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/*
* Copyright (C) 2010 Alex Milowski (alex@milowski.com). All rights reserved.
* Copyright (C) 2010 François Sausset (sausset@gmail.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 "RenderMathMLOperator.h"
#include "FontSelector.h"
#include "MathMLNames.h"
#include "RenderText.h"
namespace WebCore {
using namespace MathMLNames;
RenderMathMLOperator::RenderMathMLOperator(Node* container)
: RenderMathMLBlock(container)
, m_stretchHeight(0)
, m_operator(0)
{
}
RenderMathMLOperator::RenderMathMLOperator(Node* container, UChar operatorChar)
: RenderMathMLBlock(container)
, m_stretchHeight(0)
, m_operator(convertHyphenMinusToMinusSign(operatorChar))
{
}
bool RenderMathMLOperator::isChildAllowed(RenderObject*, RenderStyle*) const
{
return false;
}
static const float gOperatorSpacer = 0.1f;
static const float gOperatorExpansion = 1.2f;
void RenderMathMLOperator::stretchToHeight(int height)
{
if (height == m_stretchHeight)
return;
m_stretchHeight = static_cast<int>(height * gOperatorExpansion);
updateBoxModelInfoFromStyle();
setNeedsLayout(true);
}
void RenderMathMLOperator::layout()
{
// FIXME: This probably shouldn't be called here but when the operator
// isn't stretched (e.g. outside of a mrow), it needs to be called somehow
updateFromElement();
RenderBlock::layout();
}
// This is a table of stretchy characters.
// FIXME: Should this be read from the unicode characteristics somehow?
// table: stretchy operator, top char, extension char, bottom char, middle char
static struct StretchyCharacter {
UChar character;
UChar topGlyph;
UChar extensionGlyph;
UChar bottomGlyph;
UChar middleGlyph;
} stretchyCharacters[13] = {
{ 0x28 , 0x239b, 0x239c, 0x239d, 0x0 }, // left parenthesis
{ 0x29 , 0x239e, 0x239f, 0x23a0, 0x0 }, // right parenthesis
{ 0x5b , 0x23a1, 0x23a2, 0x23a3, 0x0 }, // left square bracket
{ 0x2308, 0x23a1, 0x23a2, 0x23a2, 0x0 }, // left ceiling
{ 0x230a, 0x23a2, 0x23a2, 0x23a3, 0x0 }, // left floor
{ 0x5d , 0x23a4, 0x23a5, 0x23a6, 0x0 }, // right square bracket
{ 0x2309, 0x23a4, 0x23a5, 0x23a5, 0x0 }, // right ceiling
{ 0x230b, 0x23a5, 0x23a5, 0x23a6, 0x0 }, // right floor
{ 0x7b , 0x23a7, 0x23aa, 0x23a9, 0x23a8 }, // left curly bracket
{ 0x7c , 0x23d0, 0x23d0, 0x23d0, 0x0 }, // vertical bar
{ 0x2016, 0x2016, 0x2016, 0x2016, 0x0 }, // double vertical line
{ 0x7d , 0x23ab, 0x23aa, 0x23ad, 0x23ac }, // right curly bracket
{ 0x222b, 0x2320, 0x23ae, 0x2321, 0x0 } // integral sign
};
// We stack glyphs using a 14px height with a displayed glyph height
// of 10px. The line height is set to less than the 14px so that there
// are no blank spaces between the stacked glyphs.
//
// Certain glyphs (e.g. middle and bottom) need to be adjusted upwards
// in the stack so that there isn't a gap.
//
// All of these settings are represented in the constants below.
// FIXME: use fractions of style()->fontSize() for proper zooming/resizing.
static const int gGlyphFontSize = 14;
static const int gGlyphLineHeight = 11;
static const int gMinimumStretchHeight = 24;
static const int gGlyphHeight = 10;
static const int gTopGlyphTopAdjust = 1;
static const int gMiddleGlyphTopAdjust = -1;
static const int gBottomGlyphTopAdjust = -3;
static const float gMinimumRatioForStretch = 0.10f;
void RenderMathMLOperator::updateFromElement()
{
// Destroy our current children
children()->destroyLeftoverChildren();
// Since we share a node with our children, destroying our children will set our node's
// renderer to 0, so we need to re-set it back to this.
