Gnome Screen Ruler is an on-screen ruler for measuring horizontal and
vertical distances in any application. Features:

	* Horizontal and vertical display
	* Multiple units: pixels, inches, centimeters, picas, points,
	  percentage
	* Configurable colors and font
	* Can be set always-on-top
	* Measurement lines track mouse cursor to help measure
	  anything on screen
	* Move and resize via click-and-drag with the mouse
	* Align with other windows while dragging (hold SHIFT key)
	* Move using the keyboard for precision (arrow keys)
	* Resize using keyboard (ALT+arrow keys)
	* Speed up keyboard operations (hold SHIFT key)

WWW: http://linuxadvocate.org/projects/gruler/