StatefulBaseRenderer.h revision 3f085429fd47ebd32ac2463b3eae2a5a6c17be25 
1/*
2 * Copyright (C) 2014 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#ifndef ANDROID_HWUI_STATEFUL_BASE_RENDERER_H
18#define ANDROID_HWUI_STATEFUL_BASE_RENDERER_H
19
20#include <utils/RefBase.h>
21
22#include "Renderer.h"
23#include "Snapshot.h"
24
25namespace android {
26namespace uirenderer {
27
28/**
29 * Abstract Renderer subclass, which implements Canvas state methods.
30 *
31 * Manages the Snapshot stack, implementing matrix, save/restore, and clipping methods in the
32 * Renderer interface. Drawing and recording classes that extend StatefulBaseRenderer will have
33 * different use cases:
34 *
35 * Drawing subclasses (i.e. OpenGLRenderer) can query attributes (such as transform) or hook into
36 * changes (e.g. save/restore) with minimal surface area for manipulating the stack itself.
37 *
38 * Recording subclasses (i.e. DisplayListRenderer) can both record and pass through state operations
39 * to StatefulBaseRenderer, so that not only will querying operations work (getClip/Matrix), but so
40 * that quickRejection can also be used.
41 */
42class StatefulBaseRenderer : public Renderer {
43public:
44    StatefulBaseRenderer();
45
46    virtual status_t prepare(bool opaque) {
47        return prepareDirty(0.0f, 0.0f, mWidth, mHeight, opaque);
48    }
49    void initializeViewport(int width, int height);
50    void initializeSaveStack(float clipLeft, float clipTop, float clipRight, float clipBottom);
51
52    // getters
53    bool hasRectToRectTransform() const {
54        return CC_LIKELY(currentTransform()->rectToRect());
55    }
56
57    // Save (layer)
58    virtual int getSaveCount() const { return mSaveCount; }
59    virtual int save(int flags);
60    virtual void restore();
61    virtual void restoreToCount(int saveCount);
62    //virtual int saveLayer(float left, float top, float right, float bottom,
63    //        int alpha, SkXfermode::Mode mode, int flags);
64
65    // Matrix
66    virtual void getMatrix(SkMatrix* outMatrix) const;
67    virtual void translate(float dx, float dy, float dz = 0.0f);
68    virtual void rotate(float degrees);
69    virtual void scale(float sx, float sy);
70    virtual void skew(float sx, float sy);
71
72    virtual void setMatrix(const SkMatrix* matrix);
73    void setMatrix(const Matrix4& matrix); // internal only convenience method
74    virtual void concatMatrix(const SkMatrix* matrix);
75    void concatMatrix(const Matrix4& matrix); // internal only convenience method
76
77    // Clip
78    virtual const Rect& getLocalClipBounds() const { return mSnapshot->getLocalClip(); }
79
80    virtual bool quickRejectConservative(float left, float top, float right, float bottom) const;
81
82    virtual bool clipRect(float left, float top, float right, float bottom, SkRegion::Op op);
83    virtual bool clipPath(const SkPath* path, SkRegion::Op op);
84    virtual bool clipRegion(const SkRegion* region, SkRegion::Op op);
85
86protected:
87    const Rect& getRenderTargetClipBounds() const { return mSnapshot->getRenderTargetClip(); }
88
89    int getWidth() { return mWidth; }
90    int getHeight() { return mHeight; }
91
92    // Save
93    int saveSnapshot(int flags);
94    void restoreSnapshot();
95
96    // allows subclasses to control what value is stored in snapshot's fbo field in
97    // initializeSaveStack
98    virtual GLuint getTargetFbo() const {
99        return -1;
100    }
101
102    // Clip
103    bool calculateQuickRejectForScissor(float left, float top, float right, float bottom,
104            bool* clipRequired, bool snapOut) const;
105
106    /**
107     * Called just after a restore has occurred. The 'removed' snapshot popped from the stack,
108     * 'restored' snapshot has become the top/current.
109     *
110     * Subclasses can override this method to handle layer restoration
111     */
112    virtual void onSnapshotRestored(const Snapshot& removed, const Snapshot& restored) {};
113
114    inline const Rect* currentClipRect() const {
115        return mSnapshot->clipRect;
116    }
117
118    inline const mat4* currentTransform() const {
119        return mSnapshot->transform;
120    }
121
122    inline const Snapshot* currentSnapshot() const {
123        return mSnapshot != NULL ? mSnapshot.get() : mFirstSnapshot.get();
124    }
125
126    inline const Snapshot* firstSnapshot() const {
127        return mFirstSnapshot.get();
128    }
129
130    // indicites that the clip has been changed since the last time it was consumed
131    bool mDirtyClip;
132
133private:
134    // Dimensions of the drawing surface
135    int mWidth, mHeight;
136
137    // Number of saved states
138    int mSaveCount;
139
140    // Base state
141    sp<Snapshot> mFirstSnapshot;
142
143protected:
144    // Current state
145    // TODO: should become private, once hooks needed by OpenGLRenderer are added
146    sp<Snapshot> mSnapshot;
147
148}; // class StatefulBaseRenderer
149
150}; // namespace uirenderer
151}; // namespace android
152
153#endif // ANDROID_HWUI_STATEFUL_BASE_RENDERER_H
154