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The QPoint class defines a point in the plane. More...
#include <qpoint.h>
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().
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.
Examples: drawlines/connect.cpp xform/xform.cpp qmag/qmag.cpp forever/forever.cpp
Constructs a point with coordinates (0,0) (isNull() returns TRUE).
Constructs a point with the x value xpos and y value ypos.
Returns TRUE if both the x value and the y value are 0.
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)).
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.
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)
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)
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)
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.
Divides both x and y by c, and return a reference to this point.
Example:
QPoint p( -2, 8 );
p /= 2; // p becomes (-1,4)
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().
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().
Sets the x coordinate of the point to x.
Sets the y coordinate of the point to y.
Returns the x coordinate of the point.
Returns the y coordinate of the point.
Returns the sum of p1 and p2; each component is added separately.
Returns the QPoint formed by multiplying both components of p by c.
Note that the result is truncated.
Returns the QPoint formed by changing the sign of both components of
p, equivalent to QPoint(0,0) - p
Writes a QPoint to the stream and returns a reference to the stream.
See also Format of the QDataStream operators
Returns the QPoint formed by dividing both components of p by c.
Returns the QPoint formed by multiplying both components of p by c.
Note that the result is truncated.
Returns the QPoint formed by multiplying both components of p by c.
Reads a QPoint from the stream and returns a reference to the stream.
See also Format of the QDataStream operators
Returns TRUE if p1 and p2 are different, or FALSE if they are equal.
Returns TRUE if p1 and p2 are equal, or FALSE if they are different.
Returns the QPoint formed by multiplying both components of p by c.
Returns p2 subtracted from p1; each component is subtracted separately.
Returns the QPoint formed by dividing both components of p by c.
Note that the result is truncated.
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