Modal Addon Keymaps

[MACHIN3]

Just wanted to express my desire for modal keymaps for addon defined modal operators.

This comes up fairly regulary as a user request, and when I was finally caving in and tried to support it, I was greated by RuntimeError: Error: Modal key-maps not supported for add-on key-config

It seems it was possible in the past, but was disabled about a year ago.

I’d like to see it come back.

[RNavega]

I’ve also asked for this before:

What is the proper way to disable keymap items in the user keyconfig via addon?

You didn’t mention it, but based on the way you’re saying things I’m assuming your add-on has a modal operator. I strongly believe these key conflicts would not be a problem if add-on devs had access to modal keymaps in the same way that the Knife Topology Tool (mesh.knife_tool), the Edge Bevel (mesh.bevel) and other built-in operators have. All Python modal operator demos suggest that we react to raw key events (‘LEFTMOUSE’, ‘BACKSPACE’, ‘LEFT_CTRL’ etc.), but the built-in modal operators han…

I think it’ll help Python add-ons greatly because (edit: most of the time) we don’t really care what keys are being hit, but what actions they translate to, so we can have the add-on reacting properly inside modal().

The work to be done seems to be exposing the functionality of defining modal keymaps to Python operators, because the built-in operators are already able to do that using an EnumProperty like this.

At the moment I have to use a hackish way, inside the register() function I add several disabled “wm.call_menu” keymaps hidden inside the “3D View Generic” input category, storing some data in their “properties.name” attribute. When my modal operator is invoked, I search for these entries and set up some simple event-handling inside modal() to detect when their key combinations are being pressed, and then call the function name that they store.
This is how I support customizable, persistent keymaps for modal actions in Bézier Mesh Shaper for 2.79 and 2.80+.

[MACHIN3]

Thanks for sharing your work-around! I may look into doing the same. Just a bit awkward and unfortunate, considering Blender does support proper modal keymaps already.

[ThatAsherGuy]

I use a JSON setup that loosely parallels the dictionary system you use for keymaps in MACHIN3tools, supported by a global object holds extra data for cross-referencing. If you adapted @RNavega’s approach to use a dummy-operator with some extra StringProperties for storing more data, and a global object that can pull your default modal configs from your keydict if a matching operator isn’t found, you’d end up with a decently robust workaround. Throw in a few ID fields, and you’d be able to support multiple modal keymaps per operator without needing excessive if...elif sequences, too.

[MACHIN3]

Yeah sure, but I’m mostly concerned with drawing the keymaps and have the user interact with them in the addon preferences. How would you approach that?