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| 1 /* | |
| 2 * Copyright (c) 2006, 2007, 2008, 2009, Google Inc. All rights reserved. | |
| 3 * | |
| 4 * Redistribution and use in source and binary forms, with or without | |
| 5 * modification, are permitted provided that the following conditions are | |
| 6 * met: | |
| 7 * | |
| 8 * * Redistributions of source code must retain the above copyright | |
| 9 * notice, this list of conditions and the following disclaimer. | |
| 10 * * Redistributions in binary form must reproduce the above | |
| 11 * copyright notice, this list of conditions and the following disclaimer | |
| 12 * in the documentation and/or other materials provided with the | |
| 13 * distribution. | |
| 14 * * Neither the name of Google Inc. nor the names of its | |
| 15 * contributors may be used to endorse or promote products derived from | |
| 16 * this software without specific prior written permission. | |
| 17 * | |
| 18 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 19 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 20 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR | |
| 21 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT | |
| 22 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | |
| 23 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT | |
| 24 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, | |
| 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY | |
| 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
| 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE | |
| 28 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
| 29 */ | |
| 30 | |
| 31 // A wrapper around Uniscribe that provides a reasonable API. | |
| 32 | |
| 33 #ifndef UniscribeHelper_h | |
| 34 #define UniscribeHelper_h | |
| 35 | |
| 36 #include <windows.h> | |
| 37 #include <usp10.h> | |
| 38 #include <map> | |
| 39 | |
| 40 #include <unicode/uchar.h> | |
| 41 #include "wtf/Vector.h" | |
| 42 | |
| 43 class UniscribeTest_TooBig_Test; // A gunit test for UniscribeHelper. | |
| 44 | |
| 45 namespace WebCore { | |
| 46 | |
| 47 class FloatRect; | |
| 48 class FontFeatureSettings; | |
| 49 class FontPlatformData; | |
| 50 class GraphicsContext; | |
| 51 | |
| 52 const unsigned cUniscribeHelperStackRuns = 8; | |
| 53 const unsigned cUniscribeHelperStackChars = 32; | |
| 54 const unsigned cUniscribeHelperFeatures = 4; | |
| 55 | |
| 56 // This object should be safe to create & destroy frequently, as long as the | |
| 57 // caller preserves the script_cache when possible (this data may be slow to | |
| 58 // compute). | |
| 59 // | |
| 60 // This object is "kind of large" (~1K) because it reserves a lot of space for | |
| 61 // working with to avoid expensive heap operations. Therefore, not only should | |
| 62 // you not worry about creating and destroying it, you should try to not keep | |
| 63 // them around. | |
| 64 class UniscribeHelper { | |
| 65 public: | |
| 66 // Initializes this Uniscribe run with the text pointed to by |run| with | |
| 67 // |length|. The input is NOT null terminated. | |
| 68 // | |
| 69 // The is_rtl flag should be set if the input script is RTL. It is assumed | |
| 70 // that the caller has already divided up the input text (using ICU, for | |
| 71 // example) into runs of the same direction of script. This avoids | |
| 72 // disagreements between the caller and Uniscribe later (see FillItems). | |
| 73 // | |
| 74 // A script cache should be provided by the caller that is initialized to | |
| 75 // NULL. When the caller is done with the cache (it may be stored between | |
| 76 // runs as long as it is used consistently with the same HFONT), it should | |
| 77 // call ScriptFreeCache(). | |
| 78 UniscribeHelper(const UChar* input, | |
| 79 int inputLength, | |
| 80 bool isRtl, | |
| 81 HFONT, | |
| 82 SCRIPT_CACHE*, | |
| 83 SCRIPT_FONTPROPERTIES*, | |
| 84 WORD); | |
| 85 | |
| 86 virtual ~UniscribeHelper(); | |
| 87 | |
| 88 // Sets Uniscribe's directional override flag. False by default. | |
| 89 bool directionalOverride() const | |
| 90 { | |
| 91 return m_directionalOverride; | |
| 92 } | |
