PathCache.h revision 7fbcc0492fca03857e3c45064f4aa040af817d55 
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    /**
75     * Left coordinate of the path bounds.
76     */
77    float left;
78    /**
79     * Top coordinate of the path bounds.
80     */
81    float top;
82    /**
83     * Offset to draw the path at the correct origin.
84     */
85    float offset;
86}; // struct PathTexture
87
88/**
89 * A simple LRU path cache. The cache has a maximum size expressed in bytes.
90 * Any texture added to the cache causing the cache to grow beyond the maximum
91 * allowed size will also cause the oldest texture to be kicked out.
92 */
93class PathCache: public OnEntryRemoved<PathCacheEntry, PathTexture*> {
94public:
95    PathCache(uint32_t maxByteSize);
96    ~PathCache();
97
98    /**
99     * Used as a callback when an entry is removed from the cache.
100     * Do not invoke directly.
101     */
102    void operator()(PathCacheEntry& path, PathTexture*& texture);
103
104    /**
105     * Returns the texture associated with the specified path. If the texture
106     * cannot be found in the cache, a new texture is generated.
107     */
108    PathTexture* get(SkPath* path, SkPaint* paint);
109    /**
110     * Clears the cache. This causes all textures to be deleted.
111     */
112    void clear();
113
114    /**
115     * Sets the maximum size of the cache in bytes.
116     */
117    void setMaxSize(uint32_t maxSize);
118    /**
119     * Returns the maximum size of the cache in bytes.
120     */
121    uint32_t getMaxSize();
122    /**
123     * Returns the current size of the cache in bytes.
124     */
125    uint32_t getSize();
126
127private:
128    /**
129     * Generates the texture from a bitmap into the specified texture structure.
130     */
131    void generateTexture(SkBitmap& bitmap, Texture* texture);
132
133    PathTexture* addTexture(const PathCacheEntry& entry, const SkPath *path, const SkPaint* paint);
134
135    GenerationCache<PathCacheEntry, PathTexture*> mCache;
136
137    uint32_t mSize;
138    uint32_t mMaxSize;
139}; // class PathCache
140
141}; // namespace uirenderer
142}; // namespace android
143
144#endif // ANDROID_UI_PATH_CACHE_H
145