1 2 /* 3 * Copyright 2006 The Android Open Source Project 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 SkTypeface_DEFINED 11 #define SkTypeface_DEFINED 12 13 #include "SkAdvancedTypefaceMetrics.h" 14 #include "SkWeakRefCnt.h" 15 16 class SkStream; 17 class SkAdvancedTypefaceMetrics; 18 class SkWStream; 19 20 typedef uint32_t SkFontID; 21 typedef uint32_t SkFontTableTag; 22 23 /** \class SkTypeface 24 25 The SkTypeface class specifies the typeface and intrinsic style of a font. 26 This is used in the paint, along with optionally algorithmic settings like 27 textSize, textSkewX, textScaleX, kFakeBoldText_Mask, to specify 28 how text appears when drawn (and measured). 29 30 Typeface objects are immutable, and so they can be shared between threads. 31 */ 32 class SK_API SkTypeface : public SkWeakRefCnt { 33 public: 34 SK_DECLARE_INST_COUNT(SkTypeface) 35 36 /** Style specifies the intrinsic style attributes of a given typeface 37 */ 38 enum Style { 39 kNormal = 0, 40 kBold = 0x01, 41 kItalic = 0x02, 42 43 // helpers 44 kBoldItalic = 0x03 45 }; 46 47 /** Returns the typeface's intrinsic style attributes 48 */ 49 Style style() const { return fStyle; } 50 51 /** Returns true if getStyle() has the kBold bit set. 52 */ 53 bool isBold() const { return (fStyle & kBold) != 0; } 54 55 /** Returns true if getStyle() has the kItalic bit set. 56 */ 57 bool isItalic() const { return (fStyle & kItalic) != 0; } 58 59 /** Returns true if the typeface is fixed-width 60 */ 61 bool isFixedWidth() const { return fIsFixedWidth; } 62 63 /** Return a 32bit value for this typeface, unique for the underlying font 64 data. Will never return 0. 65 */ 66 SkFontID uniqueID() const { return fUniqueID; } 67 68 /** Return the uniqueID for the specified typeface. If the face is null, 69 resolve it to the default font and return its uniqueID. Will never 70 return 0. 71 */ 72 static SkFontID UniqueID(const SkTypeface* face); 73 74 /** Returns true if the two typefaces reference the same underlying font, 75 handling either being null (treating null as the default font) 76 */ 77 static bool Equal(const SkTypeface* facea, const SkTypeface* faceb); 78 79 /** Return a new reference to the typeface that most closely matches the 80 requested familyName and style. Pass null as the familyName to return 81 the default font for the requested style. Will never return null 82 83 @param familyName May be NULL. The name of the font family. 84 @param style The style (normal, bold, italic) of the typeface. 85 @return reference to the closest-matching typeface. Call must call 86 unref() when they are done. 87 */ 88 static SkTypeface* CreateFromName(const char familyName[], Style style); 89 90 /** Return a new reference to the typeface that most closely matches the 91 requested typeface and specified Style. Use this call if you want to 92 pick a new style from the same family of the existing typeface. 93 If family is NULL, this selects from the default font's family. 94 95 @param family May be NULL. The name of the existing type face. 96 @param s The style (normal, bold, italic) of the type face. 97 @return reference to the closest-matching typeface. Call must call 98 unref() when they are done. 99 */ 100 static SkTypeface* CreateFromTypeface(const SkTypeface* family, Style s); 101 102 /** Return a new typeface given a file. If the file does not exist, or is 103 not a valid font file, returns null. 104 */ 105 static SkTypeface* CreateFromFile(const char path[]); 106 107 /** Return a new typeface given a stream. If the stream is 108 not a valid font file, returns null. Ownership of the stream is 109 transferred, so the caller must not reference it again. 110 */ 111 static SkTypeface* CreateFromStream(SkStream* stream); 112 113 /** Write a unique signature to a stream, sufficient to reconstruct a 114 typeface referencing the same font when Deserialize is called. 115 */ 116 void serialize(SkWStream*) const; 117 118 /** Given the data previously written by serialize(), return a new instance 119 to a typeface referring to the same font. If that font is not available, 120 return null. If an instance is returned, the caller is responsible for 121 calling unref() when they are done with it. 122 */ 123 static SkTypeface* Deserialize(SkStream*); 124 125 /** Retrieve detailed typeface metrics. Used by the PDF backend. 126 @param perGlyphInfo Indicate what glyph specific information (advances, 127 names, etc.) should be populated. 128 @param glyphIDs For per-glyph info, specify subset of the font by 129 giving glyph ids. Each integer represents a glyph 130 id. Passing NULL means all glyphs in the font. 131 @param glyphIDsCount Number of elements in subsetGlyphIds. Ignored if 132 glyphIDs is NULL. 133 @return The returned object has already been referenced. 134 */ 135 SkAdvancedTypefaceMetrics* getAdvancedTypefaceMetrics( 136 SkAdvancedTypefaceMetrics::PerGlyphInfo perGlyphInfo, 137 const uint32_t* glyphIDs = NULL, 138 uint32_t glyphIDsCount = 0) const; 139 140 // Table getters -- may fail if the underlying font format is not organized 141 // as 4-byte tables. 142 143 /** Return the number of tables in the font. */ 144 int countTables() const; 145 146 /** Copy into tags[] (allocated by the caller) the list of table tags in 147 * the font, and return the number. This will be the same as CountTables() 148 * or 0 if an error occured. If tags == NULL, this only returns the count 149 * (the same as calling countTables()). 150 */ 151 int getTableTags(SkFontTableTag tags[]) const; 152 153 /** Given a table tag, return the size of its contents, or 0 if not present 154 */ 155 size_t getTableSize(SkFontTableTag) const; 156 157 /** Copy the contents of a table into data (allocated by the caller). Note 158 * that the contents of the table will be in their native endian order 159 * (which for most truetype tables is big endian). If the table tag is 160 * not found, or there is an error copying the data, then 0 is returned. 161 * If this happens, it is possible that some or all of the memory pointed 162 * to by data may have been written to, even though an error has occured. 163 * 164 * @param fontID the font to copy the table from 165 * @param tag The table tag whose contents are to be copied 166 * @param offset The offset in bytes into the table's contents where the 167 * copy should start from. 168 * @param length The number of bytes, starting at offset, of table data 169 * to copy. 170 * @param data storage address where the table contents are copied to 171 * @return the number of bytes actually copied into data. If offset+length 172 * exceeds the table's size, then only the bytes up to the table's 173 * size are actually copied, and this is the value returned. If 174 * offset > the table's size, or tag is not a valid table, 175 * then 0 is returned. 176 */ 177 size_t getTableData(SkFontTableTag tag, size_t offset, size_t length, 178 void* data) const; 179 180 /** 181 * Return the units-per-em value for this typeface, or zero if there is an 182 * error. 183 */ 184 int getUnitsPerEm() const; 185 186 protected: 187 /** uniqueID must be unique (please!) and non-zero 188 */ 189 SkTypeface(Style style, SkFontID uniqueID, bool isFixedWidth = false); 190 virtual ~SkTypeface(); 191 192 friend class SkScalerContext; 193 static SkTypeface* GetDefaultTypeface(); 194 195 private: 196 SkFontID fUniqueID; 197 Style fStyle; 198 bool fIsFixedWidth; 199 200 typedef SkWeakRefCnt INHERITED; 201 }; 202 203 #endif 204