| 93 void setDirectionalOverride(bool override) | |
| 94 { | |
| 95 m_directionalOverride = override; | |
| 96 } | |
| 97 | |
| 98 // Set's Uniscribe's no-ligate override flag. False by default. | |
| 99 bool inhibitLigate() const | |
| 100 { | |
| 101 return m_inhibitLigate; | |
| 102 } | |
| 103 void setInhibitLigate(bool inhibit) | |
| 104 { | |
| 105 m_inhibitLigate = inhibit; | |
| 106 } | |
| 107 | |
| 108 // Set letter spacing. We will try to insert this much space between | |
| 109 // graphemes (one or more glyphs perceived as a single unit by ordinary | |
| 110 // users of a script). Positive values increase letter spacing, negative | |
| 111 // values decrease it. 0 by default. | |
| 112 int letterSpacing() const | |
| 113 { | |
| 114 return m_letterSpacing; | |
| 115 } | |
| 116 void setLetterSpacing(int letterSpacing) | |
| 117 { | |
| 118 m_letterSpacing = letterSpacing; | |
| 119 } | |
| 120 | |
| 121 // Set the width of a standard space character. We use this to normalize | |
| 122 // space widths. Windows will make spaces after Hindi characters larger than | |
| 123 // other spaces. A space_width of 0 means to use the default space width. | |
| 124 // | |
| 125 // Must be set before Init() is called. | |
| 126 int spaceWidth() const | |
| 127 { | |
| 128 return m_spaceWidth; | |
| 129 } | |
| 130 void setSpaceWidth(int spaceWidth) | |
| 131 { | |
| 132 m_spaceWidth = spaceWidth; | |
| 133 } | |
| 134 | |
| 135 // Set word spacing. We will try to insert this much extra space between | |
| 136 // each word in the input (beyond whatever whitespace character separates | |
| 137 // words). Positive values lead to increased letter spacing, negative values | |
| 138 // decrease it. 0 by default. | |
| 139 // | |
| 140 // Must be set before Init() is called. | |
| 141 int wordSpacing() const | |
| 142 { | |
| 143 return m_wordSpacing; | |
| 144 } | |
| 145 void setWordSpacing(int wordSpacing) | |
| 146 { | |
| 147 m_wordSpacing = wordSpacing; | |
| 148 } | |
| 149 | |
| 150 void setAscent(int ascent) | |
| 151 { | |
| 152 m_ascent = ascent; | |
| 153 } | |
| 154 | |
| 155 // When set to true, this class is used only to look up glyph | |
| 156 // indices for a range of Unicode characters without glyph placement. | |
| 157 // By default, it's false. This should be set to true when this | |
| 158 // class is used for glyph index look-up for non-BMP characters | |
| 159 // in GlyphPageNodeChromiumWin.cpp. | |
| 160 void setDisableFontFallback(bool disableFontFallback) | |
| 161 { | |
| 162 m_disableFontFallback = true; | |
| 163 } | |
| 164 | |
| 165 // Set TEXTRANGE_PROPERTIES structure which contains | |
| 166 // OpenType feature records generated from FontFeatureSettings. | |
| 167 void setRangeProperties(const FontFeatureSettings*); | |
| 168 | |
| 169 // You must call this after setting any options but before doing any | |
| 170 // other calls like asking for widths or drawing. | |
| 171 void init() | |
| 172 { | |
| 173 initWithOptionalLengthProtection(true); | |
| 174 } | |
| 175 | |
| 176 // Returns the total width in pixels of the text run. | |
| 177 int width() const; | |
| 178 | |
| 179 // Call to justify the text, with the amount of space that should be ADDED | |
| 180 // to get the desired width that the column should be justified to. | |
| 181 // Normally, spaces are inserted, but for Arabic there will be kashidas | |
| 182 // (extra strokes) inserted instead. | |
| 183 // | |
| 184 // This function MUST be called AFTER Init(). | |
| 185 void justify(int additionalSpace); | |
| 186 | |
| 187 // Computes the given character offset into a pixel offset of the beginning | |
| 188 // of that character. | |
| 189 int characterToX(int offset) const; | |
| 190 | |
| 191 // Converts the given pixel X position into a logical character offset into | |
| 192 // the run. For positions appearing before the first character, this will | |
| 193 // return -1. | |
| 194 int xToCharacter(int x) const; | |
| 195 | |
| 196 // Draws the given characters to (x, y) in the given DC. The font will be | |
| 197 // handled by this function, but the font color and other attributes should | |
