiver
        if (0 == nestLevel || !displayList.containsProjectionReceiver()) {
            SkAutoCanvasRestore acr(canvas, true);
            SkMatrix nodeMatrix;
            mat4 hwuiMatrix(child.getRecordedMatrix());
            auto childNode = child.getRenderNode();
            childNode->applyViewPropertyTransforms(hwuiMatrix);
            hwuiMatrix.copyTo(nodeMatrix);
            canvas->concat(nodeMatrix);
            SkiaDisplayList* childDisplayList = static_cast<SkiaDisplayList*>(
                (const_cast<DisplayList*>(childNode->getDisplayList())));
            if (childDisplayList) {
                drawBackwardsProjectedNodes(canvas, *childDisplayList, nestLevel+1);
            }
        }
    }
}

static void clipOutline(const Outline& outline, SkCanvas* canvas, const SkRect* pendingClip) {
    Rect possibleRect;
    float radius;

    /* To match the existing HWUI behavior we only supports rectangles or
     * rounded rectangles; passing in a more complicated outline fails silently.
     */
    if (!outline.getAsRoundRect(&possibleRect, &radius)) {
        if (pendingClip) {
            canvas->clipRect(*pendingClip);
        }
        return;
    }

    SkRect rect = possibleRect.toSkRect();
    if (radius != 0.0f) {
        if (pendingClip && !pendingClip->contains(rect)) {
            canvas->clipRect(*pendingClip);
        }
        canvas->clipRRect(SkRRect::MakeRectXY(rect, radius, radius), SkClipOp::kIntersect, true);
    } else {
        if (pendingClip) {
            (void)rect.intersect(*pendingClip);
        }
        canvas->clipRect(rect);
    }
}

const RenderProperties& RenderNodeDrawable::getNodeProperties() const {
    return mRenderNode->properties();
}

void RenderNodeDrawable::onDraw(SkCanvas* canvas) {
    //negative and positive Z order are drawn out of order, if this render node drawable is in
    //a reordering section
    if ((!mInReorderingSection) || MathUtils::isZero(mRenderNode->properties().getZ())) {
        this->forceDraw(canvas);
    }
}

void RenderNodeDrawable::forceDraw(SkCanvas* canvas) {
    RenderNode* renderNode = mRenderNode.get();
    if (CC_UNLIKELY(Properties::skpCaptureEnabled)) {
        SkRect dimensions = SkRect::MakeWH(renderNode->getWidth(), renderNode->getHeight());
        canvas->drawAnnotation(dimensions, renderNode->getName(), nullptr);
    }

    // We only respect the nothingToDraw check when we are composing a layer. This
    // ensures that we paint the layer even if it is not currently visible in the
    // event that the properties change and it becomes visible.
    if (!renderNode->isRenderable() || (renderNode->nothingToDraw() && mComposeLayer)) {
        return;
    }

    SkASSERT(renderNode->getDisplayList()->isSkiaDL());
    SkiaDisplayList* displayList = (SkiaDisplayList*)renderNode->getDisplayList();

    SkAutoCanvasRestore acr(canvas, true);
    const RenderProperties& properties = this->getNodeProperties();
    //pass this outline to the children that may clip backward projected nodes
    displayList->mProjectedOutline = displayList->containsProjectionReceiver()
            ? &properties.getOutline() : nullptr;
    if (!properties.getProjectBackwards()) {
        drawContent(canvas);
        if (mProjectedDisplayList) {
            acr.restore(); //draw projected children using parent matrix
            LOG_ALWAYS_FATAL_IF(!mProjectedDisplayList->mProjectedOutline);
            const bool shouldClip = mProjectedDisplayList->mProjectedOutline->getPath();
            SkAutoCanvasRestore acr2(canvas, shouldClip);
            canvas->setMatrix(mProjectedDisplayList->mProjectedReceiverParentMatrix);
            if (shouldClip) {
                clipOutline(*mProjectedDisplayList->mProjectedOutline, canvas, nullptr);
            }
            drawBackwardsProjectedNodes(canvas, *mProjectedDisplayList);
        }
    }
    displayList->mProjectedOutline = nullptr;
}

