QPoint(3qt)QPoint(3qt)NAME
QPoint - Defines a point in the plane
#include <qpoint.h>
Public Members
QPoint ()
QPoint ( int xpos, int ypos )
bool isNull () const
int x () const
int y () const
void setX ( int x )
void setY ( int y )
int manhattanLength () const
QCOORD& rx ()
QCOORD& ry ()
QPoint& operator+= ( const QPoint & p )
QPoint& operator-= ( const QPoint & p )
QPoint& operator*= ( int c )
QPoint& operator*= ( double c )
QPoint& operator/= ( int c )
QPoint& operator/= ( double c )
RELATED FUNCTION DOCUMENTATION
(Note that these are not member functions.)
QPoint operator+ (const QPoint & p1, const QPoint & p2)
QPoint operator* (double c, const QPoint & p)
QPoint operator- (const QPoint & p)
QDataStream & operator<< (QDataStream & s, const QPoint &
p)
QPoint operator/ (const QPoint & p, int c)
QPoint operator* (const QPoint & p, double c)
QPoint operator* (int c, const QPoint & p)
QDataStream & operator>> (QDataStream & s, QPoint & p)
bool operator!= (const QPoint & p1, const QPoint & p2)
bool operator== (const QPoint & p1, const QPoint & p2)
QPoint operator* (const QPoint & p, int c)
QPoint operator- (const QPoint & p1, const QPoint & p2)
QPoint operator/ (const QPoint & p, double c)
DESCRIPTION
The QPoint class defines a point in the plane.
A point is specified by an x coordinate and a y
coordinate.
The coordinate type is QCOORD (a 32-bit integer). The
minimum value of QCOORD is QCOORD_MIN (-2147483648) and
the maximum value is QCOORD_MAX (2147483647).
The coordinates are accessed by the functions x() and y(),
they can be set by setX() and setY(), or by the reference
functions rx() and ry().
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QPoint(3qt)QPoint(3qt)
Given a point p, the following statements are all
equivalent:
p.setX( p.x() + 1 );
p += QPoint( 1, 0 );
p.rx()++;
A QPoint can also be used as a vector. Addition and
subtraction of QPoint are defined as for vectors (each
component is added separately). You can divide or multiply
a QPoint by an int or a double. The function
manhattanLength() gives an inexpensive approximation to
the length of the QPoint interpreted as a vector.
Example:
//QPoint oldPos is defined somewhere else
MyWidget::mouseMoveEvent( QMouseEvent *e )
{
QPoint vector = e->pos() - oldPos;
if ( vector.manhattanLength() > 3 )
... //mouse has moved more than 3 pixels since oldPos
}
QPoints can be compared for equality or inequality, and
they can be written to and read from a QStream.
See also QSize and QRect.
Examples: drawlines/connect.cpp xform/xform.cpp
qmag/qmag.cpp forever/forever.cpp
MEMBER FUNCTION DOCUMENTATIONQPoint::QPoint ()
Constructs a point with coordinates (0,0) (isNull()
returns TRUE).
QPoint::QPoint ( int xpos, int ypos )
Constructs a point with the x value xpos and y value ypos.
bool QPoint::isNull () const
Returns TRUE if both the x value and the y value are 0.
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. The tradition arises
since such distances apply to travelers who can only
travel on a rectangular grid, like the streets of
Manhattan.
This is a useful approximation to the true length,
sqrt(pow(x(),2)+pow(y(),2)).
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QPoint(3qt)QPoint(3qt)QPoint & QPoint::operator*= ( double c )
Multiplies both x and y with c, and return a reference to
this point.
Example:
QPoint p( -1, 4 );
p *= 2.5; // p becomes (-3,10)
Note that the result is truncated.
QPoint & QPoint::operator*= ( int c )
Multiplies both x and y with c, and return a reference to
this point.
Example:
QPoint p( -1, 4 );
p *= 2; // p becomes (-2,8)
QPoint & QPoint::operator+= ( const QPoint & p )
Adds p to the point and returns a reference to this point.
Example:
QPoint p( 3, 7 );
QPoint q( -1, 4 );
p += q; // p becomes (2,11)
QPoint & QPoint::operator-= ( const QPoint & p )
Subtracts p from the point and returns a reference to this
point.
