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      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 #ifndef SkAdvancedTypefaceMetrics_DEFINED
     11 #define SkAdvancedTypefaceMetrics_DEFINED
     12 
     13 #include "SkRect.h"
     14 #include "SkRefCnt.h"
     15 #include "SkString.h"
     16 #include "SkTDArray.h"
     17 #include "SkTemplates.h"
     18 #include "SkTScopedPtr.h"
     19 
     20 /** \class SkAdvancedTypefaceMetrics
     21 
     22     The SkAdvancedTypefaceMetrics class is used by the PDF backend to correctly
     23     embed typefaces.  This class is filled in with information about a given
     24     typeface by the SkFontHost class.
     25 */
     26 
     27 class SkAdvancedTypefaceMetrics : public SkRefCnt {
     28 public:
     29     SK_DECLARE_INST_COUNT(SkAdvancedTypefaceMetrics)
     30 
     31     SkString fFontName;
     32 
     33     enum FontType {
     34         kType1_Font,
     35         kType1CID_Font,
     36         kCFF_Font,
     37         kTrueType_Font,
     38         kOther_Font,
     39         kNotEmbeddable_Font
     40     };
     41     // The type of the underlying font program.  This field determines which
     42     // of the following fields are valid.  If it is kOther_Font or
     43     // kNotEmbeddable_Font, the per glyph information will never be populated.
     44     FontType fType;
     45 
     46     // fMultiMaster may be true for Type1_Font or CFF_Font.
     47     bool fMultiMaster;
     48     uint16_t fLastGlyphID; // The last valid glyph ID in the font.
     49     uint16_t fEmSize;  // The size of the em box (defines font units).
     50 
     51     // These enum values match the values used in the PDF file format.
     52     enum StyleFlags {
     53         kFixedPitch_Style  = 0x00001,
     54         kSerif_Style       = 0x00002,
     55         kScript_Style      = 0x00008,
     56         kItalic_Style      = 0x00040,
     57         kAllCaps_Style     = 0x10000,
     58         kSmallCaps_Style   = 0x20000,
     59         kForceBold_Style   = 0x40000
     60     };
     61     uint16_t fStyle;        // Font style characteristics.
     62     int16_t fItalicAngle;   // Counterclockwise degrees from vertical of the
     63                             // dominant vertical stroke for an Italic face.
     64     // The following fields are all in font units.
     65     int16_t fAscent;       // Max height above baseline, not including accents.
     66     int16_t fDescent;      // Max depth below baseline (negative).
     67     int16_t fStemV;        // Thickness of dominant vertical stem.
     68     int16_t fCapHeight;    // Height (from baseline) of top of flat capitals.
     69 
     70     SkIRect fBBox;  // The bounding box of all glyphs (in font units).
     71 
     72     // The type of advance data wanted.
     73     enum PerGlyphInfo {
     74       kNo_PerGlyphInfo         = 0x0, // Don't populate any per glyph info.
     75       kHAdvance_PerGlyphInfo   = 0x1, // Populate horizontal advance data.
     76       kVAdvance_PerGlyphInfo   = 0x2, // Populate vertical advance data.
     77       kGlyphNames_PerGlyphInfo = 0x4, // Populate glyph names (Type 1 only).
     78       kToUnicode_PerGlyphInfo  = 0x8  // Populate ToUnicode table, ignored
     79                                       // for Type 1 fonts
     80     };
     81 
     82     template <typename Data>
     83     struct AdvanceMetric {
     84         enum MetricType {
     85             kDefault,  // Default advance: fAdvance.count = 1
     86             kRange,    // Advances for a range: fAdvance.count = fEndID-fStartID
     87             kRun       // fStartID-fEndID have same advance: fAdvance.count = 1
     88         };
     89         MetricType fType;
     90         uint16_t fStartId;
     91         uint16_t fEndId;
     92         SkTDArray<Data> fAdvance;
     93         SkTScopedPtr<AdvanceMetric<Data> > fNext;
     94     };
     95 
     96     struct VerticalMetric {
     97         int16_t fVerticalAdvance;
     98         int16_t fOriginXDisp;  // Horiz. displacement of the secondary origin.
     99         int16_t fOriginYDisp;  // Vert. displacement of the secondary origin.
    100     };
    101     typedef AdvanceMetric<int16_t> WidthRange;
    102     typedef AdvanceMetric<VerticalMetric> VerticalAdvanceRange;
    103 
    104     // This is indexed by glyph id.
    105     SkTScopedPtr<WidthRange> fGlyphWidths;
    106     // Only used for Vertical CID fonts.
    107     SkTScopedPtr<VerticalAdvanceRange> fVerticalMetrics;
    108 
    109     // The names of each glyph, only populated for postscript fonts.
    110     SkTScopedPtr<SkAutoTArray<SkString> > fGlyphNames;
    111 
    112     // The mapping from glyph to Unicode, only populated if
    113     // kToUnicode_PerGlyphInfo is passed to GetAdvancedTypefaceMetrics.
    114     SkTDArray<SkUnichar> fGlyphToUnicode;
    115 
    116 private:
    117     typedef SkRefCnt INHERITED;
    118 };
    119 
    120 namespace skia_advanced_typeface_metrics_utils {
    121 
    122 template <typename Data>
    123 void resetRange(SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* range,
    124                        int startId);
    125 
    126 template <typename Data>
    127 SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* appendRange(
    128         SkTScopedPtr<SkAdvancedTypefaceMetrics::AdvanceMetric<Data> >* nextSlot,
    129         int startId);
    130 
    131 template <typename Data>
    132 void finishRange(
    133         SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* range,
    134         int endId,
    135         typename SkAdvancedTypefaceMetrics::AdvanceMetric<Data>::MetricType
    136                 type);
    137 
    138 /** Retrieve advance data for glyphs. Used by the PDF backend. It calls
    139     underlying platform dependent API getAdvance to acquire the data.
    140     @param num_glyphs    Total number of glyphs in the given font.
    141     @param glyphIDs      For per-glyph info, specify subset of the font by
    142                          giving glyph ids.  Each integer represents a glyph
    143                          id.  Passing NULL means all glyphs in the font.
    144     @param glyphIDsCount Number of elements in subsetGlyphIds. Ignored if
    145                          glyphIDs is NULL.
    146 */
    147 template <typename Data, typename FontHandle>
    148 SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* getAdvanceData(
    149         FontHandle fontHandle,
    150         int num_glyphs,
    151         const uint32_t* glyphIDs,
    152         uint32_t glyphIDsCount,
    153         bool (*getAdvance)(FontHandle fontHandle, int gId, Data* data));
    154 
    155 } // namespace skia_advanced_typeface_metrics_utils
    156 
    157 #endif
    158