SkPDF: cache metrics once.

src/pdf/SkPDFFont.h

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkPDFFont_DEFINED
 #define SkPDFFont_DEFINED
@@ skipping 42 matching lines @@
 
     void noteGlyphUsage(SkPDFFont* font, const uint16_t* glyphIDs,
                         int numGlyphs);
 
 private:
     SkPDFGlyphSet* getGlyphSetForFont(SkPDFFont* font);
 
     SkTArray<FontGlyphSetPair> fMap;
 };
 
-
 /** \class SkPDFFont
     A PDF Object class representing a font.  The font may have resources
     attached to it in order to embed the font.  SkPDFFonts are canonicalized
     so that resource deduplication will only include one copy of a font.
     This class uses the same pattern as SkPDFGraphicState, a static weak
     reference to each instantiated class.
 */
 class SkPDFFont : public SkPDFDict {
 
 public:
     virtual ~SkPDFFont();
 
     /** Returns the typeface represented by this class. Returns nullptr for the
      *  default typeface.
      */
-    SkTypeface* typeface() { return fTypeface.get(); }
+    SkTypeface* typeface() const { return fTypeface.get(); }
 
     /** Returns the font type represented in this font.  For Type0 fonts,
      *  returns the type of the decendant font.
      */
-    SkAdvancedTypefaceMetrics::FontType getType() { return fFontType; }
+    SkAdvancedTypefaceMetrics::FontType getType() const { return fFontType; }
+
+    static bool IsMultiByte(SkAdvancedTypefaceMetrics::FontType type) {
+        return type == SkAdvancedTypefaceMetrics::kType1CID_Font ||
+               type == SkAdvancedTypefaceMetrics::kTrueType_Font;
+    }
 
     /** Returns true if this font encoding supports glyph IDs above 255.
      */
-    bool multiByteGlyphs() const { return fMultiByteGlyphs; }
-
-    /** Returns true if the machine readable licensing bits allow embedding.
-     */
-    bool canEmbed() const;
-
-    /** Returns true if the machine readable licensing bits allow subsetting.
-     */
-    bool canSubset() const;
+    bool multiByteGlyphs() const { return SkPDFFont::IsMultiByte(this->getType()); }
 
     /** Return true if this font has an encoding for the passed glyph id.
      */
-    bool hasGlyph(uint16_t glyphID);
+    bool hasGlyph(SkGlyphID gid) {
+        return (gid >= fFirstGlyphID && gid <= fLastGlyphID) || gid == 0;
+    }
 
     /** Convert (in place) the input glyph IDs into the font encoding.  If the
      *  font has more glyphs than can be encoded (like a type 1 font with more
      *  than 255 glyphs) this method only converts up to the first out of range
      *  glyph ID.
      *  @param glyphIDs       The input text as glyph IDs.
      *  @param numGlyphs      The number of input glyphs.
      *  @return               Returns the number of glyphs consumed.
      */
     int glyphsToPDFFontEncoding(SkGlyphID* glyphIDs, int numGlyphs) const;
     /**
      * Like above, but does not modify glyphIDs array.
      */
     int glyphsToPDFFontEncodingCount(const SkGlyphID* glyphIDs,
                                      int numGlyphs) const;
 
     /** Get the font resource for the passed typeface and glyphID. The
      *  reference count of the object is incremented and it is the caller's
      *  responsibility to unreference it when done.  This is needed to
      *  accommodate the weak reference pattern used when the returned object
      *  is new and has no other references.
      *  @param typeface  The typeface to find.
      *  @param glyphID   Specify which section of a large font is of interest.
      */
     static SkPDFFont* GetFontResource(SkPDFCanon* canon,
                                       SkTypeface* typeface,
-                                      uint16_t glyphID);
+                                      SkGlyphID glyphID);
 
-    static sk_sp<const SkAdvancedTypefaceMetrics> GetFontMetricsWithToUnicode(
-            SkTypeface*, uint32_t* glyphs, uint32_t glyphsCount);
+    // Uses (kGlyphNames_PerGlyphInfo | kToUnicode_PerGlyphInfo).
+    static const SkAdvancedTypefaceMetrics* GetMetrics(SkTypeface* typeface,
+                                                       SkPDFCanon* canon);
 
