com.trolltech.qt.core
Class QPoint

java.lang.Object
  extended by com.trolltech.qt.internal.QSignalEmitterInternal
      extended by com.trolltech.qt.QSignalEmitter
          extended by com.trolltech.qt.QtJambiObject
              extended by com.trolltech.qt.core.QPoint
All Implemented Interfaces:
QtJambiInterface, java.lang.Cloneable

public class QPoint
extends QtJambiObject
implements java.lang.Cloneable

The QPoint class defines a point in the plane using integer precision. A point is specified by a x coordinate and an y coordinate which can be accessed using the x() and y() functions. The isNull() function returns true if both x and y are set to 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:

        QPoint p = new QPoint();

        p.setX(p.x() + 1);
        p.add(new QPoint(1, 0));
A QPoint object can also be used as a vector: Addition and subtraction are defined as for vectors (each component is added separately). A QPoint object can also be divided or multiplied by an int or a qreal.

In addition, the QPoint class provides the manhattanLength() function which gives an inexpensive approximation of the length of the QPoint object interpreted as a vector. Finally, QPoint objects can be streamed as well as compared.

See also:
QPointF, and QPolygon.


Nested Class Summary
 
Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter
QSignalEmitter.AbstractSignal, QSignalEmitter.PrivateSignal0, QSignalEmitter.PrivateSignal1, QSignalEmitter.PrivateSignal2, QSignalEmitter.PrivateSignal3, QSignalEmitter.PrivateSignal4, QSignalEmitter.PrivateSignal5, QSignalEmitter.PrivateSignal6, QSignalEmitter.PrivateSignal7, QSignalEmitter.PrivateSignal8, QSignalEmitter.PrivateSignal9, QSignalEmitter.Signal0, QSignalEmitter.Signal1, QSignalEmitter.Signal2, QSignalEmitter.Signal3, QSignalEmitter.Signal4, QSignalEmitter.Signal5, QSignalEmitter.Signal6, QSignalEmitter.Signal7, QSignalEmitter.Signal8, QSignalEmitter.Signal9
 
Nested classes/interfaces inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
com.trolltech.qt.internal.QSignalEmitterInternal.AbstractSignalInternal
 
Field Summary
 
Fields inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
currentSender
 
Constructor Summary
QPoint()
          Constructs a null point, i.
QPoint(int xpos, int ypos)
          Constructs a point with the given coordinates (x, y).
 
Method Summary
 QPoint add(QPoint p)
          Adds this QPoint to p and returns the result.
 QPoint clone()
          This method is reimplemented for internal reasons
 QPoint divide(double d)
          Divides this QPoint by divisor d and returns the result.
 boolean isNull()
          Returns true if both the x and y coordinates are set to 0, otherwise returns false.
 int manhattanLength()
          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.
 QPoint multiply(double d)
          Multiplies this QPoint by factor d and returns the result.
 void readFrom(QDataStream arg__1)
          Reads a QPoint
 void setX(int x)
          Sets the x coordinate of this point to the given x coordinate.
 void setY(int y)
          Sets the y coordinate of this point to the given y coordinate.
 QPoint subtract(QPoint p)
          Subtracts this QPoint by p and returns the result.
 java.lang.String toString()
          Returns a string representation of the this QPoint.
 void writeTo(QDataStream arg__1)
          Writes thisQPoint
 int x()
          Returns the x coordinate of this point.
 int y()
          Returns the y coordinate of this point.
 
Methods inherited from class com.trolltech.qt.QtJambiObject
dispose, disposed, equals, finalize, reassignNativeResources, tr, tr, tr
 
Methods inherited from class com.trolltech.qt.QSignalEmitter
blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread
 
Methods inherited from class com.trolltech.qt.internal.QSignalEmitterInternal
__qt_signalInitialization
 
Methods inherited from class java.lang.Object
getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Constructor Detail

QPoint

public QPoint()
Constructs a null point, i. . with coordinates (0, 0)

See also:
isNull().


QPoint

public QPoint(int xpos,
              int ypos)
Constructs a point with the given coordinates (x, y).

See also:
setX(), and setY().

Method Detail

isNull

public final boolean isNull()
Returns true if both the x and y coordinates are set to 0, otherwise returns false.


manhattanLength

public final int manhattanLength()
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. For example:
        protected QPoint oldPosition = new QPoint();

        protected void mouseMoveEvent(QMouseEvent event)
        {
            QPoint point = new QPoint(event.pos().x(), event.pos().y());
            point.subtract(oldPosition);
            if (point.manhattanLength() > 3) {
                // the mouse has moved more than 3 pixels since the oldPosition
            }
        }
This is a useful, and quick to calculate, approximation to the true length:
        double trueLength = Math.hypot(p.x(), p.y());
The tradition of "Manhattan length" arises because such distances apply to travelers who can only travel on a rectangular grid, like the streets of Manhattan.


writeTo

public final void writeTo(QDataStream arg__1)
Writes thisQPoint


readFrom

public final void readFrom(QDataStream arg__1)
Reads a QPoint


setX

public final void setX(int x)
Sets the x coordinate of this point to the given x coordinate.

See also:
x(), and setY().


setY

public final void setY(int y)
Sets the y coordinate of this point to the given y coordinate.

See also:
y(), and setX().


x

public final int x()
Returns the x coordinate of this point.

See also:
setX(), and rx().


y

public final int y()
Returns the y coordinate of this point.

See also:
setY(), and ry().


multiply

public final QPoint multiply(double d)
Multiplies this QPoint by factor d and returns the result. d

Returns:

divide

public final QPoint divide(double d)
Divides this QPoint by divisor d and returns the result.


add

public final QPoint add(QPoint p)
Adds this QPoint to p and returns the result.


subtract

public final QPoint subtract(QPoint p)
Subtracts this QPoint by p and returns the result.


toString

public java.lang.String toString()
Returns a string representation of the this QPoint.

Overrides:
toString in class java.lang.Object

clone

public QPoint clone()
This method is reimplemented for internal reasons

Overrides:
clone in class java.lang.Object