xwininfo

xwininfo  – This command will return information on a specified window.

sudo apt-get install x11-utils

 

Here is an example:  xwininfo

xwininfo: Please select the window about which you
would like information by clicking the
mouse in that window.

xwininfo: Window id: 0x34006c2 “The GIMP”

Absolute upper-left X: 1150
Absolute upper-left Y: 688
Relative upper-left X: 5
Relative upper-left Y: 23
Width: 192
Height: 245
Depth: 24
Visual Class: TrueColor
Border width: 0
Class: InputOutput
Colormap: 0x20 (installed)
Bit Gravity State: NorthWestGravity
Window Gravity State: NorthWestGravity
Backing Store State: NotUseful
Save Under State: no
Map State: IsViewable
Override Redirect State: no
Corners: +1150+688 -58+688 -58-117 +1150-117
-geometry 4×0-53+665