| 198 // be pre-set. | |
| 199 // | |
| 200 // The y position is the upper left corner, NOT the baseline. | |
| 201 void draw(GraphicsContext*, const FontPlatformData&, HDC, | |
| 202 int x, int y, const FloatRect& textRect, | |
| 203 int from, int to); | |
| 204 | |
| 205 // Returns the first glyph assigned to the character at the given offset. | |
| 206 // This function is used to retrieve glyph information when Uniscribe is | |
| 207 // being used to generate glyphs for non-complex, non-BMP (above U+FFFF) | |
| 208 // characters. These characters are not otherwise special and have no | |
| 209 // complex shaping rules, so we don't otherwise need Uniscribe, except | |
| 210 // Uniscribe is the only way to get glyphs for non-BMP characters. | |
| 211 // | |
| 212 // Returns 0 if there is no glyph for the given character. | |
| 213 WORD firstGlyphForCharacter(int charOffset) const; | |
| 214 | |
| 215 protected: | |
| 216 // Backend for init. The flag allows the unit test to specify whether we | |
| 217 // should fail early for very long strings like normal, or try to pass the | |
| 218 // long string to Uniscribe. The latter provides a way to force failure of | |
| 219 // shaping. | |
| 220 void initWithOptionalLengthProtection(bool lengthProtection); | |
| 221 | |
| 222 // Tries to preload the font when the it is not accessible. | |
| 223 // This is the default implementation and it does not do anything. | |
| 224 virtual void tryToPreloadFont(HFONT) {} | |
| 225 | |
| 226 // Let our subclasses provide the input lazily in case they can't compute | |
| 227 // it in their constructors. Once we have input, however, we don't let | |
| 228 // our subclasses change it. | |
| 229 void setInput(const UChar* input) { ASSERT(!m_input); m_input = input; } | |
| 230 | |
| 231 private: | |
| 232 friend class UniscribeTest_TooBig_Test; | |
| 233 | |
| 234 // An array corresponding to each item in runs_ containing information | |
| 235 // on each of the glyphs that were generated. Like runs_, this is in | |
| 236 // reading order. However, for rtl text, the characters within each | |
| 237 // item will be reversed. | |
| 238 struct Shaping { | |
| 239 Shaping() | |
| 240 : m_prePadding(0) | |
| 241 , m_hfont(NULL) | |
| 242 , m_scriptCache(NULL) | |
| 243 , m_ascentOffset(0) | |
| 244 , m_spaceGlyph(0) | |
| 245 { | |
| 246 m_abc.abcA = 0; | |
| 247 m_abc.abcB = 0; | |
| 248 m_abc.abcC = 0; | |
| 249 } | |
| 250 | |
| 251 // Returns the number of glyphs (which will be drawn to the screen) | |
| 252 // in this run. | |
| 253 int glyphLength() const | |
| 254 { | |
| 255 return static_cast<int>(m_glyphs.size()); | |
| 256 } | |
| 257 | |
| 258 // Returns the number of characters (that we started with) in this run. | |
| 259 int charLength() const | |
| 260 { | |
| 261 return static_cast<int>(m_logs.size()); | |
| 262 } | |
| 263 | |
| 264 // Returns the advance array that should be used when measuring glyphs. | |
| 265 // The returned pointer will indicate an array with glyph_length() | |
| 266 // elements and the advance that should be used for each one. This is | |
| 267 // either the real advance, or the justified advances if there is one, | |
| 268 // and is the array we want to use for measurement. | |
| 269 const int* effectiveAdvances() const | |
| 270 { | |
| 271 if (m_advance.size() == 0) | |
| 272 return 0; | |
| 273 if (m_justify.size() == 0) | |
| 274 return &m_advance[0]; | |
| 275 return &m_justify[0]; | |
| 276 } | |
| 277 | |
| 278 // This is the advance amount of space that we have added to the | |
| 279 // beginning of the run. It is like the ABC's |A| advance but one that | |
| 280 // we create and must handle internally whenever computing with pixel | |
| 281 // offsets. | |
| 282 int m_prePadding; | |
| 283 | |
| 284 // Glyph indices in the font used to display this item. These indices | |
| 285 // are in screen order. | |
| 286 Vector<WORD, cUniscribeHelperStackChars> m_glyphs; | |
| 287 | |
| 288 // For each input character, this tells us the first glyph index it | |
| 289 // generated. This is the only array with size of the input chars. | |
