Snapshot.h revision ae5575b3421c8fbe590ab046d7d5f2b36ecfd821 
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_UI_SNAPSHOT_H
18#define ANDROID_UI_SNAPSHOT_H
19
20#include <GLES2/gl2.h>
21#include <GLES2/gl2ext.h>
22
23#include <utils/RefBase.h>
24
25#include <SkRegion.h>
26
27#include "Layer.h"
28#include "Matrix.h"
29#include "Rect.h"
30
31namespace android {
32namespace uirenderer {
33
34/**
35 * A snapshot holds information about the current state of the rendering
36 * surface. A snapshot is usually created whenever the user calls save()
37 * and discarded when the user calls restore(). Once a snapshot is created,
38 * it can hold information for deferred rendering.
39 *
40 * Each snapshot has a link to a previous snapshot, indicating the previous
41 * state of the renderer.
42 */
43class Snapshot: public LightRefBase<Snapshot> {
44public:
45    Snapshot(): flags(0), previous(NULL), layer(NULL), fbo(0) { }
46
47    /**
48     * Copies the specified snapshot. Only the transform and clip rectangle
49     * are copied. The layer information is set to 0 and the transform is
50     * assumed to be dirty. The specified snapshot is stored as the previous
51     * snapshot.
52     */
53    Snapshot(const sp<Snapshot>& s):
54            height(s->height),
55            transform(s->transform),
56            clipRect(s->clipRect),
57            flags(0),
58            previous(s),
59            layer(NULL),
60            fbo(s->fbo),
61            localClip(s->localClip) {
62    }
63
64    /**
65     * Various flags set on #flags.
66     */
67    enum Flags {
68        /**
69         * Indicates that the clip region was modified. When this
70         * snapshot is restored so must the clip.
71         */
72        kFlagClipSet = 0x1,
73        /**
74         * Indicates that this snapshot was created when saving
75         * a new layer.
76         */
77        kFlagIsLayer = 0x2,
78        /**
79         * Indicates that this snapshot has changed the ortho matrix.
80         */
81        kFlagDirtyOrtho = 0x4,
82        /**
83         * Indicates that the local clip should be recomputed.
84         */
85        kFlagDirtyLocalClip = 0x8,
86    };
87
88    /**
89     * Intersects the current clip with the new clip rectangle.
90     */
91    bool clip(float left, float top, float right, float bottom, SkRegion::Op op) {
92        bool clipped = false;
93
94        Rect r(left, top, right, bottom);
95        transform.mapRect(r);
96
97        switch (op) {
98            case SkRegion::kDifference_Op:
99                break;
100            case SkRegion::kIntersect_Op:
101                clipped = clipRect.intersect(r);
102                break;
103            case SkRegion::kUnion_Op:
104                clipped = clipRect.unionWith(r);
105                break;
106            case SkRegion::kXOR_Op:
107                break;
108            case SkRegion::kReverseDifference_Op:
109                break;
110            case SkRegion::kReplace_Op:
111                clipRect.set(r);
112                clipped = true;
113                break;
114        }
115
116        if (clipped) {
117            flags |= Snapshot::kFlagClipSet | Snapshot::kFlagDirtyLocalClip;
118        }
119
120        return clipped;
121    }
122
123    /**
124     * Sets the current clip.
125     */
126    void setClip(float left, float top, float right, float bottom) {
127        clipRect.set(left, top, right, bottom);
128        flags |= Snapshot::kFlagClipSet | Snapshot::kFlagDirtyLocalClip;
129    }
130
131    const Rect& getLocalClip() {
132        if (flags & Snapshot::kFlagDirtyLocalClip) {
133            mat4 inverse;
134            inverse.loadInverse(transform);
135            localClip.set(clipRect);
136            inverse.mapRect(localClip);
137            flags &= ~Snapshot::kFlagDirtyLocalClip;
138        }
139        return localClip;
140    }
141
142    /**
143     * Height of the framebuffer the snapshot is rendering into.
144     */
145    int height;
146
147    /**
148     * Local transformation. Holds the current translation, scale and
149     * rotation values.
150     */
151    mat4 transform;
152
153    /**
154     * Current clip region. The clip is stored in canvas-space coordinates,
155     * (screen-space coordinates in the regular case.)
156     */
157    Rect clipRect;
158
159    /**
160     * Dirty flags.
161     */
162    int flags;
163
164    /**
165     * Previous snapshot.
166     */
167    sp<Snapshot> previous;
168
169    /**
170     * Only set when the flag kFlagIsLayer is set.
171     */
172    Layer* layer;
173    GLuint fbo;
174
175    /**
176     * Contains the previous ortho matrix.
177     */
178    mat4 orthoMatrix;
179
180private:
181    Rect localClip;
182
183}; // class Snapshot
184
185}; // namespace uirenderer
186}; // namespace android
187
188#endif // ANDROID_UI_SNAPSHOT_H
189