com.trolltech.qt.gui
Class QGraphicsItemAnimation

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.QObject
                  extended by com.trolltech.qt.gui.QGraphicsItemAnimation
All Implemented Interfaces:
QtJambiInterface

public class QGraphicsItemAnimation
extends QObject

The QGraphicsItemAnimation class provides simple animation support for QGraphicsItem. The QGraphicsItemAnimation class animates a QGraphicsItem. You can schedule changes to the item's transformation matrix at specified steps. The QGraphicsItemAnimation class has a current step value. When this value changes the transformations scheduled at that step are performed. The current step of the animation is set with the setStep() function.

QGraphicsItemAnimation will do a simple linear interpolation between the nearest adjacent scheduled changes to calculate the matrix. For instance, if you set the position of an item at values 0.0 and 1.0, the animation will show the item moving in a straight line between these positions. The same is true for scaling and rotation.

It is usual to use the class with a QTimeLine. The timeline's valueChanged() signal is then connected to the setStep() slot. For example, you can set up an item for rotation by calling setRotationAt() for different step values. The animations timeline is set with the setTimeLine() function.

An example animation with a timeline follows:

        QGraphicsEllipseItem ball = new QGraphicsEllipseItem(0, 0, 20, 20);

        QTimeLine timer = new QTimeLine(5000);
        timer.setFrameRange(0, 100);

        QGraphicsItemAnimation animation = new QGraphicsItemAnimation();
        animation.setItem(ball);
        animation.setTimeLine(timer);

        for (int i = 0; i < 200; ++i)
            animation.setPosAt(i / 200.0, new QPointF(i, i));

        QGraphicsScene scene = new QGraphicsScene();
        scene.setSceneRect(new QRectF(0, 0, 250, 250));
        scene.addItem(ball);

        QGraphicsView view = new QGraphicsView(scene);
        view.show();

        timer.start();
    
Note that steps lie between 0.0 and 1.0. It may be necessary to use setUpdateInterval(). The default update interval is 40 ms. A scheduled transformation cannot be removed when set, so scheduling several transformations of the same kind (e.g., rotations) at the same step is not recommended.

See also:
QTimeLine, and The Graphics View Framework.


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
QGraphicsItemAnimation()
          Constructs an animation object with the given parent.
QGraphicsItemAnimation(QObject parent)
          Constructs an animation object with the given parent.
 
Method Summary
protected  void afterAnimationStep(double step)
          This method is meant to be overridden in subclasses that need to execute additional code after a new step has taken place.
protected  void beforeAnimationStep(double step)
          This method is meant to be overridden by subclassed that needs to execute additional code before a new step takes place.
 void clear()
          Clears the scheduled transformations used for the animation, but retains the item and timeline.
 double horizontalScaleAt(double step)
          Returns the horizontal scale for the item at the specified step value.
 double horizontalShearAt(double step)
          Returns the horizontal shear for the item at the specified step value.
 QGraphicsItemInterface item()
          Returns the item on which the animation object operates.
 QMatrix matrixAt(double step)
          Returns the matrix used to transform the item at the specified step value.
 QPointF posAt(double step)
          Returns the position of the item at the given step value.
 java.util.List posList()
          Returns all explicitly inserted positions.
 void reset()
          Resets the item to its starting position and transformation.
 double rotationAt(double step)
          Returns the angle at which the item is rotated at the specified step value.
 java.util.List rotationList()
          Returns all explicitly inserted rotations.
 java.util.List scaleList()
          Returns all explicitly inserted scales.
 void setItem(QGraphicsItemInterface item)
          Sets the specified item to be used in the animation.
 void setPosAt(double step, QPointF pos)
          Sets the position of the item at the given step value to the point specified.
 void setRotationAt(double step, double angle)
          Sets the rotation of the item at the given step value to the angle specified.
 void setScaleAt(double step, double sx, double sy)
          Sets the scale of the item at the given step value using the horizontal and vertical scale factors specified by sx and sy.
 void setShearAt(double step, double sh, double sv)
          Sets the shear of the item at the given step value using the horizontal and vertical shear factors specified by sh and sv.
 void setStep(double x)
          Sets the current step value for the animation, causing the transformations scheduled at this step to be performed.
 void setTimeLine(QTimeLine timeLine)
          Sets the timeline object used to control the rate of animation to the timeLine specified.
 void setTranslationAt(double step, double dx, double dy)
          Sets the translation of the item at the given step value using the horizontal and vertical coordinates specified by dx and dy.
 java.util.List shearList()
          Returns all explicitly inserted shears.
 QTimeLine timeLine()
          Returns the timeline object used to control the rate at which the animation occurs.
 java.util.List translationList()
          Returns all explicitly inserted translations.
 double verticalScaleAt(double step)
          Returns the vertical scale for the item at the specified step value.
 double verticalShearAt(double step)
          Returns the vertical shear for the item at the specified step value.
 double xTranslationAt(double step)
          Returns the horizontal translation of the item at the specified step value.
 double yTranslationAt(double step)
          Returns the vertical translation of the item at the specified step value.
 
