Re: master fe7c015b20: Support XFCE in wallpaper.el

[Stefan Kangas <stefankangas@gmail.com>]

Po Lu <luangruo@yahoo.com> writes:

> Thierry Volpiatto <thievol@posteo.net> writes:
>
>> Or to use xrandr directly if available.
>
> If a display is not available, what X server will the xrandr utility
> connect to?  And how will you ensure the X server that the xrandr
> utility connects to is correct?

Won't it just use whatever is in $DISPLAY?  I'm seeing this in
"emacs -Q -nw", running in an xterm:

  ELISP> (display-monitor-attributes-list)
  (((geometry 0 0 255 78)
    (workarea 0 0 255 78)
    (mm-size nil nil)
    (frames #<frame F1 0x55f85d4ed4d0>)))
  ELISP> (getenv "DISPLAY")
  ":0"
  ELISP> (shell-command "xrandr" t)
  293 (#o445, #x125)
  ELISP> Screen 0: minimum 8 x 8, current 2560 x 1440, maximum 16384 x 16384
  DVI-I-0 disconnected primary (normal left inverted right x axis y axis)
  DVI-I-1 connected 2560x1440+0+0 (normal left inverted right x axis y
axis) 597mm x 336mm
     2560x1440     59.95*+
     1920x1200     59.88
     1920x1080     60.00
     1680x1050     59.95
     1600x1200     60.00
     1280x1024     75.02    60.02
     1280x800      59.81
     1152x864      75.00
     1024x768      75.03    60.00
     800x600       75.00    60.32
     640x480       75.00    59.94
  HDMI-0 disconnected (normal left inverted right x axis y axis)
  DP-0 disconnected (normal left inverted right x axis y axis)
  DVI-D-0 disconnected (normal left inverted right x axis y axis)
  DP-1 disconnected (normal left inverted right x axis y axis)

So it seems like we could just look for "^\\([^ ]\\)+ connected" and
just use the first one?  If nothing else, couldn't we use it to get a
default value?