1 2 /* 3 * Copyright 2011 Google Inc. 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 11 #ifndef SkTypefaceCache_DEFINED 12 #define SkTypefaceCache_DEFINED 13 14 #include "SkTypeface.h" 15 #include "SkTDArray.h" 16 17 /* TODO 18 * Provide std way to cache name+requestedStyle aliases to the same typeface. 19 * 20 * The current mechanism ends up create a diff typeface for each one, even if 21 * they map to the same internal obj (e.g. CTFontRef on the mac) 22 */ 23 24 class SkTypefaceCache { 25 public: 26 /** 27 * Callback for FindByProc. Returns true if the given typeface is a match 28 * for the given context. The passed typeface is owned by the cache and is 29 * not additionally ref()ed. 30 */ 31 typedef bool (*FindProc)(SkTypeface*, SkTypeface::Style, void* context); 32 33 /** 34 * Helper: returns a unique fontID to pass to the constructor of 35 * your subclass of SkTypeface 36 */ 37 static SkFontID NewFontID(); 38 39 /** 40 * Add a typeface to the cache. This ref()s the typeface, so that the 41 * cache is also an owner. Later, if we need to purge the cache, typefaces 42 * whose refcnt is 1 (meaning only the cache is an owner) will be 43 * unref()ed. 44 */ 45 static void Add(SkTypeface*, SkTypeface::Style requested); 46 47 /** 48 * Search the cache for a typeface with the specified fontID (uniqueID). 49 * If one is found, return it (its reference count is unmodified). If none 50 * is found, return NULL. The reference count is unmodified as it is 51 * assumed that the stack will contain a ref to the typeface. 52 */ 53 static SkTypeface* FindByID(SkFontID fontID); 54 55 /** 56 * Iterate through the cache, calling proc(typeface, ctx) with each 57 * typeface. If proc returns true, then we return that typeface (this 58 * ref()s the typeface). If it never returns true, we return NULL. 59 */ 60 static SkTypeface* FindByProcAndRef(FindProc proc, void* ctx); 61 62 /** 63 * This will unref all of the typefaces in the cache for which the cache 64 * is the only owner. Normally this is handled automatically as needed. 65 * This function is exposed for clients that explicitly want to purge the 66 * cache (e.g. to look for leaks). 67 */ 68 static void PurgeAll(); 69 70 /** 71 * Debugging only: dumps the status of the typefaces in the cache 72 */ 73 static void Dump(); 74 75 private: 76 static SkTypefaceCache& Get(); 77 78 void add(SkTypeface*, SkTypeface::Style requested); 79 SkTypeface* findByID(SkFontID findID) const; 80 SkTypeface* findByProc(FindProc proc, void* ctx) const; 81 void purge(int count); 82 void purgeAll(); 83 84 struct Rec { 85 SkTypeface* fFace; 86 SkTypeface::Style fRequestedStyle; 87 }; 88 SkTDArray<Rec> fArray; 89 }; 90 91 #endif 92
