//  DrawingGraphicalObjectsApplet.java  (c) Kari Laitinen

//  http://www.naturalprogramming.com/

//  2007-01-21  File created.
//  2008-02-29  Name changed GraphicalObject -> DrawableObject
//  2008-02-29  Last modification.

/*  This program is a simple drawing tool with which you can draw
    graphical objects onto the screen. There is a menu which allows
    you to choose the type of the graphical object.

    This program demonstrates the following things:
      -  the use of a class hierarchy that represents graphical objects
         such as curvy lines and circles
      -  the use of the GeneralPath class to record mouse movements
      -  the use of menus in a window whose drawings are painted onto a panel
         (This is a JPanel-based applet athough the word 'Panel' is not
         present in the file name.)

*/

import java.awt.* ;
import java.awt.event.* ;
import java.awt.geom.* ; //  Classes GeneralPath etc.
import javax.swing.* ;
import java.util.ArrayList ;

class DrawableObject
{
   int             line_thickness  =  10 ;
   Color           object_color    =  Color.black ;
   GeneralPath     drawing_path    =  null ;
   Point2D.Double  starting_point  =  null ;
   boolean         object_is_completed  =  false ;

   public void mouse_pressed( Point mouse_position )
   {
      drawing_path    =  new  GeneralPath() ;
      starting_point  =  new  Point2D.Double( mouse_position.x,
                                              mouse_position.y ) ;
      drawing_path.moveTo( mouse_position.x, mouse_position.y ) ;
   }

   public void mouse_dragged( Point mouse_position )
   {
      if ( drawing_path  !=  null )
      {
         drawing_path.lineTo( mouse_position.x, mouse_position.y ) ;
      }
   }

   public void mouse_released( Point mouse_position )
   {
      if ( drawing_path  !=  null )
      {
         object_is_completed  =  true ;
      }
   }

   //  The following draw() method should be called at the beginning
   //  of each subclass' redefined draw() method.

   public void draw( Graphics2D graphics2D )
   {
      if ( object_is_completed  ==  true )
      {
         graphics2D.setPaint( object_color ) ;
      }
      else
      {
         graphics2D.setPaint( Color.red ) ;
      }

      graphics2D.setStroke( new BasicStroke( line_thickness,
                                             BasicStroke.CAP_ROUND,
                                             BasicStroke.JOIN_ROUND ) ) ; 
   }
}


class CurvyLine extends DrawableObject
{
   public CurvyLine( int given_line_thickness )
   {
      line_thickness  =  given_line_thickness ;
   }

   public void draw( Graphics2D graphics2D )
   {
      super.draw( graphics2D ) ;

      graphics2D.draw( drawing_path ) ;
   }
}

class Circle extends DrawableObject
{
   public Circle( int given_line_thickness )
   {
      line_thickness  =  given_line_thickness ;
   }

   public void draw( Graphics2D graphics2D )
   {
      super.draw( graphics2D ) ;

      Point2D last_mouse_position  =  drawing_path.getCurrentPoint() ;

      int circle_radius  =
               (int) starting_point.distance( last_mouse_position ) / 2 ;

      int circle_center_point_x =  (int) ( ( starting_point.x  +
                                             last_mouse_position.getX() ) / 2 );

      int circle_center_point_y =  (int) ( ( starting_point.y  +
                                             last_mouse_position.getY() ) / 2 );

      graphics2D.drawOval( circle_center_point_x - circle_radius,
                           circle_center_point_y - circle_radius,
                           2 * circle_radius, 2 * circle_radius ) ;
   }
}

class GraphicalObjectsPanel extends JPanel
                            implements MouseListener,
                                       MouseMotionListener
{
   String  selected_object_type     =  "Circle" ;
   int     selected_line_thickness  =  10 ;
   Color   selected_drawing_color   =  Color.black ;

   DrawableObject object_being_drawn = null ;

   ArrayList<DrawableObject> objects_on_screen  =
                                    new ArrayList<DrawableObject>() ;

   public GraphicalObjectsPanel()
   {
      //  Event listeners must be registered.
      addMouseListener(this);
      addMouseMotionListener(this);
   }

   public void set_object_type( String given_object_type )
   {
      selected_object_type  =  given_object_type ;
   }

   public void set_line_thickness( int given_line_thickness )
   {
      selected_line_thickness  =  given_line_thickness ;
   }

   public void set_drawing_color( Color given_drawing_color )
   {
      selected_drawing_color   =  given_drawing_color ;
   }

