TextureCache.h revision 9cccc2b9bdd4850a3f9679569aaec3ab98477a5d 
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 "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(uint32_t maxByteSize);
36    ~TextureCache();
37
38    /**
39     * Used as a callback when an entry is removed from the cache.
40     * Do not invoke directly.
41     */
42    void operator()(SkBitmap*& bitmap, Texture*& texture);
43
44    /**
45     * Returns the texture associated with the specified bitmap. If the texture
46     * cannot be found in the cache, a new texture is generated.
47     */
48    Texture* get(SkBitmap* bitmap);
49    /**
50     * Removes the texture associated with the specified bitmap. Returns NULL
51     * if the texture cannot be found. Upon remove the texture is freed.
52     */
53    void remove(SkBitmap* bitmap);
54    /**
55     * Clears the cache. This causes all textures to be deleted.
56     */
57    void clear();
58
59    /**
60     * Sets the maximum size of the cache in bytes.
61     */
62    void setMaxSize(uint32_t maxSize);
63    /**
64     * Returns the maximum size of the cache in bytes.
65     */
66    uint32_t getMaxSize();
67    /**
68     * Returns the current size of the cache in bytes.
69     */
70    uint32_t getSize();
71
72private:
73    /**
74     * Generates the texture from a bitmap into the specified texture structure.
75     *
76     * @param regenerate If true, the bitmap data is reuploaded into the texture, but
77     *        no new texture is generated.
78     */
79    void generateTexture(SkBitmap* bitmap, Texture* texture, bool regenerate = false);
80
81    GenerationCache<SkBitmap*, Texture*> mCache;
82
83    uint32_t mSize;
84    uint32_t mMaxSize;
85    GLuint mMaxTextureSize;
86}; // class TextureCache
87
88}; // namespace uirenderer
89}; // namespace android
90
91#endif // ANDROID_UI_TEXTURE_CACHE_H
92