\inmodule QtCore More...

#include <qline.h>

Collaboration diagram for QLine:

Public Member Functions
constexpr	QLine ()
	Constructs a null line.

constexpr	QLine (const QPoint &pt1, const QPoint &pt2)
	Constructs a line object that represents the line between p1 and p2.

constexpr	QLine (int x1, int y1, int x2, int y2)
	Constructs a line object that represents the line between (x1, y1) and (x2, y2).

constexpr bool	isNull () const
	Returns `true` if the line does not have distinct start and end points; otherwise returns `false`.

constexpr QPoint	p1 () const
	Returns the line's start point.

constexpr QPoint	p2 () const
	Returns the line's end point.

constexpr int	x1 () const
	Returns the x-coordinate of the line's start point.

constexpr int	y1 () const
	Returns the y-coordinate of the line's start point.

constexpr int	x2 () const
	Returns the x-coordinate of the line's end point.

constexpr int	y2 () const
	Returns the y-coordinate of the line's end point.

constexpr int	dx () const
	Returns the horizontal component of the line's vector.

constexpr int	dy () const
	Returns the vertical component of the line's vector.

void	translate (const QPoint &p)
	Translates this line by the given offset.

void	translate (int dx, int dy)
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Translates this line the distance specified by dx and dy.

constexpr QLine	translated (const QPoint &p) const

constexpr QLine	translated (int dx, int dy) const
	This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

constexpr QPoint	center () const

void	setP1 (const QPoint &p1)

void	setP2 (const QPoint &p2)

void	setPoints (const QPoint &p1, const QPoint &p2)

void	setLine (int x1, int y1, int x2, int y2)

constexpr bool	operator== (const QLine &d) const noexcept
	Returns `true` if the given line is the same as this line.

constexpr bool	operator!= (const QLine &d) const noexcept
	Returns `true` if the given line is not the same as this line.

constexpr QLineF	toLineF () const noexcept

Related Symbols
(Note that these are not member symbols.)
QDataStream &	operator<< (QDataStream &stream, const QLine &line)
	Writes the given line to the given stream and returns a reference to the stream.

QDataStream &	operator>> (QDataStream &stream, QLine &line)
	Reads a line from the given stream into the given line and returns a reference to the stream.

Detailed Description

\inmodule QtCore

The QLine class provides a two-dimensional vector using integer precision.

A QLine describes a finite length line (or a line segment) on a two-dimensional surface. The start and end points of the line are specified using integer point accuracy for coordinates. Use the QLineF constructor to retrieve a floating point copy.

\table \row

\inlineimage qline-point.png
\inlineimage qline-coordinates.png \endtable

The positions of the line's start and end points can be retrieved using the p1(), x1(), y1(), p2(), x2(), and y2() functions. The dx() and dy() functions return the horizontal and vertical components of the line. Use isNull() to determine whether the QLine represents a valid line or a null line.

Finally, the line can be translated a given offset using the translate() function.

See also: QLineF, QPolygon, QRect

Definition at line 17 of file qline.h.

Constructor & Destructor Documentation

◆ QLine() [1/3]

constexpr QLine::QLine ( )

inlineconstexpr

Constructs a null line.

Definition at line 65 of file qline.h.

Referenced by translated().

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◆ QLine() [2/3]

constexpr QLine::QLine	(	const QPoint &	pt1,
		const QPoint &	pt2
	)

inlineconstexpr

Constructs a line object that represents the line between p1 and p2.

Definition at line 67 of file qline.h.

◆ QLine() [3/3]

constexpr QLine::QLine	(	int	x1,
		int	y1,
		int	x2,
		int	y2
	)

inlineconstexpr

Constructs a line object that represents the line between (x1, y1) and (x2, y2).

Definition at line 69 of file qline.h.

Member Function Documentation

◆ center()

constexpr QPoint QLine::center ( ) const

inlineconstexpr

Since: 5.8

Returns the center point of this line. This is equivalent to (p1() + p2()) / 2, except it will never overflow.

Definition at line 137 of file qline.h.

References QPoint::x(), and QPoint::y().

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◆ dx()

constexpr int QLine::dx ( ) const

inlineconstexpr

Returns the horizontal component of the line's vector.

See also: dy()

Definition at line 106 of file qline.h.

References QPoint::x().

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◆ dy()

constexpr int QLine::dy ( ) const

inlineconstexpr

Returns the vertical component of the line's vector.

See also: dx()

Definition at line 111 of file qline.h.

References QPoint::y().

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◆ isNull()

constexpr bool QLine::isNull ( ) const

inlineconstexpr

Returns true if the line does not have distinct start and end points; otherwise returns false.

Definition at line 71 of file qline.h.

◆ operator!=()

bool QLine::operator!= ( const QLine & line ) const

inlineconstexprnoexcept

Returns true if the given line is not the same as this line.

A line is different from another line if any of their start or end points differ, or the internal order of the points is different.

Definition at line 52 of file qline.h.

References d.

◆ operator==()

constexpr bool QLine::operator== ( const QLine & line ) const

inlineconstexprnoexcept

Returns true if the given line is the same as this line.

A line is identical to another line if the start and end points are identical, and the internal order of the points is the same.

Definition at line 164 of file qline.h.

References d.