| 290 // | |
| 291 // All offsets are from the beginning of this run. Multiple characters | |
| 292 // can generate one glyph, in which case there will be adjacent | |
| 293 // duplicates in this list. One character can also generate multiple | |
| 294 // glyphs, in which case there will be skipped indices in this list. | |
| 295 Vector<WORD, cUniscribeHelperStackChars> m_logs; | |
| 296 | |
| 297 // Flags and such for each glyph. | |
| 298 Vector<SCRIPT_VISATTR, cUniscribeHelperStackChars> m_visualAttributes; | |
| 299 | |
| 300 // Horizontal advances for each glyph listed above, this is basically | |
| 301 // how wide each glyph is. | |
| 302 Vector<int, cUniscribeHelperStackChars> m_advance; | |
| 303 | |
| 304 // This contains glyph offsets, from the nominal position of a glyph. | |
| 305 // It is used to adjust the positions of multiple combining characters | |
| 306 // around/above/below base characters in a context-sensitive manner so | |
| 307 // that they don't bump against each other and the base character. | |
| 308 Vector<GOFFSET, cUniscribeHelperStackChars> m_offsets; | |
| 309 | |
| 310 // Filled by a call to Justify, this is empty for nonjustified text. | |
| 311 // If nonempty, this contains the array of justify characters for each | |
| 312 // character as returned by ScriptJustify. | |
| 313 // | |
| 314 // This is the same as the advance array, but with extra space added | |
| 315 // for some characters. The difference between a glyph's |justify| | |
| 316 // width and it's |advance| width is the extra space added. | |
| 317 Vector<int, cUniscribeHelperStackChars> m_justify; | |
| 318 | |
| 319 // Sizing information for this run. This treats the entire run as a | |
| 320 // character with a preceeding advance, width, and ending advance. The | |
| 321 // B width is the sum of the |advance| array, and the A and C widths | |
| 322 // are any extra spacing applied to each end. | |
| 323 // | |
| 324 // It is unclear from the documentation what this actually means. From | |
| 325 // experimentation, it seems that the sum of the character advances is | |
| 326 // always the sum of the ABC values, and I'm not sure what you're | |
| 327 // supposed to do with the ABC values. | |
| 328 ABC m_abc; | |
| 329 | |
| 330 // Pointers to windows font data used to render this run. | |
| 331 HFONT m_hfont; | |
| 332 SCRIPT_CACHE* m_scriptCache; | |
| 333 | |
| 334 // Ascent offset between the ascent of the primary font | |
| 335 // and that of the fallback font. The offset needs to be applied, | |
| 336 // when drawing a string, to align multiple runs rendered with | |
| 337 // different fonts. | |
| 338 int m_ascentOffset; | |
| 339 | |
| 340 WORD m_spaceGlyph; | |
| 341 }; | |
| 342 | |
| 343 // Computes the runs_ array from the text run. | |
| 344 void fillRuns(); | |
| 345 | |
| 346 // Computes the shapes_ array given an runs_ array already filled in. | |
| 347 void fillShapes(); | |
| 348 | |
| 349 // Fills in the screen_order_ array (see below). | |
| 350 void fillScreenOrder(); | |
| 351 | |
| 352 // Called to update the glyph positions based on the current spacing | |
| 353 // options that are set. | |
| 354 void applySpacing(); | |
| 355 | |
| 356 // Normalizes all advances for spaces to the same width. This keeps windows | |
| 357 // from making spaces after Hindi characters larger, which is then | |
| 358 // inconsistent with our meaure of the width since WebKit doesn't include | |
| 359 // spaces in text-runs sent to uniscribe unless white-space:pre. | |
| 360 void adjustSpaceAdvances(); | |
| 361 | |
| 362 // Returns the total width of a single item. | |
| 363 int advanceForItem(int) const; | |
| 364 | |
| 365 bool containsMissingGlyphs(const Shaping&, | |
| 366 const SCRIPT_ITEM&, | |
| 367 const SCRIPT_FONTPROPERTIES*) const; | |
| 368 | |
| 369 // Shapes a run (pointed to by |input|) using |hfont| first. | |
| 370 // Tries a series of fonts specified retrieved with NextWinFontData | |
| 371 // and finally a font covering characters in |*input|. A string pointed | |
| 372 // by |input| comes from ScriptItemize and is supposed to contain | |
