khtml/svg/SVGFont.cpp

   1 /**
   2  * Copyright (C) 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Library General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library General Public License
  15  * along with this library; see the file COPYING.LIB.  If not, write to
  16  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA 02110-1301, USA.
  18  *
  19  */
  20
  21 #include "config.h"
  22
  23 #if ENABLE(SVG_FONTS)
  24 #include "Font.h"
  25
  26 #include "CSSFontSelector.h"
  27 #include "GraphicsContext.h"
  28 #include "RenderObject.h"
  29 #include "SimpleFontData.h"
  30 #include "SVGAltGlyphElement.h"
  31 #include "SVGFontData.h"
  32 #include "SVGGlyphElement.h"
  33 #include "SVGGlyphMap.h"
  34 #include "SVGFontElement.h"
  35 #include "SVGFontFaceElement.h"
  36 #include "SVGMissingGlyphElement.h"
  37 #include "SVGPaintServer.h"
  38 #include "SVGPaintServerSolid.h"
  39 #include "XMLNames.h"
  40
  41 using namespace WTF::Unicode;
  42
  43 namespace WebCore {
  44
  45 static inline float convertEmUnitToPixel(float fontSize, float unitsPerEm, float value)
  46 {
  47     if (unitsPerEm == 0.0f)
  48         return 0.0f;
  49
  50     return value * fontSize / unitsPerEm;
  51 }
  52
  53 static inline bool isVerticalWritingMode(const SVGRenderStyle* style)
  54 {
  55     return style->writingMode() == WM_TBRL || style->writingMode() == WM_TB;
  56 }
  57
  58 // Helper functions to determine the arabic character forms (initial, medial, terminal, isolated)
  59 enum ArabicCharShapingMode {
  60     SNone = 0,
  61     SRight = 1,
  62     SDual = 2
  63 };
  64
  65 static const ArabicCharShapingMode s_arabicCharShapingMode[222] = {
  66     SRight, SRight, SRight, SRight, SDual , SRight, SDual , SRight, SDual , SDual , SDual , SDual , SDual , SRight,                 /* 0x0622 - 0x062F */
  67     SRight, SRight, SRight, SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SNone , SNone , SNone , SNone , SNone , /* 0x0630 - 0x063F */
  68     SNone , SDual , SDual , SDual , SDual , SDual , SDual , SRight, SDual , SDual , SNone , SNone , SNone , SNone , SNone , SNone , /* 0x0640 - 0x064F */
  69     SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , /* 0x0650 - 0x065F */
  70     SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , /* 0x0660 - 0x066F */
  71     SNone , SRight, SRight, SRight, SNone , SRight, SRight, SRight, SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , /* 0x0670 - 0x067F */
  72     SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SRight, SRight, SRight, SRight, SRight, SRight, SRight, SRight, /* 0x0680 - 0x068F */
  73     SRight, SRight, SRight, SRight, SRight, SRight, SRight, SRight, SRight, SRight, SDual , SDual , SDual , SDual , SDual , SDual , /* 0x0690 - 0x069F */
  74     SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , /* 0x06A0 - 0x06AF */
  75     SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , SDual , /* 0x06B0 - 0x06BF */
  76     SRight, SDual , SRight, SRight, SRight, SRight, SRight, SRight, SRight, SRight, SRight, SRight, SDual , SRight, SDual , SRight, /* 0x06C0 - 0x06CF */
  77     SDual , SDual , SRight, SRight, SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , /* 0x06D0 - 0x06DF */
  78     SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , /* 0x06E0 - 0x06EF */
  79     SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SNone , SDual , SDual , SDual , SNone , SNone , SNone   /* 0x06F0 - 0x06FF */
  80 };
  81
  82 static inline SVGGlyphIdentifier::ArabicForm processArabicFormDetection(const UChar& curChar, bool& lastCharShapesRight, SVGGlyphIdentifier::ArabicForm* prevForm)
  83 {
  84     SVGGlyphIdentifier::ArabicForm curForm;
  85
  86     ArabicCharShapingMode shapingMode = SNone;
