1
2/*
3 * Copyright 2006 The Android Open Source Project
4 *
5 * Use of this source code is governed by a BSD-style license that can be
6 * found in the LICENSE file.
7 */
8
9
10#ifndef SkGraphics_DEFINED
11#define SkGraphics_DEFINED
12
13#include "SkTypes.h"
14
15class SK_API SkGraphics {
16public:
17    /**
18     *  Call this at process initialization time if your environment does not
19     *  permit static global initializers that execute code. Note that
20     *  Init() is not thread-safe.
21     */
22    static void Init();
23
24    /**
25     *  Call this to release any memory held privately, such as the font cache.
26     */
27    static void Term();
28
29    /**
30     *  Return the version numbers for the library. If the parameter is not
31     *  null, it is set to the version number.
32     */
33    static void GetVersion(int32_t* major, int32_t* minor, int32_t* patch);
34
35    /**
36     *  Return the max number of bytes that should be used by the font cache.
37     *  If the cache needs to allocate more, it will purge previous entries.
38     *  This max can be changed by calling SetFontCacheLimit().
39     */
40    static size_t GetFontCacheLimit();
41
42    /**
43     *  Specify the max number of bytes that should be used by the font cache.
44     *  If the cache needs to allocate more, it will purge previous entries.
45     *
46     *  This function returns the previous setting, as if GetFontCacheLimit()
47     *  had be called before the new limit was set.
48     */
49    static size_t SetFontCacheLimit(size_t bytes);
50
51    /**
52     *  Return the number of bytes currently used by the font cache.
53     */
54    static size_t GetFontCacheUsed();
55
56    /**
57     *  Return the number of entries in the font cache.
58     *  A cache "entry" is associated with each typeface + pointSize + matrix.
59     */
60    static int GetFontCacheCountUsed();
61
62    /**
63     *  Return the current limit to the number of entries in the font cache.
64     *  A cache "entry" is associated with each typeface + pointSize + matrix.
65     */
66    static int GetFontCacheCountLimit();
67
68    /**
69     *  Set the limit to the number of entries in the font cache, and return
70     *  the previous value. If this new value is lower than the previous,
71     *  it will automatically try to purge entries to meet the new limit.
72     */
73    static int SetFontCacheCountLimit(int count);
74
75    /**
76     *  For debugging purposes, this will attempt to purge the font cache. It
77     *  does not change the limit, but will cause subsequent font measures and
78     *  draws to be recreated, since they will no longer be in the cache.
79     */
80    static void PurgeFontCache();
81
82    /**
83     *  Scaling bitmaps with the SkPaint::kHigh_FilterLevel setting is
84     *  expensive, so the result is saved in the global Scaled Image
85     *  Cache.
86     *
87     *  This function returns the memory usage of the Scaled Image Cache.
88     */
89    static size_t GetResourceCacheTotalBytesUsed();
90
91    /**
92     *  These functions get/set the memory usage limit for the resource cache, used for temporary
93     *  bitmaps and other resources. Entries are purged from the cache when the memory useage
94     *  exceeds this limit.
95     */
96    static size_t GetResourceCacheTotalByteLimit();
97    static size_t SetResourceCacheTotalByteLimit(size_t newLimit);
98
99    /**
100     *  For debugging purposes, this will attempt to purge the resource cache. It
101     *  does not change the limit.
102     */
103    static void PurgeResourceCache();
104
105    /**
106     *  When the cachable entry is very lage (e.g. a large scaled bitmap), adding it to the cache
107     *  can cause most/all of the existing entries to be purged. To avoid the, the client can set
108     *  a limit for a single allocation. If a cacheable entry would have been cached, but its size
109     *  exceeds this limit, then we do not attempt to cache it at all.
110     *
111     *  Zero is the default value, meaning we always attempt to cache entries.
112     */
113    static size_t GetResourceCacheSingleAllocationByteLimit();
114    static size_t SetResourceCacheSingleAllocationByteLimit(size_t newLimit);
115
116#ifdef SK_SUPPORT_LEGACY_IMAGECACHE_NAME
117    static size_t GetImageCacheBytesUsed() {
118        return GetImageCacheTotalBytesUsed();
119    }
120    static size_t GetImageCacheByteLimit() {
121        return GetImageCacheTotalByteLimit();
122    }
123    static size_t SetImageCacheByteLimit(size_t newLimit) {
124        return SetImageCacheTotalByteLimit(newLimit);
125    }
126    static size_t GetImageCacheTotalBytesUsed() {
127        return GetResourceCacheTotalBytesUsed();
128    }
129    static size_t GetImageCacheTotalByteLimit() {
130        return GetResourceCacheTotalByteLimit();
131    }
132    static size_t SetImageCacheTotalByteLimit(size_t newLimit) {
133        return SetResourceCacheTotalByteLimit(newLimit);
134    }
135    static size_t GetImageCacheSingleAllocationByteLimit() {
136        return GetResourceCacheSingleAllocationByteLimit();
137    }
138    static size_t SetImageCacheSingleAllocationByteLimit(size_t newLimit) {
139        return SetResourceCacheSingleAllocationByteLimit(newLimit);
140    }
141#endif
142
143    /**
144     *  Applications with command line options may pass optional state, such
145     *  as cache sizes, here, for instance:
146     *  font-cache-limit=12345678
147     *
148     *  The flags format is name=value[;name=value...] with no spaces.
149     *  This format is subject to change.
150     */
151    static void SetFlags(const char* flags);
152
153    /**
154     *  Return the max number of bytes that should be used by the thread-local
155     *  font cache.
156     *  If the cache needs to allocate more, it will purge previous entries.
157     *  This max can be changed by calling SetFontCacheLimit().
158     *
159     *  If this thread has never called SetTLSFontCacheLimit, or has called it
160     *  with 0, then this thread is using the shared font cache. In that case,
161     *  this function will always return 0, and the caller may want to call
162     *  GetFontCacheLimit.
163     */
164    static size_t GetTLSFontCacheLimit();
165
166    /**
167     *  Specify the max number of bytes that should be used by the thread-local
168     *  font cache. If this value is 0, then this thread will use the shared
169     *  global font cache.
170     */
171    static void SetTLSFontCacheLimit(size_t bytes);
172
173private:
174    /** This is automatically called by SkGraphics::Init(), and must be
175        implemented by the host OS. This allows the host OS to register a callback
176        with the C++ runtime to call SkGraphics::FreeCaches()
177    */
178    static void InstallNewHandler();
179};
180
181class SkAutoGraphics {
182public:
183    SkAutoGraphics() {
184        SkGraphics::Init();
185    }
186    ~SkAutoGraphics() {
187        SkGraphics::Term();
188    }
189};
190
191#endif
192