If you are a web designer then you may have encountered that problem when you are adding code in the style sheets but you are not getting the expected results, then you have to sometimes measure the exact dimensions of things as they appear in a web browser. One way to do this is to take a screenshot of the webpage and then crop it to the object that you want to measure – the size of the remaining image would tell you the dimensions in pixels. But you can avoid all this hassle if you use an open-source tool called Ruler.
Ruler is a portable program that appears like an ordinary ruler on your screen – something that we have all used in high-school when studying mathematics. But unlike the plastic ruler of the school students, it measures in terms of pixels. You can use Ruler to measure the various objects on your screen and find out their dimensions.
By default, it shows up in a horizontal position and with a length of 400 pixels. But you can drag its short edges to make it longer or shorter. You can also right-click on it to change its orientation to vertical but there are no option to rotate it to a custom angle. You can also duplicate the ruler which basically launches another instance of Ruler and set the pixel dimensions of ruler manually.
Conclusion: Rule is an open-source tool that can be used to measure distances on your screen in terms of pixels. It would be wonderful if it could measure in other usual units as well like centimeter or inches, but seems like the tool is meant only for the user interface designers who want to measure the size of various objects in a window or webpage.
You can download Ruler from https://github.com/andrijac/ruler.