//  MovingBallAWTApplet.java  (c) Kari Laitinen

//  http://www.naturalprogramming.com

//  2001-03-31  File created.
//  2009-11-05  Latest modification.

//  This program is a traditional Java applet that draws a ball
//  onto the screen. There is also a "control panel" which provides
//  buttons to move the ball and a possibility to change the
//  color of the ball.

/*  Other versions of this program are 'swing' programs which means
    that swing classes like JPanel, JButton, JComboBox, etc. are
    in use. Swing classes represent newer Java technology and thus
    they should be favored in Java programming. When swing classes are
    in use, Java programs should always provide the same Graphical User
    Interface (GUI) regardless of the environment (Windows, UNIX, Linux,
    Macintosh, etc.) in which the programs are executed.
*/

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

public class MovingBallAWTApplet extends    java.applet.Applet
                                 implements ActionListener,
                                            ItemListener
{
   Button  left_button, up_button, down_button, right_button ;

   int  applet_width, applet_height ;

   int  ball_center_point_x, ball_center_point_y ;

   Color  current_ball_color   =  Color.red ;

   public void init()
   {
      setLayout( new BorderLayout() ) ;

      Panel operations_panel  =  new  Panel() ;

      left_button     =  new Button( " < " ) ;
      up_button       =  new Button( " Up " ) ;
      down_button     =  new Button( " Down " ) ;
      right_button    =  new Button( " > " ) ;

      left_button.addActionListener( this ) ;
      up_button.addActionListener( this ) ;
      down_button.addActionListener( this ) ;
      right_button.addActionListener( this ) ;

      operations_panel.add( left_button ) ;
      operations_panel.add( up_button ) ;
      operations_panel.add( down_button ) ;
      operations_panel.add( right_button ) ;

      Choice  color_selection_menu  =  new Choice() ;

      color_selection_menu.addItem( "red" ) ;
      color_selection_menu.addItem( "orange" ) ;
      color_selection_menu.addItem( "yellow" ) ;
      color_selection_menu.addItem( "green" ) ;
      color_selection_menu.addItem( "blue" ) ;
      color_selection_menu.addItem( "magenta" ) ;
      color_selection_menu.addItem( "cyan" ) ;
      color_selection_menu.addItem( "pink" ) ;
      color_selection_menu.addItem( "lightGray" ) ;

      color_selection_menu.addItemListener( this ) ;

      operations_panel.add( color_selection_menu ) ;

      add( "South", operations_panel ) ;


      //  Let's get the size of the applet (defined in .html file)

      applet_width   =  getSize().width ;
      applet_height  =  getSize().height ;

      ball_center_point_x  =  applet_width / 2 ;
      ball_center_point_y  =  applet_height / 2 ;

   }

   public void actionPerformed( ActionEvent event )
   {
      if ( event.getSource() instanceof Button )
      {
         if ( event.getSource()  ==  left_button )
         {
            ball_center_point_x  -=  3 ;
         }
         else if ( event.getSource()  ==  up_button )
         {
            ball_center_point_y  -=  3 ;
         }
         else if ( event.getSource()  ==  down_button )
         {
            ball_center_point_y  +=  3 ;
         }
         else if ( event.getSource()  ==  right_button )
         {
            ball_center_point_x  +=  3 ;
         }

         repaint() ;
      }
   }

   public void itemStateChanged( ItemEvent menu_selection )
   {
      String selected_color  =  (String) menu_selection.getItem() ;

      if ( selected_color.equals( "red" ) )
      {
         current_ball_color  =  Color.red ;
      }
      else if ( selected_color.equals( "orange" ) )
      {
         current_ball_color  =  Color.orange ;
      }
      else if ( selected_color.equals( "yellow" ) )
      {
         current_ball_color  =  Color.yellow ;
      }
      else if ( selected_color.equals( "green" ) )
      {
         current_ball_color  =  Color.green ;
      }
      else if ( selected_color.equals( "blue" ) )
      {
         current_ball_color  =  Color.blue ;
      }
      else if ( selected_color.equals( "magenta" ) )
      {
         current_ball_color  =  Color.magenta ;
      }
      else if ( selected_color.equals( "cyan" ) )
      {
         current_ball_color  =  Color.cyan ;
      }
      else if ( selected_color.equals( "pink" ) )
      {
         current_ball_color  =  Color.pink ;
      }
      else if ( selected_color.equals( "lightGray" ) )
      {
         current_ball_color  =  Color.lightGray ;
      }

      repaint() ;
   }

   public void paint( Graphics graphics )
   {
      graphics.setColor( current_ball_color ) ;

      graphics.fillOval( ball_center_point_x - 50, ball_center_point_y - 50,
                         100, 100 ) ;

      graphics.setColor( Color.black ) ;

      graphics.drawString( "("   +  ball_center_point_x  +
                           ", "  +  ball_center_point_y  +
                           ")",  20, 20 ) ;

      graphics.drawOval( ball_center_point_x - 50, ball_center_point_y - 50,
                         100, 100 ) ;
   }
}