tg_windows5.12.6/Telegram/lib_ui/ui/text/text_word_parser.h

// This file is part of Desktop App Toolkit,
// a set of libraries for developing nice desktop applications.
//
// For license and copyright information please follow this link:
// https://github.com/desktop-app/legal/blob/master/LEGAL
//
#pragma once

#include "ui/text/text.h"
#include "ui/text/text_block.h"
#include "ui/text/text_stack_engine.h"
#include "ui/text/text_word.h"

struct QGlyphLayout;
struct QScriptItem;

namespace Ui::Text {

class WordParser {
public:
	explicit WordParser(not_null<String*> string);

private:
	struct ScriptLine {
		int length = 0;
		QFixed textWidth;
	};
	struct LineBreakHelper {
		ScriptLine tmpData;
		ScriptLine spaceData;

		QGlyphLayout glyphs;

		int glyphCount = 0;
		int maxGlyphs = INT_MAX;
		int currentPosition = 0;

		glyph_t previousGlyph = 0;
		QExplicitlySharedDataPointer<QFontEngine> previousGlyphFontEngine;

		QFixed rightBearing;

		QExplicitlySharedDataPointer<QFontEngine> fontEngine;
		const unsigned short *logClusters = nullptr;

		bool whiteSpaceOrObject = true;

		glyph_t currentGlyph() const;
		void saveCurrentGlyph();
		void calculateRightBearing(QFontEngine *engine, glyph_t glyph);
		void calculateRightBearing();
		void calculateRightBearingForPreviousGlyph();

		// We always calculate the right bearing right before it is needed.
		// So we don't need caching / optimizations referred to
		// delayed right bearing calculations.

		//static const QFixed RightBearingNotCalculated;

		//inline void resetRightBearing()
		//{
		//	rightBearing = RightBearingNotCalculated;
		//}

		// We express the negative right bearing as an absolute number
		// so that it can be applied to the width using addition.
		QFixed negativeRightBearing() const;

	};
	struct BidiInitedAnalysis {
		explicit BidiInitedAnalysis(not_null<String*> text);

		QVarLengthArray<QScriptAnalysis, 4096> list;
	};

	void parse();

	const QCharAttributes *moveToNewItemGetAttributes();

	void pushAccumulatedWord();
	void processSingleGlyphItem(QFixed added = 0);
	void wordProcessed(int nextWordStart, bool spaces = false);
	void wordContinued(int nextPartStart, bool spaces = false);
	void accumulateWhitespaces();
	void ensureWordForRightPadding();
	void maybeStartUnfinishedWord();
	void pushFinishedWord(uint16 position, QFixed width, QFixed rbearing);
	void pushUnfinishedWord(uint16 position, QFixed width, QFixed rbearing);
	void pushNewline(uint16 position, int newlineBlockIndex);

	void addNextCluster(
		int &pos,
		int end,
		ScriptLine &line,
		int &glyphCount,
		const QScriptItem &current,
		const unsigned short *logClusters,
		const QGlyphLayout &glyphs);

	[[nodiscard]] bool isLineBreak(
		const QCharAttributes *attributes,
		int index) const;
	[[nodiscard]] bool isSpaceBreak(
		const QCharAttributes *attributes,
		int index) const;

	const not_null<String*> _t;
	QString &_tText;
	std::vector<Block> &_tBlocks;
	std::vector<Word> &_tWords;
	BidiInitedAnalysis _analysis;
	StackEngine _engine;
	QTextEngine &_e;
	LineBreakHelper _lbh;
	const QCharAttributes *_attributes = nullptr;
	int _wordStart = 0;
	bool _addingEachGrapheme = false;
	int _lastGraphemeBoundaryPosition = -1;
	ScriptLine _lastGraphemeBoundaryLine;
	int _item = -1;
	int _newItem = -1;
	int _itemEnd = 0;

};

} // namespace Ui::Text