1/*
2 * Copyright (C) 2010 Alex Milowski (alex@milowski.com). All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
14 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
15 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
16 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
17 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
18 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
19 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#include "config.h"
27
28#if ENABLE(MATHML)
29
30#include "RenderMathMLSubSup.h"
31
32#include "FontSelector.h"
33#include "MathMLNames.h"
34#include "RenderInline.h"
35#include "RenderTable.h"
36#include "RenderTableCell.h"
37#include "RenderTableRow.h"
38#include "RenderTableSection.h"
39#include "RenderText.h"
40
41namespace WebCore {
42
43using namespace MathMLNames;
44
45static const int gTopAdjustDivisor = 3;
46static const int gSubsupScriptMargin = 1;
47static const float gSubSupStretch = 1.2f;
48
49RenderMathMLSubSup::RenderMathMLSubSup(Element* element)
50    : RenderMathMLBlock(element)
51    , m_scripts(0)
52{
53    // Determine what kind of under/over expression we have by element name
54    if (element->hasLocalName(MathMLNames::msubTag))
55        m_kind = Sub;
56    else if (element->hasLocalName(MathMLNames::msupTag))
57        m_kind = Sup;
58    else if (element->hasLocalName(MathMLNames::msubsupTag))
59        m_kind = SubSup;
60    else
61        m_kind = SubSup;
62}
63
64void RenderMathMLSubSup::addChild(RenderObject* child, RenderObject* beforeChild)
65{
66    if (firstChild()) {
67        // We already have a base, so this is the super/subscripts being added.
68
69        if (m_kind == SubSup) {
70            if (!m_scripts) {
71                m_scripts = new (renderArena()) RenderMathMLBlock(node());
72                RefPtr<RenderStyle> scriptsStyle = RenderStyle::create();
73                scriptsStyle->inheritFrom(style());
74                scriptsStyle->setDisplay(INLINE_BLOCK);
75                scriptsStyle->setVerticalAlign(TOP);
76                scriptsStyle->setMarginLeft(Length(gSubsupScriptMargin, Fixed));
77                scriptsStyle->setTextAlign(LEFT);
78                m_scripts->setStyle(scriptsStyle.release());
79                RenderMathMLBlock::addChild(m_scripts, beforeChild);
80            }
81
82            RenderBlock* script = new (renderArena()) RenderMathMLBlock(node());
83            RefPtr<RenderStyle> scriptStyle = RenderStyle::create();
84            scriptStyle->inheritFrom(m_scripts->style());
85            scriptStyle->setDisplay(BLOCK);
86            script->setStyle(scriptStyle.release());
87
88            m_scripts->addChild(script, m_scripts->firstChild());
89            script->addChild(child);
90        } else
91            RenderMathMLBlock::addChild(child, beforeChild);
92
93    } else {
94        RenderMathMLBlock* wrapper = new (renderArena()) RenderMathMLBlock(node());
95        RefPtr<RenderStyle> wrapperStyle = RenderStyle::create();
96        wrapperStyle->inheritFrom(style());
97        wrapperStyle->setDisplay(INLINE_BLOCK);
98        wrapperStyle->setVerticalAlign(BASELINE);
99        wrapper->setStyle(wrapperStyle.release());
100        RenderMathMLBlock::addChild(wrapper, beforeChild);
101        wrapper->addChild(child);
102
103    }
104}
105
106void RenderMathMLSubSup::stretchToHeight(int height)
107{
108    RenderObject* base = firstChild();
109    if (!base)
110        return;
111
112    if (base->firstChild()->isRenderMathMLBlock()) {
113        RenderMathMLBlock* block = toRenderMathMLBlock(base->firstChild());
114        block->stretchToHeight(static_cast<int>(gSubSupStretch * height));
115
116        // Adjust the script placement after we stretch
117        if (height > 0 && m_kind == SubSup && m_scripts) {
118            RenderObject* script = m_scripts->firstChild();
119            if (script) {
120                // Calculate the script height without the container margins.
121                RenderObject* top = script;
122                int topHeight = getBoxModelObjectHeight(top->firstChild());
123                int topAdjust = topHeight / gTopAdjustDivisor;
124                top->style()->setMarginTop(Length(-topAdjust, Fixed));
125                top->style()->setMarginBottom(Length(height - topHeight + topAdjust, Fixed));
126                if (top->isBoxModelObject()) {
127                    RenderBoxModelObject* topBox = toRenderBoxModelObject(top);
128                    topBox->updateBoxModelInfoFromStyle();
129                }
130                m_scripts->setNeedsLayout(true);
131                setNeedsLayout(true);
132            }
133        }
134
135    }
136}
137
138int RenderMathMLSubSup::nonOperatorHeight() const
139{
140    if (m_kind == SubSup)
141       return static_cast<int>(style()->fontSize()*gSubSupStretch);
142    return static_cast<int>(style()->fontSize());
143}
144
145void RenderMathMLSubSup::layout()
146{
147    if (firstChild())
148        firstChild()->setNeedsLayout(true);
149    if (m_scripts)
150        m_scripts->setNeedsLayout(true);
151
152    RenderBlock::layout();
153
154    if (m_kind == SubSup) {
155        if (RenderObject* base = firstChild()) {
156            int maxHeight = 0;
157            RenderObject* current = base->firstChild();
158            while (current) {
159                int height = getBoxModelObjectHeight(current);
160                if (height > maxHeight)
161                    maxHeight = height;
162                current = current->nextSibling();
163            }
164            int heightDiff = m_scripts ? (m_scripts->offsetHeight() - maxHeight) / 2 : 0;
165            if (heightDiff < 0)
166                heightDiff = 0;
167            base->style()->setPaddingTop(Length(heightDiff, Fixed));
168            base->setNeedsLayout(true);
169        }
170        setNeedsLayout(true);
171        RenderBlock::layout();
172    }
173}
174
175int RenderMathMLSubSup::baselinePosition(FontBaseline, bool firstLine, LineDirectionMode direction, LinePositionMode linePositionMode) const
176{
177    RenderObject* base = firstChild();
178    if (!base)
179        return offsetHeight();
180
181    int baseline = offsetHeight();
182    if (!base || !base->isBoxModelObject())
183        return baseline;
184
185    switch (m_kind) {
186    case SubSup:
187        base = base->firstChild();
188        if (m_scripts && base->isBoxModelObject()) {
189            RenderBoxModelObject* box = toRenderBoxModelObject(base);
190
191            int topAdjust = (m_scripts->offsetHeight() - box->offsetHeight()) / 2;
192
193            // FIXME: The last bit of this calculation should be more exact.  Why is the 2-3px scaled for zoom necessary?
194            // The baseline is top spacing of the base + the baseline of the base + adjusted space for zoom
195            float zoomFactor = style()->effectiveZoom();
196            return topAdjust + box->baselinePosition(AlphabeticBaseline, firstLine, direction, linePositionMode) + static_cast<int>((zoomFactor > 1.25 ? 2 : 3) * zoomFactor);
197        }
198        break;
199    case Sup:
200    case Sub:
201        RenderBoxModelObject* box = toRenderBoxModelObject(base);
202        baseline = box->baselinePosition(AlphabeticBaseline, firstLine, direction, linePositionMode);
203        break;
204    }
205
206    return baseline;
207
208}
209
210}
211
212#endif // ENABLE(MATHML)
213