CanvasState.h revision fca52b7583d1e5f5ff8ed06554875d2a30ef56fa 
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_CANVAS_STATE_H
18#define ANDROID_HWUI_CANVAS_STATE_H
19
20#include <SkMatrix.h>
21#include <SkPath.h>
22#include <SkRegion.h>
23
24#include "Snapshot.h"
25
26namespace android {
27namespace uirenderer {
28
29/**
30 * Abstract base class for any class containing CanvasState.
31 * Defines three mandatory callbacks.
32 */
33class CanvasStateClient {
34public:
35    CanvasStateClient() { }
36    virtual ~CanvasStateClient() { }
37
38    /**
39     * Callback allowing embedder to take actions in the middle of a
40     * setViewport() call.
41     */
42    virtual void onViewportInitialized() = 0;
43
44    /**
45     * Callback allowing embedder to take actions in the middle of a
46     * restore() call.  May be called several times sequentially.
47     */
48    virtual void onSnapshotRestored(const Snapshot& removed, const Snapshot& restored) = 0;
49
50    /**
51     * Allows subclasses to control what value is stored in snapshot's
52     * fbo field in * initializeSaveStack.
53     */
54    virtual GLuint getTargetFbo() const = 0;
55
56}; // class CanvasStateClient
57
58/**
59 * Implements Canvas state methods on behalf of Renderers.
60 *
61 * Manages the Snapshot stack, implementing matrix, save/restore, and clipping methods in the
62 * Renderer interface. Drawing and recording classes that include a CanvasState will have
63 * different use cases:
64 *
65 * Drawing code maintaining canvas state (i.e. OpenGLRenderer) can query attributes (such as
66 * transform) or hook into changes (e.g. save/restore) with minimal surface area for manipulating
67 * the stack itself.
68 *
69 * Recording code maintaining canvas state (i.e. DisplayListCanvas) can both record and pass
70 * through state operations to CanvasState, so that not only will querying operations work
71 * (getClip/Matrix), but so that quickRejection can also be used.
72 */
73
74class ANDROID_API CanvasState {
75public:
76    CanvasState(CanvasStateClient& renderer);
77    ~CanvasState();
78
79    /**
80     * Initializes the first snapshot, computing the projection matrix,
81     * and stores the dimensions of the render target.
82     */
83    void initializeSaveStack(float clipLeft, float clipTop, float clipRight, float clipBottom,
84            const Vector3& lightCenter);
85
86    void setViewport(int width, int height);
87
88    bool hasRectToRectTransform() const {
89        return CC_LIKELY(currentTransform()->rectToRect());
90    }
91
92    // Save (layer)
93    int getSaveCount() const { return mSaveCount; }
94    int save(int flags);
95    void restore();
96    void restoreToCount(int saveCount);
97
98    // Save/Restore without side-effects
99    int saveSnapshot(int flags);
100    void restoreSnapshot();
101
102    // Matrix
103    void getMatrix(SkMatrix* outMatrix) const;
104    void translate(float dx, float dy, float dz = 0.0f);
105    void rotate(float degrees);
106    void scale(float sx, float sy);
107    void skew(float sx, float sy);
108
109    void setMatrix(const SkMatrix& matrix);
110    void setMatrix(const Matrix4& matrix); // internal only convenience method
111    void concatMatrix(const SkMatrix& matrix);
112    void concatMatrix(const Matrix4& matrix); // internal only convenience method
113
114    // Clip
115    const Rect& getLocalClipBounds() const { return mSnapshot->getLocalClip(); }
116    const Rect& getRenderTargetClipBounds() const { return mSnapshot->getRenderTargetClip(); }
117
118    bool quickRejectConservative(float left, float top, float right, float bottom) const;
119
120    bool clipRect(float left, float top, float right, float bottom, SkRegion::Op op);
121    bool clipPath(const SkPath* path, SkRegion::Op op);
122    bool clipRegion(const SkRegion* region, SkRegion::Op op);
123
124    /**
125     * Sets a "clipping outline", which is independent from the regular clip.
126     * Currently only supports rectangles or rounded rectangles; passing in a
127     * more complicated outline fails silently. Replaces any previous clipping
128     * outline.
129     */
130    void setClippingOutline(LinearAllocator& allocator, const Outline* outline);
131    void setClippingRoundRect(LinearAllocator& allocator,
132            const Rect& rect, float radius, bool highPriority = true);
133    void setProjectionPathMask(LinearAllocator& allocator, const SkPath* path);
134
135    /**
136     * Returns true if drawing in the rectangle (left, top, right, bottom)
137     * will be clipped out. Is conservative: might return false when subpixel-
138     * perfect tests would return true.
139     */
140    bool calculateQuickRejectForScissor(float left, float top, float right, float bottom,
141            bool* clipRequired, bool* roundRectClipRequired, bool snapOut) const;
142
143    void setDirtyClip(bool opaque) { mDirtyClip = opaque; }
144    bool getDirtyClip() const { return mDirtyClip; }
145
146    void scaleAlpha(float alpha) { mSnapshot->alpha *= alpha; }
147    void setEmpty(bool value) { mSnapshot->empty = value; }
148    void setInvisible(bool value) { mSnapshot->invisible = value; }
149
150    inline const mat4* currentTransform() const { return currentSnapshot()->transform; }
151    inline const Rect& currentClipRect() const { return currentSnapshot()->getClipRect(); }
152    inline Region* currentRegion() const { return currentSnapshot()->region; }
153    inline int currentFlags() const { return currentSnapshot()->flags; }
154    const Vector3& currentLightCenter() const { return currentSnapshot()->getRelativeLightCenter(); }
155    inline bool currentlyIgnored() const { return currentSnapshot()->isIgnored(); }
156    int getViewportWidth() const { return currentSnapshot()->getViewportWidth(); }
157    int getViewportHeight() const { return currentSnapshot()->getViewportHeight(); }
158    int getWidth() { return mWidth; }
159    int getHeight() { return mHeight; }
160
161    inline const Snapshot* currentSnapshot() const {
162        return mSnapshot != nullptr ? mSnapshot.get() : mFirstSnapshot.get();
163    }
164    inline Snapshot* writableSnapshot() { return mSnapshot.get(); }
165    inline const Snapshot* firstSnapshot() const { return mFirstSnapshot.get(); }
166
167private:
168    /// No default constructor - must supply a CanvasStateClient (mCanvas).
169    CanvasState();
170
171    /// indicates that the clip has been changed since the last time it was consumed
172    bool mDirtyClip;
173
174    /// Dimensions of the drawing surface
175    int mWidth, mHeight;
176
177    /// Number of saved states
178    int mSaveCount;
179
180    /// Base state
181    sp<Snapshot> mFirstSnapshot;
182
183    /// Host providing callbacks
184    CanvasStateClient& mCanvas;
185
186    /// Current state
187    sp<Snapshot> mSnapshot;
188
189}; // class CanvasState
190
191}; // namespace uirenderer
192}; // namespace android
193
194#endif // ANDROID_HWUI_CANVAS_STATE_H
195