Support FN Key as Modifier

[mmmichl]

Add support for the fn key as a modifier in addition to ctrl, option and command.

This would clear up the area of conflicts with other keyboard shortcuts! I saw the support in the following project, if this might help the implementation: https://github.com/finestructure/Hummingbird

[rxhanson]

This is actually a limitation imposed by the shortcut recorder, MASShortcut. I don't know the details, but I think there is a reason that the fn key isn't supported there. Note that shift is a supported modifier. If this does get implemented in MASShortcut, then I can pull the latest MASShortcut into Rectangle.

[smammy]

I just noticed that the MASShortcut repo was archived on March 5th of this year. Are you using any particular fork now?

[rxhanson]

Yes, I forked it a while ago but haven't made any modifications for Rectangle:
https://github.com/rxhanson/MASShortcut

The nice thing with owning it is that I can promptly roll in any changes anyone wants to make.

I have a private fork that I use for Rectangle Pro and Multitouch where I include a few more tweaks to it for recording only modifier keys, etc.

It's actually a macOS restriction that prevents fn from being used in shortcuts.

[smammy]

Got it; thanks. I wonder how BetterTouchTool manages to support fn in shortcuts.

[rxhanson]

It likely listens to your keystrokes rather than registering shortcuts with the OS (this is something I prefer not to do with Rectangle/Pro). If you think of it that way, it's less of a macOS restriction and more of a convention that I prefer to follow.

[smammy]

No yeah, I'm totally with you on this one. BTT does a bunch of wild stuff that I would never do! 🤣

[yochem]

A workaround might be to install Karabiner Elements and remap the fn keys to something like cmd + ctrl + shift + num, so for example F1 would become cmd-ctrl-shift-1 etc. Then you can just use these in rectangle as shortcuts.