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      1 /*
      2  * Copyright (C) 2009 Alex Milowski (alex (at) milowski.com). All rights reserved.
      3  * Copyright (C) 2010 Franois Sausset (sausset (at) gmail.com). All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  *
     14  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     15  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     16  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     17  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     18  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     19  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     20  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     24  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     25  */
     26 
     27 #include "config.h"
     28 
     29 #if ENABLE(MATHML)
     30 
     31 #include "RenderMathMLFraction.h"
     32 
     33 #include "GraphicsContext.h"
     34 #include "MathMLNames.h"
     35 #include "PaintInfo.h"
     36 #include "RenderText.h"
     37 
     38 namespace WebCore {
     39 
     40 using namespace MathMLNames;
     41 
     42 static const float gHorizontalPad = 0.2f;
     43 static const float gLineThin = 0.33f;
     44 static const float gLineMedium = 1.f;
     45 static const float gLineThick = 3.f;
     46 static const float gFractionBarWidth = 0.05f;
     47 static const float gDenominatorPad = 0.1f;
     48 
     49 RenderMathMLFraction::RenderMathMLFraction(Element* fraction)
     50     : RenderMathMLBlock(fraction)
     51     , m_lineThickness(gLineMedium)
     52 {
     53     setChildrenInline(false);
     54 }
     55 
     56 void RenderMathMLFraction::updateFromElement()
     57 {
     58     // FIXME: mfrac where bevelled=true will need to reorganize the descendants
     59     if (isEmpty())
     60         return;
     61 
     62     Element* fraction = static_cast<Element*>(node());
     63 
     64     RenderObject* numerator = firstChild();
     65     String nalign = fraction->getAttribute(MathMLNames::numalignAttr);
     66     if (equalIgnoringCase(nalign, "left"))
     67         numerator->style()->setTextAlign(LEFT);
     68     else if (equalIgnoringCase(nalign, "right"))
     69         numerator->style()->setTextAlign(RIGHT);
     70     else
     71         numerator->style()->setTextAlign(CENTER);
     72 
     73     RenderObject* denominator = numerator->nextSibling();
     74     if (!denominator)
     75         return;
     76 
     77     String dalign = fraction->getAttribute(MathMLNames::denomalignAttr);
     78     if (equalIgnoringCase(dalign, "left"))
     79         denominator->style()->setTextAlign(LEFT);
     80     else if (equalIgnoringCase(dalign, "right"))
     81         denominator->style()->setTextAlign(RIGHT);
     82     else
     83         denominator->style()->setTextAlign(CENTER);
     84 
     85     // FIXME: parse units
     86     String thickness = fraction->getAttribute(MathMLNames::linethicknessAttr);
     87     m_lineThickness = gLineMedium;
     88     if (equalIgnoringCase(thickness, "thin"))
     89         m_lineThickness = gLineThin;
     90     else if (equalIgnoringCase(thickness, "medium"))
     91         m_lineThickness = gLineMedium;
     92     else if (equalIgnoringCase(thickness, "thick"))
     93         m_lineThickness = gLineThick;
     94     else if (equalIgnoringCase(thickness, "0"))
     95         m_lineThickness = 0;
     96 
     97     // Update the style for the padding of the denominator for the line thickness
     98     lastChild()->style()->setPaddingTop(Length(static_cast<int>(m_lineThickness + style()->fontSize() * gDenominatorPad), Fixed));
     99 }
    100 
    101 void RenderMathMLFraction::addChild(RenderObject* child, RenderObject* beforeChild)
    102 {
    103     RenderBlock* row = new (renderArena()) RenderMathMLBlock(node());
    104     RefPtr<RenderStyle> rowStyle = makeBlockStyle();
    105 
    106     rowStyle->setTextAlign(CENTER);
    107     Length pad(static_cast<int>(rowStyle->fontSize() * gHorizontalPad), Fixed);
    108     rowStyle->setPaddingLeft(pad);
    109     rowStyle->setPaddingRight(pad);
    110 
    111     // Only add padding for rows as denominators
    112     bool isNumerator = isEmpty();
    113     if (!isNumerator)
    114         rowStyle->setPaddingTop(Length(2, Fixed));
    115 
    116     row->setStyle(rowStyle.release());
    117     RenderBlock::addChild(row, beforeChild);
    118     row->addChild(child);
    119     updateFromElement();
    120 }
    121 
    122 void RenderMathMLFraction::layout()
    123 {
    124     updateFromElement();
    125 
    126     // Adjust the fraction line thickness for the zoom
    127     if (lastChild() && lastChild()->isRenderBlock())
    128         m_lineThickness *= ceilf(gFractionBarWidth * style()->fontSize());
    129 
    130     RenderBlock::layout();
    131 
    132 }
    133 
    134 void RenderMathMLFraction::paint(PaintInfo& info, int tx, int ty)
    135 {
    136     RenderMathMLBlock::paint(info, tx, ty);
    137     if (info.context->paintingDisabled() || info.phase != PaintPhaseForeground)
    138         return;
    139 
    140     if (!firstChild() ||!m_lineThickness)
    141         return;
    142 
    143     int verticalOffset = 0;
    144     // The children are always RenderMathMLBlock instances
    145     if (firstChild()->isRenderMathMLBlock()) {
    146         int adjustForThickness = m_lineThickness > 1 ? int(m_lineThickness / 2) : 1;
    147         if (int(m_lineThickness) % 2 == 1)
    148             adjustForThickness++;
    149         RenderMathMLBlock* numerator = toRenderMathMLBlock(firstChild());
    150         if (numerator->isRenderMathMLRow())
    151             verticalOffset = numerator->offsetHeight() + adjustForThickness;
    152         else
    153             verticalOffset = numerator->offsetHeight();
    154     }
    155 
    156     tx += x();
    157     ty += y() + verticalOffset;
    158 
    159     info.context->save();
    160 
    161     info.context->setStrokeThickness(m_lineThickness);
    162     info.context->setStrokeStyle(SolidStroke);
    163     info.context->setStrokeColor(style()->visitedDependentColor(CSSPropertyColor), ColorSpaceSRGB);
    164 
    165     info.context->drawLine(IntPoint(tx, ty), IntPoint(tx + offsetWidth(), ty));
    166 
    167     info.context->restore();
    168 }
    169 
    170 int RenderMathMLFraction::baselinePosition(FontBaseline, bool firstLine, LineDirectionMode lineDirection, LinePositionMode linePositionMode) const
    171 {
    172     if (firstChild() && firstChild()->isRenderMathMLBlock()) {
    173         RenderMathMLBlock* numerator = toRenderMathMLBlock(firstChild());
    174         RenderStyle* refStyle = style();
    175         if (previousSibling())
    176             refStyle = previousSibling()->style();
    177         else if (nextSibling())
    178             refStyle = nextSibling()->style();
    179         int shift = int(ceil((refStyle->fontMetrics().xHeight() + 1) / 2));
    180         return numerator->offsetHeight() + shift;
    181     }
    182     return RenderBlock::baselinePosition(AlphabeticBaseline, firstLine, lineDirection, linePositionMode);
    183 }
    184 
    185 }
    186 
    187 
    188 #endif // ENABLE(MATHML)
    189