SkPDF: cache metrics once.

src/pdf/SkPDFCanon.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #ifndef SkPDFCanon_DEFINED
 #define SkPDFCanon_DEFINED
 
 #include "SkPDFGraphicState.h"
 #include "SkPDFShader.h"
 #include "SkPixelSerializer.h"
 #include "SkTDArray.h"
 #include "SkTHash.h"
 #include "SkBitmapKey.h"
 
+class SkAdvancedTypefaceMetrics;
 class SkPDFFont;
 
 /**
  *  The SkPDFCanon canonicalizes objects across PDF pages
  *  (SkPDFDevices) and across draw calls.
  *
  *  The PDF backend works correctly if:
  *  -  There is no more than one SkPDFCanon for each thread.
  *  -  Every SkPDFDevice is given a pointer to a SkPDFCanon on creation.
  *  -  All SkPDFDevices in a document share the same SkPDFCanon.
  *  The SkPDFDocument class makes this happen by owning a single
  *  SkPDFCanon.
  *
  *  The addFoo() methods will ref the Foo; the canon's destructor will
  *  call foo->unref() on all of these objects.
  *
  *  The findFoo() methods do not change the ref count of the Foo
  *  objects.
  */
 class SkPDFCanon : SkNoncopyable {
 public:
-    ~SkPDFCanon() { this->reset(); }
+    ~SkPDFCanon();
 
     // reset to original setting, unrefs all objects.
     void reset();
 
-    // Returns exact match if there is one.  If not, it returns nullptr.
-    // If there is no exact match, but there is a related font, we
-    // still return nullptr, but also set *relatedFont.
-    SkPDFFont* findFont(uint32_t fontID,
-                        uint16_t glyphID,
-                        SkPDFFont** relatedFont) const;
-    void addFont(SkPDFFont* font, uint32_t fontID, uint16_t fGlyphID);
-
     sk_sp<SkPDFObject> findFunctionShader(const SkPDFShader::State&) const;
     void addFunctionShader(sk_sp<SkPDFObject>, SkPDFShader::State);
 
     sk_sp<SkPDFObject> findAlphaShader(const SkPDFShader::State&) const;
     void addAlphaShader(sk_sp<SkPDFObject>, SkPDFShader::State);
 
     sk_sp<SkPDFObject> findImageShader(const SkPDFShader::State&) const;
     void addImageShader(sk_sp<SkPDFObject>, SkPDFShader::State);
 
     const SkPDFGraphicState* findGraphicState(const SkPDFGraphicState&) const;
     void addGraphicState(const SkPDFGraphicState*);
 
     sk_sp<SkPDFObject> findPDFBitmap(SkBitmapKey key) const;
     void addPDFBitmap(SkBitmapKey key, sk_sp<SkPDFObject>);
 
-    SkTHashMap<uint32_t, bool> fCanEmbedTypeface;
+    SkTHashMap<uint32_t, SkAdvancedTypefaceMetrics*> fTypefaceMetrics;
+    SkTHashMap<uint32_t, SkPDFDict*> fFontDescriptors;
+    SkTHashMap<uint64_t, SkPDFFont*> fFontMap;
 
     SkPixelSerializer* getPixelSerializer() const { return fPixelSerializer.get(); }
     void setPixelSerializer(sk_sp<SkPixelSerializer> ps) {
         fPixelSerializer = std::move(ps);
     }
 
     sk_sp<SkPDFStream> makeInvertFunction();
     sk_sp<SkPDFDict> makeNoSmaskGraphicState();
     sk_sp<SkPDFArray> makeRangeObject();
 
 private:
-    struct FontRec {
-        SkPDFFont* fFont;
-        uint32_t fFontID;
-        uint16_t fGlyphID;
-    };
-    SkTDArray<FontRec> fFontRecords;
-
     struct ShaderRec {
         SkPDFShader::State fShaderState;
         sk_sp<SkPDFObject> fShaderObject;
         ShaderRec(SkPDFShader::State s, sk_sp<SkPDFObject> o)
             : fShaderState(std::move(s)), fShaderObject(std::move(o)) {}
     };
     SkTArray<ShaderRec> fFunctionShaderRecords;
     SkTArray<ShaderRec> fAlphaShaderRecords;
     SkTArray<ShaderRec> fImageShaderRecords;
 
@@ skipping 16 matching lines @@
 
     // TODO(halcanary): make SkTHashMap<K, sk_sp<V>> work correctly.
     SkTHashMap<SkBitmapKey, SkPDFObject*> fPDFBitmapMap;
 
     sk_sp<SkPixelSerializer> fPixelSerializer;
     sk_sp<SkPDFStream> fInvertFunction;
     sk_sp<SkPDFDict> fNoSmaskGraphicState;
     sk_sp<SkPDFArray> fRangeObject;
 };
 #endif  // SkPDFCanon_DEFINED