Philer Ruler PRO is a handy utility designed to enable you to easily measure anything  on your desktop in pixels, inches, centimeters, as well as typographic picas. The ruler works with a range of perfect accuracy due to DPI parameter (original data on your monitor).

You can set the needed markers-serifs, in order to change the orientation of the line, its dimensions and position relative to the screen. By using additional tool Desktop Ruler you can also measure the distance at an angle, and Magnifier (which is added in Informatuion Form) will be an excellent guide for the installation of the main window in the right place.