#  DrawingDemoGTK.py  (c) Kari Laitinen

#  http://www.naturalprogramming.com

#  2006-08-08  File created.
#  2006-10-02  Last modification.

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

import gtk

class DrawingDemo :

   def __init__( self ) :

      self.application_window = gtk.Window( gtk.WINDOW_TOPLEVEL )
      self.application_window.set_title( "DRAWING OPERATIONS DEMONSTRATED" )
      self.application_window.connect("destroy", lambda w: gtk.main_quit() )

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

      self.application_window.add( self.drawing_area )

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

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

   def drawing_area_exposed( self, area, event ) :

      graphics_context = self.drawing_area.get_style().fg_gc[gtk.STATE_NORMAL]

      this_drawable  =  self.drawing_area.window

      window_width, window_height  =  self.application_window.get_size()

      text_to_show  =  self.drawing_area.create_pango_layout( "" )

      text_to_show.set_text( "Window size is %dx%d "  %  \
                             ( window_width, window_height ) )

      this_drawable.draw_layout( graphics_context, 20, 20, text_to_show )

      this_drawable.draw_line( graphics_context, 0, 100, 500, 100 )
      this_drawable.draw_line( graphics_context, 0, 300, 500, 300 )

      this_drawable.draw_line( graphics_context,
                               window_width / 2, 0,
                               window_width / 2, window_height ) ;

      this_drawable.draw_rectangle( graphics_context, True, 20, 50, 100, 40 )

      this_drawable.draw_rectangle(graphics_context, True,  20, 200, 100,  80 )
      this_drawable.draw_rectangle(graphics_context, False, 10, 190, 120, 100 )

      #  The following statement copies a specified sub-area to another
      #  location on the drawable area.

      this_drawable.draw_drawable( graphics_context, this_drawable,
                                   10, 190, 160, 190, 120, 100 )

      #  Note that angles are expressed in 1/64ths of a degree.
      #  45 degrees is thus represented by value 45*64

      this_drawable.draw_arc( graphics_context, True,
                               20, 350, 100, 80,  45*64, 270*64 )
      this_drawable.draw_arc( graphics_context, True,
                              170, 350, 100, 80, 315*64,  90*64 )


      this_drawable.draw_rectangle( graphics_context, True, 350, 50, 100, 40 )

      #  By setting the drawing color to background color, we'll be able to
      #  clear a part of the just drawn rectangle.

      saved_foreground_color  =  graphics_context.foreground

      background_color  =  \
             self.drawing_area.get_style().bg[ gtk.STATE_NORMAL ] 

      graphics_context.foreground  =  background_color

      this_drawable.draw_rectangle( graphics_context, True, 360, 60,  80, 20 )

      #  The drawing color will be switched back to the original color.

      graphics_context.foreground  =  saved_foreground_color

      polygon_coordinates  =  [ ( 400, 150 ), (450, 180 ), ( 450, 220 ),
                                ( 400, 250 ), (350, 220 ), ( 350, 180 ) ]

      this_drawable.draw_polygon( graphics_context, True, polygon_coordinates )

      this_drawable.draw_arc( graphics_context, False,
                              350, 350, 100, 80, 0, 360*64 )
      this_drawable.draw_rectangle( graphics_context, False,
                              350, 350, 100, 80 )

      text_to_show.set_text( "X" )
      this_drawable.draw_layout( graphics_context, 350, 350, text_to_show )

      return True

   def run( self ) :
      gtk.main()

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


#  NOTES

#  The following statement would set the foreground color to
#  white:

#      graphics_context.foreground  =  \
#                  this_drawable.get_colormap().alloc_color( "white" )