Three PyQt components that could be useful if you wanted to make a midi/audio sequencer. it's a work in progress so it's pretty unrefined but the basics are sort of there.
one intention is to be used in Carla as a standalone single-loop sequencer (work is being done on that)
- quantization is confusing for nonstandard note lengths / doesn't always seem to work
- implement loop-around-from-beginning notes
- disable ghost note and insertion when hovering over the piano and existing notes
- refine the rest of the UI (e.g. auto escape comboboxes)
- start making keyboard shorcuts
- anchor piano and measure indicator
- cut, copy, paste
- undo/redo
- velocity editor
- pitchbend (will be overlayed envelope)
- fix piano playing
- marquee, basically c/p the stuff done in the pianoroll
- change behavior so it's easier to make sawtooths
- clicking the line selects the two points it connects