Fix   fallback glyph lookup

Source/platform/fonts/Font.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2003, 2006, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (c) 2007, 2008, 2010 Google Inc. All rights reserved.
  *
  * 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
@@ skipping 506 matching lines @@
 
     const FontData* fontData = fontDataAt(0);
     if (fontData) {
         const SimpleFontData* fontDataToSubstitute = fontData->fontDataForCharacter(characterToRender);
         RefPtr<SimpleFontData> characterFontData = FontCache::fontCache()->fallbackFontForCharacter(m_fontDescription, characterToRender, fontDataToSubstitute);
         if (characterFontData && variant != NormalVariant) {
             characterFontData = characterFontData->variantFontData(m_fontDescription, variant);
         }
         if (characterFontData) {
             // Got the fallback glyph and font.
-            GlyphPage* fallbackPage = GlyphPageTreeNode::getRootChild(characterFontData.get(), pageNumber)->page();
-            GlyphData data = fallbackPage && fallbackPage->glyphForCharacter(c) ? fallbackPage->glyphDataForCharacter(c) : characterFontData->missingGlyphData();
+            unsigned pageNumberForRendering = characterToRender / GlyphPage::size;
+            GlyphPage* fallbackPage = GlyphPageTreeNode::getRootChild(characterFontData.get(), pageNumberForRendering)->page();
+            GlyphData data = fallbackPage && fallbackPage->glyphForCharacter(characterToRender) ? fallbackPage->glyphDataForCharacter(characterToRender) : characterFontData->missingGlyphData();
             // Cache it so we don't have to do system fallback again next time.
             if (variant == NormalVariant) {
                 page->setGlyphDataForCharacter(c, data.glyph, data.fontData);
                 data.fontData->setMaxGlyphPageTreeLevel(std::max(data.fontData->maxGlyphPageTreeLevel(), node->level()));
-                if (data.fontData->platformData().isVerticalAnyUpright() && !data.fontData->isTextOrientationFallback() && !Character::isCJKIdeographOrSymbol(c))
-                    return glyphDataForNonCJKCharacterWithGlyphOrientation(c, m_fontDescription.isVerticalUpright(c), data, pageNumber);
+                if (data.fontData->platformData().isVerticalAnyUpright() && !data.fontData->isTextOrientationFallback() && !Character::isCJKIdeographOrSymbol(characterToRender))
+                    return glyphDataForNonCJKCharacterWithGlyphOrientation(characterToRender, m_fontDescription.isVerticalUpright(characterToRender), data, pageNumberForRendering);
             }
             return data;
         }
     }
 
     // Even system fallback can fail; use the missing glyph in that case.
     // FIXME: It would be nicer to use the missing glyph from the last resort font instead.
     ASSERT(primaryFont());
     GlyphData data = primaryFont()->missingGlyphData();
     if (variant == NormalVariant) {
@@ skipping 275 matching lines @@
 {
     return m_fontFallbackList && m_fontFallbackList->loadingCustomFonts();
 }
 
 bool Font::isFallbackValid() const
 {
     return !m_fontFallbackList || m_fontFallbackList->isValid();
 }
 
 } // namespace blink