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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.
     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     typedef std::unique_ptr<SkImageGenerator>
    165                                             (*ImageGeneratorFromEncodedDataFactory)(sk_sp<SkData>);
    166 
    167     /**
    168      *  To instantiate images from encoded data, first looks at this runtime function-ptr. If it
    169      *  exists, it is called to create an SkImageGenerator from SkData. If there is no function-ptr
    170      *  or there is, but it returns NULL, then skia will call its internal default implementation.
    171      *
    172      *  Returns the previous factory (which could be NULL).
    173      */
    174     static ImageGeneratorFromEncodedDataFactory
    175                     SetImageGeneratorFromEncodedDataFactory(ImageGeneratorFromEncodedDataFactory);
    176 };
    177 
    178 class SkAutoGraphics {
    179 public:
    180     SkAutoGraphics() {
    181         SkGraphics::Init();
    182     }
    183 };
    184 
    185 #endif
    186