If two monitors are not aligned on the top or bottom edge, is there a way to find out the value of the offset on either one of the edges? I want to do it without purely visual inspection using a screen ruler like jruler because I need it to be exact (+/- 0 pixels). I'm looking for an Win7 and up solution (those can be separate solutions as well, mainly I'm focused on Win7).
I have no problem with 3rd party applications, if it's not possible to do without, but I prefer "portable"ones (no installation needed).
To make sure what "offset" I'm referring to here's a screenshot in which the bottom and top offset of two monitors is marked (note: this is a Win10 screenshot).