| 373 // characters belonging to a single script aside from characters common to | |
| 374 // all scripts (e.g. space). | |
| 375 bool shape(const UChar* input, int itemLength, int numGlyphs, SCRIPT_ITEM& r
un, OPENTYPE_TAG, Shaping&); | |
| 376 | |
| 377 // Gets Windows font data for the next best font to try in the list | |
| 378 // of fonts. When there's no more font available, returns false | |
| 379 // without touching any of out params. Need to call ResetFontIndex | |
| 380 // to start scanning of the font list from the beginning. | |
| 381 virtual bool nextWinFontData(HFONT&, SCRIPT_CACHE*&, SCRIPT_FONTPROPERTIES*&
, int&, WORD&) | |
| 382 { | |
| 383 return false; | |
| 384 } | |
| 385 | |
| 386 // Resets the font index to the first in the list of fonts to try after the | |
| 387 // primaryFont turns out not to work. With fontIndex reset, | |
| 388 // NextWinFontData scans fallback fonts from the beginning. | |
| 389 virtual void resetFontIndex() {} | |
| 390 | |
| 391 // If m_cachedDC is 0, creates one that is compatible with the screen DC. | |
| 392 void EnsureCachedDCCreated(); | |
| 393 | |
| 394 // The input data for this run of Uniscribe. See the constructor. | |
| 395 const UChar* m_input; | |
| 396 const int m_inputLength; | |
| 397 const bool m_isRtl; | |
| 398 | |
| 399 // Windows font data for the primary font. In a sense, m_logfont and m_style | |
| 400 // are redundant because m_hfont contains all the information. However, | |
| 401 // invoking GetObject, everytime we need the height and the style, is rather | |
| 402 // expensive so that we cache them. Would it be better to add getter and | |
| 403 // (virtual) setter for the height and the style of the primary font, | |
| 404 // instead of m_logfont? Then, a derived class ctor can set m_ascent, | |
| 405 // m_height and m_style if they're known. Getters for them would have to | |
| 406 // 'infer' their values from m_hfont ONLY when they're not set. | |
| 407 HFONT m_hfont; | |
| 408 // We cache the DC to use with ScriptShape/ScriptPlace. | |
| 409 static HDC m_cachedDC; | |
| 410 SCRIPT_CACHE* m_scriptCache; | |
| 411 SCRIPT_FONTPROPERTIES* m_fontProperties; | |
| 412 int m_ascent; | |
| 413 LOGFONT m_logfont; | |
| 414 int m_style; | |
| 415 WORD m_spaceGlyph; | |
| 416 | |
| 417 // Options, see the getters/setters above. | |
| 418 bool m_directionalOverride; | |
| 419 bool m_inhibitLigate; | |
| 420 int m_letterSpacing; | |
| 421 int m_spaceWidth; | |
| 422 int m_wordSpacing; | |
| 423 bool m_disableFontFallback; | |
| 424 | |
| 425 // Uniscribe breaks the text into Runs. These are one length of text that is | |
| 426 // in one script and one direction. This array is in reading order. | |
| 427 Vector<SCRIPT_ITEM, cUniscribeHelperStackRuns> m_runs; | |
| 428 | |
| 429 Vector<Shaping, cUniscribeHelperStackRuns> m_shapes; | |
| 430 Vector<OPENTYPE_TAG, cUniscribeHelperStackRuns> m_scriptTags; | |
| 431 | |
| 432 // This is a mapping between reading order and screen order for the items. | |
| 433 // Uniscribe's items array are in reading order. For right-to-left text, | |
| 434 // or mixed (although WebKit's |TextRun| should really be only one | |
| 435 // direction), this makes it very difficult to compute character offsets | |
| 436 // and positions. This list is in screen order from left to right, and | |
| 437 // gives the index into the |m_runs| and |m_shapes| arrays of each | |
| 438 // subsequent item. | |
| 439 Vector<int, cUniscribeHelperStackRuns> m_screenOrder; | |
| 440 | |
| 441 // This contains Uniscribe's OpenType feature settings. This structure | |
| 442 // is filled by using WebKit's |FontFeatureSettings|. | |
| 443 TEXTRANGE_PROPERTIES m_rangeProperties; | |
| 444 Vector<OPENTYPE_FEATURE_RECORD, cUniscribeHelperFeatures> m_featureRecords; | |
| 445 }; | |
| 446 | |
| 447 } // namespace WebCore | |
| 448 | |
| 449 #endif // UniscribeHelper_h | |
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Chromium Code Reviews
Issue 26679003:
Move platform/graphics/chromium/* to platform/graphics/ (Closed)
Base URL: https://chromium.googlesource.com/chromium/blink.git@master