[JAVA3D] Modified MouseZoom but canvas hangs

Jasmine Kwok Mon, 17 Feb 2003 01:05:22 -0800

Hi all,

I modified the MouseZoom.java class to work such that it uses scaling instead of translation. However,

there is a tendency for the canvas to "hang" after zooming in/out continuously.

The frame still works but no mouse activity within the canvas can be carried out (i.e. MouseRotate, MouseTranslate).

What can be the problem?

Apparantly, I only changed significantly one line of code (in red) , which is from set(Vector 3d) to set(double).

public class MouseZoom extends MouseBehavior {
double scale_factor;

private MouseBehaviorCallback callback = null;

/**
* Creates a zoom behavior given the transform group.
* @param transformGroup The transformGroup to operate on.
*/
public MouseZoom(TransformGroup transformGroup) {
  super(transformGroup);
}

/**
* Creates a default mouse zoom behavior.
**/
public MouseZoom(){
  super(0);
}

/**
* Creates a zoom behavior.
* Note that this behavior still needs a transform
* group to work on (use setTransformGroup(tg)) and
* the transform group must add this behavior.
* @param flags
*/
public MouseZoom(int flags) {
  super(flags);
}

public void initialize() {
  super.initialize();
  scale_factor = .04;

  if ((flags & INVERT_INPUT) == INVERT_INPUT) {
   scale_factor *= -1;
   invert = true;
  }

}

/**
* Return the y-axis movement multipler.
**/

public double getFactor() {
  return scale_factor;
}

/**
* Set the y-axis movement multipler with factor.
**/

public void setFactor( double factor) {
  scale_factor = factor;

}

public void processStimulus (Enumeration criteria) {
  WakeupCriterion wakeup;
  AWTEvent[] event;
  int id;
  int dx, dy;

  while (criteria.hasMoreElements()) {
   wakeup = (WakeupCriterion) criteria.nextElement();
   if (wakeup instanceof WakeupOnAWTEvent) {
    event = ((WakeupOnAWTEvent)wakeup).getAWTEvent();
    for (int i=0; i<event.length; i++) {
     processMouseEvent((MouseEvent) event[i]);

     if (((buttonPress)&&((flags & MANUAL_WAKEUP) == 0)) ||
      ((wakeUp)&&((flags & MANUAL_WAKEUP) != 0))){
      id = event[i].getID();
      if ((id == MouseEvent.MOUSE_DRAGGED) &&
       ((MouseEvent)event[i]).isAltDown() &&
       !((MouseEvent)event[i]).isMetaDown()){


       x = ((MouseEvent)event[i]).getX();
       y = ((MouseEvent)event[i]).getY();

       dx = x - x_last;
       dy = y - y_last;

       if (!reset){
        transformGroup.getTransform(currXform);

        transformX.set(1+(dy*scale_factor)); //*****************CHANGED******************//

        if (invert) {
         currXform.mul(currXform, transformX);
        } else {
         currXform.mul(transformX, currXform);
        }

        transformGroup.setTransform(currXform);

        transformChanged( currXform );

        if (callback!=null)
         callback.transformChanged( MouseBehaviorCallback.ZOOM,
         currXform );

       }
       else {
        reset = false;
       }

       x_last = x;
       y_last = y;
      }
      else if (id == MouseEvent.MOUSE_PRESSED) {
       x_last = ((MouseEvent)event[i]).getX();
       y_last = ((MouseEvent)event[i]).getY();
      }
     }
    }
   }
  }

  wakeupOn (mouseCriterion);
}
/**
* Users can overload this method which is called every time
* the Behavior updates the transform
*
* Default implementation does nothing
*/
public void transformChanged( Transform3D transform ) {
}

/**
* The transformChanged method in the callback class will
* be called every time the transform is updated
*/
public void setupCallback( MouseBehaviorCallback callback ) {
  this.callback = callback;
}
}

[JAVA3D] Modified MouseZoom but canvas hangs

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