How can i tell if a window is in fullscreen from command line

Question

So I found that with wmctrl -F -r "SomeWin" -b add,fullscreen I can make a window fullscreen, now i want to run a cron so that it stays open, but also verifies that it's fullscreen.

Is there something that can tell me if it's fullscreen or not? or do i have to compare the window size with the screen size. If so, with wmctrl -G -l I get the window size, but I have nothing to compare it with, wmctrl -d says 0 * DG: 2880x1800 VP: 0,0 WA: 65,24 1375x876 N/A, the resolution is 1440x900, so none of those are it.

Answer 1

Something like

xprop -name TitleGoesHere _NET_WM_STATE | grep -q _NET_WM_STATE_FULLSCREEN

should do it. Note that the window title used by xprop is the legacy ISO8859/1 title, so Unicode characters won't work; it may also need to be the full title and not just a substring. xprop itself can be used in interactive mode to get the right string; run

xprop WM_NAME

and wait for the cursor to change to a crosshair, then click on the window.