Desktop Ruler is, just as its name indicates, a virtual ruler utility/tool for your desktop. It has customizable size, color, transparency, orientation and scale in pixels, centimeters or inches, as well as some other useful features like Precise Measuring Tool with adjustable zoom, capable of measuring on-screen distances in any angle, not just along the ruler, support for multiple monitors systems and customizable double-click action.
Full Specifications
What's new in version 3.28
corrected wrong positioning of information and hints in case of scale drawn on the lower edge of the ruler