Snapshot.h revision 3d58c03de0d8877b36cdb78b0ca8b5cac7f600e2 
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        mappedClip.set(s->clipRect);
60        transform.mapRect(mappedClip);
61    }
62
63    /**
64     * Various flags set on #flags.
65     */
66    enum Flags {
67        /**
68         * Indicates that the clip region was modified. When this
69         * snapshot is restored so must the clip.
70         */
71        kFlagClipSet = 0x1,
72        /**
73         * Indicates that the snapshot holds new transform
74         * information.
75         */
76        kFlagDirtyTransform = 0x2,
77        /**
78         * Indicates that this snapshot was created when saving
79         * a new layer.
80         */
81        kFlagIsLayer = 0x4,
82        /**
83         * Indicates that this snapshot has changed the ortho matrix.
84         */
85        kFlagDirtyOrtho = 0x8,
86    };
87
88    /**
89     * Returns the current clip region mapped by the current transform.
90     */
91    const Rect& getMappedClip() {
92        return mappedClip;
93    }
94
95    /**
96     * Intersects the current clip with the new clip rectangle.
97     */
98    bool clip(float left, float top, float right, float bottom) {
99        bool clipped = clipRect.intersect(left, top, right, bottom);
100        if (flags & kFlagDirtyTransform) {
101            flags &= ~kFlagDirtyTransform;
102            mappedClip.set(clipRect);
103            transform.mapRect(mappedClip);
104        }
105        return clipped;
106    }
107
108    /**
109     * Height of the framebuffer the snapshot is rendering into.
110     */
111    int height;
112
113    /**
114     * Local transformation. Holds the current translation, scale and
115     * rotation values.
116     */
117    mat4 transform;
118
119    /**
120     * Current clip region.
121     */
122    Rect clipRect;
123
124    /**
125     * Dirty flags.
126     */
127    int flags;
128
129    /**
130     * Previous snapshot.
131     */
132    sp<Snapshot> previous;
133
134    /**
135     * Only set when the flag kFlagIsLayer is set.
136     */
137    Layer* layer;
138    GLuint fbo;
139
140    /**
141     * Contains the previous ortho matrix.
142     */
143    mat4 orthoMatrix;
144
145private:
146    // Clipping rectangle mapped with the transform
147    Rect mappedClip;
148}; // class Snapshot
149
150}; // namespace uirenderer
151}; // namespace android
152
153#endif // ANDROID_UI_SNAPSHOT_H
154