TextureCache.h revision 21b028a44f3e0bd9b0f0432b8b92c45f661d22a4 
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_TEXTURE_CACHE_H
18#define ANDROID_UI_TEXTURE_CACHE_H
19
20#include <SkBitmap.h>
21
22#include "Texture.h"
23#include "utils/GenerationCache.h"
24
25namespace android {
26namespace uirenderer {
27
28/**
29 * A simple LRU texture cache. The cache has a maximum size expressed in bytes.
30 * Any texture added to the cache causing the cache to grow beyond the maximum
31 * allowed size will also cause the oldest texture to be kicked out.
32 */
33class TextureCache: public OnEntryRemoved<SkBitmap*, Texture*> {
34public:
35    TextureCache();
36    TextureCache(uint32_t maxByteSize);
37    ~TextureCache();
38
39    /**
40     * Used as a callback when an entry is removed from the cache.
41     * Do not invoke directly.
42     */
43    void operator()(SkBitmap*& bitmap, Texture*& texture);
44
45    /**
46     * Returns the texture associated with the specified bitmap. If the texture
47     * cannot be found in the cache, a new texture is generated.
48     */
49    Texture* get(SkBitmap* bitmap);
50    /**
51     * Removes the texture associated with the specified bitmap. Returns NULL
52     * if the texture cannot be found. Upon remove the texture is freed.
53     */
54    void remove(SkBitmap* bitmap);
55    /**
56     * Clears the cache. This causes all textures to be deleted.
57     */
58    void clear();
59
60    /**
61     * Sets the maximum size of the cache in bytes.
62     */
63    void setMaxSize(uint32_t maxSize);
64    /**
65     * Returns the maximum size of the cache in bytes.
66     */
67    uint32_t getMaxSize();
68    /**
69     * Returns the current size of the cache in bytes.
70     */
71    uint32_t getSize();
72
73private:
74    /**
75     * Generates the texture from a bitmap into the specified texture structure.
76     *
77     * @param regenerate If true, the bitmap data is reuploaded into the texture, but
78     *        no new texture is generated.
79     */
80    void generateTexture(SkBitmap* bitmap, Texture* texture, bool regenerate = false);
81
82    void uploadPalettedTexture(bool resize, SkBitmap* bitmap, uint32_t width, uint32_t height);
83    void uploadToTexture(bool resize, GLenum format, GLsizei width, GLsizei height,
84            GLenum type, const GLvoid * data);
85
86    void init();
87
88    GenerationCache<SkBitmap*, Texture*> mCache;
89
90    uint32_t mSize;
91    uint32_t mMaxSize;
92    GLint mMaxTextureSize;
93
94    /**
95     * Used to access mCache and mSize. All methods are accessed from a single
96     * thread except for remove().
97     */
98    mutable Mutex mLock;
99}; // class TextureCache
100
101}; // namespace uirenderer
102}; // namespace android
103
104#endif // ANDROID_UI_TEXTURE_CACHE_H
105