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I was finally able to get my four identically sized screens to work together, with three on one graphics card ( GeForce GTX 750 ) and one on a second card ( GeForce GT 730 ) in X11. It was a really tough configuration, because one monitors is left rotated, one is right rotated, and one extends above the top of all the others, and two extend below the bottom of all the others. In general, the layout is a strange shape for X11 to come to terms with. But it is mostly working now:

But my layout is odd, and is causing problems:

enter image description here

When I grasp the top edge of a window, and begin to move it, even on the same screen, very often it will jump down ( presumably 536 pixels ) to where it believes my cursor actually is. Often I will need to wrestle the window, with my cursor going into the next screen above, just to get it to where it needs to be, in the screen below.

When I begin to resize a window from the top edge, often it will jump down in size, again, presumably 536 pixels, and again I need to wrestle with the window, otherwise it can end up being 50px tall and unusable.

Is this having to do with no viewport information being used? 50% of the time, everything is fine. Windows move fine at perfect alignment from screen to screen. But then 50% of the time, the above issue happens.

Also, right now when I went to make the screenshot of my screen layout, the screenshot tool could not figure out where my "screen selection was" and I had to take a screenshot of the whole desktop and crop down to what I wanted. In general, my X11/Cinnamon instance is having some issues knowing its own dimensions... but I can't reproduce the circumstances.

How do I get perfect behavior when moving windows, resizing, and selecting regions of the screen, which is made up of four monitors?

UPDATE: The shape is due to how I mounted them. That's within the constraints of my wall-mount ( 1-screen ) and desk-mount ( 3-screen) working together:

enter image description here

UPDATE: This is confirmed to be a side-effect of Absolute positioning, but I see no way for me to use Relative positioning, given the shape. This would be what I would use, if negative numbers were allowed in Relative offsets:

Section "ServerLayout"
    Identifier     "QuatroTest"
    Screen      0  "Center"
    Screen      1  "Left" Relative "Center" -1080 -536
    Screen      2  "Right" Relative "Center" 1920 -536
    Screen      3  "Top" Above "Center"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
    Option         "Xinerama" "1"
EndSection

This is the Absolute positioning I have now, except for Top which is Above the Center screen:

Section "ServerLayout"
    Identifier     "Quatro"
    Screen      0  "Center" 1080 1080
    Screen      1  "Left" 0 536
    Screen      2  "Right" 3000 536
    Screen      3  "Top" Above "Center"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
    Option         "Xinerama" "1"
EndSection

The problem as I understand it is: Top is 1080px off the left corner of the total screen, and Left is 536px off the top of the total screen... so there is a void at the top left, and another at the top right. Technically there's a void below Center too.

Also tried this layout, which looked correct like the one I am currently using, but behaved the same:

Section "ServerLayout"
    Identifier     "QuatroTest"
    Screen      0  "Left" 0 544
    Screen      1  "Center" Relative "Left" 1080 536
    Screen      2  "Right" Relative "Left" 3000 0
    Screen      3  "Top" Above "Center"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
    Option         "Xinerama" "1"
EndSection

How do I plot the relative positioning I need with the above shape?

Without spending $500 on a 4k display for the center right now ...

Major discovery...

Even with this setup, the window move/resize behavior problem remains!

Section "ServerLayout"
    Identifier     "QuatroWide"
    Screen      0  "Center"
    Screen      1  "Left" LeftOf "Center"
    Screen      2  "Right" RightOf "Center"
    Screen      3  "Top" Above "Center"
    InputDevice    "Keyboard0" "CoreKeyboard"
    InputDevice    "Mouse0" "CorePointer"
    Option         "Xinerama" "1"
EndSection

That looks like this...

enter image description here

digitalextremist
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  • Any reason why the lower landscape and portrait mode don't align at the bottom (nor at the top)? – Anthon May 24 '15 at 10:12
  • Also, depending on where your primary screen is, you might end up with icons on the desktop that you cannot see (e.g. because they are in the space above the left monitor if that is the primary one) – Anthon May 24 '15 at 10:14
  • Added a photo of how they are mounted so you see why it is the way it is. And yes, you are correct! I just notice that the icons at the top left are not visible, probably they are lost to an unreachable zone. – digitalextremist May 24 '15 at 10:19
  • To be sure my Cinnamon panel is in a convenient place, the primary monitor is the center/bottom one. The layout is 0(center/bottom), 1(left), 2(right), 3(center/top). – digitalextremist May 24 '15 at 10:20
  • Nice setup. My avatar picture is my setup. (landscape, landscape, portrait) aligned at the bottom, with the left one being 0. Hence my experience with missing desktop icons. But I don't seem to be having your resize problems. (My monitors are 1920x**1200**) maybe that is why I did not think about adding a fourth one ;-) ) – Anthon May 24 '15 at 10:26
  • Thanks @Anthon. Cool avatar :) I could see how with your right-most screen being portrait and your two left screens being below the top of the virtual desktop, your icons would be out of view. And yes, with the resolution I have per screen, using three only doesn't *quite* cut it, so once I had a load-bearing wall behind my desk (new lab) within a day I sprung for another graphics card, and attached my fourth. I wonder if some sort of `viewport` information needs to be added per screen, to keep everything properly in place. How'd you solve your icon issue? – digitalextremist May 24 '15 at 10:44
  • I played around with automatically repositioning the ones out of view, but notifying the desktop about new positions was not so clean. I ended up with adding a few dummy icons at the top left corner of the virtual screen. I don't like to much on my desktop, mostly using the commandline and using desktop primarily as a huge drop on area that I scan for new files every few seconds (and process + remove based on their content). – Anthon May 24 '15 at 11:04
  • Agreed, I generally don't even have desktop icons enabled. I just wonder if the icon situation can be a canary-in-the-mineshaft to let me know if I've fixed the issue. – digitalextremist May 24 '15 at 11:06
  • The other trick I employ is that I have an Icon on the desktop that is a link to the desktop, clicking it opens nemo with the desktop contents. I was glad I got things to work, before I did, I had a 2monitor graphics card and drove the third from an old XP laptop, sharing keyboard and mouse over x2vnc. That was easier to set up. – Anthon May 24 '15 at 11:15
  • Before this I was using Synergy to populate the top monitor with a desktop from my MacBook Pro, but now I'm looking for perfection with X11 alone. Thinking I might try messing with metamodes, but I might be doomed. – digitalextremist May 24 '15 at 11:21
  • I'd just go to three screens with a big one for the middle one. We know that is generally well handled. – Michael Durrant May 24 '15 at 21:18

0 Answers0