Path: utzoo!utgpu!news-server.csri.toronto.edu!mailrus!cs.utexas.edu!sdd.hp.com!ucsd!ames!sgi!shinobu!odin!ramoth.esd.sgi.com!msc
From: msc@ramoth.esd.sgi.com (Mark Callow)
Newsgroups: comp.windows.news
Subject: Re: NeWS Tips for Silicon Graphics 4D
Message-ID: <7477@odin.corp.sgi.com>
Date: 9 May 90 17:36:51 GMT
References: <9005041643.AA08069@>
Sender: news@odin.corp.sgi.com
Reply-To: msc@sgi.com
Organization: Silicon Graphics Inc., Entry Systems Division
Lines: 49


In article <9005041643.AA08069@>, bice@hbo.UUCP (Brent A. Bice) writes:
|> 
|>    The biggest things I've run across are:
|>       1) In the latest version of news on the SGIs, Canvases don't appear to
|>          be retained.  When I asked the SGI techies 'bout this, they said
|>          "Hmmm.. Seems ta be a bug.  Why doncha use our 4d libraries
instead"
|>          So, it seems retained canvases can't be counted on.
The news server on the SGI runs on one of 2 modes: 8-bit color index and
24-bit rgb.  Retained canvases have never worked when the server runs in
24-bit mode.  They have always worked (modulo a bug in rendering text into
memory) when the server runs in 8-bit mode.

In 24-bit mode retained canvases sort of 1/2 worked.  Bits would be saved
from the screen when windows were obscured but nothing would ever be
rendered into the obscured retained portions of the windows.  I decided
that this was worse than them not working at all so in release 3.2 I
completely disabled retained canvases when running in 24-bit mode.
At least that way clients would get /Damaged notification when windows
needed to be redrawn.  Those clients that payed attention to the NeWS
spec. (retained canvases are a performance optimization only and the server
may stop supporting them at any time) would work correctly.

Did you upgrade your hardware to 24-bits as well as upgrading your software?
It's hard to believe that any program would have found the retained canvas
behaviour on 24-bits useful.

The good news is that in the next release (IRIX 3.3, 4Sight 1.5) retained
canvases are completely operational in both 8- and 24-bits.  Even the
text rendering bug has been fixed.  Backgammon works like a charm.

Incidently, a lot of NeWS clients use retained canvases when they should
really use buildimage and imagecanvas.  With the latter they can save
memory and actually work faster than retained canvases.

|>       4) Text itself appears to be REALLY slow on the SGI (yep, even
worse than
|>          under OPENLOOK on a SUN)!  Don't assume that it'll be fast
like it is
|>          on the SUNs.

Hmm!  This is news to me.  Please send me more details.

--
From the TARDIS of Mark Callow
msc@ramoth.sgi.com, ...{ames,decwrl}!sgi!msc
"There is much virtue in a window.  It is to a human being as a frame is to
a painting, as a proscenium to a play.  It strongly defines its content."