Snapshot.h revision 260e102162322958cf17dbd895cd6bd30dc87e32 
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 "Layer.h"
26#include "Matrix.h"
27#include "Rect.h"
28
29namespace android {
30namespace uirenderer {
31
32/**
33 * A snapshot holds information about the current state of the rendering
34 * surface. A snapshot is usually created whenever the user calls save()
35 * and discarded when the user calls restore(). Once a snapshot is created,
36 * it can hold information for deferred rendering.
37 *
38 * Each snapshot has a link to a previous snapshot, indicating the previous
39 * state of the renderer.
40 */
41class Snapshot: public LightRefBase<Snapshot> {
42public:
43    Snapshot(): layer(NULL), fbo(0) { }
44
45    /**
46     * Copies the specified snapshot. Only the transform and clip rectangle
47     * are copied. The layer information is set to 0 and the transform is
48     * assumed to be dirty. The specified snapshot is stored as the previous
49     * snapshot.
50     */
51    Snapshot(const sp<Snapshot> s):
52            height(s->height),
53            transform(s->transform),
54            clipRect(s->clipRect),
55            flags(kFlagDirtyTransform),
56            previous(s),
57            layer(NULL),
58            fbo(s->fbo) {
59    }
60
61    /**
62     * Various flags set on #flags.
63     */
64    enum Flags {
65        /**
66         * Indicates that the clip region was modified. When this
67         * snapshot is restored so must the clip.
68         */
69        kFlagClipSet = 0x1,
70        /**
71         * Indicates that the snapshot holds new transform
72         * information.
73         */
74        kFlagDirtyTransform = 0x2,
75        /**
76         * Indicates that this snapshot was created when saving
77         * a new layer.
78         */
79        kFlagIsLayer = 0x4,
80        /**
81         * Indicates that this snapshot has changed the ortho matrix.
82         */
83        kFlagDirtyOrtho = 0x8,
84    };
85
86    /**
87     * Returns the current clip region mapped by the current transform.
88     */
89    const Rect& getMappedClip() {
90        if (flags & kFlagDirtyTransform) {
91            flags &= ~kFlagDirtyTransform;
92            mappedClip.set(clipRect);
93            transform.mapRect(mappedClip);
94        }
95        return mappedClip;
96    }
97
98    /**
99     * Height of the framebuffer the snapshot is rendering into.
100     */
101    int height;
102
103    /**
104     * Local transformation. Holds the current translation, scale and
105     * rotation values.
106     */
107    mat4 transform;
108
109    /**
110     * Current clip region.
111     */
112    Rect clipRect;
113
114    /**
115     * Dirty flags.
116     */
117    int flags;
118
119    /**
120     * Previous snapshot.
121     */
122    sp<Snapshot> previous;
123
124    /**
125     * Only set when the flag kFlagIsLayer is set.
126     */
127    Layer* layer;
128    GLuint fbo;
129
130    /**
131     * Contains the previous ortho matrix.
132     */
133    mat4 orthoMatrix;
134
135private:
136    // Clipping rectangle mapped with the transform
137    Rect mappedClip;
138}; // class Snapshot
139
140}; // namespace uirenderer
141}; // namespace android
142
143#endif // ANDROID_UI_SNAPSHOT_H
144