Re: xmosaic experience
Message-id: <>
To: Bill Janssen <>
Cc: (Marc Andreessen),,
Subject: Re: xmosaic experience 
In-reply-to: Your message of "Thu, 25 Feb 1993 16:19:16 MET."
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
>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

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 <>