_imageDisplay = new ImageDisplay("pan window");
_imageDisplay.setPrescaled(true);
_imageDisplay.addImageGraphicsHandler(this);
ImageProcessor ip = _imageDisplay.getImageProcessor();
ip.removeChangeListener((ChangeListener) _imageDisplay); // not needed here
ip.setName("Panner ip"); // for debugging
JComponent c = (JComponent) _imageDisplay;
_panWidth = width;
_panHeight = height;