1 /* 2 * Copyright (C) 2011 Apple Inc. All rights reserved. 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 #include "RenderCombineText.h" 23 24 #include "TextRun.h" 25 26 namespace WebCore { 27 28 const float textCombineMargin = 1.1f; // Allow em + 10% margin 29 30 RenderCombineText::RenderCombineText(Node* node, PassRefPtr<StringImpl> string) 31 : RenderText(node, string) 32 , m_combinedTextWidth(0) 33 , m_isCombined(false) 34 , m_needsFontUpdate(false) 35 { 36 } 37 38 void RenderCombineText::styleDidChange(StyleDifference diff, const RenderStyle* oldStyle) 39 { 40 setStyleInternal(RenderStyle::clone(style())); 41 RenderText::styleDidChange(diff, oldStyle); 42 43 if (m_isCombined) 44 RenderText::setTextInternal(originalText()); // This RenderCombineText has been combined once. Restore the original text for the next combineText(). 45 46 m_needsFontUpdate = true; 47 } 48 49 void RenderCombineText::setTextInternal(PassRefPtr<StringImpl> text) 50 { 51 RenderText::setTextInternal(text); 52 53 m_needsFontUpdate = true; 54 } 55 56 float RenderCombineText::width(unsigned from, unsigned length, const Font& font, float xPosition, HashSet<const SimpleFontData*>* fallbackFonts, GlyphOverflow* glyphOverflow) const 57 { 58 if (!characters()) 59 return 0; 60 61 if (m_isCombined) 62 return font.size(); 63 64 return RenderText::width(from, length, font, xPosition, fallbackFonts, glyphOverflow); 65 } 66 67 void RenderCombineText::adjustTextOrigin(FloatPoint& textOrigin, const FloatRect& boxRect) const 68 { 69 if (m_isCombined) 70 textOrigin.move(boxRect.height() / 2 - ceilf(m_combinedTextWidth) / 2, style()->font().pixelSize()); 71 } 72 73 void RenderCombineText::charactersToRender(int start, const UChar*& characters, int& length) const 74 { 75 if (m_isCombined) { 76 length = originalText()->length(); 77 characters = originalText()->characters(); 78 return; 79 } 80 81 characters = text()->characters() + start; 82 } 83 84 void RenderCombineText::combineText() 85 { 86 if (!m_needsFontUpdate) 87 return; 88 89 m_isCombined = false; 90 m_needsFontUpdate = false; 91 92 // CSS3 spec says text-combine works only in vertical writing mode. 93 if (style()->isHorizontalWritingMode()) 94 return; 95 96 TextRun run = TextRun(String(text())); 97 FontDescription description = originalFont().fontDescription(); 98 float emWidth = description.computedSize() * textCombineMargin; 99 bool shouldUpdateFont = false; 100 101 description.setOrientation(Horizontal); // We are going to draw combined text horizontally. 102 m_combinedTextWidth = originalFont().width(run); 103 m_isCombined = m_combinedTextWidth <= emWidth; 104 105 if (m_isCombined) 106 shouldUpdateFont = style()->setFontDescription(description); // Need to change font orientation to horizontal. 107 else { 108 // Need to try compressed glyphs. 109 static const FontWidthVariant widthVariants[] = { HalfWidth, ThirdWidth, QuarterWidth }; 110 for (size_t i = 0 ; i < WTF_ARRAY_LENGTH(widthVariants) ; ++i) { 111 description.setWidthVariant(widthVariants[i]); 112 Font compressedFont = Font(description, style()->font().letterSpacing(), style()->font().wordSpacing()); 113 compressedFont.update(style()->font().fontSelector()); 114 float runWidth = compressedFont.width(run); 115 if (runWidth <= emWidth) { 116 m_combinedTextWidth = runWidth; 117 m_isCombined = true; 118 119 // Replace my font with the new one. 120 shouldUpdateFont = style()->setFontDescription(description); 121 break; 122 } 123 } 124 } 125 126 if (!m_isCombined) 127 shouldUpdateFont = style()->setFontDescription(originalFont().fontDescription()); 128 129 if (shouldUpdateFont) 130 style()->font().update(style()->font().fontSelector()); 131 132 if (m_isCombined) { 133 DEFINE_STATIC_LOCAL(String, objectReplacementCharacterString, (&objectReplacementCharacter, 1)); 134 RenderText::setTextInternal(objectReplacementCharacterString.impl()); 135 } 136 } 137 138 } // namespace WebCore 139