Re: clipping

[mj@cs.brown.edu (Mark Johnson)]

> I can't get clipping regions to work.
> For instance, if I do the following...

> (let ((bob (make-instance 'window)))
>       (frame-rect bob 20 20 50 50)
 ...
> ...I would expect both the line and the string to get clipped, but
> they don't.

(Ignoring the fact that bob is unbound in the second let defn...)
The problem is that the MCL Quickdraw.lisp fn defs all include
with-focused-view, which sets the clipregion.  If you want to 
manipulate the clipregion yourself (either for clipping a display,
or else for saving a PICTure larger than the current view), you
have to call the Quickdraw traps directly, rather than use the
MCL Quickdraw interface.  This also means that you can't rely on
MCL's "view" mechanism.

This "feature" came into MCL at around version 1.3, I think.
It singlehandedly broke quite a bit of my code.

Mark


Mark Johnson
Cognitive Science, Box 1978
Brown University