Example:
QPoint p( 3, 7 );
QPoint q( -1, 4 );
p -= q; // p becomes (4,3)
QPoint & QPoint::operator/= ( double c )
Divides both x and y by c, and return a reference to this
point.
Example:
QPoint p( -3, 10 );
p /= 2.5; // p becomes (-1,4)
Note that the result is truncated.
QPoint & QPoint::operator/= ( int c )
Divides both x and y by c, and return a reference to this
point.
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QPoint(3qt)QPoint(3qt)
Example:
QPoint p( -2, 8 );
p /= 2; // p becomes (-1,4)
QCOORD & QPoint::rx ()
Returns a reference to the x coordinate of the point.
Using a reference makes it possible to directly manipulate
x.
Example:
QPoint p( 1, 2 );
p.rx()--; // p becomes (0,2)
See also ry().
QCOORD & QPoint::ry ()
Returns a reference to the y coordinate of the point.
Using a reference makes it possible to directly manipulate
y.
Example:
QPoint p( 1, 2 );
p.ry()++; // p becomes (1,3)
See also rx().
void QPoint::setX ( int x )
Sets the x coordinate of the point to x.
See also x() and setY().
void QPoint::setY ( int y )
Sets the y coordinate of the point to y.
See also y() and setX().
int QPoint::x () const
Returns the x coordinate of the point.
See also setX() and y().
int QPoint::y () const
Returns the y coordinate of the point.
See also setY() and x().
RELATED FUNCTION DOCUMENTATIONQPoint operator+ (const QPoint & p1, const QPoint & p2)
Returns the sum of p1 and p2; each component is added
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QPoint(3qt)QPoint(3qt)
separately.
QPoint operator* (double c, const QPoint & p)
Returns the QPoint formed by multiplying both components
of p by c.
Note that the result is truncated.
QPoint operator- (const QPoint & p)
Returns the QPoint formed by changing the sign of both
components of p, equivalent to QPoint(0,0) - p
QDataStream & operator<;< (QDataStream & s, const QPoint & p)
Writes a QPoint to the stream and returns a reference to
the stream.
See also Format of the QDataStream operators
QPoint operator/ (const QPoint & p, int c)
Returns the QPoint formed by dividing both components of p
by c.
QPoint operator* (const QPoint & p, double c)
Returns the QPoint formed by multiplying both components
of p by c.
Note that the result is truncated.
QPoint operator* (int c, const QPoint & p)
Returns the QPoint formed by multiplying both components
of p by c.
QDataStream & operator>> (QDataStream & s, QPoint & p)
Reads a QPoint from the stream and returns a reference to
the stream.
See also Format of the QDataStream operators
bool operator!= (const QPoint & p1, const QPoint & p2)
Returns TRUE if p1 and p2 are different, or FALSE if they
are equal.
bool operator== (const QPoint & p1, const QPoint & p2)
Returns TRUE if p1 and p2 are equal, or FALSE if they are
different.
QPoint operator* (const QPoint & p, int c)
Returns the QPoint formed by multiplying both components
of p by c.
QPoint operator- (const QPoint & p1, const QPoint & p2)
Returns p2 subtracted from p1; each component is
subtracted separately.
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QPoint(3qt)QPoint(3qt)QPoint operator/ (const QPoint & p, double c)
Returns the QPoint formed by dividing both components of p
by c.
Note that the result is truncated.
SEE ALSO
http://doc.trolltech.com/qpoint.html
http://www.trolltech.com/faq/tech.html
COPYRIGHT
Copyright 1992-2001 Trolltech AS,
http://www.trolltech.com. See the license file included
in the distribution for a complete license statement.
AUTHOR
Generated automatically from the source code.
BUGS
If you find a bug in Qt, please report it as described in
http://doc.trolltech.com/bughowto.html. Good bug reports
make our job much simpler. Thank you.
In case of content or formattting problems with this
manual page, please report them to qt-bugs@trolltech.com.
Please include the name of the manual page (qpoint.3qt)
and the Qt version (2.3.1).
Trolltech AS 13 June 2001 6
