Virtual Combos

[minusfive]

It'd be nice to have the option to define "virtual combos". Use case: pressing T + G or N + M on my layout gives you an implicit HYPER, without actually having to define it in firmware. I'd like to highlight it in the drawing / docs, though.

[caksoylar]

Below are a few options I can think of and whether they make sense or not:

1. Put a section in config or reuse zmk_combos to add combos if they don't exist:
   • I don't think this belongs in the config, because it is very keymap dependent (e.g. due to key positions). zmk_combos is for modifying zmk combo nodes during parsing, so not ideal either
2. Use keymap parse --base-keymap:
   • This won't currently work as is. If a combo exists in the base keymap but not the new one, it is assumed that you removed it from the keymap, hence ignored, during the "rebase". If this assumption is changed, the original intention won't be preserved
3. Merge two yaml's before passing to keymap draw
   • This would obviously work and the reason I chose a data format like YAML for keymaps is to ease this sort of processing
   • However, it is hard to add this step to the CI workflow
4. Add a way to parse multiple keymap YAMLs during keymap draw
   • This conceptually sounds good to me; it is equivalent to 3. but the merging can be done by keymap instead.
   • Example: keymap draw keymap.yaml extra_combos.yaml
   • Technically, this can first merge layers, combos and draw_config fields coming from each keymap as dictionaries, then construct the KeymapData object from the result.

I think 4. is the only good option, so I am inclined towards that. In the workflow, this can be enabled by adding a extra_keymap_yaml parameter to pass the path to yaml. Maybe it can be specified per-keyboard, like draw_args.

[caksoylar]

Thanks for testing! Pushed it to main now. It looks like you have some wrong offsets in your config for some combo box contents, but that doesn't seem related to this change.

mise looks pretty good, I spent some time going through docs. These days I sadly don't do much in terminal besides the hobby projects, but I might give it a try.

[minusfive]

@caksoylar 🤔 mind sharing a screenshot of the offset issue you see? Wonder if it’s related to the gfont I’m loading in the SVG. Gotta get rid of that.

[caksoylar]

See this "swipe" preview from the PR, where some of the combo legends move to the center of the diagram:

Screen.Recording.2025-03-22.121926.mp4

I was guessing it is due to these tweaks: https://github.com/minusfive/zmk-config/pull/39/files#diff-398a6ee1f1a37af297e7d180c3a1e23f67342958466d5c73f0a0ddae350a0deb

[minusfive]

Oh dang, I shouldn't have only tested that on Safari 🤦‍♂️ . I see it's all borked in Chrome. Was trying to manipulate the glyph size on Combos exclusively, but I should know better than to try and manipulate inner SVG coordinates through CSS 🤣 . Thanks!

[minusfive]

Fixed https://github.com/minusfive/zmk-config/pull/43/files (by removing the hacks).

[minusfive]

Thanks @caksoylar !