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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 "SkTypes.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      *  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 kHigh_SkFilterQuality 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     /**
    117      *  Dumps memory usage of caches using the SkTraceMemoryDump interface. See SkTraceMemoryDump
    118      *  for usage of this method.
    119      */
    120     static void DumpMemoryStatistics(SkTraceMemoryDump* dump);
    121 
    122     /**
    123      *  Free as much globally cached memory as possible. This will purge all private caches in Skia,
    124      *  including font and image caches.
    125      *
    126      *  If there are caches associated with GPU context, those will not be affected by this call.
    127      */
    128     static void PurgeAllCaches();
    129 
    130     /**
    131      *  Applications with command line options may pass optional state, such
    132      *  as cache sizes, here, for instance:
    133      *  font-cache-limit=12345678
    134      *
    135      *  The flags format is name=value[;name=value...] with no spaces.
    136      *  This format is subject to change.
    137      */
    138     static void SetFlags(const char* flags);
    139 
    140     /**
    141      *  Return the max number of bytes that should be used by the thread-local
    142      *  font cache.
    143      *  If the cache needs to allocate more, it will purge previous entries.
    144      *  This max can be changed by calling SetFontCacheLimit().
    145      *
    146      *  If this thread has never called SetTLSFontCacheLimit, or has called it
    147      *  with 0, then this thread is using the shared font cache. In that case,
    148      *  this function will always return 0, and the caller may want to call
    149      *  GetFontCacheLimit.
    150      */
    151     static size_t GetTLSFontCacheLimit();
    152 
    153     /**
    154      *  Specify the max number of bytes that should be used by the thread-local
    155      *  font cache. If this value is 0, then this thread will use the shared
    156      *  global font cache.
    157      */
    158     static void SetTLSFontCacheLimit(size_t bytes);
    159 
    160     typedef SkImageGenerator* (*ImageGeneratorFromEncodedFactory)(SkData*);
    161 
    162     /**
    163      *  To instantiate images from encoded data, first looks at this runtime function-ptr. If it
    164      *  exists, it is called to create an SkImageGenerator from SkData. If there is no function-ptr
    165      *  or there is, but it returns NULL, then skia will call its internal default implementation.
    166      *
    167      *  Returns the previous factory (which could be NULL).
    168      */
    169     static ImageGeneratorFromEncodedFactory
    170            SetImageGeneratorFromEncodedFactory(ImageGeneratorFromEncodedFactory);
    171 };
    172 
    173 class SkAutoGraphics {
    174 public:
    175     SkAutoGraphics() {
    176         SkGraphics::Init();
    177     }
    178 };
    179 
    180 #endif
    181