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/*
* Copyright (C) 2010 Alex Milowski (alex@milowski.com). All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#if ENABLE(MATHML)
#include "RenderMathMLSubSup.h"
#include "MathMLNames.h"
namespace WebCore {
using namespace MathMLNames;
static const int gTopAdjustDivisor = 3;
static const int gSubsupScriptMargin = 1;
static const float gSubSupStretch = 1.2f;
RenderMathMLSubSup::RenderMathMLSubSup(Element* element)
: RenderMathMLBlock(element)
, m_scripts(0)
{
// Determine what kind of sub/sup expression we have by element name
if (element->hasLocalName(MathMLNames::msubTag))
m_kind = Sub;
else if (element->hasLocalName(MathMLNames::msupTag))
m_kind = Sup;
else {
ASSERT(element->hasLocalName(MathMLNames::msubsupTag));
m_kind = SubSup;
}
}
RenderBoxModelObject* RenderMathMLSubSup::base() const
{
RenderObject* baseWrapper = firstChild();
if (!baseWrapper)
return 0;
RenderObject* base = baseWrapper->firstChild();
if (!base || !base->isBoxModelObject())
return 0;
return toRenderBoxModelObject(base);
}
void RenderMathMLSubSup::addChild(RenderObject* child, RenderObject* beforeChild)
{
// Note: The RenderMathMLBlock only allows element children to be added.
Element* childElement = toElement(child->node());
if (!childElement->previousElementSibling()) {
// Position 1 is always the base of the msub/msup/msubsup.
RenderMathMLBlock* wrapper = new (renderArena()) RenderMathMLBlock(node());
RefPtr<RenderStyle> wrapperStyle = RenderStyle::create();
wrapperStyle->inheritFrom(style());
wrapperStyle->setDisplay(INLINE_BLOCK);
wrapperStyle->setVerticalAlign(BASELINE);
wrapper->setStyle(wrapperStyle.release());
RenderMathMLBlock::addChild(wrapper, firstChild());
wrapper->addChild(child);
// Make sure we have a script block for rendering.
if (m_kind == SubSup && !m_scripts) {
m_scripts = new (renderArena()) RenderMathMLBlock(node());
RefPtr<RenderStyle> scriptsStyle = RenderStyle::create();
scriptsStyle->inheritFrom(style());
scriptsStyle->setDisplay(INLINE_BLOCK);
scriptsStyle->setVerticalAlign(TOP);
scriptsStyle->setMarginLeft(Length(gSubsupScriptMargin, Fixed));
scriptsStyle->setTextAlign(LEFT);
m_scripts->setStyle(scriptsStyle.release());
RenderMathMLBlock::addChild(m_scripts, beforeChild);
}
} else {
if (m_kind == SubSup) {
RenderBlock* script = new (renderArena()) RenderMathMLBlock(node());
RefPtr<RenderStyle> scriptStyle = RenderStyle::create();
scriptStyle->inheritFrom(m_scripts->style());
scriptStyle->setDisplay(BLOCK);
script->setStyle(scriptStyle.release());
// The order is always backwards so the first script is the subscript and the superscript
// is last. That means the superscript is the first to render vertically.
Element* previousSibling = childElement->previousElementSibling();
if (previousSibling && !previousSibling->previousElementSibling())
m_scripts->addChild(script);
else
m_scripts->addChild(script, m_scripts->firstChild());
script->addChild(child);
} else
RenderMathMLBlock::addChild(child, beforeChild);
}
}
RenderMathMLOperator* RenderMathMLSubSup::unembellishedOperator()
{
RenderBoxModelObject* base = this->base();
if (!base || !base->isRenderMathMLBlock())
return 0;
return toRenderMathMLBlock(base)->unembellishedOperator();
}
void RenderMathMLSubSup::stretchToHeight(int height)
{
RenderObject* baseWrapper = firstChild();
if (!baseWrapper || !baseWrapper->firstChild())
return;
if (baseWrapper->firstChild() && baseWrapper->firstChild()->isRenderMathMLBlock()) {
RenderMathMLBlock* block = toRenderMathMLBlock(baseWrapper->firstChild());
block->stretchToHeight(static_cast<int>(gSubSupStretch * height));
// Adjust the script placement after we stretch
if (height > 0 && m_kind == SubSup && m_scripts) {
RenderObject* script = m_scripts->firstChild();
if (script) {
// Calculate the script height without the container margins.
RenderObject* top = script;
int topHeight = getBoxModelObjectHeight(top->firstChild());
int topAdjust = topHeight / gTopAdjustDivisor;
top->style()->setMarginTop(Length(-topAdjust, Fixed));
top->style()->setMarginBottom(Length(height - topHeight + topAdjust, Fixed));
if (top->isBoxModelObject()) {
RenderBoxModelObject* topBox = toRenderBoxModelObject(top);
topBox->updateBoxModelInfoFromStyle();
}
m_scripts->setNeedsLayout(true);
setNeedsLayout(true);
}
}
}
}
int RenderMathMLSubSup::nonOperatorHeight() const
{
if (m_kind == SubSup)
return static_cast<int>(style()->fontSize()*gSubSupStretch);
return static_cast<int>(style()->fontSize());
}
void RenderMathMLSubSup::layout()
{
if (firstChild())
firstChild()->setNeedsLayout(true);
if (m_scripts)
m_scripts->setNeedsLayout(true);
RenderBlock::layout();
if (m_kind == SubSup) {
if (RenderObject* baseWrapper = firstChild()) {
LayoutUnit maxHeight = 0;
RenderObject* current = baseWrapper->firstChild();
while (current) {
LayoutUnit height = getBoxModelObjectHeight(current);
if (height > maxHeight)
maxHeight = height;
current = current->nextSibling();
}
LayoutUnit heightDiff = m_scripts ? (m_scripts->offsetHeight() - maxHeight) / 2 : zeroLayoutUnit;
if (heightDiff < 0)
heightDiff = 0;
baseWrapper->style()->setPaddingTop(Length(heightDiff, Fixed));
baseWrapper->setNeedsLayout(true);
}
setNeedsLayout(true);
RenderBlock::layout();
}
}
LayoutUnit RenderMathMLSubSup::baselinePosition(FontBaseline, bool firstLine, LineDirectionMode direction, LinePositionMode linePositionMode) const
{
RenderObject* base = firstChild();
if (!base)
return offsetHeight();
LayoutUnit baseline = offsetHeight();
if (!base || !base->isBoxModelObject())
return baseline;
switch (m_kind) {
case SubSup:
base = base->firstChild();
if (m_scripts && base && base->isBoxModelObject()) {
RenderBoxModelObject* box = toRenderBoxModelObject(base);
int topAdjust = (m_scripts->offsetHeight() - box->offsetHeight()) / 2;
// FIXME: The last bit of this calculation should be more exact. Why is the 2-3px scaled for zoom necessary?
// The baseline is top spacing of the base + the baseline of the base + adjusted space for zoom
float zoomFactor = style()->effectiveZoom();
return topAdjust + box->baselinePosition(AlphabeticBaseline, firstLine, direction, linePositionMode) + static_cast<int>((zoomFactor > 1.25 ? 2 : 3) * zoomFactor);
}
break;
case Sup:
case Sub:
return RenderMathMLBlock::baselinePosition(AlphabeticBaseline, firstLine, direction, linePositionMode);
}
return baseline;
}
}
#endif // ENABLE(MATHML)
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