The QPointF class defines a point in the plane using floating point precision. More...

Public Methods
	QPointF ()

	QPointF (const QPoint &point)

	QPointF (qreal xPos, qreal yPos)

bool	isNull () const

qreal	manhattanLength () const

QPointF &	operator*= (qreal factor)

QPointF &	operator+= (const QPointF &point)

QPointF &	operator-= (const QPointF &point)

QPointF &	operator/= (qreal factor)

qreal &	rx ()

qreal &	ry ()

void	setX (qreal xPos)

void	setY (qreal yPos)

QPoint	toPoint () const

qreal	x () const

qreal	y () const

Static Public Methods
static qreal	dotProduct (const QPointF &p1, const QPointF &p2)

Friends
bool	operator!= (const QPointF &point1, const QPointF &point2)

const QPointF	operator* (const QPointF &point, qreal factor)

const QPointF	operator* (qreal factor, const QPointF &point)

const QPointF	operator+ (const QPointF &point1, const QPointF &point2)

const QPointF	operator- (const QPointF &point)

const QPointF	operator- (const QPointF &point1, const QPointF &point2)

const QPointF	operator/ (const QPointF &point, qreal factor)

bool	operator== (const QPointF &point1, const QPointF &point2)

class	QMatrix

class	QTransform

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

QDataStream &	operator>> (QDataStream &stream, QPointF &pointF)

Detailed Description

The QPointF class defines a point using an X coordinate and a Y coordinate. The coordinates of the point are specified using floating point numbers for accuracy. The value of the coordinates can be retrieved by calling x() and y(). The methods rx() and ry() return a reference to the coordinates. To set or modify the coordinates, call setX() and setY().

The isNull() method returns true if both x and y are set to 0.0.

Methods

The QPointF class provides a constructor converting a QPoint into a QPointF. The method toPoint() returns a QPoint with the x and y coordinates truncated to integer values.

Addition and subtraction of a QPointF is done by adding both x coordinates and then adding both y coordinates. A QPointF can also be multiplied or divided by an int or a double value.

Example

Given a point p the following code shows three different ways to increment the X coordinate.

QPointF p;
 
p.setX(p.x() + 1.0);            // approach one
 
p += QPointF(1.0, 0.0);         // approach two
 
p.rx()++;                       // approach three

See also: QPoint, QPolygonF

Constructor & Destructor Documentation

QPointF::QPointF ( )

inline

Constructs a new QPointF with the coordinates (0.0, 0.0). This is considered to be a null point.

See also: isNull()

QPointF::QPointF ( const QPoint & point )

inline

Constructs a copy of the given point.

See also: toPoint()

QPointF::QPointF	(	qreal	xPos,
		qreal	yPos
	)

inline

Constructs a new QPointF with the given coordinates (xPos, yPos).

See also: setX(), setY()

Method Documentation

qreal QPointF::dotProduct	(	const QPointF &	p1,
		const QPointF &	p2
	)

inlinestatic

Returns the dot product of p1 and p2.

QPointF p1( 8.3,  7.9);
QPointF p2(-1.2, 12.5);
 
int result = QPointF::dotProduct(p1, p2);     // result = (8.3 * -1.2) + (7.9 * 12.5) = -9.96 + 98.75 = 88.79

bool QPointF::isNull ( ) const

inline

Returns true if both the x and y coordinates are set to +0.0, otherwise returns false.

Since this method treats +0.0 and -0.0 differently, points with zero-valued coordinates where either or both values have a negative sign are not defined to be null points.

qreal QPointF::manhattanLength ( ) const

Returns the sum of the absolute values of x() and y(), traditionally known as the "Manhattan Length" of the vector from the origin to the point.

See also: QPoint::manhattanLength()

QPointF & QPointF::operator*= ( qreal factor )

inline

Multiplies the coordinates by the given factor and returns a reference to this QPointF.

QPointF p(-1.1, 4.1);

p *= 2.5; // p becomes (-2.75, 10.25)

See also: operator/=()

QPointF & QPointF::operator+= ( const QPointF & point )

inline

Adds the given point to this QPointF and returns a reference to this QPointF.

