Posted by Manu on Oct 07, 2018; 3:44pm
URL: https://forum.jogamp.org/Java3D-1-6-1-Release-tp4039241p4039256.html

If Canvas3D instances are correctly displayed and resized with HiDPI screens in Java 3D 1.6.1, mouse event coordinates are not correctly scaled yet
The xscale and yscale fields added to Canvas3D should also be used to scale mouse coordinates, probably in addMouseListener, addMouseMotionListener, addMouseWheelListener  overridden methods of Canvas3D, which would scale these coordinates before calling user listeners. But maybe, it's more tricky than that, because MouseBehavior class handles mouse events too.

Meanwhile, here's a dirty hack that you can use to convert your coordinates if needed. The following method will return fixed mouse coordinates with Java 3D 1.6.1:

Point getMouseLocation(MouseEvent ev) {
  try {
    Field xscaleField = Canvas3D.class.getDeclaredField("xscale");
    xscaleField.setAccessible(true);
    double xscale = (Double)(xscaleField.get(ev.getSource()));
    Field yscaleField = Canvas3D.class.getDeclaredField("yscale");
    yscaleField.setAccessible(true);
    double yscale = (Double)(yscaleField.get(ev.getSource()));
    return new Point((int)(ev.getX() * xscale), (int)(ev.getY() * yscale));
  } catch (Exception ex) {
    return ev.getPoint();
  }
}