Code
class KineticScrollingListener2 extends MouseAdapter {
private static final int SPEED = 4;
private static final int DELAY = 10;
private static final double D = 0.8;
private final Cursor dc;
private final Cursor hc = Cursor.getPredefinedCursor(Cursor.HAND_CURSOR);
private final javax.swing.Timer inside;
private final javax.swing.Timer outside;
private final JComponent label;
private Point startPt = new Point();
private Point delta = new Point();
private static boolean isInside(JViewport vport, JComponent comp) {
Point vp = vport.getViewPosition();
return (vp.x>=0 && vp.x+vport.getWidth()-comp.getWidth()<=0 &&
vp.y>=0 && vp.y+vport.getHeight()-comp.getHeight()<=0);
}
public KineticScrollingListener2(JComponent comp) {
this.label = comp;
this.dc = comp.getCursor();
this.inside = new javax.swing.Timer(DELAY, new ActionListener() {
@Override public void actionPerformed(ActionEvent e) {
JViewport vport = (JViewport)label.getParent();
Point vp = vport.getViewPosition();
//System.out.format("s: %s, %s\n", delta, vp);
vp.translate(-delta.x, -delta.y);
vport.setViewPosition(vp);
if (Math.abs(delta.x)>0 || Math.abs(delta.y)>0) {
delta.setLocation((int)(delta.x*D), (int)(delta.y*D));
//Outside
if (vp.x<0 || vp.x+vport.getWidth()-label.getWidth()>0 )
delta.x = (int)(delta.x*D);
if (vp.y<0 || vp.y+vport.getHeight()-label.getHeight()>0)
delta.y = (int)(delta.y*D);
} else {
inside.stop();
if (!isInside(vport, label)) outside.start();
}
}
});
this.outside = new javax.swing.Timer(DELAY, new ActionListener() {
@Override public void actionPerformed(ActionEvent e) {
JViewport vport = (JViewport)label.getParent();
Point vp = vport.getViewPosition();
//System.out.format("r: %s\n", vp);
if (vp.x<0) vp.x = (int)(vp.x*D);
if (vp.y<0) vp.y = (int)(vp.y*D);
if (vp.x+vport.getWidth()-label.getWidth()>0)
vp.x=(int)(vp.x-(vp.x+vport.getWidth()-label.getWidth())*(1.0-D));
if (vp.y+vport.getHeight()>label.getHeight())
vp.y=(int)(vp.y-(vp.y+vport.getHeight()-label.getHeight())*(1.0-D));
vport.setViewPosition(vp);
if (isInside(vport, label)) outside.stop();
}
});
}
@Override public void mousePressed(MouseEvent e) {
label.setCursor(hc);
startPt.setLocation(e.getPoint());
inside.stop();
outside.stop();
}
@Override public void mouseDragged(MouseEvent e) {
Point pt = e.getPoint();
JViewport vport = (JViewport)label.getParent();
Point vp = vport.getViewPosition();
vp.translate(startPt.x-pt.x, startPt.y-pt.y);
vport.setViewPosition(vp);
delta.setLocation(SPEED*(pt.x-startPt.x), SPEED*(pt.y-startPt.y));
startPt.setLocation(pt);
}
@Override public void mouseReleased(MouseEvent e) {
label.setCursor(dc);
if (isInside((JViewport)label.getParent(), label)) {
inside.start();
} else {
outside.start();
}
}
}
References
