This is not caused by commit_reversible_command, but because
NoteDrag::total_dx calls Evoral::Note<Evoral::Beats>::time()
with invalid MIDI note (deleted).
- for those not in the know, this series provides a way to
remove the temporal distortion introduced when using an
audio frame-based gui for music-locked objects.
In short, the gui uses an audio frame representation to move
objects. It displays the object using frame_at_beat(), quantizing
the time value to audio frames. This is fine until the user selects
that frame but expects it to be interpreted as a beat.
Thus beat_at_frame() would not produce the user-expected beat
(temporal quantization error of up to 0.5 audio samples).
This is one method of mapping audio time to music time accurately.
Each MidiRegionView(MRV) is connected to the Selection::ClearMidiNoteSelection
signal that is used to notify the all MRV instances to clear their note
selection.
The MRV class also has a private static SelectionCleared signal that is used to
signal other MRV instances when their selection has been cleared. When the
Selection::ClearMidiNoteSelection signal is emitted it causes each MRV to also
emit the SelectionCleared signal. So the emission takes quadratic time.
With 1500 MRV instances emission takes about 2.2 seconds on my machine, and
some operations like track selection cause it to be emitted 3 times(another
issue).
The Selection class in the Editor knows which MRV instances have note
selections, as it is notified by MidiRegionView whenever the selection count
becomes zero or becomes non-zero. Clearing the Note selection should then just
be O(N) and direct calls can be used rather than signals.
This change removes both the signals and uses the existing references between
Selection and MRV class to control note selection. There should be no
behavioural changes in Midi note selection with this change.
I don't think this is necessary, if some synth cannot deal with that,
perhaps Ardour could try to send the note off right before the next
note on, even-though they supposedly occur simultaneously.
The shortcut for 'change velocities together' had to be changed to
achieve that. The new shortcut is now primary+tertiary modifier +scroll,
i.e. ctrl+shift+scroll for the default keys.