  87     if (curChar >= 0x0622 && curChar <= 0x06FF)
  88         shapingMode = s_arabicCharShapingMode[curChar - 0x0622];
  89
  90     // Use a simple state machine to identify the actual arabic form
  91     // It depends on the order of the arabic form enum:
  92     // enum ArabicForm { None = 0, Isolated, Terminal, Initial, Medial };
  93
  94     if (lastCharShapesRight && shapingMode == SDual) {
  95         if (prevForm) {
  96             int correctedForm = (int) *prevForm + 1;
  97             ASSERT(correctedForm >= SVGGlyphIdentifier::None && correctedForm <= SVGGlyphIdentifier::Medial);
  98             *prevForm = static_cast<SVGGlyphIdentifier::ArabicForm>(correctedForm);
  99         }
 100
 101         curForm = SVGGlyphIdentifier::Initial;
 102     } else
 103         curForm = shapingMode == SNone ? SVGGlyphIdentifier::None : SVGGlyphIdentifier::Isolated;
 104
 105     lastCharShapesRight = shapingMode != SNone;
 106     return curForm;
 107 }
 108
 109 static Vector<SVGGlyphIdentifier::ArabicForm> charactersWithArabicForm(const String& input, bool rtl)
 110 {
 111     Vector<SVGGlyphIdentifier::ArabicForm> forms;
 112     unsigned int length = input.length();
 113
 114     bool containsArabic = false;
 115     for (unsigned int i = 0; i < length; ++i) {
 116         if (isArabicChar(input[i])) {
 117             containsArabic = true;
 118             break;
 119         }
 120     }
 121
 122     if (!containsArabic)
 123         return forms;
 124
 125     bool lastCharShapesRight = false;
 126
 127     // Start identifying arabic forms
 128     if (rtl)
 129         for (int i = length - 1; i >= 0; --i)
 130             forms.prepend(processArabicFormDetection(input[i], lastCharShapesRight, forms.isEmpty() ? 0 : &forms.first()));
 131     else
 132         for (unsigned int i = 0; i < length; ++i)
 133             forms.append(processArabicFormDetection(input[i], lastCharShapesRight, forms.isEmpty() ? 0 : &forms.last()));
 134
 135     return forms;
 136 }
 137
 138 static inline bool isCompatibleArabicForm(const SVGGlyphIdentifier& identifier, const Vector<SVGGlyphIdentifier::ArabicForm>& chars, unsigned int startPosition, unsigned int endPosition)
 139 {
 140     if (chars.isEmpty())
 141         return true;
 142
 143     Vector<SVGGlyphIdentifier::ArabicForm>::const_iterator it = chars.begin() + startPosition;
 144     Vector<SVGGlyphIdentifier::ArabicForm>::const_iterator end = chars.begin() + endPosition;
 145
 146     ASSERT(end <= chars.end());
 147     for (; it != end; ++it) {
 148         if ((*it) != identifier.arabicForm && (*it) != SVGGlyphIdentifier::None)
 149             return false;
 150     }
 151
 152     return true;
 153 }
 154
 155 static inline bool isCompatibleGlyph(const SVGGlyphIdentifier& identifier, bool isVerticalText, const String& language,
 156                                      const Vector<SVGGlyphIdentifier::ArabicForm>& chars, unsigned int startPosition, unsigned int endPosition)
 157 {
 158     bool valid = true;
 159
 160     // Check whether orientation if glyph fits within the request
 161     switch (identifier.orientation) {
 162     case SVGGlyphIdentifier::Vertical:
 163         valid = isVerticalText;
 164         break;
 165     case SVGGlyphIdentifier::Horizontal:
 166         valid = !isVerticalText;
 167         break;
 168     case SVGGlyphIdentifier::Both:
 169         break;
 170     }
 171
 172     if (!valid)
 173         return false;
 174
 175     // Check whether languages are compatible
 176     if (!identifier.languages.isEmpty()) {
 177         // This glyph exists only in certain languages, if we're not specifying a
 178         // language on the referencing element we're unable to use this glyph.
