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 "SkiaUtils.h"
20 
21 #include <SkCanvas.h>
22 #include <SkDrawable.h>
23 #include <SkMatrix.h>
24 #include <utils/RefBase.h>
25 
26 namespace android {
27 namespace uirenderer {
28 
29 class RenderNode;
30 class RenderProperties;
31 
32 namespace skiapipeline {
33 
34 class SkiaDisplayList;
35 
36 /**
37  * This drawable wraps a RenderNode and enables it to be recorded into a list
38  * of Skia drawing commands.
39  */
40 class RenderNodeDrawable : public SkDrawable {
41 public:
42     /**
43      * Creates a new RenderNodeDrawable backed by a render node.
44      *
45      * @param node that has to be drawn
46      * @param canvas is a recording canvas used to extract its matrix
47      * @param composeLayer if the node's layer type is RenderLayer this flag determines whether
48      *      we should draw into the contents of the layer or compose the existing contents of the
49      *      layer into the canvas.
50      */
51     explicit RenderNodeDrawable(RenderNode* node, SkCanvas* canvas, bool composeLayer = true,
52                                 bool inReorderingSection = false);
53 
54     ~RenderNodeDrawable();
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) const;
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      */
getRenderNode()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      */
getRecordedMatrix()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      */
setProjectedDisplayList(SkiaDisplayList * projectedDisplayList)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      */
onGetBounds()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 SkRectMakeLargest();
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) const;
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