Diatonic transposition plugin? [SOLVED]

Bitwig Studio has a very useful plugin that can transpose a MIDI track from a given key and mode to a different key and different mode. You could select a track in C maj, let’s say, and have it transposed to D harmonic minor, for instance, or keep it in C but move it to myxolydian or … you get my drift. I believe people call this transposition “diatonic” (as opposed to the more common chromatic kind). That is how Bitwig Studio calls it too.
it Is there anything similar available for Ardour? I didn’t see anything in the plugin list, with the exception of the MIDI note transpose, which would however require me to create presets for all keys and all modes to achieve a similar result.

actually you only have to create a preset for all the modes. There is another midi plugin that can handle the keys.

Silly me. I never think about chaining plugins. That shows how new to this game I am, I guess.

Thanks.

Could you elaborate how that would work, or make sense musically?
How are accidentals mapped? Say you have a b9 chord, or use Bb as a passing tone.

I could see that it can be useful for some parallel melodies, but there you only change the mode. J.S. Bach did that in some fugues, then again those melodies don’t adhere to strict rules like a plugin would.

I considered adding some presets to the “MIDI Note Transpose” plugin, but could not think of any universally useful ones. If you could share some that’d be awesome!

Edit: I guess I could just add shifts. Key remains the same e.g.

+1 diatone
C → D
D → E
E → F
F → G
G → A
A → B
B → C

Hi Robin, I wasn’t think of transposing harmony but only monophonic melodic lines—you would have a line (with all notes within the scale, hence diatonic, I guess) in a given mode and key and transpose it to a different key/mode pair.
I am not sure mode-transpose presets could be universally useful, but they would in my use case, which, admittedly, may not be that close to Ardour’s core audience. I use it as a practice tool, and I play (or rather, I’m learning to play) a monophonic instrument in a jazz setting, where learning to transpose scale, patterns, and licks in different keys/modes is a skill I’m trying to build up with Ardour’s help.
I hadn’t given much thought to accidentals/outside notes, truth to be told, and I am not even sure it would make much sense in that context. I suppose they would be left untouched, or shifted up/down regardless of the mode.

BTW, in Lilypond, which is my favorite notation editor, there is a modalTranspose function that does exactly what you’re suggesting at the end (tone-shifting), but allows the user to indicate the mode: you give it a scale and two pitches as parameters and it shifts an input motif that starts on the first pitch to start on the second pitch. That would be very useful too (pitches in the motif that are not in the parameter scale are just ignored).