WebCore/mathml/RenderMathMLRoot.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 2009 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 "RenderMathMLRoot.h"

 #include "GraphicsContext.h"
 #include "MathMLNames.h"

 namespace WebCore {

 using namespace MathMLNames;

 // Left margin of the radical (px)
 const int gRadicalLeftMargin = 3;
 // Bottom padding of the radical (px)
 const int gRadicalBasePad = 3;
 // Threshold above which the radical shape is modified to look nice with big bases (%)
 const float gThresholdBaseHeight = 1.5;
 // Radical width (%)
 const float gRadicalWidth = 0.75;
 // Horizontal position of the bottom point of the radical (%)
 const float gRadicalBottomPointXPos= 0.5;
 // Horizontal position of the top left point of the radical (%)
 const float gRadicalTopLeftPointXPos = 0.8;
 // Vertical position of the top left point of the radical (%)
 const float gRadicalTopLeftPointYPos = 0.625;
 // Vertical shift of the left end point of the radical (%)
 const float gRadicalLeftEndYShift = 0.05;
 // Root padding around the base (%)
 const float gRootPadding = 0.2;
 // Additional bottom root padding (%)
 const float gRootBottomPadding = 0.2;

 // Radical line thickness (%)
 const float gRadicalLineThickness = 0.02;
 // Radical thick line thickness (%)
 const float gRadicalThickLineThickness = 0.1;

 RenderMathMLRoot::RenderMathMLRoot(Node *expression)
 : RenderMathMLBlock(expression)
 {
 }

 void RenderMathMLRoot::addChild(RenderObject* child, RenderObject* )
 {
     if (isEmpty()) {
         // Add a block for the index
         RenderBlock* block = new (renderArena()) RenderBlock(node());
         RefPtr<RenderStyle> indexStyle = makeBlockStyle();
         indexStyle->setDisplay(INLINE_BLOCK);
         block->setStyle(indexStyle.release());
         RenderBlock::addChild(block);

         // FIXME: the wrapping does not seem to be needed anymore.
         // this is the base, so wrap it so we can pad it
         block = new (renderArena()) RenderBlock(node());
         RefPtr<RenderStyle> baseStyle = makeBlockStyle();
         baseStyle->setDisplay(INLINE_BLOCK);
         baseStyle->setPaddingLeft(Length(5 * gRadicalWidth , Percent));
         block->setStyle(baseStyle.release());
         RenderBlock::addChild(block);
         block->addChild(child);
     } else {
         // always add to the index
         firstChild()->addChild(child);
     }
 }

 void RenderMathMLRoot::paint(PaintInfo& info, int tx, int ty)
 {
     RenderMathMLBlock::paint(info , tx , ty);

     if (info.context->paintingDisabled())
         return;

     tx += x();
     ty += y();

     RenderBoxModelObject* indexBox = toRenderBoxModelObject(lastChild());

     int maxHeight = indexBox->offsetHeight();
     // default to the font size in pixels if we're empty
     if (!maxHeight)
         maxHeight = style()->fontSize();
     int width = indexBox->offsetWidth();

     int indexWidth = 0;
     RenderObject* current = firstChild();
     while (current != lastChild()) {
         if (current->isBoxModelObject()) {
             RenderBoxModelObject* box = toRenderBoxModelObject(current);
             indexWidth += box->offsetWidth();
         }
         current = current->nextSibling();
     }

     int frontWidth = static_cast<int>(style()->fontSize() * gRadicalWidth);
     int topStartShift = 0;
     // Base height above which the shape of the root changes
     int thresholdHeight = static_cast<int>(gThresholdBaseHeight * style()->fontSize());

     if (maxHeight > thresholdHeight && thresholdHeight) {
         float shift = (maxHeight - thresholdHeight) / static_cast<float>(thresholdHeight);
         if (shift > 1.)
             shift = 1.;
         topStartShift = static_cast<int>(gRadicalBottomPointXPos * frontWidth * shift);
     }

     width += topStartShift;

     int rootPad = static_cast<int>(gRootPadding * style()->fontSize());
     int start = tx + indexWidth + gRadicalLeftMargin + style()->paddingLeft().value() - rootPad;
     ty += style()->paddingTop().value() - rootPad;

