QPointF Class▲
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Header: QPointF
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qmake: QT += core
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Inherited By:
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Group: QPointF is part of painting
Detailed Description▲
A point is specified by a x coordinate and an y coordinate which can be accessed using the x() and y() functions. The coordinates of the point are specified using floating point numbers for accuracy. The isNull() function returns true if both x and y are set to 0.0. 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:
QPointF p;
p.setX(p.x() + 1.0);
p += QPointF(1.0, 0.0);
p.rx()++;A QPointF object can also be used as a vector: Addition and subtraction are defined as for vectors (each component is added separately). A QPointF object can also be divided or multiplied by an int or a qreal.
In addition, the QPointF class provides a constructor converting a QPoint object into a QPointF object, and a corresponding toPoint() function which returns a QPoint copy of this point. Finally, QPointF objects can be streamed as well as compared.
See Also▲
Member Function Documentation▲
QPointF::QPointF()▲
QPointF::QPointF(const QPoint &point)▲
QPointF::QPointF(qreal xpos, qreal ypos)▲
[static, since 5.1] qreal QPointF::dotProduct(const QPointF &p1, const QPointF &p2)▲
QPointF p( 3.1, 7.1);
QPointF q(-1.0, 4.1);
int lengthSquared = QPointF::dotProduct(p, q); // lengthSquared becomes 26.01Returns the dot product of p1 and p2.
This function was introduced in Qt 5.1.
[static, since 5.8] QPointF QPointF::fromCGPoint(CGPoint point)▲
Creates a QRectF from CGPoint point.
This function was introduced in Qt 5.8.
See Also▲
See also toCGPoint()
bool QPointF::isNull() const▲
Returns true if both the x and y coordinates are set to 0.0 (ignoring the sign); otherwise returns false.
[since 4.6] 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.
This function was introduced in Qt 4.6.
See Also▲
See also QPoint::manhattanLength()
qreal &QPointF::rx()▲
Returns a reference to the x coordinate of this point.
Using a reference makes it possible to directly manipulate x. For example:
QPointF p(1.1, 2.5);
p.rx()--; // p becomes (0.1, 2.5)See Also▲
qreal &QPointF::ry()▲
Returns a reference to the y coordinate of this point.
Using a reference makes it possible to directly manipulate y. For example:
QPointF p(1.1, 2.5);
p.ry()++; // p becomes (1.1, 3.5)See Also▲
void QPointF::setX(qreal x)▲
void QPointF::setY(qreal y)▲
[since 5.8] CGPoint QPointF::toCGPoint() const▲
Creates a CGPoint from a QPointF.
This function was introduced in Qt 5.8.
See Also▲
See also fromCGPoint()
QPoint QPointF::toPoint() const▲
Rounds the coordinates of this point to the nearest integer, and returns a QPoint object with the rounded coordinates.
See Also▲
See also QPointF()
[since 5.14] QPointF QPointF::transposed() const▲
Returns a point with x and y coordinates exchanged:
QPointF{1.0, 2.0}.transposed() // {2.0, 1.0}This function was introduced in Qt 5.14.
See Also▲
qreal QPointF::x() const▲
qreal QPointF::y() const▲
QPointF &QPointF::operator*=(qreal factor)▲
Multiplies this point's coordinates by the given factor, and returns a reference to this point. For example:
QPointF p(-1.1, 4.1);
p *= 2.5; // p becomes (-2.75, 10.25)See Also▲
See also operator/=()
QPointF &QPointF::operator+=(const QPointF &point)▲
Adds the given point to this point and returns a reference to this point. For example:
QPointF p( 3.1, 7.1);
QPointF q(-1.0, 4.1);
p += q; // p becomes (2.1, 11.2)See Also▲
See also operator-=()
QPointF &QPointF::operator-=(const QPointF &point)▲
Subtracts the given point from this point and returns a reference to this point. For example:
QPointF p( 3.1, 7.1);
QPointF q(-1.0, 4.1);
p -= q; // p becomes (4.1, 3.0)See Also▲
See also operator+=()
QPointF &QPointF::operator/=(qreal divisor)▲
Divides both x and y by the given divisor, and returns a reference to this point. For example:
QPointF p(-2.75, 10.25);
p /= 2.5; // p becomes (-1.1, 4.1)See Also▲
See also operator*=()
Related Non-Members▲
bool operator!=(const QPointF &p1, const QPointF &p2)▲
Returns true if p1 is not equal to p2; otherwise returns false.
const QPointF operator*(const QPointF &point, qreal factor)▲
Returns a copy of the given point, multiplied by the given factor.
See Also▲
See also QPointF::operator*=()
const QPointF operator*(qreal factor, const QPointF &point)▲
This is an overloaded function.
Returns a copy of the given point, multiplied by the given factor.
const QPointF operator+(const QPointF &p1, const QPointF &p2)▲
Returns a QPointF object that is the sum of the given points, p1 and p2; each component is added separately.
See Also▲
See also QPointF::operator+=()
[since 5.0] const QPointF operator+(const QPointF &point)▲
Returns point unmodified.
This function was introduced in Qt 5.0.
const QPointF operator-(const QPointF &p1, const QPointF &p2)▲
Returns a QPointF object that is formed by subtracting p2 from p1; each component is subtracted separately.
See Also▲
See also QPointF::operator-=()
const QPointF operator-(const QPointF &point)▲
This is an overloaded function.
Returns a QPointF object that is formed by changing the sign of both components of the given point.
Equivalent to QPointF(0,0) - point.
const QPointF operator/(const QPointF &point, qreal divisor)▲
Returns the QPointF object formed by dividing both components of the given point by the given divisor.
See Also▲
See also QPointF::operator/=()
QDataStream &operator<<(QDataStream &stream, const QPointF &point)▲
Writes the given point to the given stream and returns a reference to the stream.
See Also▲
See also Serializing Qt Data Types
bool operator==(const QPointF &p1, const QPointF &p2)▲
Returns true if p1 is equal to p2; otherwise returns false.
QDataStream &operator>>(QDataStream &stream, QPointF &point)▲
Reads a point from the given stream into the given point and returns a reference to the stream.
See Also▲
See also Serializing Qt Data Types