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/*
* Copyright (C) 2014 Frédéric Wang (fred.wang@free.fr). 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 "RenderMathMLRadicalOperator.h"
namespace WebCore {
using namespace MathMLNames;
static const UChar gRadicalCharacter = 0x221A;
// This class relies on the RenderMathMLOperator class to draw a radical symbol.
// This does not work well when an OpenType MATH font is not available.
// In that case, we fallback to the old implementation of RenderMathMLRoot.cpp with graphic primitives.
// Normal width of the front of the radical sign, before the base & overbar (em)
const float gFrontWidthEms = 0.75f;
// Horizontal position of the bottom point of the radical (* frontWidth)
const float gRadicalBottomPointXFront = 0.5f;
// Lower the radical sign's bottom point (px)
const int gRadicalBottomPointLower = 3;
// Horizontal position of the top left point of the radical "dip" (* frontWidth)
const float gRadicalDipLeftPointXFront = 0.8f;
// Vertical position of the top left point of a sqrt radical "dip" (* baseHeight)
const float gSqrtRadicalDipLeftPointYPos = 0.5f;
// Vertical shift of the left end point of the radical (em)
const float gRadicalLeftEndYShiftEms = 0.05f;
// Radical line thickness (em)
const float gRadicalLineThicknessEms = 0.02f;
// Radical thick line thickness (em)
const float gRadicalThickLineThicknessEms = 0.1f;
RenderMathMLRadicalOperator::RenderMathMLRadicalOperator(Document& document, PassRef<RenderStyle> style)
: RenderMathMLOperator(document, WTF::move(style), String(&gRadicalCharacter, 1), MathMLOperatorDictionary::Prefix)
{
}
void RenderMathMLRadicalOperator::stretchTo(LayoutUnit heightAboveBaseline, LayoutUnit depthBelowBaseline)
{
const auto& primaryFontData = style().font().primaryFont();
if (!primaryFontData || !primaryFontData->mathData()) {
// If we do not have an OpenType MATH font, we always make the radical depth a bit larger than the target.
depthBelowBaseline += gRadicalBottomPointLower;
}
RenderMathMLOperator::stretchTo(heightAboveBaseline, depthBelowBaseline);
}
void RenderMathMLRadicalOperator::SetOperatorProperties()
{
RenderMathMLOperator::SetOperatorProperties();
// We remove spacing around the radical symbol.
m_leadingSpace = 0;
m_trailingSpace = 0;
}
void RenderMathMLRadicalOperator::computePreferredLogicalWidths()
{
ASSERT(preferredLogicalWidthsDirty());
const auto& primaryFontData = style().font().primaryFont();
if (primaryFontData && primaryFontData->mathData()) {
RenderMathMLOperator::computePreferredLogicalWidths();
return;
}
// If we do not have an OpenType MATH font, the front width is just given by the gFrontWidthEms constant.
int frontWidth = lroundf(gFrontWidthEms * style().fontSize());
m_minPreferredLogicalWidth = frontWidth;
m_maxPreferredLogicalWidth = frontWidth;
}
void RenderMathMLRadicalOperator::computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit logicalTop, LogicalExtentComputedValues& computedValues) const
{
const auto& primaryFontData = style().font().primaryFont();
if (primaryFontData && primaryFontData->mathData()) {
RenderMathMLOperator::computeLogicalHeight(logicalHeight, logicalTop, computedValues);
return;
}
// If we do not have an OpenType MATH font, the logical height is always the stretch size.
logicalHeight = stretchSize();
RenderBox::computeLogicalHeight(logicalHeight, logicalTop, computedValues);
}
void RenderMathMLRadicalOperator::paint(PaintInfo& info, const LayoutPoint& paintOffset)
{
if (info.context->paintingDisabled() || info.phase != PaintPhaseForeground || style().visibility() != VISIBLE)
return;
const auto& primaryFontData = style().font().primaryFont();
if (primaryFontData && primaryFontData->mathData()) {
RenderMathMLOperator::paint(info, paintOffset);
return;
}
// If we do not have an OpenType MATH font, we paint the radical sign with graphic primitives.
