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
19/** \class SkAdvancedTypefaceMetrics
20
21    The SkAdvancedTypefaceMetrics class is used by the PDF backend to correctly
22    embed typefaces.  This class is filled in with information about a given
23    typeface by the SkFontHost class.
24*/
25
26class SkAdvancedTypefaceMetrics : public SkRefCnt {
27public:
28    SK_DECLARE_INST_COUNT(SkAdvancedTypefaceMetrics)
29
30    SkString fFontName;
31
32    enum FontType {
33        kType1_Font,
34        kType1CID_Font,
35        kCFF_Font,
36        kTrueType_Font,
37        kOther_Font,
38    };
39    // The type of the underlying font program.  This field determines which
40    // of the following fields are valid.  If it is kOther_Font the per glyph
41    // information will never be populated.
42    FontType fType;
43
44    enum FontFlags {
45        kEmpty_FontFlag          = 0x0,  //!<No flags set
46        kMultiMaster_FontFlag    = 0x1,  //!<May be true for Type1 or CFF fonts.
47        kNotEmbeddable_FontFlag  = 0x2,  //!<May not be embedded.
48        kNotSubsettable_FontFlag = 0x4,  //!<May not be subset.
49    };
50    // Global font flags.
51    FontFlags fFlags;
52
53    uint16_t fLastGlyphID; // The last valid glyph ID in the font.
54    uint16_t fEmSize;  // The size of the em box (defines font units).
55
56    // These enum values match the values used in the PDF file format.
57    enum StyleFlags {
58        kFixedPitch_Style  = 0x00001,
59        kSerif_Style       = 0x00002,
60        kScript_Style      = 0x00008,
61        kItalic_Style      = 0x00040,
62        kAllCaps_Style     = 0x10000,
63        kSmallCaps_Style   = 0x20000,
64        kForceBold_Style   = 0x40000
65    };
66    uint16_t fStyle;        // Font style characteristics.
67    int16_t fItalicAngle;   // Counterclockwise degrees from vertical of the
68                            // dominant vertical stroke for an Italic face.
69    // The following fields are all in font units.
70    int16_t fAscent;       // Max height above baseline, not including accents.
71    int16_t fDescent;      // Max depth below baseline (negative).
72    int16_t fStemV;        // Thickness of dominant vertical stem.
73    int16_t fCapHeight;    // Height (from baseline) of top of flat capitals.
74
75    SkIRect fBBox;  // The bounding box of all glyphs (in font units).
76
77    // The type of advance data wanted.
78    enum PerGlyphInfo {
79      kNo_PerGlyphInfo         = 0x0, // Don't populate any per glyph info.
80      kHAdvance_PerGlyphInfo   = 0x1, // Populate horizontal advance data.
81      kVAdvance_PerGlyphInfo   = 0x2, // Populate vertical advance data.
82      kGlyphNames_PerGlyphInfo = 0x4, // Populate glyph names (Type 1 only).
83      kToUnicode_PerGlyphInfo  = 0x8  // Populate ToUnicode table, ignored
84                                      // for Type 1 fonts
85    };
86
87    template <typename Data>
88    struct AdvanceMetric {
89        enum MetricType {
90            kDefault,  // Default advance: fAdvance.count = 1
91            kRange,    // Advances for a range: fAdvance.count = fEndID-fStartID
92            kRun       // fStartID-fEndID have same advance: fAdvance.count = 1
93        };
94        MetricType fType;
95        uint16_t fStartId;
96        uint16_t fEndId;
97        SkTDArray<Data> fAdvance;
98        SkAutoTDelete<AdvanceMetric<Data> > fNext;
99    };
100
101    struct VerticalMetric {
102        int16_t fVerticalAdvance;
103        int16_t fOriginXDisp;  // Horiz. displacement of the secondary origin.
104        int16_t fOriginYDisp;  // Vert. displacement of the secondary origin.
105    };
106    typedef AdvanceMetric<int16_t> WidthRange;
107    typedef AdvanceMetric<VerticalMetric> VerticalAdvanceRange;
108
109    // This is indexed by glyph id.
110    SkAutoTDelete<WidthRange> fGlyphWidths;
111    // Only used for Vertical CID fonts.
112    SkAutoTDelete<VerticalAdvanceRange> fVerticalMetrics;
113
114    // The names of each glyph, only populated for postscript fonts.
115    SkAutoTDelete<SkAutoTArray<SkString> > fGlyphNames;
116
117    // The mapping from glyph to Unicode, only populated if
118    // kToUnicode_PerGlyphInfo is passed to GetAdvancedTypefaceMetrics.
119    SkTDArray<SkUnichar> fGlyphToUnicode;
120
121private:
122    typedef SkRefCnt INHERITED;
123};
124
125namespace skia_advanced_typeface_metrics_utils {
126
127template <typename Data>
128void resetRange(SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* range,
129                       int startId);
130
131template <typename Data>
132SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* appendRange(
133        SkAutoTDelete<SkAdvancedTypefaceMetrics::AdvanceMetric<Data> >* nextSlot,
134        int startId);
135
136template <typename Data>
137void finishRange(
138        SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* range,
139        int endId,
140        typename SkAdvancedTypefaceMetrics::AdvanceMetric<Data>::MetricType
141                type);
142
143/** Retrieve advance data for glyphs. Used by the PDF backend. It calls
144    underlying platform dependent API getAdvance to acquire the data.
145    @param num_glyphs    Total number of glyphs in the given font.
146    @param glyphIDs      For per-glyph info, specify subset of the font by
147                         giving glyph ids.  Each integer represents a glyph
148                         id.  Passing NULL means all glyphs in the font.
149    @param glyphIDsCount Number of elements in subsetGlyphIds. Ignored if
150                         glyphIDs is NULL.
151*/
152template <typename Data, typename FontHandle>
153SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* getAdvanceData(
154        FontHandle fontHandle,
155        int num_glyphs,
156        const uint32_t* glyphIDs,
157        uint32_t glyphIDsCount,
158        bool (*getAdvance)(FontHandle fontHandle, int gId, Data* data));
159
160} // namespace skia_advanced_typeface_metrics_utils
161
162#endif
163