node()->setRenderer(this);
// If the operator is fixed, it will be contained in m_operator
UChar firstChar = m_operator;
// This boolean indicates whether stretching is disabled via the markup.
bool stretchDisabled = false;
// We made need the element later if we can't stretch.
if (node()->nodeType() == Node::ELEMENT_NODE) {
if (Element* mo = static_cast<Element*>(node())) {
AtomicString stretchyAttr = mo->getAttribute(MathMLNames::stretchyAttr);
stretchDisabled = equalIgnoringCase(stretchyAttr, "false");
// If stretching isn't disabled, get the character from the text content.
if (!stretchDisabled && !firstChar) {
String opText = mo->textContent();
for (unsigned int i = 0; !firstChar && i < opText.length(); i++) {
if (!isSpaceOrNewline(opText[i]))
firstChar = opText[i];
}
}
}
}
// The 'index' holds the stretchable character's glyph information
int index = -1;
// isStretchy indicates whether the character is streatchable via a number of factors.
bool isStretchy = false;
// Check for a stretchable character.
if (!stretchDisabled && firstChar) {
const int maxIndex = WTF_ARRAY_LENGTH(stretchyCharacters);
for (index++; index < maxIndex; index++) {
if (stretchyCharacters[index].character == firstChar) {
isStretchy = true;
break;
}
}
}
// We only stretch character if the stretch height is larger than a minimum size (e.g. 24px).
bool shouldStretch = isStretchy && m_stretchHeight>gMinimumStretchHeight;
// Either stretch is disabled or we don't have a stretchable character over the minimum height
if (stretchDisabled || !shouldStretch) {
m_isStacked = false;
RenderBlock* container = new (renderArena()) RenderMathMLBlock(node());
RefPtr<RenderStyle> newStyle = RenderStyle::create();
newStyle->inheritFrom(style());
newStyle->setDisplay(INLINE_BLOCK);
newStyle->setVerticalAlign(BASELINE);
// Check for a stretchable character that is under the minimum height and use the
// font size to adjust the glyph size.
int currentFontSize = style()->fontSize();
if (!stretchDisabled && isStretchy && m_stretchHeight > 0 && m_stretchHeight <= gMinimumStretchHeight && m_stretchHeight > currentFontSize) {
FontDescription desc;
desc.setIsAbsoluteSize(true);
desc.setSpecifiedSize(m_stretchHeight);
desc.setComputedSize(m_stretchHeight);
newStyle->setFontDescription(desc);
newStyle->font().update(newStyle->font().fontSelector());
}
container->setStyle(newStyle.release());
addChild(container);
// Build the text of the operator.
RenderText* text = 0;
if (m_operator)
text = new (renderArena()) RenderText(node(), StringImpl::create(&m_operator, 1));
else if (node()->nodeType() == Node::ELEMENT_NODE)
if (Element* mo = static_cast<Element*>(node()))
text = new (renderArena()) RenderText(node(), mo->textContent().replace(hyphenMinus, minusSign).impl());
// If we can't figure out the text, leave it blank.
if (text) {
RefPtr<RenderStyle> textStyle = RenderStyle::create();
textStyle->inheritFrom(container->style());
text->setStyle(textStyle.release());
container->addChild(text);
}
} else {
// Build stretchable characters as a stack of glyphs.
m_isStacked = true;
if (stretchyCharacters[index].middleGlyph) {
// We have a middle glyph (e.g. a curly bracket) that requires special processing.
int half = (m_stretchHeight - gGlyphHeight) / 2;
if (half <= gGlyphHeight) {
// We only have enough space for a single middle glyph.
createGlyph(stretchyCharacters[index].topGlyph, half, gTopGlyphTopAdjust);
createGlyph(stretchyCharacters[index].middleGlyph, gGlyphHeight, gMiddleGlyphTopAdjust);
createGlyph(stretchyCharacters[index].bottomGlyph, 0, gBottomGlyphTopAdjust);
} else {
// We have to extend both the top and bottom to the middle.