static bool layerNeedsPaint(const LayerProperties& properties,
                            float alphaMultiplier, SkPaint* paint) {
    if (alphaMultiplier < 1.0f
            || properties.alpha() < 255
            || properties.xferMode() != SkBlendMode::kSrcOver
            || properties.colorFilter() != nullptr) {
        paint->setAlpha(properties.alpha() * alphaMultiplier);
        paint->setBlendMode(properties.xferMode());
        paint->setColorFilter(sk_ref_sp(properties.colorFilter()));
        return true;
    }
    return false;
}

class AlphaFilterCanvas : public SkPaintFilterCanvas {
public:
    AlphaFilterCanvas(SkCanvas* canvas, float alpha) : SkPaintFilterCanvas(canvas), mAlpha(alpha) {}
protected:
    bool onFilter(SkTCopyOnFirstWrite<SkPaint>* paint, Type t) const override {
        SkTLazy<SkPaint> defaultPaint;
        if (!*paint) {
            paint->init(*defaultPaint.init());
        }
        paint->writable()->setAlpha((uint8_t)(*paint)->getAlpha()*mAlpha);
        return true;
    }
    void onDrawDrawable(SkDrawable* drawable, const SkMatrix* matrix) override {
        // We unroll the drawable using "this" canvas, so that draw calls contained inside will
        // get their alpha applied. THe default SkPaintFilterCanvas::onDrawDrawable does not unroll.
        drawable->draw(this, matrix);
    }
private:
    float mAlpha;
};

void RenderNodeDrawable::drawContent(SkCanvas* canvas) const {
    RenderNode* renderNode = mRenderNode.get();
    float alphaMultiplier = 1.0f;
    const RenderProperties& properties = renderNode->properties();

    // If we are drawing the contents of layer, we don't want to apply any of
    // the RenderNode's properties during this pass. Those will all be applied
    // when the layer is composited.
    if (mComposeLayer) {
        setViewProperties(properties, canvas, &alphaMultiplier);
    }
    SkiaDisplayList* displayList = (SkiaDisplayList*)mRenderNode->getDisplayList();
    if (displayList->containsProjectionReceiver()) {
        displayList->mProjectedReceiverParentMatrix = canvas->getTotalMatrix();
    }

    //TODO should we let the bound of the drawable do this for us?
    const SkRect bounds = SkRect::MakeWH(properties.getWidth(), properties.getHeight());
    bool quickRejected = properties.getClipToBounds() && canvas->quickReject(bounds);
    if (!quickRejected) {
        SkiaDisplayList* displayList = (SkiaDisplayList*)renderNode->getDisplayList();
        const LayerProperties& layerProperties = properties.layerProperties();
        // composing a hardware layer
        if (renderNode->getLayerSurface() && mComposeLayer) {
            SkASSERT(properties.effectiveLayerType() == LayerType::RenderLayer);
            SkPaint* paint = nullptr;
            SkPaint tmpPaint;
            if (layerNeedsPaint(layerProperties, alphaMultiplier, &tmpPaint)) {
                paint = &tmpPaint;
            }
            renderNode->getLayerSurface()->draw(canvas, 0, 0, paint);

            if (!renderNode->getSkiaLayer()->hasRenderedSinceRepaint) {
                renderNode->getSkiaLayer()->hasRenderedSinceRepaint = true;
                if (CC_UNLIKELY(Properties::debugLayersUpdates)) {
                    SkPaint layerPaint;
                    layerPaint.setColor(0x7f00ff00);
                    canvas->drawRect(bounds, layerPaint);
                } else if (CC_UNLIKELY(Properties::debugOverdraw)) {
                    // Render transparent rect to increment overdraw for repaint area.
                    // This can be "else if" because flashing green on layer updates
                    // will also increment the overdraw if it happens to be turned on.
                    SkPaint transparentPaint;
                    transparentPaint.setColor(SK_ColorTRANSPARENT);
                    canvas->drawRect(bounds, transparentPaint);
                }
            }

