Very Computer

Ok,

I understand multihead support in X  to a degree and I've seen a few
resources on the net, but everything I've found assumes one of two
things:
1. You are using a dual head card (matrox G450 etc)
2. You have two identical(ish) monitors.

If I had either of those (or both) I'd be so sorted. :-)

What I want to know is, can I run two different monitors off two
different cards at two different resolutions (in theory it can be done
- in practice ...)?

I'm a web developer and it's handy to be able to view sites I produce
in "end-user" size rather than on my nice big monitor.

So ideally I'd like to have my Geforce2 hooked to my big monitor and
then some other card I have kicking around (some old matrox millenium
or mystique probably) hooked to a 14/15 inch monitor running a lower
resolution.

Whether this would be running as one large desktop or two desktops
makes no odds really.

Can anybody answer this with a definite yes or no?  

And then perhaps give me a few links/tips cos I'm *ed if I can
find anything of use (I've got to the point where I'm manually wading
through the docs at xfree86.org looking for anything useful).

Also if anyone knows if Windowmaker will play nice with multi desktops
on more than one monitor, that'd be good to.

Thanks.

 -- Nick.

I've done it with a Radeon AGP and a VooDoo3 2000 PCI. Once you
get the two cards installed, from a shell prompt (as root) run
"XFree86 -configure", and it'll give you a skeleton XF86Config
that you can modify to your preferences.

Quote:> Whether this would be running as one large desktop or two desktops
> makes no odds really.

You can run different resolutions as independent desktops...
I think you have to have at least the same color depth for
Xinerama (one large desktop) to work, if not the same screen
resolution.

Quote:> Also if anyone knows if Windowmaker will play nice with multi desktops
> on more than one monitor, that'd be good to.

Can't say about Windowmaker, but KDE, GNOME, and Blackbox all seem to
play nice with two independent desktops as well as Xinerama. There are
slight hitches to either scheme; if you're running independent desktops,
you can't make a window traverse the two, but if you're running
Xinerama,
the xdm/kdm/whatever login window will be centered in the virtual
desktop
space and will therefore be split down the middle by the gap between the
monitors. Take your pick. (It's also possible that some apps, Blender in
particular comes to mind, will get confused by the wierd screen size
under
Xinerama and will not paint a full screen properly.)

Hope this helps.

--
Steve Martin, CPBE CBNT

MacOS eh?  perhaps not, as much as I'd like a powerbook I have no urge
to have a mac as a desktop.:-)

MacOS eh?  perhaps not, as much as I'd like a powerbook I have no urge
to have a mac as a desktop.:-)

That helps loads thanks Steve; you've told me more in one post than a
day searching the net!!.

-- Nick

: I'm a web developer and it's handy to be able to view sites I produce
: in "end-user" size rather than on my nice big monitor.
:
: So ideally I'd like to have my Geforce2 hooked to my big monitor and
: then some other card I have kicking around (some old matrox millenium
: or mystique probably) hooked to a 14/15 inch monitor running a lower
: resolution.
:
: Whether this would be running as one large desktop or two desktops
: makes no odds really.
:
: Can anybody answer this with a definite yes or no?  

A "very nearly definite" yes (though that may not help you).
That is, I've not actually done this on my own hardware, but
I've seen it working.  The "nearly" part is, it is possible
I misunderstood what I saw and what was described to me.

What I really wanted to mention was that there is a software-only
solution that might be useful in some situations.  Either Xnest or Xvnc
will allow you to create a virtual display with any number of pixels
across and down.  Both Xvnc and Xnest would appear to apps as a separate
desktop.  And with Xvnc you can even have your test environment have a
different pixel depth, or have truecolor even if your real display is
running pseudocolor, etc, etc.

The downside is, you still get the itty-bitty dense pixels of your real
display, so your virtual desktop with a smaller pixel width/height will
cover only a fraction of your screen.  That might be sufficient, or it
might be sufficient in conjunction with, say, a screen dump into xv of
imagemagic which you scale to the right physical size (this latter could be
done as an action on a WM or panel button) to do previewings of "snapshots".

But better than snapshots, Xvnc could also do this scaling in realtime
(or rather, an rfb proxy and/or client should), and scaling software has
been discussed a lot in proxy form, or for the unix vnc/rfb client, but
hasn't been delivered; one of those things in a "Real Soon Now" state
for a long time, so not to be counted on.  But would be very nice
if/when it occurs.  

In the meantime, even though it is a bit elderly now and lacks tight
encoding etc, xfrbviewer has a crude form of real-time scaling, and
might work well enough for your purpose.  Especially if it can be, eg,
2-to-1 so all the pixels scale equally -- like the physical screen has
1600x1200 pixels, and you want to see how it would look at 800x600.
Mind you, you can still use, eg, 3/2 or 4/3 or whatever; you just get
slightly knobbly looking fonts and such; the "crude" above means that
the scaling is done without interpolation, but merely pixel replication
and discarding.  But still, real-time interactive access to the web page
as it would exist on a lower-res display, no extra hardware needed.

Quote:>Ok,

>I understand multihead support in X  to a degree and I've seen a few
>resources on the net, but everything I've found assumes one of two
>things:
>1. You are using a dual head card (matrox G450 etc)
>2. You have two identical(ish) monitors.

>If I had either of those (or both) I'd be so sorted. :-)

>What I want to know is, can I run two different monitors off two
>different cards at two different resolutions (in theory it can be done
>- in practice ...)?

There's an article in the July Linux Journal on the subject, if you can
track that down.
--
Joe

<snip>

Quote:> What I really wanted to mention was that there is a software-only
> solution that might be useful in some situations.  Either Xnest or Xvnc
> will allow you to create a virtual display with any number of pixels
> across and down.  Both Xvnc and Xnest would appear to apps as a separate
> desktop.  And with Xvnc you can even have your test environment have a
> different pixel depth, or have truecolor even if your real display is
> running pseudocolor, etc, etc.

</snip>

I can't count the number of times I use vnx to get to other machines,
why I didn't think of running a local version I'll never know!  Never
heard of Xnest though, I'll have to check it out.

<snip>

Quote:> In the meantime, even though it is a bit elderly now and lacks tight
> encoding etc, xfrbviewer has a crude form of real-time scaling, and
> might work well enough for your purpose.  Especially if it can be, eg,
> 2-to-1 so all the pixels scale equally -- like the physical screen has
> 1600x1200 pixels, and you want to see how it would look at 800x600.
> Mind you, you can still use, eg, 3/2 or 4/3 or whatever; you just get
> slightly knobbly looking fonts and such; the "crude" above means that
> the scaling is done without interpolation, but merely pixel replication
> and discarding.  But still, real-time interactive access to the web page
> as it would exist on a lower-res display, no extra hardware needed.

</snip>

Again, never heard of this one, but I'll certainly consider it.

Thanks for the advice Wayne, very useful.  I'll probably still go for
the hardware solution - something about the geek in me wants a dual
headed system; just because I can. ;-)

  -- Nick

Ah fantastic, and if it's Linux Journal then it should be good.  Most
the newsagents areound here seem to stock LJ  one month behind so I
should be able to get it.

Thanks Joe.

-- Nick.

Glad I could help (at least, I *hope* I helped).
Good luck.

--
Steve Martin, CPBE CBNT