AssetAtlas.h revision 87ffb63d90fb6dd2689fe72dcb24fda9a6156220 
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 "Texture.h"
31#include "UvMapper.h"
32
33namespace android {
34namespace uirenderer {
35
36class Caches;
37class Image;
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    class Entry {
52    public:
53        /*
54         * A "virtual texture" object that represents the texture
55         * this entry belongs to. This texture should never be
56         * modified.
57         */
58        Texture* texture;
59
60        /**
61         * Maps texture coordinates in the [0..1] range into the
62         * correct range to sample this entry from the atlas.
63         */
64        const UvMapper uvMapper;
65
66        /**
67         * Unique identifier used to merge bitmaps and 9-patches stored
68         * in the atlas.
69         */
70        const void* getMergeId() const {
71            return texture->blend ? &atlas.mBlendKey : &atlas.mOpaqueKey;
72        }
73
74    private:
75        /**
76         * The pixel ref that generated this atlas entry.
77         */
78        SkPixelRef* pixelRef;
79
80        /**
81         * Location of the bitmap inside the atlas, in pixels.
82         */
83        int x;
84        int y;
85
86        /**
87         * If set, the bitmap is rotated 90 degrees (clockwise)
88         * inside the atlas.
89         */
90        bool rotated;
91
92        /**
93         * Atlas this entry belongs to.
94         */
95        const AssetAtlas& atlas;
96
97        Entry(SkPixelRef* pixelRef, int x, int y, bool rotated,
98                    Texture* texture, const UvMapper& mapper, const AssetAtlas& atlas)
99                : texture(texture)
100                , uvMapper(mapper)
101                , pixelRef(pixelRef)
102                , x(x)
103                , y(y)
104                , rotated(rotated)
105                , atlas(atlas) {
106        }
107
108        ~Entry() {
109            delete texture;
110        }
111
112        friend class AssetAtlas;
113    };
114
115    AssetAtlas(): mTexture(nullptr), mImage(nullptr),
116            mBlendKey(true), mOpaqueKey(false) { }
117    ~AssetAtlas() { terminate(); }
118
119    /**
120     * Initializes the atlas with the specified buffer and
121     * map. The buffer is a gralloc'd texture that will be
122     * used as an EGLImage. The map is a list of SkBitmap*
123     * and their (x, y) positions as well as their rotation
124     * flags.
125     *
126     * This method returns immediately if the atlas is already
127     * initialized. To re-initialize the atlas, you must
128     * first call terminate().
129     */
130    ANDROID_API void init(sp<GraphicBuffer> buffer, int64_t* map, int count);
131
132    /**
133     * Destroys the atlas texture. This object can be
134     * re-initialized after calling this method.
135     *
136     * After calling this method, the width, height
137     * and texture are set to 0.
138     */
139    void terminate();
140
141    /**
142     * Returns the width of this atlas in pixels.
143     * Can return 0 if the atlas is not initialized.
144     */
145    uint32_t getWidth() const {
146        return mTexture ? mTexture->width : 0;
147    }
148
149    /**
150     * Returns the height of this atlas in pixels.
151     * Can return 0 if the atlas is not initialized.
152     */
153    uint32_t getHeight() const {
154        return mTexture ? mTexture->height : 0;
155    }
156
157    /**
158     * Returns the OpenGL name of the texture backing this atlas.
159     * Can return 0 if the atlas is not initialized.
160     */
161    GLuint getTexture() const {
162        return mTexture ? mTexture->id : 0;
163    }
164
165    /**
166     * Returns the entry in the atlas associated with the specified
167     * bitmap. If the bitmap is not in the atlas, return NULL.
168     */
169    Entry* getEntry(const SkBitmap* bitmap) const;
170
171    /**
172     * Returns the texture for the atlas entry associated with the
173     * specified bitmap. If the bitmap is not in the atlas, return NULL.
174     */
175    Texture* getEntryTexture(const SkBitmap* bitmap) const;
176
177private:
178    void createEntries(Caches& caches, int64_t* map, int count);
179    void updateTextureId();
180
181    Texture* mTexture;
182    Image* mImage;
183
184    const bool mBlendKey;
185    const bool mOpaqueKey;
186
187    KeyedVector<const SkPixelRef*, Entry*> mEntries;
188}; // class AssetAtlas
189
190}; // namespace uirenderer
191}; // namespace android
192
193#endif // ANDROID_HWUI_ASSET_ATLAS_H
194