/* 
 *  ===================================================================
 *  PolygonGUI.java : Simple GUI with canvas connected to a mouse listener
 *  and buttons connected to button listeners.
 * 
 *  Written By : Mark Austin                               May 18, 2001
 *  ===================================================================
 */ 

import java.util.*;
import java.io.*;
import java.text.*;
import javax.swing.*;
import javax.swing.event.*;
import java.awt.*;
import java.awt.event.*;

public class PolygonGUI extends JApplet {
    Container container = null;
    DemoGraphicsScreen gs;

    public void init() {

      // 1. Get a handle on the applet's content pane.
   
      container = this.getContentPane();

      // 2. Create a graphics screen and mouse listener,
      //    and add content pane to center of applet.

      DemoGraphicsScreen gs = new DemoGraphicsScreen();
      gs.addMouseListener( new GraphicsListener( gs ));

      // 3. Create buttons and button listeners.

      JButton buttons[] = new JButton [4]; 

      buttons[0] = new JButton ("Clear");
      buttons[0].addActionListener( new ButtonAction( buttons[0], gs ));
      buttons[1] = new JButton ("Load");
      buttons[1].addActionListener( new ButtonAction( buttons[1], gs ));
      buttons[2] = new JButton ("Draw");
      buttons[2].addActionListener( new ButtonAction( buttons[2], gs ));
      buttons[3] = new JButton ("Properties");
      buttons[3].addActionListener( new ButtonAction( buttons[3], gs ));

      // 4. Create panel. Add buttons to panel.

      Panel p1 = new Panel();
      for(int ii = 1; ii <= 4; ii++ )
          p1.add( buttons[ii-1] );

      // 5. Position canvas and panel within the frame.

      container.add("Center", gs );
      container.add( "South", p1 );
   }
}

/*
 *  =================================================================
 *  This class listens for action events associated with the buttons.
 *  =================================================================
 */

class ButtonAction implements ActionListener {
      private JButton b;
      private DemoGraphicsScreen gs;

      public ButtonAction ( JButton b, DemoGraphicsScreen gs ) {
         this.b  = b;
         this.gs = gs;
      }

      public void actionPerformed ( ActionEvent e ) {
         String s = new String( e.getActionCommand() );

         // Clear Screen ....

         if( s.compareTo("Clear") == 0 ) {
             gs.clearScreen();
         }

         // Load polygon from file 

         if( s.compareTo("Load") == 0 ) {
             gs.loadPolygon();
         }

         // Draw polygon on canvas ....

         if( s.compareTo("Draw") == 0 ) {
             gs.drawPolygon();
         }

         // Draw polygon properties on canvas ....

         if( s.compareTo("Properties") == 0 ) {
             gs.drawProperties();
         }
      }
}

/*
 *  ==============================================================
 *  This class listens for mouse events associated with the canvas
 *  ==============================================================
 */

class GraphicsListener implements MouseListener {
      private DemoGraphicsScreen gs;

      public GraphicsListener( DemoGraphicsScreen gs ) {
         this.gs = gs;
      }

      // When the mouse is released, we clear the screen
      // and draw the polygon and its properties ....

      public void mouseReleased ( MouseEvent e ) {
          gs.clearScreen();
          gs.drawPolygon();
          gs.drawProperties();
      }

      public void mouseClicked ( MouseEvent e ) {};
      public void mouseEntered ( MouseEvent e ) {};
      public void mouseExited ( MouseEvent e ) {};
      public void mousePressed ( MouseEvent e ) {};
}

/*
 *  =======================
 *  Create graphics screen.
 *  =======================
 */

class DemoGraphicsScreen extends Canvas {
    int iXcoord, iYcoord;
    float ScaleFactor = 60;
    private Dimension size;
    private Graphics    gs;

    PolygonAnalysis poly = new PolygonAnalysis();

    //  Use the paint() method to display the (x,y) coordinates of the
    //  mouse when it is clicked...

    public void paint(Graphics g) {
       size = getSize();
       clearScreen();
    }

    // Get graphics and fill in background ....

    public void clearScreen () {
        gs = getGraphics();
        Graphics2D g2D = (Graphics2D) gs;

        g2D.setColor( Color.white );
        g2D.fillRect( 0, 0, size.width-1, size.height-1 );
    }

    // Method to load and print polygon .....

    public void loadPolygon () {

        // Load polygon coordinates from input file ....

        try {
            poly.polygonInput();
        }
        catch (FileNotFoundException e){}
        catch (IOException e){}

        // Print polygon coordinates to scieen ...

        poly.polygonPrint();
    }

    // Method to draw polygon .....

    public void drawPolygon () {
       float fX1, fX2, fY1, fY2; 

       gs = getGraphics();
       Graphics2D g2D = (Graphics2D) gs;

       // Translate graphics coordinate system .....

       g2D.translate ( 20, 20 );

       // Draw coordinate axes ....

       g2D.drawLine ( -5,  0, (int) ScaleFactor,  0 );
       g2D.drawLine (  0, -5,  0, (int) ScaleFactor );

       // Draw polygon ....

       for (int i = 0; i <= poly.NoPoints - 2; i = i + 1) { 
            fX1 = poly.getX(i);     fX2 = poly.getX(i+1);
            fY1 = poly.getY(i);     fY2 = poly.getY(i+1);
            g2D.drawLine ( (int) (ScaleFactor*fX1),
                           (int) (ScaleFactor*fY1),
                           (int) (ScaleFactor*fX2),
                           (int) (ScaleFactor*fY2) );
       }
       fX1 = poly.getX( poly.NoPoints - 1); fX2 = poly.getX( 0 ); 
       fY1 = poly.getY( poly.NoPoints - 1); fY2 = poly.getY( 0 );
       g2D.drawLine ( (int) (ScaleFactor*fX1),
                      (int) (ScaleFactor*fY1),
                      (int) (ScaleFactor*fX2),
                      (int) (ScaleFactor*fY2) );
    }

    // Method to compute and print the polygon properties ....

    public void drawProperties () {
       float fPerimeter = poly.polygonPerimeter();
       float fArea      = poly.polygonArea();

       gs = getGraphics();
       Graphics2D g2D = (Graphics2D) gs;
       g2D.translate ( 20, 20 );

       // Let's use a big "black" font ....

       Font f = new Font("Courier", Font.BOLD, 16 );
       g2D.setFont( f );
       g2D.setColor( Color.black );

       // Draw area and perimeter on graphics screen  ....

       g2D.drawString( "Polygon Area      = " + fArea,     
                       ScaleFactor, 350 );
       g2D.drawString( "Polygon Perimeter = " + fPerimeter, 
                       ScaleFactor, 380 );

       // Draw max/min polygon properties ....

          // .... add details for assignment .....

    }

    // Method to draw centroid of polygon .....

    public void drawCentroid () {

          // .... add details for assignment .....

    }
}