IntPoint adjustedPaintOffset = roundedIntPoint(paintOffset + location() + contentBoxRect().location());
int frontWidth = lroundf(gFrontWidthEms * style().fontSize());
int startX = adjustedPaintOffset.x() + frontWidth;
int baseHeight = stretchSize() - gRadicalBottomPointLower;
float radicalDipLeftPointYPos = gSqrtRadicalDipLeftPointYPos * baseHeight;
FloatPoint overbarLeftPoint(startX, adjustedPaintOffset.y());
FloatPoint bottomPoint(startX - gRadicalBottomPointXFront * frontWidth, adjustedPaintOffset.y() + baseHeight + gRadicalBottomPointLower);
FloatPoint dipLeftPoint(startX - gRadicalDipLeftPointXFront * frontWidth, adjustedPaintOffset.y() + radicalDipLeftPointYPos);
FloatPoint leftEnd(startX - frontWidth, dipLeftPoint.y() + gRadicalLeftEndYShiftEms * style().fontSize());
GraphicsContextStateSaver stateSaver(*info.context);
info.context->setStrokeThickness(gRadicalLineThicknessEms * style().fontSize());
info.context->setStrokeStyle(SolidStroke);
info.context->setStrokeColor(style().visitedDependentColor(CSSPropertyColor), ColorSpaceDeviceRGB);
info.context->setLineJoin(MiterJoin);
info.context->setMiterLimit(style().fontSize());
Path root;
root.moveTo(FloatPoint(overbarLeftPoint.x(), adjustedPaintOffset.y()));
// draw from top left corner to bottom point of radical
root.addLineTo(bottomPoint);
// draw from bottom point to top of left part of radical base "dip"
root.addLineTo(dipLeftPoint);
// draw to end
root.addLineTo(leftEnd);
info.context->strokePath(root);
GraphicsContextStateSaver maskStateSaver(*info.context);
// Build a mask to draw the thick part of the root.
Path mask;
mask.moveTo(overbarLeftPoint);
mask.addLineTo(bottomPoint);
mask.addLineTo(dipLeftPoint);
mask.addLineTo(FloatPoint(2 * dipLeftPoint.x() - leftEnd.x(), 2 * dipLeftPoint.y() - leftEnd.y()));
info.context->clip(mask);
// Draw the thick part of the root.
info.context->setStrokeThickness(gRadicalThickLineThicknessEms * style().fontSize());
info.context->setLineCap(SquareCap);
Path line;
line.moveTo(bottomPoint);
line.addLineTo(dipLeftPoint);
info.context->strokePath(line);
}
LayoutUnit RenderMathMLRadicalOperator::trailingSpaceError()
{
const auto& primaryFontData = style().font().primaryFont();
if (!primaryFontData || !primaryFontData->mathData())
return 0;
// For OpenType MATH font, the layout is based on RenderMathOperator for which the preferred width is sometimes overestimated (bug https://bugs.webkit.org/show_bug.cgi?id=130326).
// Hence we determine the error in the logical width with respect to the actual width of the glyph(s) used to paint the radical.
LayoutUnit width = logicalWidth();
if (m_stretchyData.mode() == DrawNormal) {
GlyphData data = style().font().glyphDataForCharacter(m_operator, !style().isLeftToRightDirection());
return width - advanceForGlyph(data);
}
if (m_stretchyData.mode() == DrawSizeVariant)
return width - advanceForGlyph(m_stretchyData.variant());
float assemblyWidth = advanceForGlyph(m_stretchyData.top());
assemblyWidth = std::max(assemblyWidth, advanceForGlyph(m_stretchyData.bottom()));
assemblyWidth = std::max(assemblyWidth, advanceForGlyph(m_stretchyData.extension()));
if (m_stretchyData.middle().glyph)
assemblyWidth = std::max(assemblyWidth, advanceForGlyph(m_stretchyData.middle()));
return width - assemblyWidth;
}
}
#endif
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