     FloatPoint topStart(start - topStartShift, ty);
     FloatPoint bottomLeft(start - gRadicalBottomPointXPos * frontWidth , ty + maxHeight + gRadicalBasePad);
     FloatPoint topLeft(start - gRadicalTopLeftPointXPos * frontWidth , ty + gRadicalTopLeftPointYPos * maxHeight);
     FloatPoint leftEnd(start - frontWidth , topLeft.y() + gRadicalLeftEndYShift * style()->fontSize());

     info.context->save();

     info.context->setStrokeThickness(gRadicalLineThickness * style()->fontSize());
     info.context->setStrokeStyle(SolidStroke);
     info.context->setStrokeColor(style()->visitedDependentColor(CSSPropertyColor), sRGBColorSpace);
     info.context->setLineJoin(MiterJoin);
     info.context->setMiterLimit(style()->fontSize());

     Path root;

     root.moveTo(FloatPoint(topStart.x() + width, ty));
     // draw top
     root.addLineTo(topStart);
     // draw from top left corner to bottom point of radical
     root.addLineTo(bottomLeft);
     // draw from bottom point to top of left part of radical base "pocket"
     root.addLineTo(topLeft);
     // draw to end
     root.addLineTo(leftEnd);

     info.context->beginPath();
     info.context->addPath(root);
     info.context->strokePath();

     info.context->save();

     // Build a mask to draw the thick part of the root.
     Path mask;

     mask.moveTo(topStart);
     mask.addLineTo(bottomLeft);
     mask.addLineTo(topLeft);
     mask.addLineTo(FloatPoint(2 * topLeft.x() - leftEnd.x(), 2 * topLeft.y() - leftEnd.y()));

     info.context->beginPath();
     info.context->addPath(mask);
     info.context->clip(mask);

     // Draw the thick part of the root.
     info.context->setStrokeThickness(gRadicalThickLineThickness * style()->fontSize());
     info.context->setLineCap(SquareCap);

     Path line;

     line = line.createLine(bottomLeft, topLeft);

     info.context->beginPath();
     info.context->addPath(line);
     info.context->strokePath();

     info.context->restore();

     info.context->restore();

 }

 void RenderMathMLRoot::layout()
 {
     RenderBlock::layout();

     int maxHeight = toRenderBoxModelObject(lastChild())->offsetHeight();

     RenderObject* current = lastChild()->firstChild();
     current->style()->setVerticalAlign(BASELINE);

     if (!maxHeight)
         maxHeight = style()->fontSize();

     // Base height above which the shape of the root changes
     int thresholdHeight = static_cast<int>(gThresholdBaseHeight * style()->fontSize());
     int topStartShift = 0;

     if (maxHeight > thresholdHeight && thresholdHeight) {
         float shift = (maxHeight - thresholdHeight) / static_cast<float>(thresholdHeight);
         if (shift > 1.)
             shift = 1.;
         int frontWidth = static_cast<int>(style()->fontSize() * gRadicalWidth);
         topStartShift = static_cast<int>(gRadicalBottomPointXPos * frontWidth * shift);

         style()->setPaddingBottom(Length(static_cast<int>(gRootBottomPadding * style()->fontSize()), Fixed));
     }

     // Positioning of the index
     RenderBoxModelObject* indexBox = toRenderBoxModelObject(firstChild()->firstChild());

     int indexShift = indexBox->offsetWidth() + topStartShift;
     int radicalHeight = static_cast<int>((1 - gRadicalTopLeftPointYPos) * maxHeight);
     int rootMarginTop = radicalHeight + style()->paddingBottom().value() + indexBox->offsetHeight() - (maxHeight + static_cast<int>(gRootPadding * style()->fontSize()));

     style()->setPaddingLeft(Length(indexShift, Fixed));
     if (rootMarginTop > 0)
         style()->setPaddingTop(Length(rootMarginTop + static_cast<int>(gRootPadding * style()->fontSize()), Fixed));

     setNeedsLayoutAndPrefWidthsRecalc();
     markContainingBlocksForLayout();
     RenderBlock::layout();

     indexBox->style()->setBottom(Length(radicalHeight + style()->paddingBottom().value(), Fixed));

     // Now that we've potentially changed its position, we need layout the index again.
     indexBox->setNeedsLayoutAndPrefWidthsRecalc();
     indexBox->layout();
 }

