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 "RenderMathMLRoot.h"
32
33 #include "GraphicsContext.h"
34 #include "MathMLNames.h"
35 #include "PaintInfo.h"
36
37 namespace WebCore {
38
39 using namespace MathMLNames;
40
41 // Left margin of the radical (px)
42 const int gRadicalLeftMargin = 3;
43 // Bottom padding of the radical (px)
44 const int gRadicalBasePad = 3;
45 // Threshold above which the radical shape is modified to look nice with big bases (%)
46 const float gThresholdBaseHeight = 1.5f;
47 // Radical width (%)
48 const float gRadicalWidth = 0.75f;
49 // Horizontal position of the bottom point of the radical (%)
50 const float gRadicalBottomPointXPos= 0.5f;
51 // Horizontal position of the top left point of the radical (%)
52 const float gRadicalTopLeftPointXPos = 0.8f;
53 // Vertical position of the top left point of the radical (%)
54 const float gRadicalTopLeftPointYPos = 0.625f;
55 // Vertical shift of the left end point of the radical (%)
56 const float gRadicalLeftEndYShift = 0.05f;
57 // Root padding around the base (%)
58 const float gRootPadding = 0.2f;
59 // Additional bottom root padding (%)
60 const float gRootBottomPadding = 0.2f;
61
62 // Radical line thickness (%)
63 const float gRadicalLineThickness = 0.02f;
64 // Radical thick line thickness (%)
65 const float gRadicalThickLineThickness = 0.1f;
66
RenderMathMLRoot(Node * expression)67 RenderMathMLRoot::RenderMathMLRoot(Node *expression)
68 : RenderMathMLBlock(expression)
69 {
70 }
71
addChild(RenderObject * child,RenderObject *)72 void RenderMathMLRoot::addChild(RenderObject* child, RenderObject* )
73 {
74 if (isEmpty()) {
75 // Add a block for the index
76 RenderBlock* block = new (renderArena()) RenderBlock(node());
77 RefPtr<RenderStyle> indexStyle = makeBlockStyle();
78 indexStyle->setDisplay(INLINE_BLOCK);
79 block->setStyle(indexStyle.release());
80 RenderBlock::addChild(block);
81
82 // FIXME: the wrapping does not seem to be needed anymore.
83 // this is the base, so wrap it so we can pad it
84 block = new (renderArena()) RenderBlock(node());
85 RefPtr<RenderStyle> baseStyle = makeBlockStyle();
86 baseStyle->setDisplay(INLINE_BLOCK);
87 baseStyle->setPaddingLeft(Length(5 * gRadicalWidth , Percent));
88 block->setStyle(baseStyle.release());
89 RenderBlock::addChild(block);
90 block->addChild(child);
91 } else {
92 // always add to the index
93 firstChild()->addChild(child);
94 }
95 }
96
paint(PaintInfo & info,int tx,int ty)97 void RenderMathMLRoot::paint(PaintInfo& info, int tx, int ty)
98 {
99 RenderMathMLBlock::paint(info , tx , ty);
100
101 if (info.context->paintingDisabled())
102 return;
103
104 if (!firstChild() || !lastChild())
105 return;
106
107 tx += x();
108 ty += y();
109
110 RenderBoxModelObject* indexBox = toRenderBoxModelObject(lastChild());
111
112 int maxHeight = indexBox->offsetHeight();
113 // default to the font size in pixels if we're empty
114 if (!maxHeight)
115 maxHeight = style()->fontSize();
116 int width = indexBox->offsetWidth();
117
118 int indexWidth = 0;
119 RenderObject* current = firstChild();
120 while (current != lastChild()) {
121 if (current->isBoxModelObject()) {
122 RenderBoxModelObject* box = toRenderBoxModelObject(current);
123 indexWidth += box->offsetWidth();
124 }
125 current = current->nextSibling();
126 }
127
128 int frontWidth = static_cast<int>(style()->fontSize() * gRadicalWidth);
129 int topStartShift = 0;
130 // Base height above which the shape of the root changes
131 int thresholdHeight = static_cast<int>(gThresholdBaseHeight * style()->fontSize());
132
133 if (maxHeight > thresholdHeight && thresholdHeight) {
134 float shift = (maxHeight - thresholdHeight) / static_cast<float>(thresholdHeight);
135 if (shift > 1.)
