#  KeyboardInputDemoQt.py  (c) Kari Laitinen

#  http://www.naturalprogramming.com

#  2009-12-02  File created.
#  2009-12-09  Last modification.

#  This program shows how to react to key pressings
#  in a Qt program.

#  http://www.riverbankcomputing.co.uk/static/Docs/PyQt4/html/qkeyevent.html

import sys

from PyQt4.QtCore import *
from PyQt4.QtGui import *
 
class KeyboardInputDemoWindow( QWidget ) :

   def __init__( self, parent = None ) :

      QWidget.__init__( self, parent )

      self.setGeometry( 100, 200, 800, 400 )

      self.setWindowTitle( "PRESS THE KEYS OF YOUR KEYBOARD" )

      self.code_of_last_pressed_key  =  63  #  The question mark ?

      self.large_font  = QFont( "SansSerif", 20, QFont.Bold )

      # The following statement may help to get keyboard input
      # to this window.

      self.setFocusPolicy( Qt.StrongFocus )


   #  The following methods will be called by the program
   #  execution system whenever keys of the keyboard are pressed.
   #  They receive a QKeyEvent object as a parameter.


   def keyPressEvent( self, event ) :

      self.code_of_last_pressed_key = event.key()

      self.update()

   def keyReleaseEvent( self, event ) :

      pass
      #print  "key release event"   #  This is Python 2.x statement.
      #print( "key release event" )  #  Python 3.x statement.


   def paintEvent( self, event ) :

      painter = QPainter()

      painter.begin( self )

      painter.setFont( self.large_font )

      #  The format specifier %c treats an integer value as a character,
      #  but the integer value must be less than 256.
      #  %s converts an object to a string.
      #  %X shows an integer in hexadecimal form.

      if  self.code_of_last_pressed_key  <  256  :

         text_to_show_as_string  =  "Last pressed key: %c %X %d"  %  \
                                    ( self.code_of_last_pressed_key,
                                      self.code_of_last_pressed_key,
                                      self.code_of_last_pressed_key )
      else :

         text_to_show_as_string  =  "Last pressed key: %s %X %d"  %  \
                                    ( self.code_of_last_pressed_key,
                                      self.code_of_last_pressed_key,
                                      self.code_of_last_pressed_key )
                                            
      painter.drawText( 100, 200, text_to_show_as_string )


      if  self.code_of_last_pressed_key  ==  Qt.Key_F1  :

         painter.drawText( 100, 250, "You pressed the F1 key" )

      elif  self.code_of_last_pressed_key  ==  Qt.Key_Up  :

         painter.drawText( 100, 250, "You pressed the Arrow Up key" )

      elif  self.code_of_last_pressed_key  ==  Qt.Key_Down  :

         painter.drawText( 100, 250, "You pressed the Arrow Down key" )

      painter.end()


#  The main program begins.

this_application = QApplication( sys.argv )

application_window = KeyboardInputDemoWindow()

application_window.show()

this_application.exec_()