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- To: firstname.lastname@example.org
- Subject: Two questions
- From: email@example.com
- Date: Fri, 3 Jan 92 18:52:12 EST
- Sender: firstname.lastname@example.org
I've been doing some low-level Quickdraw hacking from MACL and am
having problems. I don't know if these represent a lack of
understanding on my part (probably) or bugs. Could someone give me a
few hints on the following two unrelated questions?
1. I define a file of macros, say mac.lisp, which contain (among
other things) the following:
(defmacro with-region (var &body body)
`(let ((,var nil))
(setq ,var (#_NewRgn))
I then compile this file, saving it as mac.fasl. I then start a fresh
MCL and load the fasl file.
In another file, say test.lisp, I define a procedure such as
(defun foo ()
(with-region foo (print t)))
When I eval this form, however, I get the warnings:
;Compiler warnings :
; Undefined function TRAPS::_DISPOSERGN, in FOO.
; Undefined function TRAPS::_NEWRGN, in FOO.
which seem to imply that the appropriate macros are not being found
If instead of loading the .fasl file, I load the .lisp file, all seems
fine. Seems like an eval-when problem? Right? But looking at the
expansion of defmacro looks like it's trying to do the right thing.
What am I missing?
2. I am blowing up my Mac by trying to do the following: I have some
CLOS objects of class IND that inherits from simple-view and some
other mixins, and I want to define a view-draw-contents method that
caches a somewhat complex pict in the object; the cache is then
cleared by other code when the image needs to change. In the course
of defining the pict, I need to use a region for clipping. Question
one is: can I DisposeRgn of this temporary region after it has gotten
used within a start-picture/get-picture context, or does the region
need to be retained as long as the picture it helped define is
retained? I have perused both MCL documentation and I-M without finding
conclusive evidence. Question two is: is my way of trying to do this
roughly right, or is there a different method that works better? What
I am essentially doing is something like
(unwind-protect (progn (open-region i)
... define new-clip region ...
(unwind-protect ; to make sure clip region is reset
(progn (#_GetClip old-clip-region)
(start-picture i r)
... draw the picture ...
i is one of these IND objects. If it's roughly right, then why am I
crashing a burning?
Thanks for any help. --Pete Szolovits