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* 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 SkAdvancedTypefaceMetrics_DEFINED
#define SkAdvancedTypefaceMetrics_DEFINED
#include "SkRect.h"
#include "SkRefCnt.h"
#include "SkString.h"
#include "SkTDArray.h"
#include "SkTemplates.h"
/** \class SkAdvancedTypefaceMetrics
The SkAdvancedTypefaceMetrics class is used by the PDF backend to correctly
embed typefaces. This class is created and filled in with information by
class SkAdvancedTypefaceMetrics : public SkRefCnt {
SkString fFontName;
enum FontType {
// The type of the underlying font program. This field determines which
// of the following fields are valid. If it is kOther_Font the per glyph
// information will never be populated.
FontType fType;
enum FontFlags {
kEmpty_FontFlag = 0x0, //!<No flags set
kMultiMaster_FontFlag = 0x1, //!<May be true for Type1, CFF, or TrueType fonts.
kNotEmbeddable_FontFlag = 0x2, //!<May not be embedded.
kNotSubsettable_FontFlag = 0x4, //!<May not be subset.
// Global font flags.
FontFlags fFlags;
uint16_t fLastGlyphID; // The last valid glyph ID in the font.
uint16_t fEmSize; // The size of the em box (defines font units).
// These enum values match the values used in the PDF file format.
enum StyleFlags {
kFixedPitch_Style = 0x00001,
kSerif_Style = 0x00002,
kScript_Style = 0x00008,
kItalic_Style = 0x00040,
kAllCaps_Style = 0x10000,
kSmallCaps_Style = 0x20000,
kForceBold_Style = 0x40000
uint16_t fStyle; // Font style characteristics.
int16_t fItalicAngle; // Counterclockwise degrees from vertical of the
// dominant vertical stroke for an Italic face.
// The following fields are all in font units.
int16_t fAscent; // Max height above baseline, not including accents.
int16_t fDescent; // Max depth below baseline (negative).
int16_t fStemV; // Thickness of dominant vertical stem.
int16_t fCapHeight; // Height (from baseline) of top of flat capitals.
SkIRect fBBox; // The bounding box of all glyphs (in font units).
template <typename Data>
struct AdvanceMetric {
enum MetricType {
kDefault, // Default advance: fAdvance.count = 1
kRange, // Advances for a range: fAdvance.count = fEndID-fStartID
kRun // fStartID-fEndID have same advance: fAdvance.count = 1
MetricType fType;
uint16_t fStartId;
uint16_t fEndId;
SkTDArray<Data> fAdvance;
SkAutoTDelete<AdvanceMetric<Data> > fNext;
struct VerticalMetric {
int16_t fVerticalAdvance;
int16_t fOriginXDisp; // Horiz. displacement of the secondary origin.
int16_t fOriginYDisp; // Vert. displacement of the secondary origin.
typedef AdvanceMetric<int16_t> WidthRange;
typedef AdvanceMetric<VerticalMetric> VerticalAdvanceRange;
// This is indexed by glyph id.
SkAutoTDelete<WidthRange> fGlyphWidths;
// Only used for Vertical CID fonts.
SkAutoTDelete<VerticalAdvanceRange> fVerticalMetrics;
// The names of each glyph, only populated for postscript fonts.
SkAutoTDelete<SkAutoTArray<SkString> > fGlyphNames;
// The mapping from glyph to Unicode, only populated if
// kToUnicode_PerGlyphInfo is passed to GetAdvancedTypefaceMetrics.
SkTDArray<SkUnichar> fGlyphToUnicode;
typedef SkRefCnt INHERITED;
namespace skia_advanced_typeface_metrics_utils {
template <typename Data>
void resetRange(SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* range,
int startId);
template <typename Data>
SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* appendRange(
SkAutoTDelete<SkAdvancedTypefaceMetrics::AdvanceMetric<Data> >* nextSlot,
int startId);
template <typename Data>
void finishRange(
SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* range,
int endId,
typename SkAdvancedTypefaceMetrics::AdvanceMetric<Data>::MetricType
/** Retrieve advance data for glyphs. Used by the PDF backend. It calls
underlying platform dependent API getAdvance to acquire the data.
@param num_glyphs Total number of glyphs in the given font.
@param glyphIDs For per-glyph info, specify subset of the font by
giving glyph ids. Each integer represents a glyph
id. Passing NULL means all glyphs in the font.
@param glyphIDsCount Number of elements in subsetGlyphIds. Ignored if
glyphIDs is NULL.
template <typename Data, typename FontHandle>
SkAdvancedTypefaceMetrics::AdvanceMetric<Data>* getAdvanceData(
FontHandle fontHandle,
int num_glyphs,
const uint32_t* glyphIDs,
uint32_t glyphIDsCount,
bool (*getAdvance)(FontHandle fontHandle, int gId, Data* data));
} // namespace skia_advanced_typeface_metrics_utils