Methods inherited from class com.trolltech.qt.core.QObject
childEvent, children, connectSlotsByName, customEvent, disposeLater, dumpObjectInfo, dumpObjectTree, dynamicPropertyNames, event, eventFilter, findChild, findChild, findChild, findChildren, findChildren, findChildren, findChildren, indexOfProperty, installEventFilter, isWidgetType, killTimer, moveToThread, objectName, parent, properties, property, removeEventFilter, setObjectName, setParent, setProperty, startTimer, timerEvent, toString, userProperty
 
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
clone, getClass, hashCode, notify, notifyAll, wait, wait, wait
 
Methods inherited from interface com.trolltech.qt.QtJambiInterface
disableGarbageCollection, nativeId, nativePointer, reenableGarbageCollection, setJavaOwnership
 

Constructor Detail

QGraphicsItemAnimation

public QGraphicsItemAnimation()
Constructs an animation object with the given parent.


QGraphicsItemAnimation

public QGraphicsItemAnimation(QObject parent)
Constructs an animation object with the given parent.

Method Detail

clear

public final void clear()
Clears the scheduled transformations used for the animation, but retains the item and timeline.


horizontalScaleAt

public final double horizontalScaleAt(double step)
Returns the horizontal scale for the item at the specified step value.

See also:
setScaleAt().


horizontalShearAt

public final double horizontalShearAt(double step)
Returns the horizontal shear for the item at the specified step value.

See also:
setShearAt().


item

public final QGraphicsItemInterface item()
Returns the item on which the animation object operates.

See also:
setItem().


matrixAt

public final QMatrix matrixAt(double step)
Returns the matrix used to transform the item at the specified step value.


posAt

public final QPointF posAt(double step)
Returns the position of the item at the given step value.

See also:
setPosAt().


posList

public final java.util.List posList()
Returns all explicitly inserted positions.

See also:
posAt(), and setPosAt().


reset

public final void reset()
Resets the item to its starting position and transformation.

You can call setStep(0) instead.


rotationAt

public final double rotationAt(double step)
Returns the angle at which the item is rotated at the specified step value.

See also:
setRotationAt().


rotationList

public final java.util.List rotationList()
Returns all explicitly inserted rotations.

See also:
rotationAt(), and setRotationAt().


scaleList

public final java.util.List scaleList()
Returns all explicitly inserted scales.

See also:
verticalScaleAt(), horizontalScaleAt(), and setScaleAt().


setItem

public final void setItem(QGraphicsItemInterface item)
Sets the specified item to be used in the animation.

See also:
item().


setPosAt

public final void setPosAt(double step,
                           QPointF pos)
Sets the position of the item at the given step value to the point specified.

See also:
posAt().


setRotationAt

public final void setRotationAt(double step,
                                double angle)
Sets the rotation of the item at the given step value to the angle specified.

See also:
rotationAt().


setScaleAt

public final void setScaleAt(double step,
                             double sx,
                             double sy)
Sets the scale of the item at the given step value using the horizontal and vertical scale factors specified by sx and sy.

See also:
verticalScaleAt(), and horizontalScaleAt().


setShearAt

public final void setShearAt(double step,
                             double sh,
                             double sv)
Sets the shear of the item at the given step value using the horizontal and vertical shear factors specified by sh and sv.

See also:
verticalShearAt(), and horizontalShearAt().


setStep

public final void setStep(double x)
Sets the current step value for the animation, causing the transformations scheduled at this step to be performed.


setTimeLine

public final void setTimeLine(QTimeLine timeLine)
Sets the timeline object used to control the rate of animation to the timeLine specified.

See also:
timeLine().


setTranslationAt

public final void setTranslationAt(double step,
                                   double dx,
                                   double dy)
Sets the translation of the item at the given step value using the horizontal and vertical coordinates specified by dx and dy.

See also:
xTranslationAt(), and yTranslationAt().


shearList

public final java.util.List shearList()
Returns all explicitly inserted shears.

See also:
verticalShearAt(), horizontalShearAt(), and setShearAt().


timeLine

public final QTimeLine timeLine()
Returns the timeline object used to control the rate at which the animation occurs.

See also:
setTimeLine().


translationList

public final java.util.List translationList()
Returns all explicitly inserted translations.

See also:
xTranslationAt(), yTranslationAt(), and setTranslationAt().


verticalScaleAt

public final double verticalScaleAt(double step)
Returns the vertical scale for the item at the specified step value.

See also:
setScaleAt().


verticalShearAt

public final double verticalShearAt(double step)
Returns the vertical shear for the item at the specified step value.

See also:
setShearAt().


xTranslationAt

public final double xTranslationAt(double step)
Returns the horizontal translation of the item at the specified step value.

See also:
setTranslationAt().


yTranslationAt

public final double yTranslationAt(double step)
Returns the vertical translation of the item at the specified step value.

See also:
setTranslationAt().


afterAnimationStep

protected void afterAnimationStep(double step)
This method is meant to be overridden in subclasses that need to execute additional code after a new step has taken place. The animation step is provided for use in cases where the action depends on its value.


beforeAnimationStep

protected void beforeAnimationStep(double step)
This method is meant to be overridden by subclassed that needs to execute additional code before a new step takes place. The animation step is provided for use in cases where the action depends on its value.