@ -42,7 +42,7 @@ For more complicated cases, like blink the LEDs, fiddle with the backlighting, a
Well, that's the bulk of it! You should now be able to work through the examples below, and to develop your own Tap Dance functionality. But if you want a deeper understanding of what's going on behind the scenes, then read on for the explanation of how it all works!
Let's go over the three functions mentioned in `ACTION_TAP_DANCE_FN_ADVANCED` in a little more detail. They all receive the same too arguments: a pointer to a structure that holds all dance related state information, and a pointer to a use case specific state variable. The three functions differ in when they are called. The first, `on_each_tap_fn()`, is called every time the tap dance key is *pressed*. Before it is called, the counter is incremented and the timer is reset. The second function, `on_dance_finished_fn()`, is called when the tap dance is interrupted or ends because `TAPPING_TERM` milliseconds have passed since the last tap. When the `finished` field of the dance state structure is set to `true`, the `on_dance_finished_fn()` is skipped. After `on_dance_finished_fn()` was called or would have been called, but no sooner than when the tap dance key is *released*, `on_dance_reset_fn()` is called. It is possible to end a tap dance immediately, skipping `on_dance_finished_fn()`, but not `on_dance_reset_fn`, by calling `reset_tap_dance(state)`.
Let's go over the three functions mentioned in `ACTION_TAP_DANCE_FN_ADVANCED` in a little more detail. They all receive the same two arguments: a pointer to a structure that holds all dance related state information, and a pointer to a use case specific state variable. The three functions differ in when they are called. The first, `on_each_tap_fn()`, is called every time the tap dance key is *pressed*. Before it is called, the counter is incremented and the timer is reset. The second function, `on_dance_finished_fn()`, is called when the tap dance is interrupted or ends because `TAPPING_TERM` milliseconds have passed since the last tap. When the `finished` field of the dance state structure is set to `true`, the `on_dance_finished_fn()` is skipped. After `on_dance_finished_fn()` was called or would have been called, but no sooner than when the tap dance key is *released*, `on_dance_reset_fn()` is called. It is possible to end a tap dance immediately, skipping `on_dance_finished_fn()`, but not `on_dance_reset_fn`, by calling `reset_tap_dance(state)`.
To accomplish this logic, the tap dance mechanics use three entry points. The main entry point is `process_tap_dance()`, called from `process_record_quantum()`*after*`process_record_kb()` and `process_record_user()`. This function is responsible for calling `on_each_tap_fn()` and `on_dance_reset_fn()`. In order to handle interruptions of a tap dance, another entry point, `preprocess_tap_dance()` is run right at the beginning of `process_record_quantum()`. This function checks whether the key pressed is a tap-dance key. If it is not, and a tap-dance was in action, we handle that first, and enqueue the newly pressed key. If it is a tap-dance key, then we check if it is the same as the already active one (if there's one active, that is). If it is not, we fire off the old one first, then register the new one. Finally, `tap_dance_task()` periodically checks whether `TAPPING_TERM` has passed since the last key press and finishes a tap dance if that is the case.
keyboard-magpie
1 year ago