[3975] in Athena Bugs
Re: vax 6.4R: xps
daemon@ATHENA.MIT.EDU (probe@ATHENA.MIT.EDU)
Sun Jan 14 15:08:07 1990
From: probe@ATHENA.MIT.EDU
Date: Sun, 14 Jan 90 15:07:52 -0500
To: tqpham@ATHENA.MIT.EDU
Cc: bugs@ATHENA.MIT.EDU
In-Reply-To: Thuan Q. Pham's message of Fri, 12 Jan 90 23:04:02 EST,
Reply-To: Richard Basch <probe@MIT.EDU>
Thank you for your report on "xps". The bug report has been sent to the
xps developers.
1) Yes, "xps" is indeed slow. Unlike "viewdoc", "xps" is a complete
PostScript interpreter, which will indeed slow it down. Viewdoc
was especially optimized for Scribe formatted files. "xps" is
still under development and was rushed into the release as it was
expected that print quotas may go into effect this term. Hopefully,
the next release will handle font display quicker if it is plain
text (I know that rotated text will not be possible to do quickly).
2) "xps" attempts to make use of a feature in the X server known as
backing-store. What this means is that if a window is covered and
then uncovered, the X server will automatically refresh the window.
For "xps" to maintain an alternate bitmap would be highly memory
consuming and slow down "xps". The X server is supposedly efficient
in this respect, which is why it is being left to the server.
However, it has been discovered that the X server has a memory leak
when this option is enabled, so backing-store has been disabled.
Hopefully, in the next release, X11R4 will be standard, and this
server is known to deal with backing-store correctly, not to mention
that the server is 30% faster overall.
-Richard Basch
Athena Systems Development
