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 "Snapshot.h"
21
22#include <SkMatrix.h>
23#include <SkPath.h>
24#include <SkRegion.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 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 initializeRecordingSaveStack(int viewportWidth, int viewportHeight);
84
85    /**
86     * Initializes the first snapshot, computing the projection matrix,
87     * and stores the dimensions of the render target.
88     */
89    void initializeSaveStack(int viewportWidth, int viewportHeight,
90            float clipLeft, float clipTop, float clipRight, float clipBottom,
91            const Vector3& lightCenter);
92
93    bool hasRectToRectTransform() const {
94        return CC_LIKELY(currentTransform()->rectToRect());
95    }
96
97    // Save (layer)
98    int getSaveCount() const { return mSaveCount; }
99    int save(int flags);
100    void restore();
101    void restoreToCount(int saveCount);
102
103    // Save/Restore without side-effects
104    int saveSnapshot(int flags);
105    void restoreSnapshot();
106
107    // Matrix
108    void getMatrix(SkMatrix* outMatrix) const;
109    void translate(float dx, float dy, float dz = 0.0f);
110    void rotate(float degrees);
111    void scale(float sx, float sy);
112    void skew(float sx, float sy);
113
114    void setMatrix(const SkMatrix& matrix);
115    void setMatrix(const Matrix4& matrix); // internal only convenience method
116    void concatMatrix(const SkMatrix& matrix);
117    void concatMatrix(const Matrix4& matrix); // internal only convenience method
118
119    // Clip
120    const Rect& getLocalClipBounds() const { return mSnapshot->getLocalClip(); }
121    const Rect& getRenderTargetClipBounds() const { return mSnapshot->getRenderTargetClip(); }
122
123    bool quickRejectConservative(float left, float top, float right, float bottom) const;
124
125    bool clipRect(float left, float top, float right, float bottom, SkRegion::Op op);
126    bool clipPath(const SkPath* path, SkRegion::Op op);
127    bool clipRegion(const SkRegion* region, SkRegion::Op op);
128
129    /**
130     * Sets a "clipping outline", which is independent from the regular clip.
131     * Currently only supports rectangles or rounded rectangles; passing in a
132     * more complicated outline fails silently. Replaces any previous clipping
133     * outline.
134     */
135    void setClippingOutline(LinearAllocator& allocator, const Outline* outline);
136    void setClippingRoundRect(LinearAllocator& allocator,
137            const Rect& rect, float radius, bool highPriority = true);
138    void setProjectionPathMask(LinearAllocator& allocator, const SkPath* path);
139
140    /**
141     * Returns true if drawing in the rectangle (left, top, right, bottom)
142     * will be clipped out. Is conservative: might return false when subpixel-
143     * perfect tests would return true.
144     */
145    bool calculateQuickRejectForScissor(float left, float top, float right, float bottom,
146            bool* clipRequired, bool* roundRectClipRequired, bool snapOut) const;
147
148    void setDirtyClip(bool opaque) { mDirtyClip = opaque; }
149    bool getDirtyClip() const { return mDirtyClip; }
150
151    void scaleAlpha(float alpha) { mSnapshot->alpha *= alpha; }
152    void setEmpty(bool value) { mSnapshot->empty = value; }
153    void setInvisible(bool value) { mSnapshot->invisible = value; }
154
155    inline const mat4* currentTransform() const { return currentSnapshot()->transform; }
156    inline const Rect& currentRenderTargetClip() const { return currentSnapshot()->getRenderTargetClip(); }
157    inline Region* currentRegion() const { return currentSnapshot()->region; }
158    inline int currentFlags() const { return currentSnapshot()->flags; }
159    const Vector3& currentLightCenter() const { return currentSnapshot()->getRelativeLightCenter(); }
160    inline bool currentlyIgnored() const { return currentSnapshot()->isIgnored(); }
161    int getViewportWidth() const { return currentSnapshot()->getViewportWidth(); }
162    int getViewportHeight() const { return currentSnapshot()->getViewportHeight(); }
163    int getWidth() const { return mWidth; }
164    int getHeight() const { return mHeight; }
165    bool clipIsSimple() const { return currentSnapshot()->clipIsSimple(); }
166
167    inline const Snapshot* currentSnapshot() const { return mSnapshot; }
168    inline Snapshot* writableSnapshot() { return mSnapshot; }
169    inline const Snapshot* firstSnapshot() const { return &mFirstSnapshot; }
170
171private:
172    Snapshot* allocSnapshot(Snapshot* previous, int savecount);
173    void freeSnapshot(Snapshot* snapshot);
174    void freeAllSnapshots();
175
176    /// indicates that the clip has been changed since the last time it was consumed
177    // TODO: delete when switching to HWUI_NEW_OPS
178    bool mDirtyClip;
179
180    /// Dimensions of the drawing surface
181    int mWidth, mHeight;
182
183    /// Number of saved states
184    int mSaveCount;
185
186    /// Base state
187    Snapshot mFirstSnapshot;
188
189    /// Host providing callbacks
190    CanvasStateClient& mCanvas;
191
192    /// Current state
193    Snapshot* mSnapshot;
194
195    // Pool of allocated snapshots to re-use
196    // NOTE: The dtors have already been invoked!
197    Snapshot* mSnapshotPool = nullptr;
198    int mSnapshotPoolCount = 0;
199
200}; // class CanvasState
201
202}; // namespace uirenderer
203}; // namespace android
204
205#endif // ANDROID_HWUI_CANVAS_STATE_H
206