 179         if (language.isEmpty())
 180             return false;
 181
 182         // Split subcode from language, if existent.
 183         String languagePrefix;
 184
 185         int subCodeSeparator = language.find('-');
 186         if (subCodeSeparator != -1)
 187             languagePrefix = language.left(subCodeSeparator);
 188
 189         Vector<String>::const_iterator it = identifier.languages.begin();
 190         Vector<String>::const_iterator end = identifier.languages.end();
 191
 192         bool found = false;
 193         for (; it != end; ++it) {
 194             String cur = (*it);
 195
 196             if (cur == language || cur == languagePrefix) {
 197                 found = true;
 198                 break;
 199             }
 200         }
 201
 202         if (!found)
 203             return false;
 204     }
 205
 206     // Check whether arabic form is compatible
 207     return isCompatibleArabicForm(identifier, chars, startPosition, endPosition);
 208 }
 209
 210 static inline const SVGFontData* svgFontAndFontFaceElementForFontData(const SimpleFontData* fontData, SVGFontFaceElement*& fontFace, SVGFontElement*& font)
 211 {
 212     ASSERT(fontData->isCustomFont());
 213     ASSERT(fontData->isSVGFont());
 214
 215     const SVGFontData* svgFontData = static_cast<const SVGFontData*>(fontData->svgFontData());
 216
 217     fontFace = svgFontData->svgFontFaceElement();
 218     ASSERT(fontFace);
 219
 220     font = fontFace->associatedFontElement();
 221     return svgFontData;
 222 }
 223
 224 // Helper class to walk a text run. Lookup a SVGGlyphIdentifier for each character
 225 // - also respecting possibly defined ligatures - and invoke a callback for each found glyph.
 226 template<typename SVGTextRunData>
 227 struct SVGTextRunWalker {
 228     typedef bool (*SVGTextRunWalkerCallback)(const SVGGlyphIdentifier&, SVGTextRunData&);
 229     typedef void (*SVGTextRunWalkerMissingGlyphCallback)(const TextRun&, SVGTextRunData&);
 230
 231     SVGTextRunWalker(const SVGFontData* fontData, SVGFontElement* fontElement, SVGTextRunData& data,
 232                      SVGTextRunWalkerCallback callback, SVGTextRunWalkerMissingGlyphCallback missingGlyphCallback)
 233         : m_fontData(fontData)
 234         , m_fontElement(fontElement)
 235         , m_walkerData(data)
 236         , m_walkerCallback(callback)
 237         , m_walkerMissingGlyphCallback(missingGlyphCallback)
 238     {
 239     }
 240
 241     void walk(const TextRun& run, bool isVerticalText, const String& language, int from, int to)
 242     {
 243         // Should hold true for SVG text, otherwhise sth. is wrong
 244         ASSERT(to - from == run.length());
 245
 246         Vector<SVGGlyphIdentifier::ArabicForm> chars(charactersWithArabicForm(String(run.data(from), run.length()), run.rtl()));
 247
 248         SVGGlyphIdentifier identifier;
 249         bool foundGlyph = false;
 250         int characterLookupRange;
 251         int endOfScanRange = to + m_walkerData.extraCharsAvailable;
 252
 253         bool haveAltGlyph = false;
 254         SVGGlyphIdentifier altGlyphIdentifier;
 255         if (RenderObject* renderObject = run.referencingRenderObject()) {
 256             if (renderObject->element() && renderObject->element()->hasTagName(SVGNames::altGlyphTag)) {
 257                 SVGGlyphElement* glyphElement = static_cast<SVGAltGlyphElement*>(renderObject->element())->glyphElement();
 258                 if (glyphElement) {
 259                     haveAltGlyph = true;
 260                     altGlyphIdentifier = glyphElement->buildGlyphIdentifier();
 261                     altGlyphIdentifier.isValid = true;
 262                     altGlyphIdentifier.nameLength = to - from;
 263                 }
 264             }
 265         }
 266
 267         for (int i = from; i < to; ++i) {
 268             // If characterLookupRange is > 0, then the font defined ligatures (length of unicode property value > 1).
