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 SkDescriptor; 17 class SkFontDescriptor; 18 class SkScalerContext; 19 struct SkScalerContextRec; 20 class SkStream; 21 class SkAdvancedTypefaceMetrics; 22 class SkWStream; 23 24 typedef uint32_t SkFontID; 25 /** Machine endian. */ 26 typedef uint32_t SkFontTableTag; 27 28 /** \class SkTypeface 29 30 The SkTypeface class specifies the typeface and intrinsic style of a font. 31 This is used in the paint, along with optionally algorithmic settings like 32 textSize, textSkewX, textScaleX, kFakeBoldText_Mask, to specify 33 how text appears when drawn (and measured). 34 35 Typeface objects are immutable, and so they can be shared between threads. 36 */ 37 class SK_API SkTypeface : public SkWeakRefCnt { 38 public: 39 SK_DECLARE_INST_COUNT(SkTypeface) 40 41 /** Style specifies the intrinsic style attributes of a given typeface 42 */ 43 enum Style { 44 kNormal = 0, 45 kBold = 0x01, 46 kItalic = 0x02, 47 48 // helpers 49 kBoldItalic = 0x03 50 }; 51 52 /** Returns the typeface's intrinsic style attributes 53 */ 54 Style style() const { return fStyle; } 55 56 /** Returns true if getStyle() has the kBold bit set. 57 */ 58 bool isBold() const { return (fStyle & kBold) != 0; } 59 60 /** Returns true if getStyle() has the kItalic bit set. 61 */ 62 bool isItalic() const { return (fStyle & kItalic) != 0; } 63 64 /** Returns true if the typeface claims to be fixed-pitch. 65 * This is a style bit, advance widths may vary even if this returns true. 66 */ 67 bool isFixedPitch() const { return fIsFixedPitch; } 68 69 /** Return a 32bit value for this typeface, unique for the underlying font 70 data. Will never return 0. 71 */ 72 SkFontID uniqueID() const { return fUniqueID; } 73 74 /** Return the uniqueID for the specified typeface. If the face is null, 75 resolve it to the default font and return its uniqueID. Will never 76 return 0. 77 */ 78 static SkFontID UniqueID(const SkTypeface* face); 79 80 /** Returns true if the two typefaces reference the same underlying font, 81 handling either being null (treating null as the default font) 82 */ 83 static bool Equal(const SkTypeface* facea, const SkTypeface* faceb); 84 85 /** 86 * Returns a ref() to the default typeface. The caller must call unref() 87 * when they are done referencing the object. Never returns NULL. 88 */ 89 static SkTypeface* RefDefault(Style style = SkTypeface::kNormal); 90 91 /** Return a new reference to the typeface that most closely matches the 92 requested familyName and style. Pass null as the familyName to return 93 the default font for the requested style. Will never return null 94 95 @param familyName May be NULL. The name of the font family. 96 @param style The style (normal, bold, italic) of the typeface. 97 @return reference to the closest-matching typeface. Call must call 98 unref() when they are done. 99 */ 100 static SkTypeface* CreateFromName(const char familyName[], Style style); 101 102 /** Return a new reference to the typeface that most closely matches the 103 requested typeface and specified Style. Use this call if you want to 104 pick a new style from the same family of the existing typeface. 105 If family is NULL, this selects from the default font's family. 106 107 @param family May be NULL. The name of the existing type face. 108 @param s The style (normal, bold, italic) of the type face. 109 @return reference to the closest-matching typeface. Call must call 110 unref() when they are done. 111 */ 112 static SkTypeface* CreateFromTypeface(const SkTypeface* family, Style s); 113 114 /** Return a new typeface given a file. If the file does not exist, or is 115 not a valid font file, returns null. 116 */ 117 static SkTypeface* CreateFromFile(const char path[]); 118 119 /** Return a new typeface given a stream. If the stream is 120 not a valid font file, returns null. Ownership of the stream is 121 transferred, so the caller must not reference it again. 122 */ 123 static SkTypeface* CreateFromStream(SkStream* stream); 124 125 /** Write a unique signature to a stream, sufficient to reconstruct a 126 typeface referencing the same font when Deserialize is called. 127 */ 128 void serialize(SkWStream*) const; 129 130 /** Given the data previously written by serialize(), return a new instance 131 to a typeface referring to the same font. If that font is not available, 132 return null. If an instance is returned, the caller is responsible for 133 calling unref() when they are done with it. 134 */ 135 static SkTypeface* Deserialize(SkStream*); 136 137 enum Encoding { 138 kUTF8_Encoding, 139 kUTF16_Encoding, 140 kUTF32_Encoding 141 }; 142 143 /** 144 * Given an array of character codes, of the specified encoding, 145 * optionally return their corresponding glyph IDs (if glyphs is not NULL). 