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- To: email@example.com
- Subject: help
- From: firstname.lastname@example.org
- Date: Thu, 14 May 1992 12:18:52 -0600
I'm building a region from a user's click-and-drag and associating it with
a target which will then be selected.
I have something like this:
(defmethod view-click-event-handler ((view zoomer) where)
(let ((rgn (build-region view where))
(target (funcall (target-selector view) view))))
(add-subviews (make-instance 'hot-spot :region rgn :target target))))
Now, it's entirely possible that after making the hot-spot, the user will
not like any of his/her choices or will realize that the region made is
Ideally, then target-selector will have a cancel option.
How do I catch whether or not the target was cancelled?
[I need to dispose the rgn, if so.]
I'm not quite sure how to use unwind-protect and/or catch-cancel in this
I *don't* want the behavior I've indicated changed:
1. User clicks on zoomer and drags to build region.
2. User is presented with a selection of targets to associate with rgn.
User *may* press cancel to forget the whole thing.
3. Call #_DisposeRgn *ONLY* if the user canceled in step 2.
I'm probably just being stupid, but I can't get my brain to figure out how
to set this up.
"TANSTAAFL" Rich email@example.com
- Re: help
- From: firstname.lastname@example.org