The QLineF class provides a two-dimensional vector using floating point precision. More...

Public Types
enum	IntersectType

Public Methods
	QLineF () = default

	QLineF (const QLine &line)

	QLineF (const QPointF &point1, const QPointF &point2)

	QLineF (qreal x1, qreal y1, qreal x2, qreal y2)

qreal	angle () const

qreal	angle (const QLineF &lineF) const

qreal	angleTo (const QLineF &lineF) const

qreal	dx () const

qreal	dy () const

IntersectType	intersect (const QLineF &lineF, QPointF *intersectionPoint) const

bool	isNull () const

qreal	length () const

QLineF	normalVector () const

bool	operator!= (const QLineF &lineF) const

bool	operator== (const QLineF &lineF) const

QPointF	p1 () const

QPointF	p2 () const

QPointF	pointAt (qreal pos) const

void	setAngle (qreal angle)

void	setLength (qreal length)

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

void	setP1 (const QPointF &point)

void	setP2 (const QPointF &point)

void	setPoints (const QPointF &point1, const QPointF &point2)

QLine	toLine () const

void	translate (const QPointF &offset)

void	translate (qreal dx, qreal dy)

QLineF	translated (const QPointF &offset) const

QLineF	translated (qreal dx, qreal dy) const

QLineF	unitVector () const

qreal	x1 () const

qreal	x2 () const

qreal	y1 () const

qreal	y2 () const

Static Public Methods
static QLineF	fromPolar (qreal length, qreal angle)

Related Functions
These are not member functions
QDataStream &	operator<< (QDataStream &stream, const QLineF &lineF)

QDataStream &	operator>> (QDataStream &stream, QLineF &lineF)

Detailed Description

The QLineF class provides a two-dimensional vector using floating point precision.

A QLineF describes a finite length line (or line segment) on a two-dimensional surface. QLineF defines the start and end points of the line using floating point accuracy for coordinates. Use the toLine() function to retrieve an integer based copy of this line.

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, respectively.

The line's length can be retrieved using the length() function, and altered using the setLength() function. Similarly, angle() and setAngle() are respectively used for retrieving and altering the angle of the line. Use the isNull() function to determine whether the QLineF represents a valid line or a null line.

The intersect() function determines the IntersectType for this line and a given line, while the angle() function returns the angle between the lines. In addition, the unitVector() function returns a line that has the same starting point as this line, but with a length of only 1, while the normalVector() function returns a line that is perpendicular to this line with the same starting point and length.

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

See also: QLine, QPolygonF, QRectF

Member Enumeration Documentation

enum QLineF::IntersectType

Describes the intersection between two lines.


QLineF::UnboundedIntersection	QLineF::BoundedIntersection

Constant	Value	Description
`QLineF::NoIntersection`	`0`	Indicates that the lines do not intersect; i.e. they are parallel.
`QLineF::UnboundedIntersection`	`2`	The two lines intersect, but not within the range defined by their lengths. This will be the case if the lines are not parallel.

intersect() will also return this value if the intersect point is within the start and end point of only one of the lines.

Constant	Value	Description
`QLineF::BoundedIntersection`	`1`	The two lines intersect with each other within the start and end points of each line.

See also: intersect()

Constructor & Destructor Documentation

QLineF::QLineF ( )

default

Constructs a null line.

QLineF::QLineF	(	const QPointF &	point1,
		const QPointF &	point2
	)

inline

Constructs a line object that represents the line between point1 and point2.

QLineF::QLineF	(	qreal	x1,
		qreal	y1,
		qreal	x2,
		qreal	y2
	)

inline

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

QLineF::QLineF ( const QLine & line )

inline

Construct a QLineF object from the given integer-based line.

See also: toLine()

Method Documentation

qreal QLineF::angle ( ) const

Returns the angle of the line in degrees.

The return value will be in the range of values from 0.0 up to but not including 360.0. The angles are measured counter-clockwise from a point on the x-axis to the right of the origin (x > 0).

See also: setAngle()

qreal QLineF::angle ( const QLineF & lineF ) const

deprecated

Deprecated:: Returns the angle (in degrees) between this line and the given line, taking the direction of the lines into account. If the lines do not intersect within their range, it is the intersection point of the extended lines that serves as origin (see QLineF::UnboundedIntersection).

When the lines are parallel, this function returns 0 if they have the same direction, otherwise it returns 180.

See also: intersect()

qreal QLineF::angleTo ( const QLineF & lineF ) const

Returns the angle (in positive degrees) from this line to the given lineF, taking the direction of the lines into account. If the lines do not intersect within their range, it is the intersection point of the extended lines that serves as origin (see QLineF::UnboundedIntersection).

The returned value represents the number of degrees you need to add to this line to make it have the same angle as the given lineF, going counter-clockwise.