     /** Subset the font based on usage set. Returns a SkPDFFont instance with
      *  subset.
      *  @param usage  Glyph subset requested.
      *  @return       nullptr if font does not support subsetting, a new instance
      *                of SkPDFFont otherwise.
      */
-    virtual sk_sp<SkPDFObject> getFontSubset(const SkPDFGlyphSet* usage);
-
-    enum Match {
-        kExact_Match,
-        kRelated_Match,
-        kNot_Match,
-    };
-    static Match IsMatch(SkPDFFont* existingFont,
-                         uint32_t existingFontID,
-                         uint16_t existingGlyphID,
-                         uint32_t searchFontID,
-                         uint16_t searchGlyphID);
+    virtual sk_sp<SkPDFObject> getFontSubset(SkPDFCanon* canon,
+                                             const SkPDFGlyphSet* usage);
 
     /**
      *  Return false iff the typeface has its NotEmbeddable flag set.
      *  If typeface is NULL, the default typeface is checked.
      */
     static bool CanEmbedTypeface(SkTypeface*, SkPDFCanon*);
 
 protected:
     // Common constructor to handle common members.
-    SkPDFFont(sk_sp<const SkAdvancedTypefaceMetrics> fontInfo,
-              sk_sp<SkTypeface> typeface,
-              sk_sp<SkPDFDict> relatedFontDescriptor,
-              SkAdvancedTypefaceMetrics::FontType fontType,
-              bool multiByteGlyphs);
+    SkPDFFont(sk_sp<SkTypeface> typeface,
+              SkAdvancedTypefaceMetrics::FontType fontType);
 
-    // Accessors for subclass.
-    const SkAdvancedTypefaceMetrics* getFontInfo() const { return fFontInfo.get(); }
-    sk_sp<const SkAdvancedTypefaceMetrics> refFontInfo() const { return fFontInfo; }
-
-    void setFontInfo(sk_sp<const SkAdvancedTypefaceMetrics> info);
     SkGlyphID firstGlyphID() const { return fFirstGlyphID; }
     SkGlyphID lastGlyphID() const { return fLastGlyphID; }
-    void setLastGlyphID(uint16_t glyphID);
-
-    // Accessors for FontDescriptor associated with this object.
-    SkPDFDict* getFontDescriptor() const { return fDescriptor.get(); }
-    sk_sp<SkPDFDict> refFontDescriptor() const { return fDescriptor; }
-    void setFontDescriptor(sk_sp<SkPDFDict> descriptor);
 
     sk_sp<SkTypeface> refTypeface() const { return fTypeface; }
 
     /** Set fFirstGlyphID and fLastGlyphID to span at most 255 glyphs,
      *  including the passed glyphID.
      */
-    void adjustGlyphRangeForSingleByteEncoding(uint16_t glyphID);
-
-    // Generate ToUnicode table according to glyph usage subset.
-    // If subset is nullptr, all available glyph ids will be used.
-    void populateToUnicodeTable(const SkPDFGlyphSet* subset);
-
-    static bool Find(uint32_t fontID, uint16_t glyphID, int* index);
+    void adjustGlyphRangeForSingleByteEncoding(SkGlyphID glyphID);
 
     void drop() override;
 
 private:
     sk_sp<SkTypeface> fTypeface;
-    sk_sp<const SkAdvancedTypefaceMetrics> fFontInfo;
-    sk_sp<SkPDFDict> fDescriptor;
 
     // The glyph IDs accessible with this font.  For Type1 (non CID) fonts,
     // this will be a subset if the font has more than 255 glyphs.
     SkGlyphID fFirstGlyphID;
     SkGlyphID fLastGlyphID;
     SkAdvancedTypefaceMetrics::FontType fFontType;
-    bool fMultiByteGlyphs;
 
     typedef SkPDFDict INHERITED;
 };
 
 #endif