问题
I want my program's window to be as big as possible without overlapping the window manager's various small windows e.g. the pager. Is there any way to ask the wm what the maximized window size is, before I create my window?
回答1:
_NET_WORKAREA property of the root window is probably closest match. However on a multi-headed system it will give you the combined work area on all monitors.
If that's what you want, fine (but see here on making a window span multiple monitors). If you want to maximize over a single monitor, then there's a problem as there's no per-monitor API like _NET_WORKAREA. Your best bet is creating a window in a maximized state and then querying its size. If that's not an option, I'm afraid you will have to query the number and sizes of available monitors, and then go and calculate the work area of each monitor by subtracting "struts" from the full area (see here about _NET_WM_STRUT and _NET_WM_STRUT_PARTIAL).
来源：https://stackoverflow.com/questions/18647983/xlib-how-to-ask-window-manager-for-maximized-window-size