/****************************************************************************
**
** Implementation of QPoint class
**
** Created : 931028
**
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#include "qpoint.h"
#include "qdatastream.h"
/*!
\class QPoint qpoint.h
\brief The QPoint class defines a point in the plane.
\ingroup images
\ingroup graphics
\mainclass
A point is specified by an x coordinate and a y coordinate.
The coordinate type is \c QCOORD (a 32-bit integer). The minimum
value of \c QCOORD is \c QCOORD_MIN (-2147483648) and the maximum
value is \c 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 \e p, the following statements are all equivalent:
\code
p.setX( p.x() + 1 );
p += QPoint( 1, 0 );
p.rx()++;
\endcode
A QPoint can also be used as a vector. Addition and subtraction
of QPoints are defined as for vectors (each component is added
separately). You can divide or multiply a QPoint by an \c int or a
\c double. The function manhattanLength() gives an inexpensive
approximation of the length of the QPoint interpreted as a vector.
Example:
\code
//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
}
\endcode
QPoints can be compared for equality or inequality, and they can
be written to and read from a QStream.
\sa QPointArray QSize, QRect
*/
/*****************************************************************************
QPoint member functions
*****************************************************************************/
/*!
\fn QPoint::QPoint()
Constructs a point with coordinates (0, 0) (isNull() returns TRUE).
*/
/*!
\fn QPoint::QPoint( int xpos, int ypos )
Constructs a point with x value \a xpos and y value \a ypos.
*/
/*!
\fn bool QPoint::isNull() const
Returns TRUE if both the x value and the y value are 0; otherwise
returns FALSE.
*/
/*!
\fn int QPoint::x() const
Returns the x coordinate of the point.
\sa setX() y()
*/
/*!
\fn int QPoint::y() const
Returns the y coordinate of the point.
\sa setY() x()
*/
/*!
\fn void QPoint::setX( int x )
Sets the x coordinate of the point to \a x.
\sa x() setY()
*/
/*!
\fn void QPoint::setY( int y )
Sets the y coordinate of the point to \a y.
\sa y() setX()
*/
/*!
\fn QCOORD &QPoint::rx()
Returns a reference to the x coordinate of the point.
Using a reference makes it possible to directly manipulate x.
Example:
\code
QPoint p( 1, 2 );
p.rx()--; // p becomes (0, 2)
\endcode
\sa ry()
*/
/*!
\fn QCOORD &QPoint::ry()
Returns a reference to the y coordinate of the point.
Using a reference makes it possible to directly manipulate y.
Example:
\code
QPoint p( 1, 2 );
p.ry()++; // p becomes (1, 3)
\endcode
\sa rx()
*/
/*!
\fn QPoint &QPoint::operator+=( const QPoint &p )
Adds point \a p to this point and returns a reference to this
point.
Example:
\code
QPoint p( 3, 7 );
QPoint q( -1, 4 );
p += q; // p becomes (2,11)
\endcode
*/
/*!
\fn QPoint &QPoint::operator-=( const QPoint &p )
Subtracts point \a p from this point and returns a reference to
this point.
Example:
\code
QPoint p( 3, 7 );
QPoint q( -1, 4 );
p -= q; // p becomes (4,3)
\endcode
*/
/*!
\fn QPoint &QPoint::operator*=( int c )
Multiplies this point's x and y by \a c, and returns a reference
to this point.
Example:
\code
QPoint p( -1, 4 );
p *= 2; // p becomes (-2,8)
\endcode
*/
/*!
\overload QPoint &QPoint::operator*=( double c )
Multiplies this point's x and y by \a c, and returns a reference
to this point.
Example:
\code
QPoint p( -1, 4 );
p *= 2.5; // p becomes (-3,10)
\endcode
Note that the result is truncated because points are held as
integers.
*/
/*!
\fn bool operator==( const QPoint &p1, const QPoint &p2 )
\relates QPoint
Returns TRUE if \a p1 and \a p2 are equal; otherwise returns FALSE.
*/
/*!