        // composing a software layer with alpha
        } else if (properties.effectiveLayerType() == LayerType::Software) {
            SkPaint paint;
            bool needsLayer = layerNeedsPaint(layerProperties, alphaMultiplier, &paint);
            if (needsLayer) {
                canvas->saveLayer(bounds, &paint);
            }
            displayList->draw(canvas);
            if (needsLayer) {
                canvas->restore();
            }
        } else {
            if (alphaMultiplier < 1.0f) {
                // Non-layer draw for a view with getHasOverlappingRendering=false, will apply
                // the alpha to the paint of each nested draw.
                AlphaFilterCanvas alphaCanvas(canvas, alphaMultiplier);
                displayList->draw(&alphaCanvas);
            } else {
                displayList->draw(canvas);
            }
        }
    }
}

void RenderNodeDrawable::setViewProperties(const RenderProperties& properties, SkCanvas* canvas,
        float* alphaMultiplier) {
    if (properties.getLeft() != 0 || properties.getTop() != 0) {
        canvas->translate(properties.getLeft(), properties.getTop());
    }
    if (properties.getStaticMatrix()) {
        canvas->concat(*properties.getStaticMatrix());
    } else if (properties.getAnimationMatrix()) {
        canvas->concat(*properties.getAnimationMatrix());
    }
    if (properties.hasTransformMatrix()) {
        if (properties.isTransformTranslateOnly()) {
            canvas->translate(properties.getTranslationX(), properties.getTranslationY());
        } else {
            canvas->concat(*properties.getTransformMatrix());
        }
    }
    const bool isLayer = properties.effectiveLayerType() != LayerType::None;
    int clipFlags = properties.getClippingFlags();
    if (properties.getAlpha() < 1) {
        if (isLayer) {
            clipFlags &= ~CLIP_TO_BOUNDS; // bounds clipping done by layer
        }
        if (CC_LIKELY(isLayer || !properties.getHasOverlappingRendering())) {
            *alphaMultiplier = properties.getAlpha();
        } else {
            // savelayer needed to create an offscreen buffer
            Rect layerBounds(0, 0, properties.getWidth(), properties.getHeight());
            if (clipFlags) {
                properties.getClippingRectForFlags(clipFlags, &layerBounds);
                clipFlags = 0; // all clipping done by savelayer
            }
            SkRect bounds = SkRect::MakeLTRB(layerBounds.left, layerBounds.top,
                    layerBounds.right, layerBounds.bottom);
            canvas->saveLayerAlpha(&bounds, (int) (properties.getAlpha() * 255));
        }

        if (CC_UNLIKELY(ATRACE_ENABLED() && properties.promotedToLayer())) {
            // pretend alpha always causes savelayer to warn about
            // performance problem affecting old versions
            ATRACE_FORMAT("alpha caused saveLayer %dx%d", properties.getWidth(),
                    properties.getHeight());
        }
    }

    const SkRect* pendingClip = nullptr;
    SkRect clipRect;

    if (clipFlags) {
        Rect tmpRect;
        properties.getClippingRectForFlags(clipFlags, &tmpRect);
        clipRect = tmpRect.toSkRect();
        pendingClip = &clipRect;
    }

    if (properties.getRevealClip().willClip()) {
        canvas->clipPath(*properties.getRevealClip().getPath(), SkClipOp::kIntersect, true);
    } else if (properties.getOutline().willClip()) {
        clipOutline(properties.getOutline(), canvas, pendingClip);
        pendingClip = nullptr;
    }

    if (pendingClip) {
        canvas->clipRect(*pendingClip);
    }
}

}; // namespace skiapipeline
}; // namespace uirenderer
}; // namespace android