Re: Audio Unit Presets and undo
Re: Audio Unit Presets and undo
- Subject: Re: Audio Unit Presets and undo
- From: Ian Kemmish <email@hidden>
- Date: Fri, 8 Jun 2007 20:43:10 +0100
On 7 Jun 2007, at 6:56 pm, Bjorn Roche <email@hidden> wrote:
On Jun 7, 2007, at 6:40 PM, William Stewart wrote:
Have a look at the audio unit event listener - there's a tech note
on this (http://developer.apple.com/audio) - you can use this with
the object API to help to ensure that you don't get notified when
you change parameters and to find out when others do
I'm all set for parameters. My issue is with properties (specifically
parameter list changes and preset changes). Am I missing something?
bjorn
I suspect that in the most general case, this is unsolvable without
more communication between host and AU. For example, my synth has
its own undo mechanisms (including the usual flipping back and forth
to compare a saved version of a voice with the edited version).
Ideally, I would want to be able to tell my host that any changes
coming up are part of an undo operation so that it could either
ignore them completely or handle them specially.
If there were more guarantees about the AU's and host's
responsibilities in the API, then this could perhaps be handled with
Mac OS X's own undo machinery, but as far as I can see there aren't.
My host may not even have an Undo item in its Edit menu.....
So, given that any solution to your problem is (as far as I can see)
going to be a kludge, how about timestamping all events that you're
going to be recording for undo purposes, and coalescing any that are
less than some time interval apart. Since properties are more
intended to be part of the GUI than performance parameters, the
actual size of the interval is probably not too critical - some
fraction of a second perhaps?
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Ian Kemmish 18 Durham Close, Biggleswade, Beds
SG18 8HZ
email@hidden Tel: +44 1767 601361 Mob: +44 7952
854387
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