Astrio Screen Ruler is an on-screen ruler for measuring objects and distances on the monitor in Windows. The Hide Ruler button hides or shows the ruler on the screen the Orientation button switches its orientation between vertical and horizontal and the Ruler length field sets the ruler length in pixels. The ruler itself is displayed over other windows as a marked scale with divisions. The Free Measure Tool button activates the free measurement tool allowing you to draw a line between two arbitrary points on the screen and get the distance between them along the dx and dy axes as well as the direct distance dist in pixels.