 269             // We have to check whether the current character & the next character define a ligature. This needs to be
 270             // extended to the n-th next character (where n is 'characterLookupRange'), to check for any possible ligature.
 271             characterLookupRange = endOfScanRange - i;
 272
 273             String lookupString(run.data(i), characterLookupRange);
 274             Vector<SVGGlyphIdentifier> glyphs;
 275             if (haveAltGlyph)
 276                 glyphs.append(altGlyphIdentifier);
 277             else
 278                 m_fontElement->getGlyphIdentifiersForString(lookupString, glyphs);
 279
 280             Vector<SVGGlyphIdentifier>::iterator it = glyphs.begin();
 281             Vector<SVGGlyphIdentifier>::iterator end = glyphs.end();
 282
 283             for (; it != end; ++it) {
 284                 identifier = *it;
 285                 if (identifier.isValid && isCompatibleGlyph(identifier, isVerticalText, language, chars, i, i + identifier.nameLength)) {
 286                     ASSERT(characterLookupRange > 0);
 287                     i += identifier.nameLength - 1;
 288                     m_walkerData.charsConsumed += identifier.nameLength;
 289                     m_walkerData.glyphName = identifier.glyphName;
 290
 291                     foundGlyph = true;
 292                     SVGGlyphElement::inheritUnspecifiedAttributes(identifier, m_fontData);
 293                     break;
 294                 }
 295             }
 296
 297             if (!foundGlyph) {
 298                 ++m_walkerData.charsConsumed;
 299                 if (SVGMissingGlyphElement* element = m_fontElement->firstMissingGlyphElement()) {
 300                     // <missing-glyph> element support
 301                     identifier = SVGGlyphElement::buildGenericGlyphIdentifier(element);
 302                     SVGGlyphElement::inheritUnspecifiedAttributes(identifier, m_fontData);
 303                     identifier.isValid = true;
 304                 } else {
 305                     // Fallback to system font fallback
 306                     TextRun subRun(run);
 307                     subRun.setText(subRun.data(i), 1);
 308
 309                     (*m_walkerMissingGlyphCallback)(subRun, m_walkerData);
 310                     continue;
 311                 }
 312             }
 313
 314             if (!(*m_walkerCallback)(identifier, m_walkerData))
 315                 break;
 316
 317             foundGlyph = false;
 318         }
 319     }
 320
 321 private:
 322     const SVGFontData* m_fontData;
 323     SVGFontElement* m_fontElement;
 324     SVGTextRunData& m_walkerData;
 325     SVGTextRunWalkerCallback m_walkerCallback;
 326     SVGTextRunWalkerMissingGlyphCallback m_walkerMissingGlyphCallback;
 327 };
 328
 329 // Callback & data structures to compute the width of text using SVG Fonts
 330 struct SVGTextRunWalkerMeasuredLengthData {
 331     int at;
 332     int from;
 333     int to;
 334     int extraCharsAvailable;
 335     int charsConsumed;
 336     String glyphName;
 337
 338     float scale;
 339     float length;
 340     const Font* font;
 341 };
 342
 343 bool floatWidthUsingSVGFontCallback(const SVGGlyphIdentifier& identifier, SVGTextRunWalkerMeasuredLengthData& data)
 344 {
 345     if (data.at >= data.from && data.at < data.to)
 346         data.length += identifier.horizontalAdvanceX * data.scale;
 347
 348     data.at++;
 349     return data.at < data.to;
 350 }
 351
 352 void floatWidthMissingGlyphCallback(const TextRun& run, SVGTextRunWalkerMeasuredLengthData& data)
 353 {
 354     // Handle system font fallback
 355     FontDescription fontDescription(data.font->fontDescription());
 356     fontDescription.setFamily(FontFamily());
