For Blender builtin configurations the option to choose the select mouse remains
and is now also in the splash screen. It works by changing the keymap dynamically
in the script, rather than using special events.
The system of automatic switching of events was not flexible enough to deal with
side effects that require further keymap changes, so it is now under more manual
control in the script.
This breaks compatibility for some scripts and exported key configurations.
These can be fixed by replacing SELECTMOUSE, ACTIONMOUSE, EVT_TWEAK_S and
EVT_TWEAK_A with appropriate LEFTMOUSE, RIGHTMOUSE, EVT_TWEAK_L and
EVT_TWEAK_R events.
Other than that, there should be no functional changes.
This should be purely an implementation change,
for end users there should be no functional difference.
The entire key configuration is in one file with ~5000 lines of code.
Mostly avoiding code duplication and preserve comments and utility
functions from the C code.
It's a bit long but for searching and editing it's also convenient to
have it all in one file.
Notes:
- Actual keymap is shared by blender / blender_legacy
and stored in `keymap_data/blender_default.py`
This only generates JSON-like data to be passed into
`keyconfig_import_from_data`, allowing other presets to load and
manipulate the default keymap.
- Each preset defines 'keyconfig_data'
which can be shared between presets.
- Some of the utility functions for generating keymap items still
need to be ported over to Python.
- Some keymap items can be made into loops (marked as TODO).
See: D3907
