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java.lang.Objectcom.trolltech.qt.QSignalEmitter
com.trolltech.qt.QtJambiObject
com.trolltech.qt.core.QPoint
public class QPoint
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; p.setX(p.x() + 1); p += QPoint(1, 0); p.rx()++;
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.
Nested Class Summary |
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Nested classes/interfaces inherited from class com.trolltech.qt.QSignalEmitter |
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QSignalEmitter.AbstractSignal, QSignalEmitter.Signal0, QSignalEmitter.Signal1<A>, QSignalEmitter.Signal2<A,B>, QSignalEmitter.Signal3<A,B,C>, QSignalEmitter.Signal4<A,B,C,D>, QSignalEmitter.Signal5<A,B,C,D,E>, QSignalEmitter.Signal6<A,B,C,D,E,F>, QSignalEmitter.Signal7<A,B,C,D,E,F,G>, QSignalEmitter.Signal8<A,B,C,D,E,F,G,H>, QSignalEmitter.Signal9<A,B,C,D,E,F,G,H,I> |
Constructor Summary | |
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QPoint()
Constructs a null point, i.e. with coordinates (0, 0) |
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QPoint(int xpos,
int ypos)
Constructs a point with the given coordinates (xpos, ypos). |
Method Summary | |
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QPoint |
add(QPoint p)
Adds this QPoint to p and returns the result. |
QPoint |
divide(double d)
Divides this QPoint by divisor d and returns the result. |
boolean |
equals(java.lang.Object other)
|
static QPoint |
fromNativePointer(QNativePointer nativePointer)
This function returns the QPoint instance pointed to by nativePointer |
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. |
static QNativePointer |
nativePointerArray(QPoint[] array)
This function returns a QNativePointer that is pointing to the specified QPoint array. |
void |
readFrom(QDataStream arg__1)
Reads a QPoint from arg__1. |
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. |
void |
writeTo(QDataStream arg__1)
Writes thisQPoint to arg__1. |
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 |
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dispose, disposed, finalize, reassignNativeResources, tr, tr, tr |
Methods inherited from class com.trolltech.qt.QSignalEmitter |
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blockSignals, disconnect, disconnect, signalsBlocked, signalSender, thread |
Methods inherited from class java.lang.Object |
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clone, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait |
Methods inherited from interface com.trolltech.qt.QtJambiInterface |
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disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership |
Constructor Detail |
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public QPoint()
Constructs a null point, i.e. with coordinates (0, 0)
public QPoint(int xpos, int ypos)
Constructs a point with the given coordinates (xpos, ypos).
Method Detail |
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public final boolean isNull()
Returns true if both the x and y coordinates are set to 0, otherwise returns false.
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:
QPoint oldPosition;
MyWidget::mouseMoveEvent(QMouseEvent *event)
{
QPoint point = event->pos() - 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:
int trueManhattanLength = sqrt(pow(x(), 2) + pow(y(), 2));
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.
public final void writeTo(QDataStream arg__1)
public final void readFrom(QDataStream arg__1)
public final void setX(int x)
Sets the x coordinate of this point to the given x coordinate.
public final void setY(int y)
Sets the y coordinate of this point to the given y coordinate.
public final int x()
Returns the x coordinate of this point.
public final int y()
Returns the y coordinate of this point.
public static QPoint fromNativePointer(QNativePointer nativePointer)
nativePointer
- the QNativePointer of which object should be returned.public static QNativePointer nativePointerArray(QPoint[] array)
array
- the array that the returned pointer will point to.
public boolean equals(java.lang.Object other)
equals
in class java.lang.Object
public final QPoint multiply(double d)
public final QPoint divide(double d)
public final QPoint add(QPoint p)
public final QPoint subtract(QPoint p)
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