 357     Font font(fontDescription, 0, 0); // spacing handled by SVG text code.
 358     font.update(data.font->fontSelector());
 359
 360     data.length += font.floatWidth(run);
 361 }
 362
 363
 364 SVGFontElement* Font::svgFont() const
 365 {
 366     if (!isSVGFont())
 367         return 0;
 368
 369     SVGFontElement* fontElement = 0;
 370     SVGFontFaceElement* fontFaceElement = 0;
 371     if (svgFontAndFontFaceElementForFontData(primaryFont(), fontFaceElement, fontElement))
 372         return fontElement;
 373
 374     return 0;
 375 }
 376
 377 static float floatWidthOfSubStringUsingSVGFont(const Font* font, const TextRun& run, int extraCharsAvailable, int from, int to, int& charsConsumed, String& glyphName)
 378 {
 379     int newFrom = to > from ? from : to;
 380     int newTo = to > from ? to : from;
 381
 382     from = newFrom;
 383     to = newTo;
 384
 385     SVGFontElement* fontElement = 0;
 386     SVGFontFaceElement* fontFaceElement = 0;
 387
 388     if (const SVGFontData* fontData = svgFontAndFontFaceElementForFontData(font->primaryFont(), fontFaceElement, fontElement)) {
 389         if (!fontElement)
 390             return 0.0f;
 391
 392         SVGTextRunWalkerMeasuredLengthData data;
 393
 394         data.font = font;
 395         data.at = from;
 396         data.from = from;
 397         data.to = to;
 398         data.extraCharsAvailable = extraCharsAvailable;
 399         data.charsConsumed = 0;
 400         data.scale = convertEmUnitToPixel(font->size(), fontFaceElement->unitsPerEm(), 1.0f);
 401         data.length = 0.0f;
 402
 403         String language;
 404         bool isVerticalText = false; // Holds true for HTML text
 405
 406         // TODO: language matching & svg glyphs should be possible for HTML text, too.
 407         if (RenderObject* renderObject = run.referencingRenderObject()) {
 408             isVerticalText = isVerticalWritingMode(renderObject->style()->svgStyle());
 409
 410             if (SVGElement* element = static_cast<SVGElement*>(renderObject->element()))
 411                 language = element->getAttribute(XMLNames::langAttr);
 412         }
 413
 414         SVGTextRunWalker<SVGTextRunWalkerMeasuredLengthData> runWalker(fontData, fontElement, data, floatWidthUsingSVGFontCallback, floatWidthMissingGlyphCallback);
 415         runWalker.walk(run, isVerticalText, language, 0, run.length());
 416         charsConsumed = data.charsConsumed;
 417         glyphName = data.glyphName;
 418         return data.length;
 419     }
 420
 421     return 0.0f;
 422 }
 423
 424 float Font::floatWidthUsingSVGFont(const TextRun& run) const
 425 {
 426     int charsConsumed;
 427     String glyphName;
 428     return floatWidthOfSubStringUsingSVGFont(this, run, 0, 0, run.length(), charsConsumed, glyphName);
 429 }
 430
 431 float Font::floatWidthUsingSVGFont(const TextRun& run, int extraCharsAvailable, int& charsConsumed, String& glyphName) const
 432 {
 433     return floatWidthOfSubStringUsingSVGFont(this, run, extraCharsAvailable, 0, run.length(), charsConsumed, glyphName);
 434 }
 435
 436 // Callback & data structures to draw text using SVG Fonts
 437 struct SVGTextRunWalkerDrawTextData {
 438     int extraCharsAvailable;
 439     int charsConsumed;
 440     String glyphName;
 441     Vector<SVGGlyphIdentifier> glyphIdentifiers;
 442     Vector<UChar> fallbackCharacters;
 443 };
 444
 445 bool drawTextUsingSVGFontCallback(const SVGGlyphIdentifier& identifier, SVGTextRunWalkerDrawTextData& data)
 446 {
