Re: The DISPLAY variable.
peter@easthope.ca wrote:
> From: deloptes <deloptes@gmail.com>
> Date: Wed, 10 Aug 2016 21:12:53 +0200
>> Screen and display are completely different things in different contexts.
>
> I have one context. A PC with a "Radeon 9600XT 256M V/D/VO" card.
> It has one DVI connector and one VGA connector.
>
it seems that you have only one screen then. Display can spread on multiple
screens, but in your case you definitely have 1 display, so 0.0 should work
for you.
>> If you have 1 graphic card you usually have 1 screen and one display,
>> which would correspond to DISPLAY=:0.0 in X11 terminology.
>> If you have some special card flavor or perhaps two cards you could have
>> 2 displays/screens.
>>
>> DISPLAY=:D.S
>> D - display
>> S - screen
>
> Many documents explain that. Appears that at some point,
> the X11 designers intended a 1:1 correspondence between
> screens and monitors. Then more and more complications.
>
yes this is true for good or for bad
>> In your case - if you want to put a program window somewhere, you should
>> work with the position parameter(s) - xoff,yoff
>>
>> xeyes --help
>> [-geometry [{width}][x{height}][{+-}{xoff}[{+-}{yoff}]]]
>
> Perfectly reasonable except that the program has no
> --geometry parameter.
>
this is also sad, but I'm not sure if these are not implicit in some way. If
not (in your case) you can not do much.
> https://wiki.archlinux.org/index.php/multihead says,
>> Screen refers to an X-Window screen (that is: a monitor attached to a
>> display).
>
> According to that, the Viewsonic here can be screen 0 and
> the Panasonic can be screen 1. Then executing
> export DISPLAY=localhost:0.1 ; program
> should always put the window on the Panasonic monitor.
>
> Reasonable but no luck creating screen 1.
>
> screen 0 extends rightward across the Viewsonic and then across
> the Panasonic. The program window is at (0,0) on the Viewsonic.
> Not on the Panasonic.
>
> Thanks for the reply, ... Peter E.
Well this depends on the xorg.conf. this is why someone asked if you have
one auto generated or custom.
I'm using a dell e5440 with intel grafics chip. I had to write my own
xorg.conf to be able to work with 2-3 monitors in a meaningful way.
Even so the card has only one screen/display in X11 terms.
I use the monitors configured via xrandr such that one is right of the other
laptop screen, monitor1, monitor2. I have never tried though to explicitly
tell a program where to position itself. Usually it works as expected.
Namely it opens on the active monitor (where my mouse is focused and other
programs are opened recently).
I once tried Xinerama ages ago, but I think it was too early as it was
causing problems, but this could be a way as it was mentioned in another
reply. Even so you end up working your own xorg.conf out.
I hope this helps understand your situation better.
regards
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