AssetAtlas.h revision 38e0c32852e3b9d8ca4a9d3791577f52536419cb 
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 "Texture.h"
21#include "UvMapper.h"
22
23#include <cutils/compiler.h>
24#include <GLES2/gl2.h>
25#include <ui/GraphicBuffer.h>
26#include <SkBitmap.h>
27
28#include <memory>
29#include <unordered_map>
30
31namespace android {
32namespace uirenderer {
33
34class Caches;
35class Image;
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 texture and uvMapper of a PixelRef in the
47     * atlas
48     */
49    class Entry {
50    public:
51        /*
52         * A "virtual texture" object that represents the texture
53         * this entry belongs to. This texture should never be
54         * modified.
55         */
56        Texture* texture;
57
58        /**
59         * Maps texture coordinates in the [0..1] range into the
60         * correct range to sample this entry from the atlas.
61         */
62        const UvMapper uvMapper;
63
64        /**
65         * Unique identifier used to merge bitmaps and 9-patches stored
66         * in the atlas.
67         */
68        const void* getMergeId() const {
69            return texture->blend ? &atlas.mBlendKey : &atlas.mOpaqueKey;
70        }
71
72        ~Entry() {
73            delete texture;
74        }
75
76    private:
77        /**
78         * The pixel ref that generated this atlas entry.
79         */
80        SkPixelRef* pixelRef;
81
82        /**
83         * Atlas this entry belongs to.
84         */
85        const AssetAtlas& atlas;
86
87        Entry(SkPixelRef* pixelRef, Texture* texture, const UvMapper& mapper,
88                    const AssetAtlas& atlas)
89                : texture(texture)
90                , uvMapper(mapper)
91                , pixelRef(pixelRef)
92                , atlas(atlas) {
93        }
94
95        friend class AssetAtlas;
96    };
97
98    AssetAtlas(): mTexture(nullptr), mImage(nullptr),
99            mBlendKey(true), mOpaqueKey(false) { }
100    ~AssetAtlas() { terminate(); }
101
102    /**
103     * Initializes the atlas with the specified buffer and
104     * map. The buffer is a gralloc'd texture that will be
105     * used as an EGLImage. The map is a list of SkBitmap*
106     * and their (x, y) positions
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, int64_t* 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    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     * pixelRef. If the pixelRef is not in the atlas, return NULL.
150     */
151    Entry* getEntry(const SkPixelRef* pixelRef) const;
152
153    /**
154     * Returns the texture for the atlas entry associated with the
155     * specified pixelRef. If the pixelRef is not in the atlas, return NULL.
156     */
157    Texture* getEntryTexture(const SkPixelRef* pixelRef) const;
158
159private:
160    void createEntries(Caches& caches, int64_t* map, int count);
161
162    Texture* mTexture;
163    Image* mImage;
164
165    const bool mBlendKey;
166    const bool mOpaqueKey;
167
168    std::unordered_map<const SkPixelRef*, std::unique_ptr<Entry>> mEntries;
169}; // class AssetAtlas
170
171}; // namespace uirenderer
172}; // namespace android
173
174#endif // ANDROID_HWUI_ASSET_ATLAS_H
175