 447     data.glyphIdentifiers.append(identifier);
 448     return true;
 449 }
 450
 451 void drawTextMissingGlyphCallback(const TextRun& run, SVGTextRunWalkerDrawTextData& data)
 452 {
 453     ASSERT(run.length() == 1);
 454     data.glyphIdentifiers.append(SVGGlyphIdentifier());
 455     data.fallbackCharacters.append(run[0]);
 456 }
 457
 458 void Font::drawTextUsingSVGFont(GraphicsContext* context, const TextRun& run,
 459                                 const FloatPoint& point, int from, int to) const
 460 {
 461     SVGFontElement* fontElement = 0;
 462     SVGFontFaceElement* fontFaceElement = 0;
 463
 464     if (const SVGFontData* fontData = svgFontAndFontFaceElementForFontData(primaryFont(), fontFaceElement, fontElement)) {
 465         if (!fontElement)
 466             return;
 467
 468         SVGTextRunWalkerDrawTextData data;
 469         FloatPoint currentPoint = point;
 470         float scale = convertEmUnitToPixel(size(), fontFaceElement->unitsPerEm(), 1.0f);
 471
 472         SVGPaintServer* activePaintServer = run.activePaintServer();
 473
 474         // If renderObject is not set, we're dealing for HTML text rendered using SVG Fonts.
 475         if (!run.referencingRenderObject()) {
 476             ASSERT(!activePaintServer);
 477
 478             // TODO: We're only supporting simple filled HTML text so far.
 479             SVGPaintServerSolid* solidPaintServer = SVGPaintServer::sharedSolidPaintServer();
 480             solidPaintServer->setColor(context->fillColor());
 481
 482             activePaintServer = solidPaintServer;
 483         }
 484
 485         ASSERT(activePaintServer);
 486
 487         int charsConsumed;
 488         String glyphName;
 489         bool isVerticalText = false;
 490         float xStartOffset = floatWidthOfSubStringUsingSVGFont(this, run, 0, run.rtl() ? to : 0, run.rtl() ? run.length() : from, charsConsumed, glyphName);
 491         FloatPoint glyphOrigin;
 492
 493         String language;
 494
 495         // TODO: language matching & svg glyphs should be possible for HTML text, too.
 496         if (run.referencingRenderObject()) {
 497             isVerticalText = isVerticalWritingMode(run.referencingRenderObject()->style()->svgStyle());
 498
 499             if (SVGElement* element = static_cast<SVGElement*>(run.referencingRenderObject()->element()))
 500                 language = element->getAttribute(XMLNames::langAttr);
 501         }
 502
 503         if (!isVerticalText) {
 504             glyphOrigin.setX(fontData->horizontalOriginX() * scale);
 505             glyphOrigin.setY(fontData->horizontalOriginY() * scale);
 506         }
 507
 508         data.extraCharsAvailable = 0;
 509
 510         SVGTextRunWalker<SVGTextRunWalkerDrawTextData> runWalker(fontData, fontElement, data, drawTextUsingSVGFontCallback, drawTextMissingGlyphCallback);
 511         runWalker.walk(run, isVerticalText, language, from, to);
 512
 513         SVGPaintTargetType targetType = context->textDrawingMode() == cTextStroke ? ApplyToStrokeTargetType : ApplyToFillTargetType;
 514
 515         unsigned numGlyphs = data.glyphIdentifiers.size();
 516         unsigned fallbackCharacterIndex = 0;
 517         for (unsigned i = 0; i < numGlyphs; ++i) {
 518             const SVGGlyphIdentifier& identifier = data.glyphIdentifiers[run.rtl() ? numGlyphs - i - 1 : i];
 519             if (identifier.isValid) {
 520                 // FIXME: Support arbitrary SVG content as glyph (currently limited to <glyph d="..."> situations).
