I was asked today how to make square crops in Acorn while keeping the aspect ratio when you resize the square. It’s pretty easy to do if you know a couple of keyboard shortcuts.

First, press the 'c' and 's' keys in quick oder (this is short for “crop square”). This will automatically add a square crop to your image. (Another good one I use all the time is pressing the 'c' key twice, which will add a general crop to your canvas).

You can then resize the crop bounds in the canvas with the shift key held down, and it will remember the aspect ratio as you resize.

There’s also a “Crop Square” Command Bar action (⌘⇧O), which will do the same thing as the 'cs' shortcut.

Some more useful keyboard shortcuts to use when a crop is active on the canvas include using the 'x' key which will swap the width and height values, the 'b' key which will toggle the “Keep crop bounds inside canvas” option (which you can then use to expand the size of your image!), and the 'h' key which will hide all pixels outside the current crop bounds.

You can find these shortcuts (and a couple of others) from the Crop section of Acorn's Keyboard Shortcuts. You might as well look over the whole page, because there‘s some good shortcuts in there.