I use the Mac screenshot utility a lot, but have never thought of using it as a ruler. I’ve always used a browser extension to measure pixels on the screen. If you’re not using this utility, you initiate it by pressing
command + shift + 4 on your keyboard.
I learned a few other tricks from the thread. Once you start dragging your mouse to create the rectangle:
shiftto lock in an axis as you continue sizing the area.
spaceto move the rectangle to a new location.
Do you have any other tips?