 }

 #endif // ENABLE(MATHML)
	/*
	* Copyright (C) 2009 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 "RenderMathMLRoot.h"

	#include "GraphicsContext.h"
	#include "MathMLNames.h"

	namespace WebCore {

	using namespace MathMLNames;

	// Left margin of the radical (px)
	const int gRadicalLeftMargin = 3;
	// Bottom padding of the radical (px)
	const int gRadicalBasePad = 3;
	// Threshold above which the radical shape is modified to look nice with big bases (%)
	const float gThresholdBaseHeight = 1.5;
	// Radical width (%)
	const float gRadicalWidth = 0.75;
	// Horizontal position of the bottom point of the radical (%)
	const float gRadicalBottomPointXPos= 0.5;
	// Horizontal position of the top left point of the radical (%)
	const float gRadicalTopLeftPointXPos = 0.8;
	// Vertical position of the top left point of the radical (%)
	const float gRadicalTopLeftPointYPos = 0.625;
	// Vertical shift of the left end point of the radical (%)
	const float gRadicalLeftEndYShift = 0.05;
	// Root padding around the base (%)
	const float gRootPadding = 0.2;
	// Additional bottom root padding (%)
	const float gRootBottomPadding = 0.2;

	// Radical line thickness (%)
	const float gRadicalLineThickness = 0.02;
	// Radical thick line thickness (%)
	const float gRadicalThickLineThickness = 0.1;

	RenderMathMLRoot::RenderMathMLRoot(Node *expression)
	: RenderMathMLBlock(expression)
	{
	}

	void RenderMathMLRoot::addChild(RenderObject* child, RenderObject* )
	{
	if (isEmpty()) {
	// Add a block for the index
	RenderBlock* block = new (renderArena()) RenderBlock(node());
	RefPtr<RenderStyle> indexStyle = makeBlockStyle();
	indexStyle->setDisplay(INLINE_BLOCK);
	block->setStyle(indexStyle.release());
	RenderBlock::addChild(block);

	// FIXME: the wrapping does not seem to be needed anymore.
	// this is the base, so wrap it so we can pad it
	block = new (renderArena()) RenderBlock(node());
	RefPtr<RenderStyle> baseStyle = makeBlockStyle();
	baseStyle->setDisplay(INLINE_BLOCK);
	baseStyle->setPaddingLeft(Length(5 * gRadicalWidth , Percent));
	block->setStyle(baseStyle.release());
	RenderBlock::addChild(block);
	block->addChild(child);
	} else {
	// always add to the index
	firstChild()->addChild(child);
	}
	}

	void RenderMathMLRoot::paint(PaintInfo& info, int tx, int ty)
	{
	RenderMathMLBlock::paint(info , tx , ty);

	if (info.context->paintingDisabled())
	return;

	tx += x();
	ty += y();

	RenderBoxModelObject* indexBox = toRenderBoxModelObject(lastChild());

	int maxHeight = indexBox->offsetHeight();
	// default to the font size in pixels if we're empty
	if (!maxHeight)
	maxHeight = style()->fontSize();
	int width = indexBox->offsetWidth();

	int indexWidth = 0;
	RenderObject* current = firstChild();
	while (current != lastChild()) {
	if (current->isBoxModelObject()) {
	RenderBoxModelObject* box = toRenderBoxModelObject(current);
	indexWidth += box->offsetWidth();
	}
	current = current->nextSibling();
	}

	int frontWidth = static_cast<int>(style()->fontSize() * gRadicalWidth);
	int topStartShift = 0;
	// Base height above which the shape of the root changes
	int thresholdHeight = static_cast<int>(gThresholdBaseHeight * style()->fontSize());

	if (maxHeight > thresholdHeight && thresholdHeight) {
	float shift = (maxHeight - thresholdHeight) / static_cast<float>(thresholdHeight);
	if (shift > 1.)
	shift = 1.;
	topStartShift = static_cast<int>(gRadicalBottomPointXPos * frontWidth * shift);
	}

	width += topStartShift;

	int rootPad = static_cast<int>(gRootPadding * style()->fontSize());
	int start = tx + indexWidth + gRadicalLeftMargin + style()->paddingLeft().value() - rootPad;
	ty += style()->paddingTop().value() - rootPad;

