AssetAtlas.h revision 55b6f95ee4ace96c97508bcd14483fb4e9dbeaa0 
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
37class Caches;
38
39/**
40 * An asset atlas holds a collection of framework bitmaps in a single OpenGL
41 * texture. Each bitmap is associated with a location, defined in pixels,
42 * inside the atlas. The atlas is generated by the framework and bound as
43 * an external texture using the EGLImageKHR extension.
44 */
45class AssetAtlas {
46public:
47    /**
48     * Entry representing the position and rotation of a
49     * bitmap inside the atlas.
50     */
51    struct Entry {
52        /**
53         * The bitmap that generated this atlas entry.
54         */
55        SkBitmap* bitmap;
56
57        /**
58         * Location of the bitmap inside the atlas, in pixels.
59         */
60        int x;
61        int y;
62
63        /**
64         * If set, the bitmap is rotated 90 degrees (clockwise)
65         * inside the atlas.
66         */
67        bool rotated;
68
69        /*
70         * A "virtual texture" object that represents the texture
71         * this entry belongs to. This texture should never be
72         * modified.
73         */
74        Texture* texture;
75
76        /**
77         * Maps texture coordinates in the [0..1] range into the
78         * correct range to sample this entry from the atlas.
79         */
80        const UvMapper uvMapper;
81
82        /**
83         * Atlas this entry belongs to.
84         */
85        const AssetAtlas& atlas;
86
87    private:
88        Entry(SkBitmap* bitmap, int x, int y, bool rotated,
89                Texture* texture, const UvMapper& mapper, const AssetAtlas& atlas):
90                bitmap(bitmap), x(x), y(y), rotated(rotated),
91                texture(texture), uvMapper(mapper), atlas(atlas) { }
92
93        ~Entry() {
94            delete texture;
95        }
96
97        friend class AssetAtlas;
98    };
99
100    AssetAtlas(): mTexture(NULL), mImage(NULL), mGenerationId(0) { }
101    ~AssetAtlas() { terminate(); }
102
103    /**
104     * Initializes the atlas with the specified buffer and
105     * map. The buffer is a gralloc'd texture that will be
106     * used as an EGLImage. The map is a list of SkBitmap*
107     * and their (x, y) positions as well as their rotation
108     * flags.
109     *
110     * This method returns immediately if the atlas is already
111     * initialized. To re-initialize the atlas, you must
112     * first call terminate().
113     */
114    ANDROID_API void init(sp<GraphicBuffer> buffer, int* map, int count);
115
116    /**
117     * Destroys the atlas texture. This object can be
118     * re-initialized after calling this method.
119     *
120     * After calling this method, the width, height
121     * and texture are set to 0.
122     */
123    ANDROID_API void terminate();
124
125    /**
126     * Returns the width of this atlas in pixels.
127     * Can return 0 if the atlas is not initialized.
128     */
129    uint32_t getWidth() const {
130        return mTexture ? mTexture->width : 0;
131    }
132
133    /**
134     * Returns the height of this atlas in pixels.
135     * Can return 0 if the atlas is not initialized.
136     */
137    uint32_t getHeight() const {
138        return mTexture ? mTexture->height : 0;
139    }
140
141    /**
142     * Returns the OpenGL name of the texture backing this atlas.
143     * Can return 0 if the atlas is not initialized.
144     */
145    GLuint getTexture() const {
146        return mTexture ? mTexture->id : 0;
147    }
148
149    /**
150     * Returns the entry in the atlas associated with the specified
151     * bitmap. If the bitmap is not in the atlas, return NULL.
152     */
153    Entry* getEntry(SkBitmap* const bitmap) const;
154
155    /**
156     * Returns the texture for the atlas entry associated with the
157     * specified bitmap. If the bitmap is not in the atlas, return NULL.
158     */
159    Texture* getEntryTexture(SkBitmap* const bitmap) const;
160
161    /**
162     * Returns the current generation id of the atlas.
163     */
164    uint32_t getGenerationId() const {
165        return mGenerationId;
166    }
167
168private:
169    void createEntries(Caches& caches, int* map, int count);
170
171    Texture* mTexture;
172    Image* mImage;
173
174    uint32_t mGenerationId;
175
176    KeyedVector<SkBitmap*, Entry*> mEntries;
177}; // class AssetAtlas
178
179}; // namespace uirenderer
180}; // namespace android
181
182#endif // ANDROID_HWUI_ASSET_ATLAS_H
183