 521                 if (!identifier.pathData.isEmpty()) {
 522                     context->save();
 523
 524                     if (isVerticalText) {
 525                         glyphOrigin.setX(identifier.verticalOriginX * scale);
 526                         glyphOrigin.setY(identifier.verticalOriginY * scale);
 527                     }
 528
 529                     context->translate(xStartOffset + currentPoint.x() + glyphOrigin.x(), currentPoint.y() + glyphOrigin.y());
 530                     context->scale(FloatSize(scale, -scale));
 531
 532                     context->beginPath();
 533                     context->addPath(identifier.pathData);
 534
 535                     if (activePaintServer->setup(context, run.referencingRenderObject(), targetType)) {
 536                         // Spec: Any properties specified on a text elements which represents a length, such as the
 537                         // 'stroke-width' property, might produce surprising results since the length value will be
 538                         // processed in the coordinate system of the glyph. (TODO: What other lengths? miter-limit? dash-offset?)
 539                         if (targetType == ApplyToStrokeTargetType && scale != 0.0f)
 540                             context->setStrokeThickness(context->strokeThickness() / scale);
 541
 542                         activePaintServer->renderPath(context, run.referencingRenderObject(), targetType);
 543                         activePaintServer->teardown(context, run.referencingRenderObject(), targetType);
 544                     }
 545
 546                     context->restore();
 547                 }
 548
 549                 if (isVerticalText)
 550                     currentPoint.move(0.0f, identifier.verticalAdvanceY * scale);
 551                 else
 552                     currentPoint.move(identifier.horizontalAdvanceX * scale, 0.0f);
 553             } else {
 554                 // Handle system font fallback
 555                 FontDescription fontDescription(context->font().fontDescription());
 556                 fontDescription.setFamily(FontFamily());
 557                 Font font(fontDescription, 0, 0); // spacing handled by SVG text code.
 558                 font.update(context->font().fontSelector());
 559
 560                 TextRun fallbackCharacterRun(run);
 561                 fallbackCharacterRun.setText(&data.fallbackCharacters[run.rtl() ? data.fallbackCharacters.size() - fallbackCharacterIndex - 1 : fallbackCharacterIndex], 1);
 562                 font.drawText(context, fallbackCharacterRun, currentPoint);
 563
 564                 if (isVerticalText)
 565                     currentPoint.move(0.0f, font.floatWidth(fallbackCharacterRun));
 566                 else
 567                     currentPoint.move(font.floatWidth(fallbackCharacterRun), 0.0f);
 568
 569                 fallbackCharacterIndex++;
 570             }
 571         }
 572     }
 573 }
 574
 575 FloatRect Font::selectionRectForTextUsingSVGFont(const TextRun& run, const IntPoint& point, int height, int from, int to) const
 576 {
 577     int charsConsumed;
 578     String glyphName;
 579
 580     return FloatRect(point.x() + floatWidthOfSubStringUsingSVGFont(this, run, 0, run.rtl() ? to : 0, run.rtl() ? run.length() : from, charsConsumed, glyphName),
 581                      point.y(), floatWidthOfSubStringUsingSVGFont(this, run, 0, from, to, charsConsumed, glyphName), height);
 582 }
 583
 584 int Font::offsetForPositionForTextUsingSVGFont(const TextRun&, int position, bool includePartialGlyphs) const
 585 {
 586     // TODO: Fix text selection when HTML text is drawn using a SVG Font
 587     // We need to integrate the SVG text selection code in the offsetForPosition() framework.
 588     // This will also fix a major issue, that SVG Text code can't select arabic strings properly.
 589     return 0;
 590 }
 591
 592 }
 593
 594 #endif