[pygsear] config canvas dimensions

[reavey]

Hi,
I'd like to use a full screen canvas. I can find the dimensions using 
the forward command in the python2.2 module turtle.py. The process is:
invoke python interpreter
$ python
>>>from turtle import *
>>>reset()
#######at this point you'll see a canvas open,
use your expand button on the canvas###########

>>>reset()
############you will now have a full screen canvas with the pen 
centered. From here you can issue forward commands to the edges of the 
canvas to find it's full screen dimensions#############

if my canvas dimension is (1200,800), how can I inform the penguin.py?
TIA
re-v