136 shift = 1.0f;
137 topStartShift = static_cast<int>(gRadicalBottomPointXPos * frontWidth * shift);
138 }
139
140 width += topStartShift;
141
142 int rootPad = static_cast<int>(gRootPadding * style()->fontSize());
143 int start = tx + indexWidth + gRadicalLeftMargin + style()->paddingLeft().value() - rootPad;
144 ty += style()->paddingTop().value() - rootPad;
145
146 FloatPoint topStart(start - topStartShift, ty);
147 FloatPoint bottomLeft(start - gRadicalBottomPointXPos * frontWidth , ty + maxHeight + gRadicalBasePad);
148 FloatPoint topLeft(start - gRadicalTopLeftPointXPos * frontWidth , ty + gRadicalTopLeftPointYPos * maxHeight);
149 FloatPoint leftEnd(start - frontWidth , topLeft.y() + gRadicalLeftEndYShift * style()->fontSize());
150
151 GraphicsContextStateSaver stateSaver(*info.context);
152
153 info.context->setStrokeThickness(gRadicalLineThickness * style()->fontSize());
154 info.context->setStrokeStyle(SolidStroke);
155 info.context->setStrokeColor(style()->visitedDependentColor(CSSPropertyColor), ColorSpaceDeviceRGB);
156 info.context->setLineJoin(MiterJoin);
157 info.context->setMiterLimit(style()->fontSize());
158
159 Path root;
160
161 root.moveTo(FloatPoint(topStart.x() + width, ty));
162 // draw top
163 root.addLineTo(topStart);
164 // draw from top left corner to bottom point of radical
165 root.addLineTo(bottomLeft);
166 // draw from bottom point to top of left part of radical base "pocket"
167 root.addLineTo(topLeft);
168 // draw to end
169 root.addLineTo(leftEnd);
170
171 info.context->strokePath(root);
172
173 GraphicsContextStateSaver maskStateSaver(*info.context);
174
175 // Build a mask to draw the thick part of the root.
176 Path mask;
177
178 mask.moveTo(topStart);
179 mask.addLineTo(bottomLeft);
180 mask.addLineTo(topLeft);
181 mask.addLineTo(FloatPoint(2 * topLeft.x() - leftEnd.x(), 2 * topLeft.y() - leftEnd.y()));
182
183 info.context->clip(mask);
184
185 // Draw the thick part of the root.
186 info.context->setStrokeThickness(gRadicalThickLineThickness * style()->fontSize());
187 info.context->setLineCap(SquareCap);
188
189 Path line;
190 line.moveTo(bottomLeft);
191 line.addLineTo(topLeft);
192
193 info.context->strokePath(line);
194 }
195
layout()196 void RenderMathMLRoot::layout()
197 {
198 RenderBlock::layout();
199
200 if (!firstChild() || !lastChild())
201 return;
202
203 int maxHeight = toRenderBoxModelObject(lastChild())->offsetHeight();
204
205 RenderObject* current = lastChild()->firstChild();
206 if (current)
207 current->style()->setVerticalAlign(BASELINE);
208
209 if (!maxHeight)
210 maxHeight = style()->fontSize();
211
212 // Base height above which the shape of the root changes
213 int thresholdHeight = static_cast<int>(gThresholdBaseHeight * style()->fontSize());
214 int topStartShift = 0;
215
216 if (maxHeight > thresholdHeight && thresholdHeight) {
217 float shift = (maxHeight - thresholdHeight) / static_cast<float>(thresholdHeight);
218 if (shift > 1.)
219 shift = 1.0f;
220 int frontWidth = static_cast<int>(style()->fontSize() * gRadicalWidth);
221 topStartShift = static_cast<int>(gRadicalBottomPointXPos * frontWidth * shift);
222
223 style()->setPaddingBottom(Length(static_cast<int>(gRootBottomPadding * style()->fontSize()), Fixed));
224 }
225
226 // Positioning of the index
227 RenderObject* possibleIndex = firstChild()->firstChild();
228 while (possibleIndex && !possibleIndex->isBoxModelObject())
229 possibleIndex = possibleIndex->nextSibling();
230 RenderBoxModelObject* indexBox = toRenderBoxModelObject(possibleIndex);
231 if (!indexBox)
232 return;
233
234 int indexShift = indexBox->offsetWidth() + topStartShift;
235 int radicalHeight = static_cast<int>((1 - gRadicalTopLeftPointYPos) * maxHeight);
236 int rootMarginTop = radicalHeight + style()->paddingBottom().value() + indexBox->offsetHeight() - (maxHeight + static_cast<int>(gRootPadding * style()->fontSize()));
237
238 style()->setPaddingLeft(Length(indexShift, Fixed));
239 if (rootMarginTop > 0)
240 style()->setPaddingTop(Length(rootMarginTop + static_cast<int>(gRootPadding * style()->fontSize()), Fixed));
241
242 setNeedsLayout(true);
243 setPreferredLogicalWidthsDirty(true, false);
244 RenderBlock::layout();
245
246 indexBox->style()->setBottom(Length(radicalHeight + style()->paddingBottom().value(), Fixed));
247
248 // Now that we've potentially changed its position, we need layout the index again.
249 indexBox->setNeedsLayout(true);
250 indexBox->layout();
251 }
252
253 }
254
255 #endif // ENABLE(MATHML)
256
257
258