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/*
* Copyright (C) 2003 - 2020 Apple Inc. All rights reserved.
* Copyright (C) 2008 Holger Hans Peter Freyther
*
* 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 WidthIterator_h
#define WidthIterator_h
#include "GlyphBuffer.h"
#include <unicode/umachine.h>
#include <wtf/HashSet.h>
#include <wtf/Vector.h>
namespace WebCore {
class FontCascade;
class Font;
class TextRun;
struct GlyphData;
struct GlyphIndexRange;
struct OriginalAdvancesForCharacterTreatedAsSpace;
using CharactersTreatedAsSpace = Vector<OriginalAdvancesForCharacterTreatedAsSpace, 64>;
struct WidthIterator {
WTF_MAKE_FAST_ALLOCATED;
public:
WidthIterator(const FontCascade&, const TextRun&, HashSet<const Font*>* fallbackFonts = 0, bool accountForGlyphBounds = false, bool forTextEmphasis = false);
void advance(unsigned to, GlyphBuffer&);
bool advanceOneCharacter(float& width, GlyphBuffer&);
void finalize(GlyphBuffer&);
float maxGlyphBoundingBoxY() const { ASSERT(m_accountForGlyphBounds); return m_maxGlyphBoundingBoxY; }
float minGlyphBoundingBoxY() const { ASSERT(m_accountForGlyphBounds); return m_minGlyphBoundingBoxY; }
float firstGlyphOverflow() const { ASSERT(m_accountForGlyphBounds); return m_firstGlyphOverflow; }
float lastGlyphOverflow() const { ASSERT(m_accountForGlyphBounds); return m_lastGlyphOverflow; }
const TextRun& run() const { return m_run; }
float runWidthSoFar() const { return m_runWidthSoFar; }
unsigned currentCharacterIndex() const { return m_currentCharacterIndex; }
static bool characterCanUseSimplifiedTextMeasuring(UChar, bool whitespaceIsCollapsed);
private:
GlyphData glyphDataForCharacter(UChar32, bool mirror);
template <typename TextIterator>
inline void advanceInternal(TextIterator&, GlyphBuffer&);
enum class TransformsType { None, Forced, NotForced };
TransformsType shouldApplyFontTransforms(const GlyphBuffer&, unsigned lastGlyphCount, unsigned currentCharacterIndex) const;
struct ApplyFontTransformsResult {
float additionalAdvance;
GlyphBufferAdvance initialAdvance;
};
ApplyFontTransformsResult applyFontTransforms(GlyphBuffer&, unsigned lastGlyphCount, const Font&, CharactersTreatedAsSpace&);
void commitCurrentFontRange(GlyphBuffer&, unsigned& lastGlyphCount, unsigned currentCharacterIndex, const Font*&, const Font& newFont, const Font& primaryFont, UChar32 character, float& widthOfCurrentFontRange, float nextCharacterWidth, CharactersTreatedAsSpace&);
void applyInitialAdvance(GlyphBuffer&, GlyphBufferAdvance initialAdvance, unsigned lastGlyphCount);
bool hasExtraSpacing() const;
void applyExtraSpacingAfterShaping(GlyphBuffer&, unsigned characterStartIndex, unsigned glyphBufferStartIndex, unsigned characterDestinationIndex, float startingRunWidth);
void applyCSSVisibilityRules(GlyphBuffer&, unsigned glyphBufferStartIndex);
struct AdditionalWidth {
float left;
float right;
float leftExpansion;
float rightExpansion;
};
AdditionalWidth calculateAdditionalWidth(GlyphBuffer&, GlyphBufferStringOffset currentCharacterIndex, unsigned leadingGlyphIndex, unsigned trailingGlyphIndex, float position) const;
void applyAdditionalWidth(GlyphBuffer&, GlyphIndexRange, float leftAdditionalWidth, float rightAdditionalWidth, float leftExpansionAdditionalWidth, float rightExpansionAdditionalWidth);
const FontCascade& m_font;
const TextRun& m_run;
HashSet<const Font*>* m_fallbackFonts { nullptr };
std::optional<unsigned> m_lastCharacterIndex;
GlyphBufferAdvance m_leftoverInitialAdvance { makeGlyphBufferAdvance() };
unsigned m_currentCharacterIndex { 0 };
float m_leftoverJustificationWidth { 0 };
float m_runWidthSoFar { 0 };
float m_expansion { 0 };
float m_expansionPerOpportunity { 0 };
float m_maxGlyphBoundingBoxY { std::numeric_limits<float>::lowest() };
float m_minGlyphBoundingBoxY { std::numeric_limits<float>::max() };
float m_firstGlyphOverflow { 0 };
float m_lastGlyphOverflow { 0 };
bool m_containsTabs { false };
bool m_isAfterExpansion { false };
bool m_accountForGlyphBounds { false };
bool m_enableKerning { false };
bool m_requiresShaping { false };
bool m_forTextEmphasis { false };
};
}
#endif
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