146 * 147 * @param chars pointer to the array of character codes 148 * @param encoding how the characters are encoded 149 * @param glyphs (optional) returns the corresponding glyph IDs for each 150 * character code, up to glyphCount values. If a character code is 151 * not found in the typeface, the corresponding glyph ID will be 0. 152 * @param glyphCount number of code points in 'chars' to process. If glyphs 153 * is not NULL, then it must point sufficient memory to write 154 * glyphCount values into it. 155 * @return the number of number of continuous non-zero glyph IDs computed 156 * from the beginning of chars. This value is valid, even if the 157 * glyphs parameter is NULL. 158 */ 159 int charsToGlyphs(const void* chars, Encoding encoding, uint16_t glyphs[], 160 int glyphCount) const; 161 162 /** 163 * Return the number of glyphs in the typeface. 164 */ 165 int countGlyphs() const; 166 167 // Table getters -- may fail if the underlying font format is not organized 168 // as 4-byte tables. 169 170 /** Return the number of tables in the font. */ 171 int countTables() const; 172 173 /** Copy into tags[] (allocated by the caller) the list of table tags in 174 * the font, and return the number. This will be the same as CountTables() 175 * or 0 if an error occured. If tags == NULL, this only returns the count 176 * (the same as calling countTables()). 177 */ 178 int getTableTags(SkFontTableTag tags[]) const; 179 180 /** Given a table tag, return the size of its contents, or 0 if not present 181 */ 182 size_t getTableSize(SkFontTableTag) const; 183 184 /** Copy the contents of a table into data (allocated by the caller). Note 185 * that the contents of the table will be in their native endian order 186 * (which for most truetype tables is big endian). If the table tag is 187 * not found, or there is an error copying the data, then 0 is returned. 188 * If this happens, it is possible that some or all of the memory pointed 189 * to by data may have been written to, even though an error has occured. 190 * 191 * @param fontID the font to copy the table from 192 * @param tag The table tag whose contents are to be copied 193 * @param offset The offset in bytes into the table's contents where the 194 * copy should start from. 195 * @param length The number of bytes, starting at offset, of table data 196 * to copy. 197 * @param data storage address where the table contents are copied to 198 * @return the number of bytes actually copied into data. If offset+length 199 * exceeds the table's size, then only the bytes up to the table's 200 * size are actually copied, and this is the value returned. If 201 * offset > the table's size, or tag is not a valid table, 202 * then 0 is returned. 203 */ 204 size_t getTableData(SkFontTableTag tag, size_t offset, size_t length, 205 void* data) const; 206 207 /** 208 * Return the units-per-em value for this typeface, or zero if there is an 209 * error. 210 */ 211 int getUnitsPerEm() const; 212 213 /** 214 * Given a run of glyphs, return the associated horizontal adjustments. 215 * Adjustments are in "design units", which are integers relative to the 216 * typeface's units per em (see getUnitsPerEm). 217 * 218 * Some typefaces are known to never support kerning. Calling this method 219 * with all zeros (e.g. getKerningPairAdustments(NULL, 0, NULL)) returns 220 * a boolean indicating if the typeface might support kerning. If it 221 * returns false, then it will always return false (no kerning) for all 222 * possible glyph runs. If it returns true, then it *may* return true for 223 * somne glyph runs. 224 * 225 * If count is non-zero, then the glyphs parameter must point to at least 226 * [count] valid glyph IDs, and the adjustments parameter must be 227 * sized to at least [count - 1] entries. If the method returns true, then 228 * [count-1] entries in the adjustments array will be set. If the method 229 * returns false, then no kerning should be applied, and the adjustments 230 * array will be in an undefined state (possibly some values may have been 231 * written, but none of them should be interpreted as valid values). 