CentOS - Jan 2016 - Monitor Dummy Device

Thank you Jonathan for your participation.

But i only want the same workflow like a second device is wired.

A hoped its possible to configure a second xorg-server or a
fakedevice/-monitor that kde recognize this and you could use this as
second desktop in same way as in dualscreen-modus.

So i ask a lot of people the last days and ok, maybe tis solution seems
unavailable without deeper knowhow.

Thank you all.
J


Am 20.01.2016 um 21:50 schrieb Jonathan Billings:
> On Wed, Jan 20, 2016 at 08:49:02PM +0100, Joey wrote:
>> Virtual Display have different meanings.
>>
>> i need a solution like a dualscreen. i want to move with mouse windows
>> from one screen to the other. and i need that i can stream the 2.
screen
>> for example with ffmpeg. with ffmpeg i can stream a part of the desktop
>> (also the second screen)
>>
>> i try to use the panning function of x-server. but with panning
(desktop
>> larger then monitor) the controlpanels and widget of the screen are
>> resized and spread to the whole desktop. after resize a lot of
>> preferences are destroyed :-(
> It sounds like what you want to do is use Xdmx (xorg-x11-server-Xdmx
> package) with maybe x11vnc on the system hooked up to the projector. 
>

On Jan 20, 2016, at 5:00 PM, Joey <forum at r5d.de>
wrote:
> 
> But i only want the same workflow like a second device is wired.
> 
> A hoped its possible to configure a second xorg-server or a
> fakedevice/-monitor that kde recognize this and you could use this as
> second desktop in same way as in dualscreen-modus.
This is why I suggested Xdmx.  Please check out the documentation:

http://dmx.sourceforge.net/

"Xdmx is proxy X server that provides multi-head support for multiple
displays attached to different machines (each of which is running a typical X
server). When Xinerama is used with Xdmx, the multiple displays on multiple
machines are presented to the user as a single unified screen.?


--
Jonathan Billings <billings at negate.org>

On Jan 20, 2016, at 5:08 PM, Jonathan Billings <billings at negate.org>
wrote:
> 
> On Jan 20, 2016, at 5:00 PM, Joey <forum at r5d.de> wrote:
>> 
>> A hoped its possible to configure a second xorg-server or a
>> fakedevice/-monitor that kde recognize this and you could use this as
>> second desktop in same way as in dualscreen-modus.
> 
> This is why I suggested Xdmx.
The X protocol is a far better choice for this sort of application than video
codecs, especially over a wireless LAN.  The local X server inherently knows
when changes occur that it needs to send to the remote X server, whereas with
video, each frame of video has to be treated like a new world, with a
brute-force search over the frame for parts which have remained unchanged, so
they can be optimized out.

And even then, a video codec is going to wastefully send frames even when it
doesn?t have to, because it?s designed with the assumption that *something*
changes in every frame, even if it?s just a text crawl and the talking head?s
lips on CNN.

That said, X is fairly laggy, increasingly so as GUIs have become piggier. 
(More pixels, more colors per pixel, more use of gradients and such rather than
solid fills, antialiasing, etc.)

Then on top of that, by using wifi, you?re going back in time something like 10
years in terms of bandwidth and latency compared to the wired LANs where X grew
up.  I just did a test here from my desktop: 36 Mbit/sec and 32 ms average ping
time over wifi to a server that gives me 940 Mbit/sec and 0.35 ms ping time over
the GigE LAN.

The wifi router is about 20 feet away from me now, through a couple of
uninsulated 2x4 and gypsum board walls; the WLAN is quiet at the moment, too. 
You speak of education, which suggests much longer distances between WAPs,
rebar-reinforced cinder block walls, and dozens of other users on each WLAN
channel.  You might be lucky to get even my 36 Mbit/sec result.

I still think wireless HDMI will give a better user experience.