SOLVED: Using 'feh' to display image on second monitor (runcommand_onstart)

[johnodon]

UPDATE: Solution detailed here: https://retropie.org.uk/forum/post/262396 I imagine you can do the same on a PI4 using fbi since it has 2x HDMI ports.

Current RP x86_64 (Ubuntu 20.04).

I am currently using the pause button on my arcade cab to pause the game and switch bezels that show the controls. Pushing the pause button again switches back to the main bezel and unpauses the game.

This approach works well but I have decided to install a 2nd monitor that will always show the controls. I figured I could just use the runcommand_onstart file to display the image on the second monitor (using 'feh' since I am x86) but I don't know how to specify the target display in the command line switches.

I've found a few articles that talk about using the --geometry switch since the desktops are essentially extended and just provide the height, width and starting position but figured I would ask here first. Is there a way to specify the display? Is there another image display software I can use that will accomplish what I want to do? Since I am using x86, I can pretty much install anything I need. Or, is the geometry switch the way to go?

Tia!
John

[brandflake11]

I have never tried this, but according to the manual you can use --xinerama-index to set the specific monitor you want with feh, assuming it is built with xinerama support:

Use --no-xinerama to treat the whole X display as one monitor when setting wallpapers.  You may also use --xinerama-index to use feh as a background set ter for a specific monitor.

This is under the header BACKGROUND SETTING in the feh manual.

EDIT: Also found this in the Arch wiki:
To setup different wallpapers for different monitors one should pass as many file paths as many monitors are available. For example, for a dual monitor setup it would be:

$ feh --bg-center path/to/file/for/first/monitor path/to/file/for/second/monitor

I hope this helps!

[johnodon]

Thanks @brandflake11

I got this one figured out. It was a PITA! :)

Long and short of it is this...

xrandr treats both displays and one large one (extended). You can see below that Screen 0: is recognized as 5760x1080 (4K TV + 1080P monitor):

Screen 0: minimum 320 x 200, current 5760 x 1080, maximum 16384 x 16384
VGA-1 disconnected (normal left inverted right x axis y axis)
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 800mm x 450mm
   3840x2160     30.00 +  24.00    29.97    23.98
   4096x2160     30.00    24.00    29.97    23.98
   1920x1080     60.00*   59.94    30.00    24.00    29.97    23.98
   1920x1080i    60.00    59.94
   1680x1050     59.88
   1280x1024     75.02    60.02
   1440x900      59.90
   1280x960      60.00
   1280x800      59.91
   1152x864      75.00
   1280x720      60.00    30.00    59.94    29.97    24.00    23.98
   1024x768      75.03    70.07    60.00
   800x600       72.19    75.00    60.32
   720x480       60.00    59.94
   720x480i      60.00    59.94
   640x480       75.00    72.81    60.00    59.94
   720x400       70.08
DP-2 connected 1920x1080+3840+0 (normal left inverted right x axis y axis) 509mm x 286mm
   1920x1080     60.00*+  50.00    59.94
   1920x1080i    60.00    50.00    59.94
   1680x1050     59.88
   1280x1024     60.02
   1440x900      59.90
   1280x800      59.91
   1152x864      75.00
   1280x720      60.00    50.00    59.94
   1024x768      70.07    60.00
   800x600       60.32    56.25
   720x576       50.00
   720x480       60.00    59.94
   640x480       66.67    60.00    59.95    59.94
   720x400       70.08
HDMI-2 disconnected (normal left inverted right x axis y axis)

This is what my autostart.sh file looks like:

#! /bin/bash

#set primary display and resolution.
xrandr --display :0 --output HDMI-1 --mode 1920x1080 --primary &

#call cvlc to play a startup animation.  Wait for it to end before continuing.
cvlc --random --play-and-stop --play-and-exit --fullscreen --video-on-top --no-video-title-show --quiet --gl=any --preferred-resolution=1080 ~/RetroPie/splashscreens &> /dev/null

#start ES in a terminal (openbox).
gnome-terminal --full-screen --hide-menubar -- emulationstation --no-splash

Naturally, feh sees the display the same way so you need to use the --geometry switch to identify the starting pixel on the 2nd monitor. This is what my runcommand-onstart.sh looks like:

#! /bin/bash
ROMPATH="$3"
ROM_BN_EXT="${ROMPATH##*/}"
ROM_BN="${ROM_BN_EXT%.*}"
CONTROLSIMAGE="/home/pi/RetroPie/roms/$1/images/$ROM_BN-controls.png"
feh --geometry +3840+0 "$CONTROLSIMAGE" &>/dev/null &

This essentially gets the full path to the romfile and trims the extension to get the rom base name.
It then builds the path to the controls image I need and displays at the starting position I tell it to (3840x0) which is the entire screen of the 2nd monitor. When I exit the game, and merely kill feh via runcommand-onend.sh:

#! /bin/bash
killall feh &

This is working perfectly. Now I just need to find a fancy graphic to display on the 2nd monitor when it isn't showing controls. :)

John