DragUsingObjectDrawModel

import acm.program.*;
import acm.graphics.*;
import java.awt.*;
 
public class DragUsingObjectDrawModel extends GraphicsProgram {
 
	public void init() {
		GRect rect = new GRect(100, 100, 150, 100);
		rect.setFilled(true);
		rect.setColor(Color.RED);
		add(rect);
 
		GOval oval = new GOval(300, 115, 100, 70);
		oval.setFilled(true);
		oval.setColor(Color.GREEN);
		add(oval);
	}
 
	public void mousePressed(GPoint pt) {
		last = pt;
		gobj = getElementAt(last);
	}
 
	public void mouseDragged(GPoint pt) {
		if (gobj != null) {
			gobj.move(pt.getX() - last.getX(), pt.getY() - last.getY());
			last = pt;
		}
	}
 
	public void mouseClicked(GPoint pt) {
		if (gobj != null) gobj.sendToFront();
	}
 
	/* Private instance variables */
	private GObject gobj;	/* The object being dragged */
	private GPoint last;	/* The last mouse position  */
 
	private static final long serialVersionUID = 1;
}