Testing tip: Enable the zoom peek gesture

using ⌘⇧4 with the intention not to take a screenshot, but just to (roughly) measure a distance between two objects, and then pressing Esc to abort

I’m glad to learn others use this trick to measure pixels between objects on screen. “Roughly” is the key word though. If you truly want precision, I recommend purchasing xScope for $50. I use it constantly to test alignment between objects.