import java.awt.*;
import java.awt.event.*;
import javax.swing.*;

/**
 * Title:        Bresenham's line algorithm
 * Description:
 * Copyright:    Copyright (c) 2000
 * Company:
 * @author Glenn Rowe
 * @version 1.0
 */

public class MainFrame extends JFrame
{
  JPanel contentPane;
  JPanel linePanel = new JPanel();
  LineCanvas lineCanvas = new LineCanvas();
  JLabel instructionLabel = new JLabel();
  BorderLayout borderLayout1 = new BorderLayout();

  /**
   * Construct the frame
   */
  public MainFrame()
  {

    // Allows main frame to respond to window closing
    // and resizing events
    enableEvents(AWTEvent.WINDOW_EVENT_MASK |
      AWTEvent.COMPONENT_EVENT_MASK);
    try {
      jbInit();
    }
    catch(Exception e) {
      e.printStackTrace();
    }
  }

  /**
   * Component initialization
   */
  private void jbInit() throws Exception
  {
    contentPane = (JPanel) this.getContentPane();
    this.getContentPane().setBackground(new Color(255, 200, 122));
    this.setFont(new java.awt.Font("SansSerif", 1, 12));
    this.setSize(new Dimension(600, 400));
    this.setTitle("Bresenham's line algorithm");
    contentPane.setLayout(borderLayout1);
    linePanel.setBackground(Color.yellow);
    instructionLabel.setFont(new java.awt.Font("SansSerif", 1, 12));
    instructionLabel.setForeground(Color.blue);
    instructionLabel.setHorizontalAlignment(SwingConstants.CENTER);
    instructionLabel.setHorizontalTextPosition(SwingConstants.CENTER);
    instructionLabel.
      setText("Click and drag the mouse to draw a line using Bresenham\'s algorithm");
    instructionLabel.setVerticalAlignment(SwingConstants.TOP);
    contentPane.setBackground(Color.yellow);

    // The LineCanvas class handles the drawing of the line
    linePanel.add(lineCanvas);
    contentPane.add(instructionLabel, BorderLayout.SOUTH);
    lineCanvas.addMouseListener(new java.awt.event.MouseAdapter() {
      public void mouseReleased(MouseEvent e) {
        lineCanvas_mouseReleased(e);
      }
      public void mousePressed(MouseEvent e) {
        lineCanvas_mousePressed(e);
      }
    });
    lineCanvas.addMouseMotionListener(new java.awt.event.MouseMotionAdapter() {
      public void mouseDragged(MouseEvent e) {
        lineCanvas_mouseDragged(e);
      }
    });
    contentPane.add(linePanel, BorderLayout.NORTH);
  }

  /**
   * Overridden so we can exit when window is closed
   */
  protected void processWindowEvent(WindowEvent e)
  {
    super.processWindowEvent(e);
    if (e.getID() == WindowEvent.WINDOW_CLOSING) {
      System.exit(0);
    }
  }

  /**
   * Resizes the panel and lineCanvas to fit a resized frame
   */
  protected void processComponentEvent(ComponentEvent e)
  {
    super.processComponentEvent(e);
    if (e.getID() == ComponentEvent.COMPONENT_RESIZED ||
      e.getID() == ComponentEvent.COMPONENT_SHOWN) {
      linePanel.setBounds(0, 0, getContentPane().getWidth(),
        getContentPane().getHeight() - instructionLabel.getHeight());
      lineCanvas.setBounds(0, 0, getContentPane().getWidth(),
        getContentPane().getHeight() - instructionLabel.getHeight());
    }
  }

  /**
   * The mouse event handlers call LineCanvas methods to
   * draw the line using Bresenham's algorithm
   */
  void lineCanvas_mouseReleased(MouseEvent event)
  {
      lineCanvas.setPoint(LineCanvas.END_POINT, event.getPoint());
      lineCanvas.repaint();
  }

  void lineCanvas_mousePressed(MouseEvent event)
  {
    lineCanvas.setPoint(LineCanvas.START_POINT, event.getPoint());
  }

  void lineCanvas_mouseDragged(MouseEvent event)
  {
    lineCanvas.rubberBand(event.getPoint());
  }
}