Path: utzoo!attcan!uunet!husc6!bloom-beacon!NRL-AIC.ARPA!schultz
From: schultz@NRL-AIC.ARPA (Alan Schultz)
Newsgroups: comp.windows.x
Subject: Question on creation on gc's
Message-ID: <8805252012.AA20876@nrl-aic.arpa>
Date: 25 May 88 20:12:17 GMT
Sender: daemon@bloom-beacon.MIT.EDU
Organization: The Internet
Lines: 35

I am using CLX and have the following question.

I have a lot of graphics functions that get called often. In each function,
I create a graphics context as needed, and assign it to a temporary
variable. Example:

(defun some-simple-graphics-primitive (x y color)
	(let ((gc (create-gcontext :drawable *window*
				   :foreground color)))
           (draw-rectangle *window* gc x y *width* *height*))
)

This is oversimplified, but the basic creation of gc's is demonstrated.
I read in the Xlib manual that gc's are valuable resources, and I also see
that primitives exist in CLX for manipulating gc's that already exist.
QUESTION: Is the above expensive? Or since the gc is assigned to a
temporary variable, is it freed up after the function returns?

I have MANY such functions that get called OFTEN. Is it better to create
one gc at the top level, and then modify it as necessary, or is the above
ok?

Also, is one approach better for time efficiency?

Thanks,

   Alan C. Schultz
   Code 5510
   Navy Center for Applied Research in Artificial Intelligence (NCAR A I)
   Naval Research Laboratory
   Washington, D.C. 20375-5000
   ARPA: schultz@nrl-aic.arpa
   (202) 767-2877