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      1 /*
      2  * Copyright (C) Research In Motion Limited 2010. 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 #include "config.h"
     21 
     22 #include "core/rendering/svg/SVGTextLayoutEngineSpacing.h"
     23 
     24 #include "core/svg/SVGLengthContext.h"
     25 #include "platform/fonts/Character.h"
     26 #include "platform/fonts/Font.h"
     27 
     28 #if ENABLE(SVG_FONTS)
     29 #include "core/svg/SVGFontData.h"
     30 #include "core/svg/SVGFontElement.h"
     31 #include "core/svg/SVGFontFaceElement.h"
     32 #endif
     33 
     34 namespace blink {
     35 
     36 SVGTextLayoutEngineSpacing::SVGTextLayoutEngineSpacing(const Font& font, float effectiveZoom)
     37     : m_font(font)
     38     , m_lastCharacter(0)
     39     , m_effectiveZoom(effectiveZoom)
     40 #if ENABLE(SVG_FONTS)
     41     , m_lastGlyph(0)
     42 #endif
     43 {
     44     ASSERT(m_effectiveZoom);
     45 }
     46 
     47 float SVGTextLayoutEngineSpacing::calculateSVGKerning(bool isVerticalText, Glyph currentGlyph)
     48 {
     49 #if ENABLE(SVG_FONTS)
     50     const SimpleFontData* fontData = m_font.primaryFont();
     51     if (!fontData->isSVGFont()) {
     52         m_lastGlyph = 0;
     53         return 0;
     54     }
     55 
     56     ASSERT(fontData->isCustomFont());
     57     ASSERT(fontData->isSVGFont());
     58 
     59     RefPtr<CustomFontData> customFontData = fontData->customFontData();
     60     SVGFontFaceElement* svgFontFace = toSVGFontData(customFontData)->svgFontFaceElement();
     61     ASSERT(svgFontFace);
     62 
     63     SVGFontElement* svgFont = svgFontFace->associatedFontElement();
     64     if (!svgFont) {
     65         m_lastGlyph = 0;
     66         return 0;
     67     }
     68 
     69     float kerning = 0;
     70     if (m_lastGlyph) {
     71         if (isVerticalText)
     72             kerning = svgFont->verticalKerningForPairOfGlyphs(m_lastGlyph, currentGlyph);
     73         else
     74             kerning = svgFont->horizontalKerningForPairOfGlyphs(m_lastGlyph, currentGlyph);
     75 
     76         kerning *= m_font.fontDescription().computedSize() / m_font.fontMetrics().unitsPerEm();
     77     }
     78 
     79     m_lastGlyph = currentGlyph;
     80     return kerning;
     81 #else
     82     return 0;
     83 #endif
     84 }
     85 
     86 float SVGTextLayoutEngineSpacing::calculateCSSSpacing(UChar currentCharacter)
     87 {
     88     UChar lastCharacter = m_lastCharacter;
     89     m_lastCharacter = currentCharacter;
     90 
     91     if (!m_font.fontDescription().letterSpacing() && !m_font.fontDescription().wordSpacing())
     92         return 0;
     93 
     94     float spacing = m_font.fontDescription().letterSpacing();
     95     if (currentCharacter && lastCharacter && m_font.fontDescription().wordSpacing()) {
     96         if (Character::treatAsSpace(currentCharacter) && !Character::treatAsSpace(lastCharacter))
     97             spacing += m_font.fontDescription().wordSpacing();
     98     }
     99 
    100     if (m_effectiveZoom != 1)
    101         spacing = spacing / m_effectiveZoom;
    102 
    103     return spacing;
    104 }
    105 
    106 }
    107