Called when a key is pressed when the canvas has focus.

def onKeyPressInCanvas(self, event):
        '''Called when a key is pressed when the canvas has focus.'''
        char_map = { 'w':'move 1', 'a':'strafe -1', 's':'move -1', 'd':'strafe 1', ' ':'jump 1' }
        keysym_map = { 'continuous': { 'Left':'turn -1', 'Right':'turn 1', 'Up':'pitch -1', 'Down':'pitch 1', 'Shift_L':'crouch 1',
                                       'Shift_R':'crouch 1', 
                                       '1':'hotbar.1 1', '2':'hotbar.2 1', '3':'hotbar.3 1', '4':'hotbar.4 1', '5':'hotbar.5 1',
                                       '6':'hotbar.6 1', '7':'hotbar.7 1', '8':'hotbar.8 1', '9':'hotbar.9 1' },
                       'discrete':   { 'Left':'turn -1', 'Right':'turn 1', 'Up':'move 1', 'Down':'move -1', 
                                       '1':'hotbar.1 1', '2':'hotbar.2 1', '3':'hotbar.3 1', '4':'hotbar.4 1', '5':'hotbar.5 1',
                                       '6':'hotbar.6 1', '7':'hotbar.7 1', '8':'hotbar.8 1', '9':'hotbar.9 1' } }
        if event.char == '/':
            self.command_entry.focus_set() # interlude to allow user to type command
        elif event.char.lower() in char_map:
            self.agent_host.sendCommand( char_map[ event.char.lower() ] )
        elif event.keysym in keysym_map[self.action_space]:
            self.agent_host.sendCommand( keysym_map[self.action_space][ event.keysym ] )