Re: xmosaic experience

Marc Andreessen (
Thu, 25 Feb 93 18:32:45 -0800

Bill Janssen writes:
> 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, 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. And this is just to avoid using the Motif text widget? As I
> say, this kind of approach would work OK on X for a HyperCard-like
> system, but not for a scrolling system.

Explain to me how we are able to allocate a 32K * 1024 * 1 byte pixmap
or image or block of random memory or whatever it is you claim we're
doing and still fit in on a typical workstation. For example, I
currently have that situation running within X Mosaic on my 24MB
workstation and not only is scrolling almost instantaneously fast but
ps -lef reports this:

30 S marca 22431 12382 0 26 25 * 1123:680 80127908 18:24:21 ttyq1 0:16 /usr/people/marca/mosaic/xmosaic/sr

Where in there is that 32MB of memory buried?

And look, goddammit, we are not trying to avoid using the Motif text
widget. The Motif text widget is not capable of supporting colors and
fonts. You show me how to put colors and fonts in a Motif text
widget, or support the rest of the functionality we need, and I'll
damn well do it.

> Hmmm, the document was plain text. Where's the parse? And of
> course if you didn't have to break it into document pages...

The parse is because I switched to using <xmp> in 0.8 to support
annotations to plaintext documents (since <xmp> can be terminated and
<plaintext> cannot). In 0.9 this will be handled as it should be and
<plaintext> will be used again, obviating the need to do a lot of the
parsing that's going on right now. But we're still going to be using
a Widget and we're still not going to be using the Motif text widget
and we're still going to have the document pages feature in there.