◆ p1()

constexpr QPoint QLine::p1 ( ) const

inlineconstexpr

Returns the line's start point.

See also: x1(), y1(), p2()

Definition at line 96 of file qline.h.

Referenced by clipStraightLine(), QRasterPaintEngine::drawLines(), and QX11PaintEngine::drawRects().

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◆ p2()

constexpr QPoint QLine::p2 ( ) const

inlineconstexpr

Returns the line's end point.

See also: x2(), y2(), p1()

Definition at line 101 of file qline.h.

Referenced by clipStraightLine(), QRasterPaintEngine::drawLines(), and QX11PaintEngine::drawRects().

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◆ setLine()

void QLine::setLine	(	int	x1,
		int	y1,
		int	x2,
		int	y2
	)

inline

Since: 4.4

Sets this line to the start in x1, y1 and end in x2, y2.

See also: setP1(), setP2(), p1(), p2()

Definition at line 158 of file qline.h.

◆ setP1()

void QLine::setP1 ( const QPoint & p1 )

inline

Since: 4.4

Sets the starting point of this line to p1.

See also: setP2(), p1()

Definition at line 142 of file qline.h.

◆ setP2()

void QLine::setP2 ( const QPoint & p2 )

inline

Since: 4.4

Sets the end point of this line to p2.

See also: setP1(), p2()

Definition at line 147 of file qline.h.

◆ setPoints()

void QLine::setPoints	(	const QPoint &	p1,
		const QPoint &	p2
	)

inline

Since: 4.4

Sets the start point of this line to p1 and the end point of this line to p2.

See also: setP1(), setP2(), p1(), p2()

Definition at line 152 of file qline.h.

◆ toLineF()

constexpr QLineF QLine::toLineF ( ) const

inlineconstexprnoexcept

Since: 6.4

Returns this line as a line with floating point accuracy.

See also: QLineF::toLine()

Definition at line 356 of file qline.h.

◆ translate() [1/2]

void QLine::translate ( const QPoint & p )

inline

Translates this line by the given offset.

Definition at line 116 of file qline.h.

Referenced by translate().

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◆ translate() [2/2]

void QLine::translate	(	int	dx,
		int	dy
	)

inline

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.Translates this line the distance specified by dx and dy.

Definition at line 122 of file qline.h.

References translate().

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◆ translated() [1/2]

constexpr QLine QLine::translated ( const QPoint & offset ) const

inlineconstexpr

Since: 4.4

Returns this line translated by the given offset.

Definition at line 127 of file qline.h.

References QLine().

Referenced by translated().

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◆ translated() [2/2]

constexpr QLine QLine::translated	(	int	dx,
		int	dy
	)		const

inlineconstexpr

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

Since: 4.4

Returns this line translated the distance specified by dx and dy.

Definition at line 132 of file qline.h.

References translated().

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◆ x1()

constexpr int QLine::x1 ( ) const

inlineconstexpr

Returns the x-coordinate of the line's start point.

See also: p1()

Definition at line 76 of file qline.h.

References QPoint::x().

Referenced by QPaintEngine::drawLines(), and QTransform::map().

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◆ x2()

constexpr int QLine::x2 ( ) const

inlineconstexpr

Returns the x-coordinate of the line's end point.

See also: p2()

Definition at line 86 of file qline.h.

References QPoint::x().

Referenced by QPaintEngine::drawLines(), and QTransform::map().

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◆ y1()

constexpr int QLine::y1 ( ) const

inlineconstexpr

Returns the y-coordinate of the line's start point.

See also: p1()

Definition at line 81 of file qline.h.

References QPoint::y().

Referenced by QPaintEngine::drawLines(), and QTransform::map().

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◆ y2()

constexpr int QLine::y2 ( ) const

inlineconstexpr

Returns the y-coordinate of the line's end point.

See also: p2()

Definition at line 91 of file qline.h.

References QPoint::y().

Referenced by QPaintEngine::drawLines(), and QTransform::map().

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Friends And Related Symbol Documentation

◆ operator<<()

QDataStream & operator<<	(	QDataStream &	stream,
		const QLine &	line
	)

See also: {Serializing Qt Data Types}

Definition at line 260 of file qline.cpp.

References line.

◆ operator>>()

QDataStream & operator>>	(	QDataStream &	stream,
		QLine &	line
	)

See also: {Serializing Qt Data Types}

Definition at line 275 of file qline.cpp.

References line, p1, and p2.

The documentation for this class was generated from the following files:

qtbase/src/corelib/tools/qline.h
qtbase/src/corelib/tools/qline.cpp

Public Member Functions

Related Symbols

Detailed Description

Constructor & Destructor Documentation

◆ QLine() [1/3]

◆ QLine() [2/3]

◆ QLine() [3/3]

Member Function Documentation

◆ center()

◆ dx()

◆ dy()

◆ isNull()

◆ operator!=()

◆ operator==()

◆ p1()

◆ p2()

◆ setLine()

◆ setP1()

◆ setP2()

◆ setPoints()

◆ toLineF()

◆ translate() [1/2]

◆ translate() [2/2]

◆ translated() [1/2]

◆ translated() [2/2]

◆ x1()

◆ x2()

◆ y1()

◆ y2()

Friends And Related Symbol Documentation

◆ operator<<()

◆ operator>>()