	FloatPoint topStart(start - topStartShift, ty);
	FloatPoint bottomLeft(start - gRadicalBottomPointXPos * frontWidth , ty + maxHeight + gRadicalBasePad);
	FloatPoint topLeft(start - gRadicalTopLeftPointXPos * frontWidth , ty + gRadicalTopLeftPointYPos * maxHeight);
	FloatPoint leftEnd(start - frontWidth , topLeft.y() + gRadicalLeftEndYShift * style()->fontSize());

	info.context->save();

	info.context->setStrokeThickness(gRadicalLineThickness * style()->fontSize());
	info.context->setStrokeStyle(SolidStroke);
	info.context->setStrokeColor(style()->visitedDependentColor(CSSPropertyColor), sRGBColorSpace);
	info.context->setLineJoin(MiterJoin);
	info.context->setMiterLimit(style()->fontSize());

	Path root;

	root.moveTo(FloatPoint(topStart.x() + width, ty));
	// draw top
	root.addLineTo(topStart);
	// draw from top left corner to bottom point of radical
	root.addLineTo(bottomLeft);
	// draw from bottom point to top of left part of radical base "pocket"
	root.addLineTo(topLeft);
	// draw to end
	root.addLineTo(leftEnd);

	info.context->beginPath();
	info.context->addPath(root);
	info.context->strokePath();

	info.context->save();

	// Build a mask to draw the thick part of the root.
	Path mask;

	mask.moveTo(topStart);
	mask.addLineTo(bottomLeft);
	mask.addLineTo(topLeft);
	mask.addLineTo(FloatPoint(2 * topLeft.x() - leftEnd.x(), 2 * topLeft.y() - leftEnd.y()));

	info.context->beginPath();
	info.context->addPath(mask);
	info.context->clip(mask);

	// Draw the thick part of the root.
	info.context->setStrokeThickness(gRadicalThickLineThickness * style()->fontSize());
	info.context->setLineCap(SquareCap);

	Path line;

	line = line.createLine(bottomLeft, topLeft);

	info.context->beginPath();
	info.context->addPath(line);
	info.context->strokePath();

	info.context->restore();

	info.context->restore();

	}

	void RenderMathMLRoot::layout()
	{
	RenderBlock::layout();

	int maxHeight = toRenderBoxModelObject(lastChild())->offsetHeight();

	RenderObject* current = lastChild()->firstChild();
	current->style()->setVerticalAlign(BASELINE);

	if (!maxHeight)
	maxHeight = style()->fontSize();

	// Base height above which the shape of the root changes
	int thresholdHeight = static_cast<int>(gThresholdBaseHeight * style()->fontSize());
	int topStartShift = 0;

	if (maxHeight > thresholdHeight && thresholdHeight) {
	float shift = (maxHeight - thresholdHeight) / static_cast<float>(thresholdHeight);
	if (shift > 1.)
	shift = 1.;
	int frontWidth = static_cast<int>(style()->fontSize() * gRadicalWidth);
	topStartShift = static_cast<int>(gRadicalBottomPointXPos * frontWidth * shift);

	style()->setPaddingBottom(Length(static_cast<int>(gRootBottomPadding * style()->fontSize()), Fixed));
	}

	// Positioning of the index
	RenderBoxModelObject* indexBox = toRenderBoxModelObject(firstChild()->firstChild());

	int indexShift = indexBox->offsetWidth() + topStartShift;
	int radicalHeight = static_cast<int>((1 - gRadicalTopLeftPointYPos) * maxHeight);
	int rootMarginTop = radicalHeight + style()->paddingBottom().value() + indexBox->offsetHeight() - (maxHeight + static_cast<int>(gRootPadding * style()->fontSize()));

	style()->setPaddingLeft(Length(indexShift, Fixed));
	if (rootMarginTop > 0)
	style()->setPaddingTop(Length(rootMarginTop + static_cast<int>(gRootPadding * style()->fontSize()), Fixed));

	setNeedsLayoutAndPrefWidthsRecalc();
	markContainingBlocksForLayout();
	RenderBlock::layout();

	indexBox->style()->setBottom(Length(radicalHeight + style()->paddingBottom().value(), Fixed));

	// Now that we've potentially changed its position, we need layout the index again.
	indexBox->setNeedsLayoutAndPrefWidthsRecalc();
	indexBox->layout();
	}

	}

	#endif // ENABLE(MATHML)