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 "RenderMathMLSquareRoot.h"
32
33 #include "GraphicsContext.h"
34 #include "MathMLNames.h"
35 #include "PaintInfo.h"
36 #include "Path.h"
37
38 namespace WebCore {
39
40 using namespace MathMLNames;
41
42 // Bottom padding of the radical (px)
43 const int gRadicalBasePad = 3;
44 // Threshold above which the radical shape is modified to look nice with big bases (%)
45 const float gThresholdBaseHeight = 1.5f;
46 // Radical width (%)
47 const float gRadicalWidth = 0.75f;
48 // Horizontal position of the bottom point of the radical (%)
49 const float gRadicalBottomPointXPos= 0.5f;
50 // Horizontal position of the top left point of the radical (%)
51 const float gRadicalTopLeftPointXPos = 0.2f;
52 // Vertical position of the top left point of the radical (%)
53 const float gRadicalTopLeftPointYPos = 0.5f;
54 // Vertical shift of the left end point of the radical (%)
55 const float gRadicalLeftEndYShift = 0.05f;
56 // Additional bottom root padding (%)
57 const float gRootBottomPadding = 0.2f;
58
59 // Radical line thickness (%)
60 const float gRadicalLineThickness = 0.02f;
61 // Radical thick line thickness (%)
62 const float gRadicalThickLineThickness = 0.1f;
63
RenderMathMLSquareRoot(Node * expression)64 RenderMathMLSquareRoot::RenderMathMLSquareRoot(Node *expression)
65 : RenderMathMLBlock(expression)
66 {
67 }
68
paint(PaintInfo & info,int tx,int ty)69 void RenderMathMLSquareRoot::paint(PaintInfo& info, int tx, int ty)
70 {
71 RenderMathMLBlock::paint(info, tx, ty);
72
73 if (info.context->paintingDisabled())
74 return;
75
76 tx += x();
77 ty += y();
78
79 int maxHeight = 0;
80 int width = 0;
81 RenderObject* current = firstChild();
82 while (current) {
83 if (current->isBoxModelObject()) {
84
85 RenderBoxModelObject* box = toRenderBoxModelObject(current);
86
87 // Check to see if this box has a larger height
88 if (box->offsetHeight() > maxHeight)
89 maxHeight = box->offsetHeight();
90 width += box->offsetWidth();
91 }
92 current = current->nextSibling();
93 }
94 // default to the font size in pixels if we're empty
95 if (!maxHeight)
96 maxHeight = style()->fontSize();
97
98 int frontWidth = static_cast<int>(style()->fontSize() * gRadicalWidth);
99 int topStartShift = 0;
100 // Base height above which the shape of the root changes
101 int thresholdHeight = static_cast<int>(gThresholdBaseHeight * style()->fontSize());
102
103 if (maxHeight > thresholdHeight && thresholdHeight) {
104 float shift = (maxHeight - thresholdHeight) / static_cast<float>(thresholdHeight);
105 if (shift > 1.)
106 shift = 1.0f;
107 topStartShift = static_cast<int>(gRadicalBottomPointXPos * frontWidth * shift);
108 }
109
110 width += topStartShift;
111
112 FloatPoint topStart(tx + frontWidth - topStartShift, ty);
113 FloatPoint bottomLeft(tx + frontWidth * gRadicalBottomPointXPos , ty + maxHeight + gRadicalBasePad);
114 FloatPoint topLeft(tx + frontWidth * gRadicalTopLeftPointXPos , ty + gRadicalTopLeftPointYPos * maxHeight);
115 FloatPoint leftEnd(tx , topLeft.y() + gRadicalLeftEndYShift * style()->fontSize());
116
117 GraphicsContextStateSaver stateSaver(*info.context);
118
119 info.context->setStrokeThickness(gRadicalLineThickness * style()->fontSize());
120 info.context->setStrokeStyle(SolidStroke);
121 info.context->setStrokeColor(style()->visitedDependentColor(CSSPropertyColor), ColorSpaceDeviceRGB);
122 info.context->setLineJoin(MiterJoin);
123 info.context->setMiterLimit(style()->fontSize());
124
125 Path root;
126
127 root.moveTo(FloatPoint(topStart.x() + width , ty));
128 // draw top
129 root.addLineTo(topStart);
130 // draw from top left corner to bottom point of radical
131 root.addLineTo(bottomLeft);
132 // draw from bottom point to top of left part of radical base "pocket"
133 root.addLineTo(topLeft);
134 // draw to end
135 root.addLineTo(leftEnd);
136
137 info.context->strokePath(root);
138
139 GraphicsContextStateSaver maskStateSaver(*info.context);
140
141 // Build a mask to draw the thick part of the root.
142 Path mask;
143
144 mask.moveTo(topStart);
145 mask.addLineTo(bottomLeft);
146 mask.addLineTo(topLeft);
147 mask.addLineTo(FloatPoint(2 * topLeft.x() - leftEnd.x(), 2 * topLeft.y() - leftEnd.y()));
148
149 info.context->clip(mask);
150
151 // Draw the thick part of the root.
152 info.context->setStrokeThickness(gRadicalThickLineThickness * style()->fontSize());
153 info.context->setLineCap(SquareCap);
154
155 Path line;
156 line.moveTo(bottomLeft);
157 line.addLineTo(topLeft);
158
159 info.context->strokePath(line);
160 }
161
layout()162 void RenderMathMLSquareRoot::layout()
163 {
164 int maxHeight = 0;
165
166 RenderObject* current = firstChild();
167 while (current) {
168 if (current->isBoxModelObject()) {
169 RenderBoxModelObject* box = toRenderBoxModelObject(current);
170
171 if (box->offsetHeight() > maxHeight)
172 maxHeight = box->offsetHeight();
173
174 box->style()->setVerticalAlign(BASELINE);
175 }
176 current = current->nextSibling();
177 }
178
179 if (!maxHeight)
180 maxHeight = style()->fontSize();
181
182
183 if (maxHeight > static_cast<int>(gThresholdBaseHeight * style()->fontSize()))
184 style()->setPaddingBottom(Length(static_cast<int>(gRootBottomPadding * style()->fontSize()), Fixed));
185
186
187 RenderBlock::layout();
188 }
189
190 }
191
192 #endif // ENABLE(MATHML)
193
194
195