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      1 /*
      2  * Copyright (C) 2016 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 #pragma once
     18 
     19 #include <SkCanvas.h>
     20 #include <SkDrawable.h>
     21 #include <SkMatrix.h>
     22 #include <utils/RefBase.h>
     23 
     24 namespace android {
     25 namespace uirenderer {
     26 
     27 class RenderNode;
     28 class RenderProperties;
     29 
     30 namespace skiapipeline {
     31 
     32 class SkiaDisplayList;
     33 
     34 /**
     35  * This drawable wraps a RenderNode and enables it to be recorded into a list
     36  * of Skia drawing commands.
     37  */
     38 class RenderNodeDrawable : public SkDrawable {
     39 public:
     40     /**
     41      * Creates a new RenderNodeDrawable backed by a render node.
     42      *
     43      * @param node that has to be drawn
     44      * @param canvas is a recording canvas used to extract its matrix
     45      * @param composeLayer if the node's layer type is RenderLayer this flag determines whether
     46      *      we should draw into the contents of the layer or compose the existing contents of the
     47      *      layer into the canvas.
     48      */
     49     explicit RenderNodeDrawable(RenderNode* node, SkCanvas* canvas, bool composeLayer = true,
     50             bool inReorderingSection = false)
     51             : mRenderNode(node)
     52             , mRecordedTransform(canvas->getTotalMatrix())
     53             , mComposeLayer(composeLayer)
     54             , mInReorderingSection(inReorderingSection) {}
     55 
     56     /**
     57      * Draws into the canvas this render node and its children. If the node is marked as a
     58      * projection receiver then all projected children (excluding direct children) will be drawn
     59      * last. Any projected node not matching those requirements will not be drawn by this function.
     60      */
     61     void forceDraw(SkCanvas* canvas);
     62 
     63     /**
     64      * Returns readonly render properties for this render node.
     65      */
     66     const RenderProperties& getNodeProperties() const;
     67 
     68     /**
     69      * The renderNode (and its properties) that is to be drawn
     70      */
     71     RenderNode* getRenderNode() const { return mRenderNode.get(); }
     72 
     73     /**
     74      * Returns the transform on the canvas at time of recording and is used for
     75      * computing total transform without rerunning DL contents.
     76      */
     77     const SkMatrix& getRecordedMatrix() const { return mRecordedTransform; }
     78 
     79     /**
     80      * Sets a pointer to a display list of the parent render node. The display list is used when
     81      * drawing backward projected nodes, when this node is a projection receiver.
     82      */
     83     void setProjectedDisplayList(SkiaDisplayList* projectedDisplayList) {
     84         mProjectedDisplayList = projectedDisplayList;
     85     }
     86 
     87 protected:
     88     /*
     89      * Return the (conservative) bounds of what the drawable will draw.
     90      */
     91     virtual SkRect onGetBounds() override {
     92         // We don't want to enable a record time quick reject because the properties
     93         // of the RenderNode may be updated on subsequent frames.
     94         return SkRect::MakeLargest();
     95     }
     96     /**
     97      * This function draws into a canvas as forceDraw, but does nothing if the render node has a
     98      * non-zero elevation.
     99      */
    100     virtual void onDraw(SkCanvas* canvas) override;
    101 
    102 private:
    103     /*
    104      * Render node that is wrapped by this class.
    105      */
    106     sp<RenderNode> mRenderNode;
    107 
    108     /**
    109      * Walks recursively the display list and draws the content of backward projected nodes.
    110      *
    111      * @param canvas used to draw the backward projected nodes
    112      * @param displayList is a display list that contains a projection receiver
    113      * @param nestLevel should be always 0. Used to track how far we are from the receiver.
    114      */
    115     void drawBackwardsProjectedNodes(SkCanvas* canvas, const SkiaDisplayList& displayList,
    116             int nestLevel = 0);
    117 
    118     /**
    119      * Applies the rendering properties of a view onto a SkCanvas.
    120      */
    121     static void setViewProperties(const RenderProperties& properties, SkCanvas* canvas,
    122             float* alphaMultiplier);
    123 
    124     /**
    125      * Stores transform on the canvas at time of recording and is used for
    126      * computing total transform without rerunning DL contents.
    127      */
    128     const SkMatrix mRecordedTransform;
    129 
    130     /**
    131      * If mRenderNode's layer type is RenderLayer this flag determines whether we
    132      * should draw into the contents of the layer or compose the existing contents
    133      * of the layer into the canvas.
    134      */
    135     const bool mComposeLayer;
    136 
    137     /*
    138      * True if the render node is in a reordering section
    139      */
    140     bool mInReorderingSection;
    141 
    142     /*
    143      *  Draw the content into a canvas, depending on the render node layer type and mComposeLayer.
    144      */
    145     void drawContent(SkCanvas* canvas) const;
    146 
    147     /*
    148      * display list that is searched for any render nodes with getProjectBackwards==true
    149      */
    150     SkiaDisplayList* mProjectedDisplayList = nullptr;
    151 };
    152 
    153 }; // namespace skiapipeline
    154 }; // namespace uirenderer
    155 }; // namespace android
    156