Enable 2 layers at the same time?

[DidierLoiseau]

I am currently designing a layout in which layer 2 should be the same as layer 1 + some keys.

Layer 2 is designed to be a momentary layer, while layer 1 would be a toggle layer.

To avoid duplicating layer 1 in layer 2, I would like to configure a key that momentarily toggles both layers 1 & 2.

Should I implement it as a macro or is there a simpler way?

[DidierLoiseau]

I implemented it as a macro and it was quite simple in the end. In action_get_macro():

switch(id) {
    case 2:
        layer_state ^= (1 << LAYERA) | (1 << LAYERB);
        break;
}

and use it with M(2) in the layout.

I don't check whether it is a key pressed or released since I need to toggle the layer states in both cases.

Anyway I would still be interested to know if there is an alternative without macro.

[ezuk]

I think there's something I don't understand here. If layer 2 is designed to be mostly the same as layer 1, why not make the keys in layer 2 transparent? I mean, those that should stay the same. Doesn't that work?

[DidierLoiseau]

That's indeed what I did, see https://github.com/DidierLoiseau/qmk_firmware/blob/typematrix/keyboard/ergodox_ez/keymaps/keymap_typematrix.c

The thing is that enabling layer 2 does not automatically enable layer 1. I thus needed a way to enable both layers at the same time.

[jackhumbert]

This is a pretty cool implementation! That's the only way I know to do something like this - I can't really see it becoming a core feature right now because of keymap readability concerns.

[DidierLoiseau]

Ok, thanks. I'm happy to know that's the proper way to implement it and that I didn't miss something.

I don't think this needs to be a core feature either, but it could be useful to document it somewhere.

[DidierLoiseau]

Playing with layer_state directly appears to be a bad idea in the end. I quite often end up with keys stuck from the temporary layers.

In fact, it appears I should have used layer_invert() instead, which does the proper cleanup if some keys are still held while switching a layer off. This appears to also be the cause of my problem in #81.