import ij.plugin.frame.*;
import ij.*;
import ij.gui.*;

import java.net.*;
import java.awt.*;
import java.awt.event.*;


//This applet is somewhat less clean than it could be for a couple of
//reasons. Note the 3 flags declared below:
//      "rubberbanding" is a flag used to let the paint() function know
//                      when it should be drawing in XOR mode. It's
//                      normally false, gets set to true when a
//                      mouse-down event occurs, and gets reset to
//                      false when a mouse-up event occurs
//      "draw_final"    is a flag used to let the paint method know
//                      when to draw a final rectangle (not in XOR mode).
//                      Unless you're drawing rectangles for the heck of it,
//                      you can probably get rid of this.
//      "refresh"       is a flag used to tell the applet when to redraw
//                      the background image. (Redrawing the background
//                      image while rubberbanding interferes with the
//                      XOR drawing mode). It's initially set to true, gets
//                      set to false in the mouse-drag event (initially, I'd
//                      set it to false in the mouse-down event, but I got
//                      a weird behavior (the image disappeared for the first,
//                      but only the first, rubberbanded rectangle), so I
//                      moved it to the mouse-drag event. Finally, when
//                      a mouse-up event occurs, it's set to true again.

public class Rubberband extends PlugInFrame implements MouseListener, MouseMotionListener{
        Image i = null;

        int start_x, start_y, curr_x, curr_y, xor_x, xor_y;

        boolean rubberbanding = false;
        boolean draw_final = false;
        boolean refresh = true;
        Graphics g;


    public Rubberband() {
        super("Rubberband");
        WindowManager.addWindow(this);
        setSize(320, 200);
        GUI.center(this);
        setVisible(true);
        init();
    }

    public void init() {
        String name = "http://rsb.info.nih.gov/ij/images/clown.jpg";
        URL url = null;
        try {
             url = new URL(name);
        } catch (Exception e) {}
             IJ.log(""+url);
        i = Toolkit.getDefaultToolkit().getImage(url);
        addMouseListener(this);
        addMouseMotionListener(this);
        start_x = start_y = curr_x = curr_y = 0;
        g = getGraphics();
    }

    public void paint(Graphics g) {
        if (refresh) {
            g.drawImage(i, 0, 0, this);
            //IJ.log("drawImage");
        }

        if (rubberbanding) {
            g.setXORMode(Color.green);
            // g.drawRect(start_x, start_y, xor_x - start_x, xor_y - start_y);
            g.drawLine(start_x, start_y, xor_x, xor_y);
            xor_x = curr_x;
            xor_y = curr_y;
            // g.drawRect(start_x, start_y, xor_x - start_x, xor_y - start_y);
             g.drawLine(start_x, start_y, xor_x, xor_y);
        }  else if (draw_final) {
            draw_final = false;
            // g.drawRect(start_x, start_y, curr_x - start_x, curr_y - start_y);
            g.setColor(Color.yellow);
            g.drawLine(start_x, start_y, curr_x, curr_y);
        }

    }

    public void update (Graphics g) {
        paint(g);
    }

    public void mousePressed(MouseEvent e) {
        rubberbanding = true;
        start_x = curr_x = xor_x = e.getX();
        start_y = curr_y = xor_y = e.getY();
    }

    public void mouseReleased(MouseEvent e) {
        rubberbanding = false;
        draw_final = true;
        refresh = true;
        repaint();
    }
	
    public void mouseDragged(MouseEvent e) {
        refresh = false;
        curr_x = e.getX();
        curr_y = e.getY();
        //repaint();
        paint(g);
    }

    public void mouseExited(MouseEvent e) {}
    public void mouseClicked(MouseEvent e) {}	
    public void mouseEntered(MouseEvent e) {}
    public void mouseMoved(MouseEvent e) {}
}