\fn bool operator!=( const QPoint &p1, const QPoint &p2 )
\relates QPoint
Returns TRUE if \a p1 and \a p2 are not equal; otherwise returns FALSE.
*/
/*!
\fn const QPoint operator+( const QPoint &p1, const QPoint &p2 )
\relates QPoint
Returns the sum of \a p1 and \a p2; each component is added separately.
*/
/*!
\fn const QPoint operator-( const QPoint &p1, const QPoint &p2 )
\relates QPoint
Returns \a p2 subtracted from \a p1; each component is subtracted
separately.
*/
/*!
\fn const QPoint operator*( const QPoint &p, int c )
\relates QPoint
Returns the QPoint formed by multiplying both components of \a p
by \a c.
*/
/*!
\overload const QPoint operator*( int c, const QPoint &p )
\relates QPoint
Returns the QPoint formed by multiplying both components of \a p
by \a c.
*/
/*!
\overload const QPoint operator*( const QPoint &p, double c )
\relates QPoint
Returns the QPoint formed by multiplying both components of \a p
by \a c.
Note that the result is truncated because points are held as
integers.
*/
/*!
\overload const QPoint operator*( double c, const QPoint &p )
\relates QPoint
Returns the QPoint formed by multiplying both components of \a p
by \a c.
Note that the result is truncated because points are held as
integers.
*/
/*!
\overload const QPoint operator-( const QPoint &p )
\relates QPoint
Returns the QPoint formed by changing the sign of both components
of \a p, equivalent to \c{QPoint(0,0) - p}.
*/
/*!
\fn QPoint &QPoint::operator/=( int c )
Divides both x and y by \a c, and returns a reference to this
point.
Example:
\code
QPoint p( -2, 8 );
p /= 2; // p becomes (-1,4)
\endcode
*/
/*!
\overload QPoint &QPoint::operator/=( double c )
Divides both x and y by \a c, and returns a reference to this
point.
Example:
\code
QPoint p( -3, 10 );
p /= 2.5; // p becomes (-1,4)
\endcode
Note that the result is truncated because points are held as
integers.
*/
/*!
\fn const QPoint operator/( const QPoint &p, int c )
\relates QPoint
Returns the QPoint formed by dividing both components of \a p by
\a c.
*/
/*!
\overload const QPoint operator/( const QPoint &p, double c )
\relates QPoint
Returns the QPoint formed by dividing both components of \a p
by \a c.
Note that the result is truncated because points are held as
integers.
*/
void QPoint::warningDivByZero()
{
#if defined(QT_CHECK_MATH)
qWarning( "QPoint: Division by zero error" );
#endif
}
/*****************************************************************************
QPoint stream functions
*****************************************************************************/
#ifndef QT_NO_DATASTREAM
/*!
\relates QPoint
Writes point \a p to the stream \a s and returns a reference to
the stream.
\sa \link datastreamformat.html Format of the QDataStream operators \endlink
*/
QDataStream &operator<<( QDataStream &s, const QPoint &p )
{
if ( s.version() == 1 )
s << (Q_INT16)p.x() << (Q_INT16)p.y();
else
s << (Q_INT32)p.x() << (Q_INT32)p.y();
return s;
}
/*!
\relates QPoint
Reads a QPoint from the stream \a s into point \a p and returns a
reference to the stream.
\sa \link datastreamformat.html Format of the QDataStream operators \endlink
*/
QDataStream &operator>>( QDataStream &s, QPoint &p )
{
if ( s.version() == 1 ) {
Q_INT16 x, y;
s >> x; p.rx() = x;
s >> y; p.ry() = y;
}
else {
Q_INT32 x, y;
s >> x; p.rx() = x;
s >> y; p.ry() = y;
}
return s;
}
#endif // QT_NO_DATASTREAM
/*!
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 because such
distances apply to travelers who can only travel on a rectangular
grid, like the streets of Manhattan.
This is a useful, and quick to calculate, approximation to the
true length: sqrt(pow(x(),2)+pow(y(),2)).
*/
int QPoint::manhattanLength() const
{
return QABS(x())+QABS(y());
}