createGlyph(stretchyCharacters[index].topGlyph, gGlyphHeight, gTopGlyphTopAdjust);
int remaining = half - gGlyphHeight;
while (remaining > 0) {
if (remaining < gGlyphHeight) {
createGlyph(stretchyCharacters[index].extensionGlyph, remaining);
remaining = 0;
} else {
createGlyph(stretchyCharacters[index].extensionGlyph, gGlyphHeight);
remaining -= gGlyphHeight;
}
}
// The middle glyph in the stack.
createGlyph(stretchyCharacters[index].middleGlyph, gGlyphHeight, gMiddleGlyphTopAdjust);
// The remaining is the top half minus the middle glyph height.
remaining = half - gGlyphHeight;
// We need to make sure we have the full height in case the height is odd.
if (m_stretchHeight % 2 == 1)
remaining++;
// Extend to the bottom glyph.
while (remaining > 0) {
if (remaining < gGlyphHeight) {
createGlyph(stretchyCharacters[index].extensionGlyph, remaining);
remaining = 0;
} else {
createGlyph(stretchyCharacters[index].extensionGlyph, gGlyphHeight);
remaining -= gGlyphHeight;
}
}
// The bottom glyph in the stack.
createGlyph(stretchyCharacters[index].bottomGlyph, 0, gBottomGlyphTopAdjust);
}
} else {
// We do not have a middle glyph and so we just extend from the top to the bottom glyph.
int remaining = m_stretchHeight - 2 * gGlyphHeight;
createGlyph(stretchyCharacters[index].topGlyph, gGlyphHeight, gTopGlyphTopAdjust);
while (remaining > 0) {
if (remaining < gGlyphHeight) {
createGlyph(stretchyCharacters[index].extensionGlyph, remaining);
remaining = 0;
} else {
createGlyph(stretchyCharacters[index].extensionGlyph, gGlyphHeight);
remaining -= gGlyphHeight;
}
}
createGlyph(stretchyCharacters[index].bottomGlyph, 0, gBottomGlyphTopAdjust);
}
}
}
RefPtr<RenderStyle> RenderMathMLOperator::createStackableStyle(int size, int topRelative)
{
RefPtr<RenderStyle> newStyle = RenderStyle::create();
newStyle->inheritFrom(style());
newStyle->setDisplay(BLOCK);
FontDescription desc;
desc.setIsAbsoluteSize(true);
desc.setSpecifiedSize(gGlyphFontSize);
desc.setComputedSize(gGlyphFontSize);
newStyle->setFontDescription(desc);
newStyle->font().update(newStyle->font().fontSelector());
newStyle->setLineHeight(Length(gGlyphLineHeight, Fixed));
newStyle->setVerticalAlign(TOP);
if (size > 0)
newStyle->setMaxHeight(Length(size, Fixed));
newStyle->setOverflowY(OHIDDEN);
newStyle->setOverflowX(OHIDDEN);
if (topRelative) {
newStyle->setTop(Length(topRelative, Fixed));
newStyle->setPosition(RelativePosition);
}
return newStyle;
}
RenderBlock* RenderMathMLOperator::createGlyph(UChar glyph, int size, int charRelative, int topRelative)
{
RenderBlock* container = new (renderArena()) RenderMathMLBlock(node());
container->setStyle(createStackableStyle(size, topRelative).release());
addChild(container);
RenderBlock* parent = container;
if (charRelative) {
RenderBlock* charBlock = new (renderArena()) RenderBlock(node());
RefPtr<RenderStyle> charStyle = RenderStyle::create();
charStyle->inheritFrom(container->style());
charStyle->setDisplay(INLINE_BLOCK);
charStyle->setTop(Length(charRelative, Fixed));
charStyle->setPosition(RelativePosition);
charBlock->setStyle(charStyle);
parent->addChild(charBlock);
parent = charBlock;
}
RenderText* text = new (renderArena()) RenderText(node(), StringImpl::create(&glyph, 1));
text->setStyle(container->style());
parent->addChild(text);
return container;
}
int RenderMathMLOperator::baselinePosition(FontBaseline, bool firstLine, LineDirectionMode lineDirection, LinePositionMode linePositionMode) const
{
if (m_isStacked)
return m_stretchHeight * 2 / 3 - (m_stretchHeight - static_cast<int>(m_stretchHeight / gOperatorExpansion)) / 2;
return RenderBlock::baselinePosition(AlphabeticBaseline, firstLine, lineDirection, linePositionMode);
}
}
#endif
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