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1 /*
2  * Copyright 2006 The Android Open Source Project
3  *
4  * Use of this source code is governed by a BSD-style license that can be
5  * found in the LICENSE file.
6  */
7 
8 #ifndef SkGraphics_DEFINED
9 #define SkGraphics_DEFINED
10 
11 #include "SkRefCnt.h"
12 
13 class SkData;
14 class SkImageGenerator;
15 class SkTraceMemoryDump;
16 
17 class SK_API SkGraphics {
18 public:
19     /**
20      *  Call this at process initialization time if your environment does not
21      *  permit static global initializers that execute code.
22      *  Init() is thread-safe and idempotent.
23      */
24     static void Init();
25 
26     // We're in the middle of cleaning this up.
Term()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      *  Returns the maximum point size for text that may be cached.
77      *
78      *  Sizes above this will be drawn directly from the font's outline.
79      *  Setting this to a large value may speed up drawing larger text (repeatedly),
80      *  but could cause the cache to purge other sizes more often.
81      *
82      *  This value is a hint to the font engine, and the actual limit may be different due to
83      *  implementation specific details.
84      */
85     static int GetFontCachePointSizeLimit();
86 
87     /*
88      *  Set the maximum point size for text that may be cached, returning the previous value.
89      *
90      *  Sizes above this will be drawn directly from the font's outline.
91      *  Setting this to a large value may speed up drawing larger text (repeatedly),
92      *  but could cause the cache to purge other sizes more often.
93      *
94      *  This value is a hint to the font engine, and the actual limit may be different due to
95      *  implementation specific details.
96      */
97     static int SetFontCachePointSizeLimit(int maxPointSize);
98 
99     /**
100      *  For debugging purposes, this will attempt to purge the font cache. It
101      *  does not change the limit, but will cause subsequent font measures and
102      *  draws to be recreated, since they will no longer be in the cache.
103      */
104     static void PurgeFontCache();
105 
106     /**
107      *  Scaling bitmaps with the kHigh_SkFilterQuality setting is
108      *  expensive, so the result is saved in the global Scaled Image
109      *  Cache.
110      *
111      *  This function returns the memory usage of the Scaled Image Cache.
112      */
113     static size_t GetResourceCacheTotalBytesUsed();
114 
115     /**
116      *  These functions get/set the memory usage limit for the resource cache, used for temporary
117      *  bitmaps and other resources. Entries are purged from the cache when the memory useage
118      *  exceeds this limit.
119      */
120     static size_t GetResourceCacheTotalByteLimit();
121     static size_t SetResourceCacheTotalByteLimit(size_t newLimit);
122 
123     /**
124      *  For debugging purposes, this will attempt to purge the resource cache. It
125      *  does not change the limit.
126      */
127     static void PurgeResourceCache();
128 
129     /**
130      *  When the cachable entry is very lage (e.g. a large scaled bitmap), adding it to the cache
131      *  can cause most/all of the existing entries to be purged. To avoid the, the client can set
132      *  a limit for a single allocation. If a cacheable entry would have been cached, but its size
133      *  exceeds this limit, then we do not attempt to cache it at all.
134      *
135      *  Zero is the default value, meaning we always attempt to cache entries.
136      */
137     static size_t GetResourceCacheSingleAllocationByteLimit();
138     static size_t SetResourceCacheSingleAllocationByteLimit(size_t newLimit);
139 
140     /**
141      *  Dumps memory usage of caches using the SkTraceMemoryDump interface. See SkTraceMemoryDump
142      *  for usage of this method.
143      */
144     static void DumpMemoryStatistics(SkTraceMemoryDump* dump);
145 
146     /**
147      *  Free as much globally cached memory as possible. This will purge all private caches in Skia,
148      *  including font and image caches.
149      *
150      *  If there are caches associated with GPU context, those will not be affected by this call.
151      */
152     static void PurgeAllCaches();
153 
154     /**
155      *  Applications with command line options may pass optional state, such
156      *  as cache sizes, here, for instance:
157      *  font-cache-limit=12345678
158      *
159      *  The flags format is name=value[;name=value...] with no spaces.
160      *  This format is subject to change.
161      */
162     static void SetFlags(const char* flags);
163 
164     /**
165      *  Return the max number of bytes that should be used by the thread-local
166      *  font cache.
167      *  If the cache needs to allocate more, it will purge previous entries.
168      *  This max can be changed by calling SetFontCacheLimit().
169      *
170      *  If this thread has never called SetTLSFontCacheLimit, or has called it
171      *  with 0, then this thread is using the shared font cache. In that case,
172      *  this function will always return 0, and the caller may want to call
173      *  GetFontCacheLimit.
174      */
175     static size_t GetTLSFontCacheLimit();
176 
177     /**
178      *  Specify the max number of bytes that should be used by the thread-local
179      *  font cache. If this value is 0, then this thread will use the shared
180      *  global font cache.
181      */
182     static void SetTLSFontCacheLimit(size_t bytes);
183 
184     typedef std::unique_ptr<SkImageGenerator>
185                                             (*ImageGeneratorFromEncodedDataFactory)(sk_sp<SkData>);
186 
187     /**
188      *  To instantiate images from encoded data, first looks at this runtime function-ptr. If it
189      *  exists, it is called to create an SkImageGenerator from SkData. If there is no function-ptr
190      *  or there is, but it returns NULL, then skia will call its internal default implementation.
191      *
192      *  Returns the previous factory (which could be NULL).
193      */
194     static ImageGeneratorFromEncodedDataFactory
195                     SetImageGeneratorFromEncodedDataFactory(ImageGeneratorFromEncodedDataFactory);
196 };
197 
198 class SkAutoGraphics {
199 public:
SkAutoGraphics()200     SkAutoGraphics() {
201         SkGraphics::Init();
202     }
203 };
204 
205 #endif
206