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1 /*
2  * Copyright (C) 2010 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_SNAPSHOT_H
18 #define ANDROID_HWUI_SNAPSHOT_H
19 
20 #include <GLES2/gl2.h>
21 #include <GLES2/gl2ext.h>
22 
23 #include <utils/RefBase.h>
24 #include <ui/Region.h>
25 
26 #include <SkRegion.h>
27 
28 #include "Layer.h"
29 #include "Matrix.h"
30 #include "Rect.h"
31 
32 namespace android {
33 namespace uirenderer {
34 
35 /**
36  * A snapshot holds information about the current state of the rendering
37  * surface. A snapshot is usually created whenever the user calls save()
38  * and discarded when the user calls restore(). Once a snapshot is created,
39  * it can hold information for deferred rendering.
40  *
41  * Each snapshot has a link to a previous snapshot, indicating the previous
42  * state of the renderer.
43  */
44 class Snapshot: public LightRefBase<Snapshot> {
45 public:
46 
47     Snapshot();
48     Snapshot(const sp<Snapshot>& s, int saveFlags);
49 
50     /**
51      * Various flags set on ::flags.
52      */
53     enum Flags {
54         /**
55          * Indicates that the clip region was modified. When this
56          * snapshot is restored so must the clip.
57          */
58         kFlagClipSet = 0x1,
59         /**
60          * Indicates that this snapshot was created when saving
61          * a new layer.
62          */
63         kFlagIsLayer = 0x2,
64         /**
65          * Indicates that this snapshot is a special type of layer
66          * backed by an FBO. This flag only makes sense when the
67          * flag kFlagIsLayer is also set.
68          */
69         kFlagIsFboLayer = 0x4,
70         /**
71          * Indicates that this snapshot has changed the ortho matrix.
72          */
73         kFlagDirtyOrtho = 0x8,
74         /**
75          * Indicates that this snapshot or an ancestor snapshot is
76          * an FBO layer.
77          */
78         kFlagFboTarget = 0x10
79     };
80 
81     /**
82      * Modifies the current clip with the new clip rectangle and
83      * the specified operation. The specified rectangle is transformed
84      * by this snapshot's trasnformation.
85      */
86     bool clip(float left, float top, float right, float bottom,
87             SkRegion::Op op = SkRegion::kIntersect_Op);
88 
89     /**
90      * Modifies the current clip with the new clip rectangle and
91      * the specified operation. The specified rectangle is considered
92      * already transformed.
93      */
94     bool clipTransformed(const Rect& r, SkRegion::Op op = SkRegion::kIntersect_Op);
95 
96     /**
97      * Modifies the current clip with the specified region and operation.
98      * The specified region is considered already transformed.
99      */
100     bool clipRegionTransformed(const SkRegion& region, SkRegion::Op op);
101 
102     /**
103      * Sets the current clip.
104      */
105     void setClip(float left, float top, float right, float bottom);
106 
107     /**
108      * Returns the current clip in local coordinates. The clip rect is
109      * transformed by the inverse transform matrix.
110      */
111     const Rect& getLocalClip();
112 
113     /**
114      * Resets the clip to the specified rect.
115      */
116     void resetClip(float left, float top, float right, float bottom);
117 
118     /**
119      * Resets the current transform to a pure 3D translation.
120      */
121     void resetTransform(float x, float y, float z);
122 
123     /**
124      * Indicates whether this snapshot should be ignored. A snapshot
125      * is typicalled ignored if its layer is invisible or empty.
126      */
127     bool isIgnored() const;
128 
129     /**
130      * Indicates whether the current transform has perspective components.
131      */
132     bool hasPerspectiveTransform() const;
133 
134     /**
135      * Dirty flags.
136      */
137     int flags;
138 
139     /**
140      * Previous snapshot.
141      */
142     sp<Snapshot> previous;
143 
144     /**
145      * A pointer to the currently active layer.
146      *
147      * This snapshot does not own the layer, this pointer must not be freed.
148      */
149     Layer* layer;
150 
151     /**
152      * Target FBO used for rendering. Set to 0 when rendering directly
153      * into the framebuffer.
154      */
155     GLuint fbo;
156 
157     /**
158      * Indicates that this snapshot is invisible and nothing should be drawn
159      * inside it. This flag is set only when the layer clips drawing to its
160      * bounds and is passed to subsequent snapshots.
161      */
162     bool invisible;
163 
164     /**
165      * If set to true, the layer will not be composited. This is similar to
166      * invisible but this flag is not passed to subsequent snapshots.
167      */
168     bool empty;
169 
170     /**
171      * Current viewport.
172      */
173     Rect viewport;
174 
175     /**
176      * Height of the framebuffer the snapshot is rendering into.
177      */
178     int height;
179 
180     /**
181      * Contains the previous ortho matrix.
182      */
183     mat4 orthoMatrix;
184 
185     /**
186      * Local transformation. Holds the current translation, scale and
187      * rotation values.
188      *
189      * This is a reference to a matrix owned by this snapshot or another
190      *  snapshot. This pointer must not be freed. See ::mTransformRoot.
191      */
192     mat4* transform;
193 
194     /**
195      * Current clip rect. The clip is stored in canvas-space coordinates,
196      * (screen-space coordinates in the regular case.)
197      *
198      * This is a reference to a rect owned by this snapshot or another
199      * snapshot. This pointer must not be freed. See ::mClipRectRoot.
200      */
201     Rect* clipRect;
202 
203     /**
204      * Current clip region. The clip is stored in canvas-space coordinates,
205      * (screen-space coordinates in the regular case.)
206      *
207      * This is a reference to a region owned by this snapshot or another
208      * snapshot. This pointer must not be freed. See ::mClipRegionRoot.
209      */
210     SkRegion* clipRegion;
211 
212     /**
213      * The ancestor layer's dirty region.
214      *
215      * This is a reference to a region owned by a layer. This pointer must
216      * not be freed.
217      */
218     Region* region;
219 
220     /**
221      * Current alpha value. This value is 1 by default, but may be set by a DisplayList which
222      * has translucent rendering in a non-overlapping View. This value will be used by
223      * the renderer to set the alpha in the current color being used for ensuing drawing
224      * operations. The value is inherited by child snapshots because the same value should
225      * be applied to descendents of the current DisplayList (for example, a TextView contains
226      * the base alpha value which should be applied to the child DisplayLists used for drawing
227      * the actual text).
228      */
229     float alpha;
230 
231     void dump() const;
232 
233 private:
234     void ensureClipRegion();
235     void copyClipRectFromRegion();
236 
237     bool clipRegionOp(float left, float top, float right, float bottom, SkRegion::Op op);
238 
239     mat4 mTransformRoot;
240     Rect mClipRectRoot;
241     Rect mLocalClip;
242 
243     SkRegion mClipRegionRoot;
244 
245 }; // class Snapshot
246 
247 }; // namespace uirenderer
248 }; // namespace android
249 
250 #endif // ANDROID_HWUI_SNAPSHOT_H
251