Re: [Musickit-users] MIDIRecord...

[Leigh S. <le...@le...>]

I must admit the last time I did anything with MIDI record was probably 
MacOS 10.1, and from memory, there was no documentation about CoreMIDI, 
it was deduced from the header files in CoreMIDI.framework. So I think 
at the time the appropriate thing to do to match the MusicKit API was 
assume destinations and sources were the same. Clearly with revised 
CoreMIDI under newer versions of the OS, this no longer applies.

So yes, we need to retrieve sources, but more fundamentally, there 
seems a mismatch between what the MusicKit deems a driver, and what the 
CoreMIDI (and probably portmusic also) distinguishes between source and 
destinations within that driver.

Clearly you only want to present source names when the pop up is to 
display sources, which is a decision which needs to be made in the 
application, so the problem is the semantics behind the method 
getDriverNames. It could be expanded to be:

typedef enum {
   MKMidiDriverSource,
   MKMidiDriverDestination,
   MKMidiDriverBoth
} MKMidiDirectionDriver;

- (NSString *) getDriverNamesFor: (MKDriverDirection) direction
{
   // Should call MKMDGetAvailableDriverSources() or 
MKMDGetAvailableDriverDestinations() appropriate to the direction 
value.
   // These need functions in MKPerformSndMIDI writing by modifying 
MKMDGetAvailableDriver()...
}

With getDriverNames being deprecated to become:

- (NSString *) getDriverNames
{
    // in order to preserve erroneous behaviour or
   return [self getDriverNamesFor: MKMidiDriverDestination];
   // return [self getDriverNamesFor: MKMidiDriverBoth] // is arguably 
more logical.
}


This is just "thinking out loud", and it will be some days before I can 
tackle this code, unless someone wants to tackle it, so I'd welcome 
other thoughts or better namings on the matter.
--
Leigh Smith
mailto:le...@le...
http://www.leighsmith.com