GradientCache.h revision c0ac193b9415680f0a69e20a3f5f22d16f8053be 
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_GRADIENT_CACHE_H
18#define ANDROID_UI_GRADIENT_CACHE_H
19
20#include <SkShader.h>
21
22#include "Texture.h"
23#include "GenerationCache.h"
24
25namespace android {
26namespace uirenderer {
27
28/**
29 * A simple LRU gradient 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 GradientCache: public OnEntryRemoved<SkShader*, Texture*> {
34public:
35    GradientCache(uint32_t maxByteSize);
36    ~GradientCache();
37
38    /**
39     * Used as a callback when an entry is removed from the cache.
40     * Do not invoke directly.
41     */
42    void operator()(SkShader*& shader, Texture*& texture);
43
44    /**
45     * Adds a new linear gradient to the cache. The generated texture is
46     * returned.
47     */
48    Texture* addLinearGradient(SkShader* shader, float* bounds, uint32_t* colors,
49            float* positions, int count, SkShader::TileMode tileMode);
50    /**
51     * Returns the texture associated with the specified shader.
52     */
53    Texture* get(SkShader* shader);
54    /**
55     * Removes the texture associated with the specified shader. Returns NULL
56     * if the texture cannot be found. Upon remove the texture is freed.
57     */
58    void remove(SkShader* shader);
59    /**
60     * Clears the cache. This causes all textures to be deleted.
61     */
62    void clear();
63
64    /**
65     * Sets the maximum size of the cache in bytes.
66     */
67    void setMaxSize(uint32_t maxSize);
68    /**
69     * Returns the maximum size of the cache in bytes.
70     */
71    uint32_t getMaxSize();
72    /**
73     * Returns the current size of the cache in bytes.
74     */
75    uint32_t getSize();
76
77private:
78    void generateTexture(SkBitmap* bitmap, Texture* texture);
79
80    GenerationCache<SkShader*, Texture*> mCache;
81
82    uint32_t mSize;
83    uint32_t mMaxSize;
84}; // class GradientCache
85
86}; // namespace uirenderer
87}; // namespace android
88
89#endif // ANDROID_UI_GRADIENT_CACHE_H
90