A Ruler for Windows is a free on-screen pixel ruler for your PC. It provides you your choice between a rich woodgrain ruler, or at the touch of a button, a clear see-through plastic ruler. A Ruler for Windows is fun to learn and very easy to use.
Pros: There are a several situations when you may need to measure screen-space exactly. Exactly measurements need to be in terms of pixels. A Ruler for Windows is a free on-screen pixel ruler for your PC. Based on your choice the ruler can look like a wood-grained one or exactly like a transparent plastic ruler. You can drag & drop the ruler anywhere on the screen, wherever you need it to be. There are several icons on the scales that help manipulating the scale easily. One of these is a magnification control that lets you magnify the ruler 1x, 2x, 3x or 4x times. That makes more accurate measurement being taken. The 2nd icon out of the total six provides transparency control. You can toggle between the transparent and non-transparent ones. Two other controls provide locking the ruler to the left or right and to resize in that direction. One of the icons lets you set the length of the ruler. The ruler can be flipped and tics can be marked where required.
With A Ruler for Windows you can use your screen normally while layering one or more rulers over of your work. The transparent rulers let you continue working/typing under the set of rulers being used. Ticks can be placed on which ever long edge you prefer. A measuring line can be automatically drawn at an exact location when you click near a ruler tick. Help is readily available on typing the question mark on top of the ruler.
Cons: No problematic issues noticed. How widespread the need to actually measure pixels is not very clear.
Overall a very easy application to use. If you do have a need to measure pixels distances accurate then this is the tool to use, easily 4 stars category.