PathCache.h revision c15008e72ec00ca20a271c3006dac649fd07533b 
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_PATH_CACHE_H
18#define ANDROID_HWUI_PATH_CACHE_H
19
20#include <SkBitmap.h>
21#include <SkPaint.h>
22#include <SkPath.h>
23
24#include "Debug.h"
25#include "Texture.h"
26#include "utils/Compare.h"
27#include "utils/GenerationCache.h"
28
29namespace android {
30namespace uirenderer {
31
32///////////////////////////////////////////////////////////////////////////////
33// Defines
34///////////////////////////////////////////////////////////////////////////////
35
36// Debug
37#if DEBUG_PATHS
38    #define PATH_LOGD(...) LOGD(__VA_ARGS__)
39#else
40    #define PATH_LOGD(...)
41#endif
42
43///////////////////////////////////////////////////////////////////////////////
44// Classes
45///////////////////////////////////////////////////////////////////////////////
46
47/**
48 * Describe a path in the path cache.
49 */
50struct PathCacheEntry {
51    PathCacheEntry() {
52        path = NULL;
53        join = SkPaint::kDefault_Join;
54        cap = SkPaint::kDefault_Cap;
55        style = SkPaint::kFill_Style;
56        miter = 4.0f;
57        strokeWidth = 1.0f;
58    }
59
60    PathCacheEntry(const PathCacheEntry& entry):
61        path(entry.path), join(entry.join), cap(entry.cap),
62        style(entry.style), miter(entry.miter),
63        strokeWidth(entry.strokeWidth) {
64    }
65
66    PathCacheEntry(SkPath* path, SkPaint* paint) {
67        this->path = path;
68        join = paint->getStrokeJoin();
69        cap = paint->getStrokeCap();
70        miter = paint->getStrokeMiter();
71        strokeWidth = paint->getStrokeWidth();
72        style = paint->getStyle();
73    }
74
75    SkPath* path;
76    SkPaint::Join join;
77    SkPaint::Cap cap;
78    SkPaint::Style style;
79    float miter;
80    float strokeWidth;
81
82    bool operator<(const PathCacheEntry& rhs) const {
83        LTE_INT(path) {
84            LTE_INT(join) {
85                LTE_INT(cap) {
86                    LTE_INT(style) {
87                        LTE_FLOAT(miter) {
88                            LTE_FLOAT(strokeWidth) return false;
89                        }
90                    }
91                }
92            }
93        }
94        return false;
95    }
96}; // struct PathCacheEntry
97
98/**
99 * Alpha texture used to represent a path.
100 */
101struct PathTexture: public Texture {
102    PathTexture(): Texture() {
103    }
104
105    /**
106     * Left coordinate of the path bounds.
107     */
108    float left;
109    /**
110     * Top coordinate of the path bounds.
111     */
112    float top;
113    /**
114     * Offset to draw the path at the correct origin.
115     */
116    float offset;
117}; // struct PathTexture
118
119/**
120 * A simple LRU path cache. The cache has a maximum size expressed in bytes.
121 * Any texture added to the cache causing the cache to grow beyond the maximum
122 * allowed size will also cause the oldest texture to be kicked out.
123 */
124class PathCache: public OnEntryRemoved<PathCacheEntry, PathTexture*> {
125public:
126    PathCache();
127    PathCache(uint32_t maxByteSize);
128    ~PathCache();
129
130    /**
131     * Used as a callback when an entry is removed from the cache.
132     * Do not invoke directly.
133     */
134    void operator()(PathCacheEntry& path, PathTexture*& texture);
135
136    /**
137     * Returns the texture associated with the specified path. If the texture
138     * cannot be found in the cache, a new texture is generated.
139     */
140    PathTexture* get(SkPath* path, SkPaint* paint);
141    /**
142     * Clears the cache. This causes all textures to be deleted.
143     */
144    void clear();
145    /**
146     * Removes an entry.
147     */
148    void remove(SkPath* path);
149
150    /**
151     * Sets the maximum size of the cache in bytes.
152     */
153    void setMaxSize(uint32_t maxSize);
154    /**
155     * Returns the maximum size of the cache in bytes.
156     */
157    uint32_t getMaxSize();
158    /**
159     * Returns the current size of the cache in bytes.
160     */
161    uint32_t getSize();
162
163private:
164    /**
165     * Generates the texture from a bitmap into the specified texture structure.
166     */
167    void generateTexture(SkBitmap& bitmap, Texture* texture);
168
169    PathTexture* addTexture(const PathCacheEntry& entry, const SkPath *path, const SkPaint* paint);
170
171    void init();
172
173    GenerationCache<PathCacheEntry, PathTexture*> mCache;
174
175    uint32_t mSize;
176    uint32_t mMaxSize;
177    GLuint mMaxTextureSize;
178
179    /**
180     * Used to access mCache and mSize. All methods are accessed from a single
181     * thread except for remove().
182     */
183    mutable Mutex mLock;
184}; // class PathCache
185
186}; // namespace uirenderer
187}; // namespace android
188
189#endif // ANDROID_HWUI_PATH_CACHE_H
190