MeeGo 1.2 Harmattan Developer Documentation Develop for the Nokia N9

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QVector2D Class Reference

The QVector2D class represents a vector or vertex in 2D space. More...

 #include <QVector2D>

This class was introduced in Qt 4.6.

Public Functions

QVector2D ()
QVector2D ( qreal xpos, qreal ypos )
QVector2D ( const QPoint & point )
QVector2D ( const QPointF & point )
QVector2D ( const QVector3D & vector )
QVector2D ( const QVector4D & vector )
bool isNull () const
qreal length () const
qreal lengthSquared () const
void normalize ()
QVector2D normalized () const
void setX ( qreal x )
void setY ( qreal y )
QPoint toPoint () const
QPointF toPointF () const
QVector3D toVector3D () const
QVector4D toVector4D () const
qreal x () const
qreal y () const
operator QVariant () const
QVector2D & operator*= ( qreal factor )
QVector2D & operator*= ( const QVector2D & vector )
QVector2D & operator+= ( const QVector2D & vector )
QVector2D & operator-= ( const QVector2D & vector )
QVector2D & operator/= ( qreal divisor )

Static Public Members

qreal dotProduct ( const QVector2D & v1, const QVector2D & v2 )

Related Non-Members

bool qFuzzyCompare ( const QVector2D & v1, const QVector2D & v2 )
bool operator!= ( const QVector2D & v1, const QVector2D & v2 )
const QVector2D operator* ( qreal factor, const QVector2D & vector )
const QVector2D operator* ( const QVector2D & vector, qreal factor )
const QVector2D operator* ( const QVector2D & v1, const QVector2D & v2 )
const QVector2D operator+ ( const QVector2D & v1, const QVector2D & v2 )
const QVector2D operator- ( const QVector2D & v1, const QVector2D & v2 )
const QVector2D operator- ( const QVector2D & vector )
const QVector2D operator/ ( const QVector2D & vector, qreal divisor )
QDataStream & operator<< ( QDataStream & stream, const QVector2D & vector )
bool operator== ( const QVector2D & v1, const QVector2D & v2 )
QDataStream & operator>> ( QDataStream & stream, QVector2D & vector )

Detailed Description

The QVector2D class represents a vector or vertex in 2D space.

The QVector2D class can also be used to represent vertices in 2D space. We therefore do not need to provide a separate vertex class.

Note: By design values in the QVector2D instance are stored as float. This means that on platforms where the qreal arguments to QVector2D functions are represented by double values, it is possible to lose precision.

See also QVector3D, QVector4D, and QQuaternion.

Member Function Documentation

QVector2D::QVector2D ()

Constructs a null vector, i.e. with coordinates (0, 0, 0).

QVector2D::QVector2D ( qreal xpos, qreal ypos )

Constructs a vector with coordinates (xpos, ypos).

QVector2D::QVector2D ( const QPoint & point )

Constructs a vector with x and y coordinates from a 2D point.

QVector2D::QVector2D ( const QPointF & point )

Constructs a vector with x and y coordinates from a 2D point.

QVector2D::QVector2D ( const QVector3D & vector )

Constructs a vector with x and y coordinates from a 3D vector. The z coordinate of vector is dropped.

See also toVector3D().

QVector2D::QVector2D ( const QVector4D & vector )

Constructs a vector with x and y coordinates from a 3D vector. The z and w coordinates of vector are dropped.

See also toVector4D().

qreal QVector2D::dotProduct ( const QVector2D & v1, const QVector2D & v2 ) [static]

Returns the dot product of v1 and v2.

bool QVector2D::isNull () const

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

qreal QVector2D::length () const

Returns the length of the vector from the origin.

See also lengthSquared() and normalized().

qreal QVector2D::lengthSquared () const

Returns the squared length of the vector from the origin. This is equivalent to the dot product of the vector with itself.

See also length() and dotProduct().

void QVector2D::normalize ()

Normalizes the currect vector in place. Nothing happens if this vector is a null vector or the length of the vector is very close to 1.

