Re: xmosaic experience
Guido.van.Rossum@cwi.nl
Message-id: <9302260908.AA15955=guido@voorn.cwi.nl>
To: Bill Janssen <janssen@parc.xerox.com>
Cc: marca@ncsa.uiuc.edu (Marc Andreessen), WWW-TALK@nxoc01.cern.ch,
ebina@ncsa.uiuc.edu
Subject: Re: xmosaic experience
In-reply-to: Your message of "Thu, 25 Feb 1993 16:19:16 MET."
<8fXK84sB0KGW8v0Ycj@holmes.parc.xerox.com>
From: Guido.van.Rossum@cwi.nl
X-Organization: CWI (Centrum voor Wiskunde en Informatica)
X-Address: P.O. Box 4079, 1009 AB Amsterdam, The Netherlands
X-Phone: +31 20 5924127 (work), +31 20 6225521 (home), +31 20 5924199 (fax)
Date: Fri, 26 Feb 1993 10:08:36 +0100
Sender: Guido.van.Rossum@cwi.nl
>What I think xmosaic does is: it creates both a fixed window as above,
>then creates a huge-ass window as a child window. It connects the
>scrollbar to the child window, and allows the user to scroll the child
>window around, instead of scrolling the text around. This is a *much*
>simpler way of doing things,
Yes. So far your story is correct.
>but now X *will* allocate an internal
>backing pixmap for that child window, even without backing store, and
>without all of it being exposed. So you're using one huge amount of
>memory.
Wrong. X does NOT allocate pixmaps just because you create a giant
window. It remembers the size of the window and gives you expose
events when parts of the window become visible. It does not even
allocate a pixmap for the visible part (since that's put directly in
screen memory). What do you think exposure events were good for if
the server allocated a pixmap? Soure that would be getting the worst
of two worlds!
I'll let Marc answer your attacks on XMosaic, but your knowledge of X
is less than what I expected.
--Guido van Rossum, CWI, Amsterdam <Guido.van.Rossum@cwi.nl>