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/*
* Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Library General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public License
* along with this library; see the file COPYING.LIB. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
* Boston, MA 02110-1301, USA.
*/
#ifndef FontMetrics_h
#define FontMetrics_h
#include "FontBaseline.h"
#include <wtf/Markable.h>
#include <wtf/MathExtras.h>
namespace WebCore {
class FontMetrics {
public:
static constexpr unsigned defaultUnitsPerEm = 1000;
struct MarkableTraits {
constexpr static bool isEmptyValue(float value)
{
return value != value;
}
constexpr static float emptyValue()
{
return std::numeric_limits<float>::quiet_NaN();
}
};
unsigned unitsPerEm() const { return m_unitsPerEm; }
void setUnitsPerEm(unsigned unitsPerEm) { m_unitsPerEm = unitsPerEm; }
float height(FontBaseline baselineType = AlphabeticBaseline) const
{
return ascent(baselineType) + descent(baselineType);
}
int intHeight(FontBaseline baselineType = AlphabeticBaseline) const
{
return intAscent(baselineType) + intDescent(baselineType);
}
float ascent(FontBaseline baselineType = AlphabeticBaseline) const
{
if (baselineType == AlphabeticBaseline)
return m_ascent.value_or(0.f);
return height() / 2;
}
int intAscent(FontBaseline baselineType = AlphabeticBaseline) const
{
if (baselineType == AlphabeticBaseline)
return m_intAscent;
return intHeight() - intHeight() / 2;
}
void setAscent(float ascent)
{
m_ascent = ascent;
m_intAscent = std::max(static_cast<int>(lroundf(ascent)), 0);
}
float descent(FontBaseline baselineType = AlphabeticBaseline) const
{
if (baselineType == AlphabeticBaseline)
return m_descent.value_or(0.f);
return height() / 2;
}
int intDescent(FontBaseline baselineType = AlphabeticBaseline) const
{
if (baselineType == AlphabeticBaseline)
return m_intDescent;
return intHeight() / 2;
}
void setDescent(float descent)
{
m_descent = descent;
m_intDescent = lroundf(descent);
}
float lineGap() const { return m_lineGap.value_or(0.f); }
int intLineGap() const { return m_intLineGap; }
void setLineGap(float lineGap)
{
m_lineGap = lineGap;
m_intLineGap = lroundf(lineGap);
}
float lineSpacing() const { return m_lineSpacing.value_or(0.f); }
int intLineSpacing() const { return m_intLineSpacing; }
void setLineSpacing(float lineSpacing)
{
m_lineSpacing = lineSpacing;
m_intLineSpacing = lroundf(lineSpacing);
}
Markable<float, FontMetrics::MarkableTraits> xHeight() const { return m_xHeight; }
void setXHeight(float xHeight) { m_xHeight = xHeight; }
Markable<float, FontMetrics::MarkableTraits> capHeight() const { return m_capHeight; }
int intCapHeight() const { return m_intCapHeight; }
void setCapHeight(float capHeight)
{
m_capHeight = capHeight;
m_intCapHeight = lroundf(capHeight);
}
Markable<float, FontMetrics::MarkableTraits> zeroWidth() const { return m_zeroWidth; }
void setZeroWidth(float zeroWidth) { m_zeroWidth = zeroWidth; }
Markable<float, FontMetrics::MarkableTraits> ideogramWidth() const { return m_ideogramWidth; }
void setIdeogramWidth(float ideogramWidth) { m_ideogramWidth = ideogramWidth; }
Markable<float, FontMetrics::MarkableTraits> underlinePosition() const { return m_underlinePosition; }
void setUnderlinePosition(float underlinePosition) { m_underlinePosition = underlinePosition; }
Markable<float, FontMetrics::MarkableTraits> underlineThickness() const { return m_underlineThickness; }
void setUnderlineThickness(float underlineThickness) { m_underlineThickness = underlineThickness; }
bool hasIdenticalAscentDescentAndLineGap(const FontMetrics& other) const
{
return intAscent() == other.intAscent()
&& intDescent() == other.intDescent()
&& intLineGap() == other.intLineGap();
}
private:
friend class Font;
void reset()
{
m_unitsPerEm = defaultUnitsPerEm;
m_ascent = { };
m_capHeight = { };
m_descent = { };
m_ideogramWidth = { };
m_lineGap = { };
m_lineSpacing = { };
m_underlinePosition = { };
m_underlineThickness = { };
m_xHeight = { };
m_zeroWidth = { };
m_intAscent = 0;
m_intDescent = 0;
m_intLineGap = 0;
m_intLineSpacing = 0;
m_intCapHeight = 0;
}
unsigned m_unitsPerEm { defaultUnitsPerEm };
Markable<float, FontMetrics::MarkableTraits> m_ascent;
Markable<float, FontMetrics::MarkableTraits> m_capHeight;
Markable<float, FontMetrics::MarkableTraits> m_descent;
Markable<float, FontMetrics::MarkableTraits> m_ideogramWidth;
Markable<float, FontMetrics::MarkableTraits> m_lineGap;
Markable<float, FontMetrics::MarkableTraits> m_lineSpacing;
Markable<float, FontMetrics::MarkableTraits> m_underlinePosition;
Markable<float, FontMetrics::MarkableTraits> m_underlineThickness;
Markable<float, FontMetrics::MarkableTraits> m_xHeight;
Markable<float, FontMetrics::MarkableTraits> m_zeroWidth;
// Integer variants of certain metrics are cached for HTML rendering performance.
int m_intAscent { 0 };
int m_intDescent { 0 };
int m_intLineGap { 0 };
int m_intLineSpacing { 0 };
int m_intCapHeight { 0 };
};
static inline float scaleEmToUnits(float x, unsigned unitsPerEm)
{
return unitsPerEm ? x / unitsPerEm : x;
}
} // namespace WebCore
#endif // FontMetrics_h
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