See also: intersect()

qreal QLineF::dx ( ) const

inline

Returns the horizontal component of the line's vector. Return value is positive if x2() >= x1() and negative if x2() < x1().

See also: dy(), pointAt()

qreal QLineF::dy ( ) const

inline

Returns the vertical component of the line's vector. Return value is positive if y2() >= y1() and negative if y2() < y1().

See also: dx(), pointAt()

QLineF QLineF::fromPolar	(	qreal	length,
		qreal	angle
	)

static

Returns a QLineF with the given length and angle. The first point of the line will be on the origin.

Positive values for the angles mean counter-clockwise while negative values mean the clockwise direction. Zero degrees is at the 3 o'clock position.

IntersectType QLineF::intersect	(	const QLineF &	lineF,
		QPointF *	intersectionPoint
	)		const

Returns a value indicating whether or not the current QLineF intersects with the given lineF. The actual intersection point is extracted to intersectionPoint (if the pointer is valid). If the lines are parallel the intersection point is undefined.

bool QLineF::isNull ( ) const

Returns true if the line is not set up with valid start and end point,, otherwise returns false.

qreal QLineF::length ( ) const

Returns the length of the line.

See also: setLength()

QLineF QLineF::normalVector ( ) const

inline

Returns a line that is perpendicular to this line with the same starting point and length.

See also: unitVector()

bool QLineF::operator!= ( const QLineF & lineF ) const

inline

Returns true if the given lineF is not the same as the current object. A line is different from another line if their start or end points differ, or the internal order of the points is different.

bool QLineF::operator== ( const QLineF & lineF ) const

inline

Returns true if the given lineF 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.

QPointF QLineF::p1 ( ) const

inline

Returns the line's start point.

See also: setP1(), x1(), y1(), p2()

QPointF QLineF::p2 ( ) const

inline

Returns the line's end point.

See also: setP2(), x2(), y2(), p1()

QPointF QLineF::pointAt ( qreal pos ) const

inline

Returns the point at the parameterized position specified by pos. The method returns the line's starting point if pos = 0 or the ending point if pos = 1.

See also: dx(), dy()

void QLineF::setAngle ( qreal angle )

Sets the angle of the line to the given angle (in degrees). This will change the position of the second point of the line such that the line has the given angle.

Positive values for the angles mean counter-clockwise while negative values mean the clockwise direction. Zero degrees is at the 3 o'clock position.

See also: angle()

void QLineF::setLength ( qreal length )

inline

Sets the length of the line to the given length. QLineF will move the end point - p2() - of the line to give the line its new length. If the given length is negative the angle() is also changed.

If the line is a null line, the length will remain zero regardless of the length specified.

See also: length(), isNull()

void QLineF::setLine	(	qreal	x1,
		qreal	y1,
		qreal	x2,
		qreal	y2
	)

inline

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

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

void QLineF::setP1 ( const QPointF & point )

inline

Sets the starting point of this line to point.

See also: setP2(), p1()

void QLineF::setP2 ( const QPointF & point )

inline

Sets the end point of this line to point.

See also: setP1(), p2()

void QLineF::setPoints	(	const QPointF &	point1,
		const QPointF &	point2
	)

inline

Sets the start point of this line to point1 and the end point of this line to point2.

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

QLine QLineF::toLine ( ) const

inline

Returns an integer based copy of this line. The returned start and end points are rounded to the nearest integer.

See also: QLineF()

void QLineF::translate ( const QPointF & offset )

inline

Translates this line by the given offset.

void QLineF::translate	(	qreal	dx,
		qreal	dy
	)

inline

Translates this line the distance specified by dx and dy.

QLineF QLineF::translated ( const QPointF & offset ) const

inline

Returns this line translated by the given offset.

QLineF QLineF::translated	(	qreal	dx,
		qreal	dy
	)		const

inline

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

QLineF QLineF::unitVector ( ) const

Returns the unit vector for this line. A unit vector is a line starting at the same point as this line with a length of 1.0.

See also: normalVector()

qreal QLineF::x1 ( ) const

inline

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

See also: p1()

qreal QLineF::x2 ( ) const

inline

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

See also: p2()

qreal QLineF::y1 ( ) const

inline

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

See also: p1()

qreal QLineF::y2 ( ) const

inline

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

See also: p2()

Friends And Related Function Documentation

QDataStream & operator<<	(	QDataStream &	stream,
		const QLineF &	lineF
	)

Refer to Serializing Data Types for additional information.

QDataStream & operator>>	(	QDataStream &	stream,
		QLineF &	lineF
	)

Refer to Serializing Data Types for additional information.

Public Types

Public Methods

Static Public Methods

Related Functions

Detailed Description

Member Enumeration Documentation

Constructor & Destructor Documentation

Method Documentation

Friends And Related Function Documentation