[Fixed 2.6 Beta] Undo / Redo From Midi Callbacks

[kazakore]

From the B6 thread:

@Airmann

Hey Taktik,

A really urgent thing to clarify for me was the explicit creation of undo/redo-data. I have an important design question here
and I want to discuss this by example of my current FaderPort code (hope it’s not too realtime-related):

I handle incoming fader values from the FaderPort right now in two ways:

1. I set the device parameter values (prefx_volume etc.) directly
2. I record the values into an automation envelope

In first case there’s the problem that it just doesn’t make sense to create undo-data for all intermediate fader positions.
Only for the final release position after all movement. But that’s exactly the problem: this can not be detected automatically, right ?
An explicit event like “mouse button released” or “fader untouched/released” is necessary to trigger the creation of the undo-data.
But I couldn’t find a function for explicit undo-data creation in the framework. Is there maybe a function planed for another beta release ?

Another design question: how to handle undo-data creation of controllers if the controller doesn’t support an explicit “released”-event.
(e.g. a fader without touch-functionality) ? How to detect the that undo-data shall be created ? Using time measurement, maybe ? How does e.g. duplex handle this ?

UPDATE 13.9: checked out B6 and now the Undo works as expected. BUT: now are all intermediate fader positions are implicitly stored in undo-Queue as mentioned above. This means: every time I move my fader the undo-Queue is polluted by lots (and I mean lots !!) of entries. I really think an explicit function is necessary.

Suggestion for a function to switch on/off undo data creation:

  
set_undo_data_creation(UNDO_ON) -- default  
set_undo_data_creation(UNDO_OFF) -- if needed for realtime / faders  
  
-- example pseudo code   
while movement do  
 if fader_touched do  
 set_undo_data_creation(UNDO_OFF)  
 deviceparameter.value = myvalue  
 else   
 set_undo_data_creation(UNDO_ON)  
 deviceparameter.value = myvalue  
 end  
end  
  

Not sure if this would be possible but would some kind of timer for MIDI recorded Undos work? Two closely related ways that may be possible.

Renoise now seems to know that a MIDI value has changed, so it creates a Undo point. Currently it is creating one at each point (or is it even sub-points/ticks as I’ve read happening in the past as MIDI updates/ppqn is higher value than the Automation Envelope?)

Anyway what I was thinking is some way of coding a limit on the time between which MIDI related Undo points can be created. Say every second or maybe longer? Renoise knows a MIDI value has changed, while this is changing it can compare current and previous value and if different record the Undo point on polling every second. Second option would be the exact opposite. On MIDI value change do not record an Undo but flag CC, poll every second and on detecting two subsequent value as being the same record the Undo point with all changes in it.

Not sure if that makes sense but hopefully something to think about…