AssetAtlas.h revision a404e16e4933857464046d763ed7629cd0c86cbf 
1/*
2 * Copyright (C) 2013 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_ASSET_ATLAS_H
18#define ANDROID_HWUI_ASSET_ATLAS_H
19
20#include <GLES2/gl2.h>
21
22#include <ui/GraphicBuffer.h>
23
24#include <utils/KeyedVector.h>
25
26#include <cutils/compiler.h>
27
28#include <SkBitmap.h>
29
30#include "Image.h"
31#include "Texture.h"
32#include "UvMapper.h"
33
34namespace android {
35namespace uirenderer {
36
37/**
38 * An asset atlas holds a collection of framework bitmaps in a single OpenGL
39 * texture. Each bitmap is associated with a location, defined in pixels,
40 * inside the atlas. The atlas is generated by the framework and bound as
41 * an external texture using the EGLImageKHR extension.
42 */
43class AssetAtlas {
44public:
45    /**
46     * Entry representing the position and rotation of a
47     * bitmap inside the atlas.
48     */
49    struct Entry {
50        /**
51         * The bitmap that generated this atlas entry.
52         */
53        SkBitmap* bitmap;
54
55        /**
56         * Location of the bitmap inside the atlas, in pixels.
57         */
58        int x;
59        int y;
60
61        /**
62         * If set, the bitmap is rotated 90 degrees (clockwise)
63         * inside the atlas.
64         */
65        bool rotated;
66
67        /*
68         * A "virtual texture" object that represents the texture
69         * this entry belongs to. This texture should never be
70         * modified.
71         */
72        Texture* texture;
73
74        /**
75         * Maps texture coordinates in the [0..1] range into the
76         * correct range to sample this entry from the atlas.
77         */
78        const UvMapper uvMapper;
79
80        /**
81         * Atlas this entry belongs to.
82         */
83        const AssetAtlas& atlas;
84
85    private:
86        Entry(SkBitmap* bitmap, int x, int y, bool rotated,
87                Texture* texture, const UvMapper& mapper, const AssetAtlas& atlas):
88                bitmap(bitmap), x(x), y(y), rotated(rotated),
89                texture(texture), uvMapper(mapper), atlas(atlas) { }
90
91        ~Entry() {
92            delete texture;
93        }
94
95        friend class AssetAtlas;
96    };
97
98    AssetAtlas(): mTexture(NULL), mImage(NULL) { }
99    ~AssetAtlas() { terminate(); }
100
101    /**
102     * Initializes the atlas with the specified buffer and
103     * map. The buffer is a gralloc'd texture that will be
104     * used as an EGLImage. The map is a list of SkBitmap*
105     * and their (x, y) positions as well as their rotation
106     * flags.
107     *
108     * This method returns immediately if the atlas is already
109     * initialized. To re-initialize the atlas, you must
110     * first call terminate().
111     */
112    ANDROID_API void init(sp<GraphicBuffer> buffer, int* map, int count);
113
114    /**
115     * Destroys the atlas texture. This object can be
116     * re-initialized after calling this method.
117     *
118     * After calling this method, the width, height
119     * and texture are set to 0.
120     */
121    ANDROID_API void terminate();
122
123    /**
124     * Returns the width of this atlas in pixels.
125     * Can return 0 if the atlas is not initialized.
126     */
127    uint32_t getWidth() const {
128        return mTexture ? mTexture->width : 0;
129    }
130
131    /**
132     * Returns the height of this atlas in pixels.
133     * Can return 0 if the atlas is not initialized.
134     */
135    uint32_t getHeight() const {
136        return mTexture ? mTexture->height : 0;
137    }
138
139    /**
140     * Returns the OpenGL name of the texture backing this atlas.
141     * Can return 0 if the atlas is not initialized.
142     */
143    GLuint getTexture() const {
144        return mTexture ? mTexture->id : 0;
145    }
146
147    /**
148     * Returns the entry in the atlas associated with the specified
149     * bitmap. If the bitmap is not in the atlas, return NULL.
150     */
151    Entry* getEntry(SkBitmap* const bitmap) const;
152
153    /**
154     * Returns the texture for the atlas entry associated with the
155     * specified bitmap. If the bitmap is not in the atlas, return NULL.
156     */
157    Texture* getEntryTexture(SkBitmap* const bitmap) const;
158
159private:
160    void createEntries(int* map, int count);
161
162    Texture* mTexture;
163    Image* mImage;
164
165    KeyedVector<SkBitmap*, Entry*> mEntries;
166}; // class AssetAtlas
167
168}; // namespace uirenderer
169}; // namespace android
170
171#endif // ANDROID_HWUI_ASSET_ATLAS_H
172