[racket] display problem

Op 5-4-2012 19:28, Danny Yoo schreef:
>>> http://www.ccs.neu.edu/home/matthias/HtDP2e/htdp2e-part1.html#(part._edit1)
>>>
>>> We need more context because there's not enough information in the
>>> question to tell what you're trying to do yet.
>>>
>>>
>>> Good luck!
>> Yes, I mean that exercise.
> Ah.  Ok.  Can you get the position where the cursor should start by
> taking the image for the left side text, and take its width?
>

Yes, I could.

Where I see a problem is here :

I start with this :

aaaaa|

now someone press 3 times the left key.
So I have  aa/aaa
How can I know where the cursor is now.
Or can I do  width - 3 times 11 ?

Roelof