PathCache.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_PATH_CACHE_H
18#define ANDROID_UI_PATH_CACHE_H
19
20#include <SkBitmap.h>
21#include <SkPaint.h>
22#include <SkPath.h>
23
24#include "Texture.h"
25#include "GenerationCache.h"
26
27namespace android {
28namespace uirenderer {
29
30/**
31 * Describe a path in the path cache.
32 */
33struct PathCacheEntry {
34    PathCacheEntry() {
35        path = NULL;
36        join = SkPaint::kDefault_Join;
37        cap = SkPaint::kDefault_Cap;
38        style = SkPaint::kFill_Style;
39        miter = 4.0f;
40        strokeWidth = 1.0f;
41    }
42
43    PathCacheEntry(const PathCacheEntry& entry):
44        path(entry.path), join(entry.join), cap(entry.cap),
45        style(entry.style), miter(entry.miter),
46        strokeWidth(entry.strokeWidth) {
47    }
48
49    PathCacheEntry(SkPath* path, SkPaint* paint) {
50        this->path = path;
51        join = paint->getStrokeJoin();
52        cap = paint->getStrokeCap();
53        miter = paint->getStrokeMiter();
54        strokeWidth = paint->getStrokeWidth();
55        style = paint->getStyle();
56    }
57
58    SkPath* path;
59    SkPaint::Join join;
60    SkPaint::Cap cap;
61    SkPaint::Style style;
62    float miter;
63    float strokeWidth;
64
65    bool operator<(const PathCacheEntry& rhs) const {
66        return memcmp(this, &rhs, sizeof(PathCacheEntry)) < 0;
67    }
68}; // struct PathCacheEntry
69
70/**
71 * Alpha texture used to represent a path.
72 */
73struct PathTexture: public Texture {
74    PathTexture(): Texture() {
75    }
76
77    /**
78     * Left coordinate of the path bounds.
79     */
80    float left;
81    /**
82     * Top coordinate of the path bounds.
83     */
84    float top;
85    /**
86     * Offset to draw the path at the correct origin.
87     */
88    float offset;
89}; // struct PathTexture
90
91/**
92 * A simple LRU path cache. The cache has a maximum size expressed in bytes.
93 * Any texture added to the cache causing the cache to grow beyond the maximum
94 * allowed size will also cause the oldest texture to be kicked out.
95 */
96class PathCache: public OnEntryRemoved<PathCacheEntry, PathTexture*> {
97public:
98    PathCache(uint32_t maxByteSize);
99    ~PathCache();
100
101    /**
102     * Used as a callback when an entry is removed from the cache.
103     * Do not invoke directly.
104     */
105    void operator()(PathCacheEntry& path, PathTexture*& texture);
106
107    /**
108     * Returns the texture associated with the specified path. If the texture
109     * cannot be found in the cache, a new texture is generated.
110     */
111    PathTexture* get(SkPath* path, SkPaint* paint);
112    /**
113     * Clears the cache. This causes all textures to be deleted.
114     */
115    void clear();
116
117    /**
118     * Sets the maximum size of the cache in bytes.
119     */
120    void setMaxSize(uint32_t maxSize);
121    /**
122     * Returns the maximum size of the cache in bytes.
123     */
124    uint32_t getMaxSize();
125    /**
126     * Returns the current size of the cache in bytes.
127     */
128    uint32_t getSize();
129
130private:
131    /**
132     * Generates the texture from a bitmap into the specified texture structure.
133     */
134    void generateTexture(SkBitmap& bitmap, Texture* texture);
135
136    PathTexture* addTexture(const PathCacheEntry& entry, const SkPath *path, const SkPaint* paint);
137
138    GenerationCache<PathCacheEntry, PathTexture*> mCache;
139
140    uint32_t mSize;
141    uint32_t mMaxSize;
142    GLuint mMaxTextureSize;
143}; // class PathCache
144
145}; // namespace uirenderer
146}; // namespace android
147
148#endif // ANDROID_UI_PATH_CACHE_H
149