232 */ 233 bool getKerningPairAdjustments(const uint16_t glyphs[], int count, 234 int32_t adjustments[]) const; 235 236 struct LocalizedString { 237 SkString fString; 238 SkString fLanguage; 239 }; 240 class LocalizedStrings : ::SkNoncopyable { 241 public: 242 virtual ~LocalizedStrings() { } 243 virtual bool next(LocalizedString* localizedString) = 0; 244 void unref() { SkDELETE(this); } 245 }; 246 /** 247 * Returns an iterator which will attempt to enumerate all of the 248 * family names specified by the font. 249 * It is the caller's responsibility to unref() the returned pointer. 250 */ 251 LocalizedStrings* createFamilyNameIterator() const; 252 253 /** 254 * Return the family name for this typeface. It will always be returned 255 * encoded as UTF8, but the language of the name is whatever the host 256 * platform chooses. 257 */ 258 void getFamilyName(SkString* name) const; 259 260 /** 261 * Return a stream for the contents of the font data, or NULL on failure. 262 * If ttcIndex is not null, it is set to the TrueTypeCollection index 263 * of this typeface within the stream, or 0 if the stream is not a 264 * collection. 265 */ 266 SkStream* openStream(int* ttcIndex) const; 267 268 /** 269 * Return a scalercontext for the given descriptor. If this fails, then 270 * if allowFailure is true, this returns NULL, else it returns a 271 * dummy scalercontext that will not crash, but will draw nothing. 272 */ 273 SkScalerContext* createScalerContext(const SkDescriptor*, 274 bool allowFailure = false) const; 275 276 // PRIVATE / EXPERIMENTAL -- do not call 277 void filterRec(SkScalerContextRec* rec) const { 278 this->onFilterRec(rec); 279 } 280 // PRIVATE / EXPERIMENTAL -- do not call 281 void getFontDescriptor(SkFontDescriptor* desc, bool* isLocal) const { 282 this->onGetFontDescriptor(desc, isLocal); 283 } 284 285 protected: 286 /** uniqueID must be unique and non-zero 287 */ 288 SkTypeface(Style style, SkFontID uniqueID, bool isFixedPitch = false); 289 virtual ~SkTypeface(); 290 291 /** Sets the fixedPitch bit. If used, must be called in the constructor. */ 292 void setIsFixedPitch(bool isFixedPitch) { fIsFixedPitch = isFixedPitch; } 293 294 friend class SkScalerContext; 295 static SkTypeface* GetDefaultTypeface(Style style = SkTypeface::kNormal); 296 297 virtual SkScalerContext* onCreateScalerContext(const SkDescriptor*) const = 0; 298 virtual void onFilterRec(SkScalerContextRec*) const = 0; 299 virtual SkAdvancedTypefaceMetrics* onGetAdvancedTypefaceMetrics( 300 SkAdvancedTypefaceMetrics::PerGlyphInfo perGlyphInfo, 301 const uint32_t* glyphIDs, 302 uint32_t glyphIDsCount) const = 0; 303 304 virtual SkStream* onOpenStream(int* ttcIndex) const = 0; 305 virtual void onGetFontDescriptor(SkFontDescriptor*, bool* isLocal) const = 0; 306 307 virtual int onCharsToGlyphs(const void* chars, Encoding, uint16_t glyphs[], 308 int glyphCount) const = 0; 309 virtual int onCountGlyphs() const = 0; 310 311 virtual int onGetUPEM() const = 0; 312 virtual bool onGetKerningPairAdjustments(const uint16_t glyphs[], int count, 313 int32_t adjustments[]) const; 314 315 virtual LocalizedStrings* onCreateFamilyNameIterator() const = 0; 316 317 virtual int onGetTableTags(SkFontTableTag tags[]) const = 0; 318 virtual size_t onGetTableData(SkFontTableTag, size_t offset, 319 size_t length, void* data) const = 0; 320 321 private: 322 friend class SkGTypeface; 323 friend class SkPDFFont; 324 friend class SkPDFCIDFont; 325 326 /** Retrieve detailed typeface metrics. Used by the PDF backend. 327 @param perGlyphInfo Indicate what glyph specific information (advances, 328 names, etc.) should be populated. 329 @param glyphIDs For per-glyph info, specify subset of the font by 330 giving glyph ids. Each integer represents a glyph 331 id. Passing NULL means all glyphs in the font. 332 @param glyphIDsCount Number of elements in subsetGlyphIds. Ignored if 333 glyphIDs is NULL. 334 @return The returned object has already been referenced. 335 */ 336 SkAdvancedTypefaceMetrics* getAdvancedTypefaceMetrics( 337 SkAdvancedTypefaceMetrics::PerGlyphInfo perGlyphInfo, 338 const uint32_t* glyphIDs = NULL, 339 uint32_t glyphIDsCount = 0) const; 340 341 private: 342 static SkTypeface* CreateDefault(int style); // SkLazyPtr requires an int, not a Style. 343 static void DeleteDefault(SkTypeface*); 344 345 SkFontID fUniqueID; 346 Style fStyle; 347 bool fIsFixedPitch; 348 349 friend class SkPaint; 350 friend class SkGlyphCache; // GetDefaultTypeface 351 // just so deprecated fonthost can call protected methods 352 friend class SkFontHost; 353 354 typedef SkWeakRefCnt INHERITED; 355 }; 356 357 #endif 358
