Rendering text-justify:distribute for 8 bit characters.

Source/core/platform/graphics/WidthIterator.cpp

 /*
  * Copyright (C) 2003, 2006, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Holger Hans Peter Freyther
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 32 matching lines @@
     , m_isAfterExpansion(!run.allowsLeadingExpansion())
     , m_finalRoundingWidth(0)
     , m_typesettingFeatures(font->typesettingFeatures())
     , m_fallbackFonts(fallbackFonts)
     , m_accountForGlyphBounds(accountForGlyphBounds)
     , m_maxGlyphBoundingBoxY(numeric_limits<float>::min())
     , m_minGlyphBoundingBoxY(numeric_limits<float>::max())
     , m_firstGlyphOverflow(0)
     , m_lastGlyphOverflow(0)
     , m_forTextEmphasis(forTextEmphasis)
+    , m_distributeJustification(false)
 {
     // If the padding is non-zero, count the number of spaces in the run
     // and divide that by the padding for per space addition.
     m_expansion = m_run.expansion();
+    m_distributeJustification = m_run.isDistributeJustification();
     if (!m_expansion)
         m_expansionPerOpportunity = 0;
     else {
         bool isAfterExpansion = m_isAfterExpansion;
-        unsigned expansionOpportunityCount = m_run.is8Bit() ? Font::expansionOpportunityCount(m_run.characters8(), m_run.length(), m_run.ltr() ? LTR : RTL, isAfterExpansion) : Font::expansionOpportunityCount(m_run.characters16(), m_run.length(), m_run.ltr() ? LTR : RTL, isAfterExpansion);
+        unsigned expansionOpportunityCount = m_run.is8Bit() ? Font::expansionOpportunityCount(m_run.characters8(), m_run.length(), m_run.ltr() ? LTR : RTL, isAfterExpansion, m_distributeJustification) : Font::expansionOpportunityCount(m_run.characters16(), m_run.length(), m_run.ltr() ? LTR : RTL, isAfterExpansion, m_distributeJustification);
+
         if (isAfterExpansion && !m_run.allowsTrailingExpansion())
             expansionOpportunityCount--;
 
         if (!expansionOpportunityCount)
             m_expansionPerOpportunity = 0;
         else
             m_expansionPerOpportunity = m_expansion / expansionOpportunityCount;
     }
 }
 
@@ skipping 131 matching lines @@
                 }
             }
         }
 
         if (hasExtraSpacing) {
             // Account for letter-spacing.
             if (width && m_font->letterSpacing())
                 width += m_font->letterSpacing();
 
             static bool expandAroundIdeographs = Font::canExpandAroundIdeographsInComplexText();
-            bool treatAsSpace = Font::treatAsSpace(character);
-            if (treatAsSpace || (expandAroundIdeographs && Font::isCJKIdeographOrSymbol(character))) {
+            bool needExpansion = Font::treatAsSpace(character) || m_distributeJustification;

[leviw_travelin_and_unemployed, 2013/11/01 20:39:14]

how about something like isExpansionOpportunity instead of needExpansion?

[dw.im, 2013/11/02 03:13:01]

could be better name.. :)

[dw.im, 2013/11/04 02:11:09]

Done.

+            if (needExpansion || (expandAroundIdeographs && Font::isCJKIdeographOrSymbol(character))) {
                 // Distribute the run's total expansion evenly over all expansion opportunities in the run.
                 if (m_expansion) {
                     float previousExpansion = m_expansion;
-                    if (!treatAsSpace && !m_isAfterExpansion) {
+                    if (!needExpansion && !m_isAfterExpansion) {
                         // Take the expansion opportunity before this ideograph.
                         m_expansion -= m_expansionPerOpportunity;
                         float expansionAtThisOpportunity = !m_run.applyWordRounding() ? m_expansionPerOpportunity : roundf(previousExpansion) - roundf(m_expansion);
                         m_runWidthSoFar += expansionAtThisOpportunity;
                         if (glyphBuffer) {
                             if (glyphBuffer->isEmpty()) {
                                 if (m_forTextEmphasis)
                                     glyphBuffer->add(fontData->zeroWidthSpaceGlyph(), fontData, m_expansionPerOpportunity);
                                 else
                                     glyphBuffer->add(fontData->spaceGlyph(), fontData, expansionAtThisOpportunity);
                             } else
                                 glyphBuffer->expandLastAdvance(expansionAtThisOpportunity);
                         }
                         previousExpansion = m_expansion;
                     }
                     if (m_run.allowsTrailingExpansion() || (m_run.ltr() && textIterator.currentCharacter() + advanceLength < static_cast<size_t>(m_run.length()))
                         || (m_run.rtl() && textIterator.currentCharacter())) {
                         m_expansion -= m_expansionPerOpportunity;
                         width += !m_run.applyWordRounding() ? m_expansionPerOpportunity : roundf(previousExpansion) - roundf(m_expansion);
                         m_isAfterExpansion = true;
                     }
                 } else
                     m_isAfterExpansion = false;
 
                 // Account for word spacing.
                 // We apply additional space between "words" by adding width to the space character.
-                if (treatAsSpace && (character != '\t' || !m_run.allowTabs()) && (textIterator.currentCharacter() || character == noBreakSpace) && m_font->wordSpacing())
+                if (needExpansion && (character != '\t' || !m_run.allowTabs()) && (textIterator.currentCharacter() || character == noBreakSpace) && m_font->wordSpacing())
                     width += m_font->wordSpacing();
             } else
                 m_isAfterExpansion = false;
         }
 
         if (shouldApplyFontTransforms() && glyphBuffer && Font::treatAsSpace(character))
             charactersTreatedAsSpace.append(make_pair(glyphBuffer->size(),
                 OriginalAdvancesForCharacterTreatedAsSpace(character == ' ', glyphBuffer->size() ? glyphBuffer->advanceAt(glyphBuffer->size() - 1) : 0, width)));
 
         if (m_accountForGlyphBounds) {
@@ skipping 82 matching lines @@
     int oldSize = glyphBuffer.size();
     advance(m_currentCharacter + 1, &glyphBuffer);
     float w = 0;
     for (int i = oldSize; i < glyphBuffer.size(); ++i)
         w += glyphBuffer.advanceAt(i);
     width = w;
     return glyphBuffer.size() > oldSize;
 }
 
 }