TextureCache.h revision 9e10841c27d973b930e1b49a099c69d866659505 
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_HWUI_TEXTURE_CACHE_H
18#define ANDROID_HWUI_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// Defines
30///////////////////////////////////////////////////////////////////////////////
31
32// Debug
33#define DEBUG_TEXTURES 0
34
35// Debug
36#if DEBUG_TEXTURES
37    #define TEXTURE_LOGD(...) LOGD(__VA_ARGS__)
38#else
39    #define TEXTURE_LOGD(...)
40#endif
41
42///////////////////////////////////////////////////////////////////////////////
43// Classes
44///////////////////////////////////////////////////////////////////////////////
45
46/**
47 * A simple LRU texture cache. The cache has a maximum size expressed in bytes.
48 * Any texture added to the cache causing the cache to grow beyond the maximum
49 * allowed size will also cause the oldest texture to be kicked out.
50 */
51class TextureCache: public OnEntryRemoved<SkBitmap*, Texture*> {
52public:
53    TextureCache();
54    TextureCache(uint32_t maxByteSize);
55    ~TextureCache();
56
57    /**
58     * Used as a callback when an entry is removed from the cache.
59     * Do not invoke directly.
60     */
61    void operator()(SkBitmap*& bitmap, Texture*& texture);
62
63    /**
64     * Returns the texture associated with the specified bitmap. If the texture
65     * cannot be found in the cache, a new texture is generated.
66     */
67    Texture* get(SkBitmap* bitmap);
68    /**
69     * Removes the texture associated with the specified bitmap. Returns NULL
70     * if the texture cannot be found. Upon remove the texture is freed.
71     */
72    void remove(SkBitmap* bitmap);
73    /**
74     * Clears the cache. This causes all textures to be deleted.
75     */
76    void clear();
77
78    /**
79     * Sets the maximum size of the cache in bytes.
80     */
81    void setMaxSize(uint32_t maxSize);
82    /**
83     * Returns the maximum size of the cache in bytes.
84     */
85    uint32_t getMaxSize();
86    /**
87     * Returns the current size of the cache in bytes.
88     */
89    uint32_t getSize();
90
91private:
92    /**
93     * Generates the texture from a bitmap into the specified texture structure.
94     *
95     * @param regenerate If true, the bitmap data is reuploaded into the texture, but
96     *        no new texture is generated.
97     */
98    void generateTexture(SkBitmap* bitmap, Texture* texture, bool regenerate = false);
99
100    void uploadLoFiTexture(bool resize, SkBitmap* bitmap, uint32_t width, uint32_t height);
101    void uploadToTexture(bool resize, GLenum format, GLsizei width, GLsizei height,
102            GLenum type, const GLvoid * data);
103
104    void init();
105
106    GenerationCache<SkBitmap*, Texture*> mCache;
107
108    uint32_t mSize;
109    uint32_t mMaxSize;
110    GLint mMaxTextureSize;
111
112    /**
113     * Used to access mCache and mSize. All methods are accessed from a single
114     * thread except for remove().
115     */
116    mutable Mutex mLock;
117}; // class TextureCache
118
119}; // namespace uirenderer
120}; // namespace android
121
122#endif // ANDROID_HWUI_TEXTURE_CACHE_H
123