   //  The following dummy methods are needed
   //  to fully implement the listener interfaces.
   public void mouseMoved( MouseEvent event ) {}
   public void mouseClicked( MouseEvent event ) {}
   public void mouseEntered( MouseEvent event ) {}
   public void mouseExited( MouseEvent event ) {}

   public void mousePressed( MouseEvent event )
   {
      if ( selected_object_type.equals( "CurvyLine" ) )
      {
         object_being_drawn  =  new CurvyLine( selected_line_thickness ) ;
      }
      else if ( selected_object_type.equals( "Circle" ) )
      {
         object_being_drawn  =  new  Circle( selected_line_thickness ) ;
      }

      if ( object_being_drawn  !=  null )
      {
         object_being_drawn.mouse_pressed( event.getPoint() ) ;
      }
   }

   public void mouseDragged( MouseEvent event )
   {
      if ( object_being_drawn  !=  null )
      {
         object_being_drawn.mouse_dragged( event.getPoint() ) ;
         repaint();
      }
   }

   public void mouseReleased( MouseEvent event )
   {
      if ( object_being_drawn  !=  null )
      {
         object_being_drawn.mouse_released( event.getPoint() ) ;
   
         objects_on_screen.add( object_being_drawn ) ;
   
         object_being_drawn  =  null ;
   
         repaint() ;
      }
   }

   //  The painting method always draws all lines that have been printed.
   //  The line that is not yet complete is drawn if object_being_drawn
   //  points to a non-null object.

   public void paintComponent( Graphics graphics )
   {
      super.paintComponent( graphics ) ;

      Graphics2D  graphics2D  =  (Graphics2D) graphics ;

      for ( DrawableObject object_in_array : objects_on_screen )
      {
         object_in_array.draw( graphics2D ) ;
      }

      if ( object_being_drawn  !=  null )
      {
         object_being_drawn.draw( graphics2D ) ;
      }
   }
}


public class DrawingGraphicalObjectsApplet extends JApplet
                                           implements ActionListener
{
   JRadioButtonMenuItem  draw_curvy_line_menu_item  =
                                   new JRadioButtonMenuItem( "Curvy line" ) ;
   JRadioButtonMenuItem  draw_circle_menu_item  =
                                   new JRadioButtonMenuItem( "Circle" ) ;

   JRadioButtonMenuItem  thin_line_menu_item  =
                                   new JRadioButtonMenuItem( "Thin" ) ;
   JRadioButtonMenuItem  thick_line_menu_item  =
                                   new JRadioButtonMenuItem( "Thick" ) ;

   GraphicalObjectsPanel  graphical_objects_panel  =
                                            new GraphicalObjectsPanel() ;

   public void init()
   {
      //  First we'll build a subnenu named "Select graphical object" 

      draw_curvy_line_menu_item.addActionListener( this ) ;
      draw_circle_menu_item.addActionListener( this ) ;

      draw_circle_menu_item.setSelected( true ) ;

      ButtonGroup  graphical_object_button_group  =  new  ButtonGroup() ;

      graphical_object_button_group.add( draw_curvy_line_menu_item ) ;
      graphical_object_button_group.add( draw_circle_menu_item ) ;

      JMenu  graphical_object_menu  =  new  JMenu( "Select graphical object" ) ;
      
      graphical_object_menu.add( draw_curvy_line_menu_item ) ;
      graphical_object_menu.add( draw_circle_menu_item ) ;

      //  Next we'll build a submenu named  "Select line thickness"

      thin_line_menu_item.addActionListener( this ) ;
      thick_line_menu_item.addActionListener( this ) ;

      thick_line_menu_item.setSelected( true ) ;

      ButtonGroup  line_thickness_button_group  =  new  ButtonGroup() ;

      line_thickness_button_group.add( thin_line_menu_item ) ;
      line_thickness_button_group.add( thick_line_menu_item ) ;

      JMenu  thickness_selection_menu  =  new  JMenu( "Select line thickness" ) ;
      
      thickness_selection_menu.add( thin_line_menu_item ) ;
      thickness_selection_menu.add( thick_line_menu_item ) ;

      //  Next we'll attach the submenus to the Settings menu.

      JMenu  settings_menu  =  new  JMenu( "Settings" ) ;

      settings_menu.add( graphical_object_menu ) ;
      settings_menu.add( thickness_selection_menu ) ;

      JMenuBar menubar_of_this_window  =  new JMenuBar() ;

      menubar_of_this_window.add( settings_menu ) ;

      setJMenuBar( menubar_of_this_window ) ;

      //  The following line adds the JPanel-based object to this applet.

      getContentPane().add( graphical_objects_panel ) ; 
   }

   public void actionPerformed( ActionEvent event )
   {
      if ( event.getSource() instanceof JMenuItem )
      {
         JMenuItem selected_menu_item  = (JMenuItem) event.getSource() ;

         if ( selected_menu_item  ==  draw_curvy_line_menu_item )
         {
            graphical_objects_panel.set_object_type( "CurvyLine" ) ;
         }
         else if ( selected_menu_item  ==  draw_circle_menu_item )
         {
            graphical_objects_panel.set_object_type( "Circle" ) ;
         }
         else if ( selected_menu_item  ==  thin_line_menu_item )
         {
            graphical_objects_panel.set_line_thickness( 2 ) ;
         }
         else if ( selected_menu_item  ==  thick_line_menu_item )
         {
            graphical_objects_panel.set_line_thickness( 10 ) ;
         }
      }
   }
}