Re: [XForms] Determine Screen Sizes

[Jens Thoms Toerring]

On Sun, Nov 16, 2014 at 08:08:05PM +0000, jon wrote:
> From memory X has two ways it can treat multiple monitors. Most setups
> are configured as one display of "monitor" times the width.  IE two
> 1920x1080 (like I am using here) is one 3840x1920 display.

And as Serge pointed out, when the heights are different the
height of the larger monitor "wins".

If I'm not completely mistaken, monitors can also "logically"
be arranged to appear on top of each other. In that case I
would expect that one will receive the added height of both
and the width of the wider monitor...

> But it is possible to have X treat them as separate displays, in that
> case X display ":0" would be 1920x1080 as would display ":1"

In that case I think XForms would only be able to use one of
the monitors - one of them is probably the default one, i.e.
what's set in the DISPLAY environment variable, and that
would be used unless the program would be started with X
'-display' option set to the other display for the second
monitor (but then the first monitor will not be used).

I don't know if there are any toolkits where you can set a
display for a certain window of the application and another
display for another window. While I have some dark memories
of a 2-person game I played about 20 years where you could
specify a display for the opponents screen I have no idea
how this was done. Perhaps it was a script that started two
instances of the game on different displays, both connected
to a common server process, or if it was handled on the X11
level, opening 2 displays at once (not many toolkits avai-
lable back then - Motif was IIRC basically the only choice
but very expensive, so people tended to program against the
Xlib directly;-)
                        Best regards, Jens
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