See also length() and normalized().

QVector2D QVector2D::normalized () const

Returns the normalized unit vector form of this vector.

If this vector is null, then a null vector is returned. If the length of the vector is very close to 1, then the vector will be returned as-is. Otherwise the normalized form of the vector of length 1 will be returned.

See also length() and normalize().

void QVector2D::setX ( qreal x )

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

See also x() and setY().

void QVector2D::setY ( qreal y )

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

See also y() and setX().

QPoint QVector2D::toPoint () const

Returns the QPoint form of this 2D vector.

See also toPointF() and toVector3D().

QPointF QVector2D::toPointF () const

Returns the QPointF form of this 2D vector.

See also toPoint() and toVector3D().

QVector3D QVector2D::toVector3D () const

Returns the 3D form of this 2D vector, with the z coordinate set to zero.

See also toVector4D() and toPoint().

QVector4D QVector2D::toVector4D () const

Returns the 4D form of this 2D vector, with the z and w coordinates set to zero.

See also toVector3D() and toPoint().

qreal QVector2D::x () const

Returns the x coordinate of this point.

See also setX() and y().

qreal QVector2D::y () const

Returns the y coordinate of this point.

See also setY() and x().

QVector2D::operator QVariant () const

Returns the 2D vector as a QVariant.

QVector2D & QVector2D::operator*= ( qreal factor )

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

See also operator/=().

QVector2D & QVector2D::operator*= ( const QVector2D & vector )

Multiplies the components of this vector by the corresponding components in vector.

QVector2D & QVector2D::operator+= ( const QVector2D & vector )

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

See also operator-=().

QVector2D & QVector2D::operator-= ( const QVector2D & vector )

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

See also operator+=().

QVector2D & QVector2D::operator/= ( qreal divisor )

Divides this vector's coordinates by the given divisor, and returns a reference to this vector.

See also operator*=().

Related Non-Members

bool qFuzzyCompare ( const QVector2D & v1, const QVector2D & v2 )

Returns true if v1 and v2 are equal, allowing for a small fuzziness factor for floating-point comparisons; false otherwise.

bool operator!= ( const QVector2D & v1, const QVector2D & v2 )

Returns true if v1 is not equal to v2; otherwise returns false. This operator uses an exact floating-point comparison.

const QVector2D operator* ( qreal factor, const QVector2D & vector )

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

See also QVector2D::operator*=().

const QVector2D operator* ( const QVector2D & vector, qreal factor )

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

See also QVector2D::operator*=().

const QVector2D operator* ( const QVector2D & v1, const QVector2D & v2 )

Multiplies the components of v1 by the corresponding components in v2.

const QVector2D operator+ ( const QVector2D & v1, const QVector2D & v2 )

Returns a QVector2D object that is the sum of the given vectors, v1 and v2; each component is added separately.

See also QVector2D::operator+=().

const QVector2D operator- ( const QVector2D & v1, const QVector2D & v2 )

Returns a QVector2D object that is formed by subtracting v2 from v1; each component is subtracted separately.

See also QVector2D::operator-=().

const QVector2D operator- ( const QVector2D & vector )

This is an overloaded function.

Returns a QVector2D object that is formed by changing the sign of the components of the given vector.

Equivalent to QVector2D(0,0) - vector.

const QVector2D operator/ ( const QVector2D & vector, qreal divisor )

Returns the QVector2D object formed by dividing all three components of the given vector by the given divisor.

See also QVector2D::operator/=().

QDataStream & operator<< ( QDataStream & stream, const QVector2D & vector )

Writes the given vector to the given stream and returns a reference to the stream.

See also Serializing Qt Data Types.

bool operator== ( const QVector2D & v1, const QVector2D & v2 )

Returns true if v1 is equal to v2; otherwise returns false. This operator uses an exact floating-point comparison.

QDataStream & operator>> ( QDataStream & stream, QVector2D & vector )

Reads a 2D vector from the given stream into the given vector and returns a reference to the stream.

See also Serializing Qt Data Types.

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