BPM/tempo lock via MIDI?

[mxmilkiib]

Feature Description

See also #9978 #13031

[FrankwaP]

Hey :-) I closed my recent PR as the work was a duplicate of yours… but as I said creating controls for locking/unlocking the tempo was my second objective, and here there are: https://github.com/FrankwaP/mixxx/tree/tempo_locking_controls

I've merged locally both our controls sets, created shortcuts and everything works! I've also checked that they were displayed in the MIDI wizard.

EDIT: One annoying thing I've noticed with my own controls, however: when calling these when the channel is empty, it causes a segmentation fault! And this happens quite fast when one thinks these controls apply to the selected track in the library and forget to load it in a channel.
So I'll get inspiration from your code. I already see you do not use new but std::make_unique.

[FrankwaP]

I've modified my code so it's closer to yours, but my controls still crash Mixxx when the Channel is empty.

Aren't these lines in the slot functions supposed to handle this ?

    if (v <= 0) {
        return;
    }

[ronso0]

crash Mixxx when the Channel is empty

Sounds like you want to set beats on a track while the classes TrackPointer is null.
Just add null check like everywhere else in functions that operate on track objects.

[FrankwaP]

Aaaaaaand done! Than you for the pointer, @ronso0 :-)

Do I make a PR ?

BTW I have fetched/merged @mxmilkiib 's work locally and made a specific/minimalist keyboard mapping for tracks preparation:

LoadSelectedTrack Shift+Left

cue_default f
play d

beats_set_halve F1
beats_set_twothirds F2
beats_set_threehalves F3
beats_set_double F4

beats_translate_earlier a
beats_translate_later z
unlock_tempo e
lock_tempo r

beatjump_backward q
beatjump_1_backward Shift+q
beatjump_forward s
beatjump_1_forward Shift+s

hotcue_1_activate w
hotcue_2_activate x
hotcue_3_activate c
hotcue_4_activate v
hotcue_5_activate Ctrl+w
hotcue_6_activate Ctrl+x
hotcue_7_activate Ctrl+c
hotcue_8_activate Ctrl+v
hotcue_1_clear Shift+w
hotcue_2_clear Shift+x
hotcue_3_clear Shift+c
hotcue_4_clear Shift+v
hotcue_5_clear Ctrl+Shift+w
hotcue_6_clear Ctrl+Shift+x
hotcue_7_clear Ctrl+Shift+c
hotcue_8_clear Ctrl+Shift+v

I just had a preparation session, and it goes faaaast <3

[ronso0]

Do I make a PR ?

Yes please!

[ronso0]

Implemented by #13041