QPointF p( 3.1, 7.1);
QPointF q(-1.0, 4.1);
p += q;                             // p becomes (2.1, 11.2)

See also: operator-=()

QPointF & QPointF::operator-= ( const QPointF & point )

inline

Subtracts the given point from this QPointF and returns a reference to this QPointF.

QPointF p( 3.1, 7.1);
QPointF q(-1.0, 4.1);
p -= q;                             // p becomes (4.1, 3.0)

See also: operator+=()

QPointF & QPointF::operator/= ( qreal factor )

inline

Divides both x and y by the given factor,and returns a reference to this QPointF.

QPointF p(-2.75, 10.25);

p /= 2.5; // p becomes (-1.1, 4.1)

See also: operator*=()

qreal & QPointF::rx ( )

inline

Returns a reference to the x coordinate of this point. Using a reference makes it possible to directly modify x.

QPointF p(1.1, 2.5);

--(p.rx()); // p becomes (0.1, 2.5)

See also: x(), setX()

qreal & QPointF::ry ( )

inline

Returns a reference to the y coordinate of this point. Using a reference makes it possible to directly modify y.

QPointF p(1.1, 2.5);

++(p.ry()); // p becomes (1.1, 3.5)

See also: y(), setY()

void QPointF::setX ( qreal xPos )

inline

Sets the x coordinate of this QPointF to the given xPos coordinate.

See also: x(), setY()

void QPointF::setY ( qreal yPos )

inline

Sets the y coordinate of this QPointF to the given yPos coordinate.

See also: y(), setX()

QPoint QPointF::toPoint ( ) const

inline

Rounds the coordinates of this QPointF to the nearest integer, and returns a QPoint object with the rounded coordinates.

See also: QPointF()

qreal QPointF::x ( ) const

inline

Returns the x coordinate of this QPointF.

See also: setX(), rx()

qreal QPointF::y ( ) const

inline

Returns the y coordinate of this QPointF.

See also: setY(), ry()

Friends And Related Function Documentation

bool operator!=	(	const QPointF &	point1,
		const QPointF &	point2
	)

friend

Returns true if point1 is not equal to point2, otherwise returns false.

const QPointF operator*	(	const QPointF &	point,
		qreal	factor
	)

friend

Returns a copy of the given point multiplied by the given factor.

See also: QPointF::operator*=()

const QPointF operator*	(	qreal	factor,
		const QPointF &	point
	)

friend

Returns a copy of the given point, multiplied by the given factor.

const QPointF operator+	(	const QPointF &	point1,
		const QPointF &	point2
	)

friend

Returns a QPointF which is the sum of the given points, point1 and point2. Each component is added separately.

See also: QPointF::operator+=()

const QPointF operator- ( const QPointF & point )

friend

Returns a QPointF which is formed by changing the sign of both components of the given point.

Equivalent to QPointF(0,0) - point.

const QPointF operator-	(	const QPointF &	point1,
		const QPointF &	point2
	)

friend

Returns a QPointF which is formed by subtracting point2 from point1. Each component is subtracted separately.

See also: QPointF::operator-=()

const QPointF operator/	(	const QPointF &	point,
		qreal	factor
	)

friend

Returns the QPointF which is formed by dividing both components of the given point by the given factor.

See also: QPointF::operator/=()

QDataStream & operator<<	(	QDataStream &	stream,
		const QPointF &	pointF
	)

Refer to Serializing Data Types for additional information.

bool operator==	(	const QPointF &	point1,
		const QPointF &	point2
	)

friend

Returns true if point1 is equal to point2, otherwise returns false.

QDataStream & operator>>	(	QDataStream &	stream,
		QPointF &	pointF
	)

Refer to Serializing Data Types for additional information.

Public Methods

Static Public Methods

Friends

Related Functions

Detailed Description

Methods

Example

Constructor & Destructor Documentation

Method Documentation

Friends And Related Function Documentation