The QPoint class defines a point in the plane using integer precision. More...

Public Methods
	QPoint ()

	QPoint (int xPos, int yPos)

bool	isNull () const

int	manhattanLength () const

QPoint &	operator*= (double factor)

QPoint &	operator*= (float factor)

QPoint &	operator*= (int factor)

QPoint &	operator+= (const QPoint &point)

QPoint &	operator-= (const QPoint &point)

QPoint &	operator/= (qreal factor)

int &	rx ()

int &	ry ()

void	setX (int xPos)

void	setY (int yPos)

int	x () const

int	y () const

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

const QPoint	operator* (const QPoint &point, double factor)

const QPoint	operator* (const QPoint &point, float factor)

const QPoint	operator* (const QPoint &point, int factor)

const QPoint	operator* (double factor, const QPoint &point)

const QPoint	operator* (float factor, const QPoint &point)

const QPoint	operator* (int factor, const QPoint &point)

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

const QPoint	operator- (const QPoint &point)

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

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

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

class	QTransform

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

QDataStream &	operator>> (QDataStream &stream, QPoint &point)

Detailed Description

The QPoint class defines a point in the plane using integer precision.

A point is specified by a x coordinate and an y coordinate which can be accessed using the x() and y() functions. The isNull() function returns true if both x and y are set to 0. The coordinates can be set (or altered) using the setX() and setY() functions, or alternatively the rx() and ry() functions which return references to the coordinates (allowing direct manipulation).

Given a point p, the following statements are all equivalent.

QPoint p;
 
p.setX(p.x() + 1);
p += QPoint(1, 0);
p.rx()++;

A QPoint object can also be used as a vector: Addition and subtraction are defined as for vectors (each component is added separately). A QPoint object can also be divided or multiplied by an int or a qreal.

In addition, the QPoint class provides the manhattanLength() function which gives an inexpensive approximation of the length of the QPoint object interpreted as a vector. Finally, QPoint objects can be streamed as well as compared.

See also: QPointF, QPolygon

Constructor & Destructor Documentation

QPoint::QPoint ( )

inline

Constructs a null QPoint with coordinates (0, 0).

See also: isNull()

QPoint::QPoint	(	int	xPos,
		int	yPos
	)

inline

Constructs a point with the given coordinates xPos and yPos.

See also: setX(), setY()

Method Documentation

bool QPoint::isNull ( ) const

inline

Returns true if both the x and y coordinates are set to 0, otherwise returns false.

int QPoint::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.

QPoint oldPosition;
 
MyWidget::mouseMoveEvent(QMouseEvent *event)
{
    QPoint point = event->pos() - oldPosition;
 
    if (point.manhattanLength() > 3) {
        // the mouse has moved more than 3 pixels since the oldPosition
    }
}

This is a useful calculation to approximate the true length.

QPoint & QPoint::operator*= ( double factor )

inline

Multiplies this point's coordinates by the given factor, and returns a reference to this point. The result is rounded to the nearest integer as points are held as integers. Use QPointF for floating point accuracy.

QPoint p(-1, 4);

p *= 2.5; // p becomes (-3, 10)

See also: operator/=()

QPoint & QPoint::operator*= ( float factor )

inline

Multiplies this point's coordinates by the given factor, and returns a reference to this point. The result is rounded to the nearest integer as points are held as integers. Use QPointF for floating point accuracy.

See also: operator/=()

QPoint & QPoint::operator*= ( int factor )

inline

Multiplies this point's coordinates by the given factor, and returns a reference to this point.

See also: operator/=()

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

inline

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

QPoint p( 3, 7);
QPoint q(-1, 4);
p += q;                 // p becomes (2, 11)

See also: operator-=()

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

inline

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

QPoint p( 3, 7);
QPoint q(-1, 4);
p -= q;                 // p becomes (4, 3)

See also: operator+=()

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

inline

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

QPoint p(-3, 10);

p /= 2.5; // p becomes (-1, 4)

The result is rounded to the nearest integer as points are held as integers. Use QPointF for floating point accuracy.

See also: operator*=()

int & QPoint::rx ( )

inline

Returns a reference to the x coordinate of this point.

Using a reference makes it possible to directly manipulate x.

QPoint p(1, 2);

p.rx()--; // p becomes (0, 2)

See also: x(), setX()

int & QPoint::ry ( )

inline

Returns a reference to the y coordinate of this point.

Using a reference makes it possible to directly manipulate y.

QPoint p(1, 2);

p.ry()++; // p becomes (1, 3)

See also: y(), setY()

void QPoint::setX ( int xPos )

inline

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

See also: x(), setY()

void QPoint::setY ( int yPos )

inline

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

See also: y(), setX()

int QPoint::x ( ) const

inline

Returns the x coordinate of this point.

See also: setX(), rx()

int QPoint::y ( ) const

inline

Returns the y coordinate of this point.

See also: setY(), ry()

Friends And Related Function Documentation

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

friend

Returns true if point1 and point2 are not equal, otherwise returns false.

const QPoint operator*	(	const QPoint &	point,
		double	factor
	)

friend

Returns a copy of the given point multiplied by the given factor. The result is rounded to the nearest integer as points are held as integers. Use QPointF for floating point accuracy.

See also: QPoint::operator*=()

const QPoint operator*	(	const QPoint &	point,
		float	factor
	)

friend

Returns a copy of the given point multiplied by the given factor. The result is rounded to the nearest integer as points are held as integers. Use QPointF for floating point accuracy.

See also: QPoint::operator*=()

const QPoint operator*	(	const QPoint &	point,
		int	factor
	)

friend

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

See also: QPoint::operator*=()

const QPoint operator*	(	double	factor,
		const QPoint &	point
	)

friend

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

const QPoint operator*	(	float	factor,
		const QPoint &	point
	)

friend

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

const QPoint operator*	(	int	factor,
		const QPoint &	point
	)

friend

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

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

friend

Returns a QPoint object that is the sum of the given points, point1 and point2, each component is added separately.

See also: QPoint::operator+=()

const QPoint operator- ( const QPoint & point )

friend

Returns a QPoint object that is formed by changing the sign of both components of the given point. Equivalent to calling QPoint(0,0) - point.

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

friend

Returns a QPoint object that is formed by subtracting point2 from point1, each component is subtracted separately.

See also: QPoint::operator-=()

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

friend

Returns the QPoint formed by dividing both components of the given point by the given factpr. The result is rounded to the nearest integer as points are held as integers. Use QPointF for floating point accuracy.

See also: QPoint::operator/=()

QDataStream & operator<<	(	QDataStream &	stream,
		const QPoint &	point
	)

Refer to Serializing Data Types for additional information.

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

friend

Returns true if point1 and point2 are equal, otherwise returns false.

QDataStream & operator>>	(	QDataStream &	stream,
		QPoint &	point
	)

Refer to Serializing Data Types for additional information.

Public Methods

Friends

Related Functions

Detailed Description

Constructor & Destructor Documentation

Method Documentation

Friends And Related Function Documentation