1 /*
2  * Copyright (C) 2009 Alex Milowski (alex@milowski.com). All rights reserved.
3  * Copyright (C) 2010 François Sausset (sausset@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 
RenderMathMLFraction(Element * fraction)49 RenderMathMLFraction::RenderMathMLFraction(Element* fraction)
50     : RenderMathMLBlock(fraction)
51     , m_lineThickness(gLineMedium)
52 {
53     setChildrenInline(false);
54 }
55 
updateFromElement()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 
addChild(RenderObject * child,RenderObject * beforeChild)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 
layout()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 
paint(PaintInfo & info,int tx,int ty)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     GraphicsContextStateSaver stateSaver(*info.context);
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 
baselinePosition(FontBaseline,bool firstLine,LineDirectionMode lineDirection,LinePositionMode linePositionMode) const168 int RenderMathMLFraction::baselinePosition(FontBaseline, bool firstLine, LineDirectionMode lineDirection, LinePositionMode linePositionMode) const
169 {
170     if (firstChild() && firstChild()->isRenderMathMLBlock()) {
171         RenderMathMLBlock* numerator = toRenderMathMLBlock(firstChild());
172         RenderStyle* refStyle = style();
173         if (previousSibling())
174             refStyle = previousSibling()->style();
175         else if (nextSibling())
176             refStyle = nextSibling()->style();
177         int shift = int(ceil((refStyle->fontMetrics().xHeight() + 1) / 2));
178         return numerator->offsetHeight() + shift;
179     }
180     return RenderBlock::baselinePosition(AlphabeticBaseline, firstLine, lineDirection, linePositionMode);
181 }
182 
183 }
184 
185 
186 #endif // ENABLE(MATHML)
187