#  SinglePictureGTK.java  (c) Kari Laitinen

#  http://www.naturalprogramming.com/

#  2006-11-17  File created.
#  2006-11-23  Last modification.

#  This program demonstrates how a Python/GTK program can show pictures.
#  The picture file must be in the same folder where this program is located.
#  In this program, a picture is handled as a Pixbuf object. Class Pixbuf
#  provides a nice set of methods for manipulating pixel information.

#  More notes at the end of this file.

import gtk

class SinglePictureDemo :

   def __init__( self ) :

      self.application_window = gtk.Window( gtk.WINDOW_TOPLEVEL )
      self.application_window.set_title( "SINGLE PICTURE IN SEVERAL SIZES" )
      self.application_window.connect("destroy", lambda w: gtk.main_quit() )
      self.application_window.set_size_request( 800, 480 )

      self.drawing_area = gtk.DrawingArea()
      self.application_window.add( self.drawing_area )
      self.drawing_area.connect( "expose-event", self.drawing_area_exposed )

      self.picture_as_pixel_buffer  =  gtk.gdk.pixbuf_new_from_file(
                                          "governor_arnold_schwarzenegger.jpg")

      self.application_window.show_all()

   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()

      picture_width   =  self.picture_as_pixel_buffer.get_width()
      picture_height  =  self.picture_as_pixel_buffer.get_height()

      picture_position_x  =  15
      picture_position_y  =  15

      this_drawable.draw_pixbuf( graphics_context,
                                 self.picture_as_pixel_buffer,
                                 0, 0,
                                 picture_position_x, picture_position_y )

      picture_position_x  =  picture_position_x  +  picture_width + 10

      #  Next we'll show a smaller version of the picture.

      small_picture_version  =  \
         self.picture_as_pixel_buffer.scale_simple( picture_width / 2,
                                                    picture_height / 2,
                                                    gtk.gdk.INTERP_BILINEAR )

      this_drawable.draw_pixbuf( graphics_context,
                                 small_picture_version,
                                 0, 0,
                                 picture_position_x, picture_position_y )

      picture_position_x  =  picture_position_x  +  picture_width / 2  +  10

      #  Finally, we'll show the picture so that its width is enlarged.

      widened_picture_version  =  \
         self.picture_as_pixel_buffer.scale_simple( int( picture_width * 1.5 ),
                                                    picture_height,
                                                    gtk.gdk.INTERP_BILINEAR )

      this_drawable.draw_pixbuf( graphics_context,
                                 widened_picture_version,
                                 0, 0,
                                 picture_position_x, picture_position_y )
   def run( self ) :

      gtk.main()

if __name__ == "__main__":

   this_application = SinglePictureDemo()
   this_application.run()


#  NOTES:

#  -  Pictures can also be handled as Image objects.
#     If you want to show a single picture in its natural size,
#     you can do it with the following statements in an __init__()
#     method.

#      self.picture_to_show = gtk.Image()
#      self.picture_to_show.set_from_file( "governor_arnold_schwarzenegger.jpg")
#      self.application_window.add( self.picture_to_show )
#      self.application_window.show_all()

#  -  An Image object can be put inside an EventBox object if it is
#     necessary to do something when the image is clicked with the
#     mouse.