Path: utzoo!news-server.csri.toronto.edu!cs.utexas.edu!sun-barr!olivea!uunet!ispd-newsserver!ism.isc.com!emisle!dvb
From: dvb@emisle.uucp (David Van Beveren)
Newsgroups: comp.windows.x
Subject: Re: PC X servers / backing store
Message-ID: <1991Mar4.170639.11726@emisle.uucp>
Date: 4 Mar 91 17:06:39 GMT
References: <9103020232.AA05738@lightning.McRCIM.McGill.EDU> <951@boing.UUCP> <21619@teda.UUCP>
Reply-To: dvb@emisle.UUCP (David Van Beveren)
Organization: Emerald Isle Systems, Ltd. Agoura Hills, CA
Lines: 38

In article <21619@teda.UUCP> mikel@teda.UUCP (Mikel Lechner) writes:
>dale@boing.UUCP (Dale Luck) writes:
>
>>This is absolutely untrue. Backing store is a feature just like colors,
>>visuals, shape extensions, pex and everything else. There is nothing
>>wrong with a package requiring properly working backstore for that [. . .]
>
>Very wrong.  Read the documentation.  It says very clearly that backing
>store is an optional feature provided by X servers.  It is merely a hint
>to the X server the backing store would be useful to the application.
>X servers are not required to support it.  All applications should be
>prepared to handle expose events in the event that backing store is not
>available.
>
>I can understand the desire for backing store in computationaly significant
>graphics applications, but not designing an X application to handle the
>situation without backing store is a design flaw IMHO.

I agree with both of you. First, all programs should not require backing store
in the server to operate correctly. The need to redraw complicated graphics
can be alleviated by using a technique involving drawing to a pixmap and
using XCopyArea to handle exposures. Therefore, not supporting an exposure
event is a definite DESIGN FLAW. However, as to a certain diminuitive rhodent
who asserts it is a BUG, I disagree. I believe that any program that does not
support resizing is flawed. But, I would not call that a bug, rather a design
deficiency. There is a BIG difference.

Let's just say it is a BAD thing rather than a bug. A bug is something that
the programmer does not understand that is causing the program to do things
in unexpected fashion. Even once a bug is found, and understood, it still has
the attribute of being uncalled for in the design. This exposure thing sounds
like it was in the design. I call that a bad design, not a bug. Is my
verbosity saying it all?

-- 
David Van Beveren                           INTERNET: emisle!dvb@ism.isc.com
EIS ltd. Professional Software Services     UUCP:   ..uunet!emisle!dvb
voice: (818) 587-1247