This feature is really indispensable when designing and developing. Back in the day I used to use the cmd-shift-4 screenshot tool for such quick measurements, leaving a pile of images on my desktop after the end of a session. The first app I found that was able to do these sort of measurements is called PixFit but has sadly been abandoned by the developer with no support for Retina displays.Dimensions thankfully has Retina support and otherwise effectively replicated PixFit with some gotchas: - Can’t hit escape key to toggle the measurements off. You have to use the same combo as opening, which can get tedious — (I use cmd-alt-z) - As mentioned in the release notes, there’s no support for multiple spaces. Oddly it supports multiple displays? With no updates since April I worry this will meet the same fate as PixFit. You can make do by quitting and reopening the app in either space, but that’s super tedious of course. - It’s sluggish.Ultimately I found what I was looking for (sadly with a bunch of other useless features) in QuickLens with the “Real-time Distances” feature of it’s Crosshair tool. And I was able to confirm that it works with a free trial.

Once Dimensions is turned on, it mostly works. But it has some problems that would make it great:- There’s no setting for having Dimensions run on startup. When I need to use it, I always have to remember the name of the application or go hunting for it in my Applications folder.- There needs to be a quicker way to activate it than clicking the menu bar icon, moving my mouse down to the enable measurement menu item and clicking that. (I can never remember the keyboard shortcut.) Proposal: single click on the menu bar icon toggles measurement. Right click on the menu bar icon opens the menu.- It doesn’t work on apps that are in fullscreen mode.

非常希望能支持多屏测量，现在只能测量主屏，还是不太方面

Same as above, you don’t want to miss it, do you?