// File: TwoCanvas.java (Module 10)
//
// Author: Rahul Simha
// Created: November 2, 1998
//
// Two canvases.

import java.awt.*;
import java.awt.event.*; // Needed for ActionListener.

class NewFrame extends Frame 
  implements ActionListener, MouseListener {

  // Data.
  Button quitb;               // Quit button.
  Button clearb1, clearb2;    // Two clear buttons.
  Canvas c1, c2;              // Two canvases.
  Panel p1, p2;               // One panel per canvas.
  Panel outerpanel;           // A panel to contain p1, p2.
  int 
    c1_current_x=0,           // Current mouse-click position
    c1_current_y=0,           // for canvas 1.
    c2_current_x=0, 
    c2_current_y=0;           // Same for canvas 2.

  // Constructor.
  public NewFrame (int width, int height)
  {
    // Set the title and other frame parameters.
    this.setTitle ("Two canvas example");
    this.setResizable (true);
    this.setBackground (Color.cyan);
    this.setSize (width, height);
    // this.setLayout (new BorderLayout());

    // Create a quit button for the whole frame.
    quitb = new Button ("Quit");
    quitb.setBackground (Color.red);
    quitb.setFont (new Font ("Serif", Font.PLAIN | Font.BOLD, 15));
    quitb.addActionListener (this);
    this.add (quitb, BorderLayout.SOUTH);

    // Create a Panel for the first canvas
    p1 = new Panel ();
    p1.setLayout (new BorderLayout());

    // Create a white canvas.
    c1 = new Canvas ();
    c1.setBackground (Color.white);
    c1.setForeground (Color.blue);
    c1.addMouseListener (this);

    // Add canvas to frame in the center.
    p1.add (c1, BorderLayout.CENTER);

    // Create a clear button.
    clearb1 = new Button ("Clear");
    clearb1.addActionListener (this);
    clearb1.setBackground (Color.green);
    p1.add (clearb1, BorderLayout.NORTH);

    // Create a Panel for the second canvas.
    p2 = new Panel ();
    p2.setLayout (new BorderLayout());

    // Create a second white canvas.
    c2 = new Canvas ();
    c2.setBackground (Color.white);
    c2.setForeground (Color.blue);
    c2.addMouseListener (this);

    // Add canvas to frame in the center.
    p2.add (c2, BorderLayout.CENTER);

    // Create a second clear button.
    clearb2 = new Button ("Clear");
    clearb2.addActionListener (this);
    clearb2.setBackground (Color.green);
    p2.add (clearb2, BorderLayout.NORTH);

    // A panel to hold the smaller panels.
    outerpanel = new Panel ();
    // Use 1-row, 2-column grid with 5-pixel gaps.
    outerpanel.setLayout (new GridLayout (1,2,5,5));
    outerpanel.add(p1);
    outerpanel.add(p2);

    // Now add the panel to the frame.
    this.add (outerpanel, BorderLayout.CENTER);

    // Show the frame.
    this.setVisible (true);
  }

  // This method is required to implement the 
  // ActionListener interface.
  public void actionPerformed (ActionEvent a)
  {
    // Get the button string.
    String s = a.getActionCommand();
    if (s.equalsIgnoreCase ("Quit"))
      System.exit(0);
    else if (s.equalsIgnoreCase ("Clear")) {
      // Need to find out which canvas:
      if (a.getSource() == clearb1) {
	c1.setBackground (Color.white);
	c1.repaint ();
	c1_current_x = c1_current_y = 0;
      }
      else {
	c2.setBackground (Color.white);
	c2.repaint ();
	c2_current_x = c2_current_y = 0;
      }
    }
  }

  // These methods are required to implement 
  // the MouseListener interface.
  public void mouseClicked (MouseEvent m)
  {
    int x = m.getX();
    int y = m.getY();
    // Need to figure out which canvas:
    if (m.getSource() == c1) {
      Graphics g = c1.getGraphics();
      g.drawLine (c1_current_x, c1_current_y, x, y);
      c1_current_x = x;
      c1_current_y = y;
    }
    else {
      Graphics g = c2.getGraphics();
      g.drawLine (c2_current_x, c2_current_y, x, y);
      c2_current_x = x;
      c2_current_y = y;
    }
  }

  // We need to implement these methods, but
  // don't actually have to do anything inside.
  public void mouseEntered (MouseEvent m) {}
  public void mouseExited (MouseEvent m) {}
  public void mousePressed (MouseEvent m) {}
  public void mouseReleased (MouseEvent m) {}

} // End of class "NewFrame"


public class TwoCanvas {

  public static void main (String[] argv)
  {
    NewFrame nf = new NewFrame (300, 200);
  }

}