#  MovingBallWithMouseGTK.py  Copyright (c) 2006 Kari Laitinen

#  http://www.naturalprogramming.com

#  2006-09-25  File created.
#  2009-02-11  Last modification.

#  This program draws three Ball objects onto the screen.
#  It is possible to move these balls by dragging them with
#  the mouse. The Ball class provides a method with which it is
#  possible to find out whether a clicked point is inside the
#  ball. In addition the Ball class provides methods for moving
#  the ball.

#  During compilation the file BallGTK.py must be in the same
#  folder (directory) with this file.

#  The development of this program has been sponsored by Nokia Multimedia.


import gtk

from BallGTK import Ball

class MovingBallWithMouseApplication :

   def __init__( self ) :

      self.application_window = gtk.Window( gtk.WINDOW_TOPLEVEL )
      self.application_window.set_title( "DRAG A BALL WITH THE MOUSE" )
      self.application_window.connect("destroy", lambda w: gtk.main_quit() )

      self.application_window.set_size_request( 600, 500 )
      self.drawing_area = gtk.DrawingArea()
      self.drawing_area.set_size_request( 600, 450 )

      self.drawing_area.connect( "expose-event", self.drawing_area_exposed )

      self.drawing_area.connect( "button_press_event",
                                 self.mouse_button_pressed )

      self.drawing_area.connect( "motion_notify_event",
                                 self.mouse_motion_notified )

      self.drawing_area.connect( "button_release_event",
                                 self.mouse_button_released )

      self.drawing_area.set_events(gtk.gdk.EXPOSURE_MASK
                                 | gtk.gdk.BUTTON_PRESS_MASK
                                 | gtk.gdk.POINTER_MOTION_MASK
                                 | gtk.gdk.POINTER_MOTION_HINT_MASK
                                 | gtk.gdk.BUTTON_RELEASE_MASK )

      self.application_window.add( self.drawing_area )

      window_width, window_height  =  self.application_window.get_size()

      self.first_ball   =  Ball( window_width / 2  -  160,
                                 window_height / 2  -  40,  "red" )

      self.second_ball  =  Ball( window_width / 2  -  40,
                                 window_height / 2  -  40,  "green" )

      self.third_ball   =  Ball( window_width / 2  + 80,
                                 window_height / 2  -  40,  "blue" )

      self.ball_being_moved  =  None

      self.previous_mouse_position_x  =  0 
      self.previous_mouse_position_y  =  0

      self.drawing_area.show()
      self.application_window.show()

   def mouse_button_pressed( self, widget, event ) :

      mouse_position_x  =  int( event.x )
      mouse_position_y  =  int( event.y )

      if  self.first_ball.contains_point( mouse_position_x,
                                          mouse_position_y ) :

         self.ball_being_moved  =  self.first_ball
         self.ball_being_moved.activate_ball()

      elif  self.second_ball.contains_point( mouse_position_x,
                                             mouse_position_y ) :

         self.ball_being_moved  =  self.second_ball
         self.ball_being_moved.activate_ball()

      elif  self.third_ball.contains_point( mouse_position_x,
                                            mouse_position_y ) :

         self.ball_being_moved  =  self.third_ball
         self.ball_being_moved.activate_ball()


      self.previous_mouse_position_x  =  mouse_position_x
      self.previous_mouse_position_y  =  mouse_position_y

      self.drawing_area.queue_draw()


   def mouse_motion_notified( self, widget, event ) :

      if  self.ball_being_moved  !=  None :

         if event.is_hint :

            new_mouse_position_x, new_mouse_position_y, state  =  \
                                            event.window.get_pointer()

         else :

            #  It seems that this else block is never entered.

            print "A non-hint motion event"

            new_mouse_position_x = event.x
            new_mouse_position_y = event.y
            state = event.state
    
         mouse_movement_x  =  int( new_mouse_position_x )  \
                                   -  self.previous_mouse_position_x
         mouse_movement_y  =  int( new_mouse_position_y )  \
                                   -  self.previous_mouse_position_y

         self.previous_mouse_position_x  =  int( new_mouse_position_x )
         self.previous_mouse_position_y  =  int( new_mouse_position_y )

         self.ball_being_moved.move_this_ball( mouse_movement_x,
                                               mouse_movement_y )
         self.drawing_area.queue_draw()

      return True


   def mouse_button_released( self, widget, event ) :

      if  self.ball_being_moved  !=  None :

         self.ball_being_moved.deactivate_ball()
         self.ball_being_moved  =  None
         self.drawing_area.queue_draw()

      return True


   def drawing_area_exposed( self, area, event ) :

      self.first_ball.draw( self.drawing_area )
      self.second_ball.draw( self.drawing_area )
      self.third_ball.draw( self.drawing_area )

      return True

   def run( self ) :
      gtk.main()

if __name__ == "__main__":
   this_application  =  MovingBallWithMouseApplication()
   this_application.run()