source: trunk/src/corelib/tools/qline.cpp@ 561

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#include "qline.h"
#include "qdebug.h"
#include "qdatastream.h"
#include "qmath.h"
#include <private/qnumeric_p.h>

QT_BEGIN_NAMESPACE

/*!
    \class QLine
    \ingroup painting

    \brief The QLine class provides a two-dimensional vector using
    integer precision.

    A QLine describes a finite length line (or a line segment) on a
    two-dimensional surface. The start and end points of the line are
    specified using integer point accuracy for coordinates. Use the
    QLineF constructor to retrieve a floating point copy.

    \table
    \row
        \o \inlineimage qline-point.png
        \o \inlineimage qline-coordinates.png
    \endtable

    The positions of the line's start and end points can be retrieved
    using the p1(), x1(), y1(), p2(), x2(), and y2() functions. The
    dx() and dy() functions return the horizontal and vertical
    components of the line. Use isNull() to determine whether the
    QLine represents a valid line or a null line.

    Finally, the line can be translated a given offset using the
    translate() function.

    \sa QLineF, QPolygon, QRect
*/

/*!
    \fn QLine::QLine()

    Constructs a null line.
*/

/*!
    \fn QLine::QLine(const QPoint &p1, const QPoint &p2)

    Constructs a line object that represents the line between \a p1 and
    \a p2.
*/

/*!
    \fn QLine::QLine(int x1, int y1, int x2, int y2)

    Constructs a line object that represents the line between (\a x1, \a y1) and
    (\a x2, \a y2).
*/

/*!
    \fn bool QLine::isNull() const

    Returns true if the line is not set up with valid start and end point;
    otherwise returns false.
*/

/*!
    \fn QPoint QLine::p1() const

    Returns the line's start point.

    \sa x1(), y1(), p2()
*/

/*!
    \fn QPoint QLine::p2() const

    Returns the line's end point.

    \sa x2(), y2(), p1()
*/

/*!
    \fn int QLine::x1() const

    Returns the x-coordinate of the line's start point.

    \sa p1()
*/

/*!
    \fn int QLine::y1() const

    Returns the y-coordinate of the line's start point.

    \sa p1()
*/

/*!
    \fn int QLine::x2() const

    Returns the x-coordinate of the line's end point.

    \sa p2()
*/

/*!
    \fn int QLine::y2() const

    Returns the y-coordinate of the line's end point.

    \sa p2()
*/

/*!
    \fn int QLine::dx() const

    Returns the horizontal component of the line's vector.

    \sa dy()
*/

/*!
    \fn int QLine::dy() const

    Returns the vertical component of the line's vector.

    \sa dx()
*/

/*!
    \fn bool QLine::operator!=(const QLine &line) const

    Returns true if the given \a line is not the same as \e this line.

    A line is different from another line if any of their start or
    end points differ, or the internal order of the points is different.
*/

/*!
    \fn bool QLine::operator==(const QLine &line) const

    Returns true if the given \a line is the same as \e this line.

    A line is identical to another line if the start and end points
    are identical, and the internal order of the points is the same.
*/

/*!
    \fn void QLine::translate(const QPoint &offset)

    Translates this line by the given \a offset.
*/

/*!
    \fn void QLine::translate(int dx, int dy)
    \overload

    Translates this line the distance specified by \a dx and \a dy.
*/

/*!
    \fn QLine QLine::translated(const QPoint &offset) const

    \since 4.4

    Returns this line translated by the given \a offset.
*/

/*!
    \fn QLine QLine::translated(int dx, int dy) const
    \overload
    \since 4.4