Re: Value of a parameter at TellListener call time ?
Re: Value of a parameter at TellListener call time ?
- Subject: Re: Value of a parameter at TellListener call time ?
- From: William Stewart <email@hidden>
- Date: Thu, 15 Apr 2004 11:08:49 -0700
There's a Tech Note on this (TellListener is not an API)
AUEventListener is the API that supports this kind of notification. It
provides two events, begin / end gesture, that don't have any arguments
except of course for the parameter involved.
The Tech Notes for Core Audio can be referenced from
http://developer.apple.com/audio
Bill
On 15/04/2004, at 8:17 AM, Raphael Dinge wrote:
>
Hi,
>
>
When I want the host to be able to write an automation,
>
I call
>
>
TellListener (
>
au_param,
>
kAudioUnitCarbonViewEvent_MouseDownInControl,
>
0
>
);
>
>
at the beginning of the automation.
>
>
In Logic for example, this will call a listener from Logic
>
that will call immediatly GetParameter to get the value of
>
the parameter at the beginning of the automation.
>
>
Now here is my question and my problem :
>
I use a button that react on mousedown rather than on
>
mouseup, so that the value of the parameter is changed
>
at mousedown. The button will only issue one value : it
>
is a flip flop.
>
>
What should be the value of that parameter of my plugin at
>
the time the mouse is down
>
(called through TellListener -> GetParameter) :
>
- the old value before the mousedown occurs ?
>
- the new value after the mousedown occurs ?
>
>
The problem is that :
>
- Logic states that at the TellListener call, the value of
>
the parameter is the one *before* the mousedown occurs,
>
- DP states that at the TellListener call, the value of the
>
parameter is the one *after* the mousedown occurs
>
>
DP version seems better, since the host is always notified
>
when a parameter change, so that the host always knows
>
(or should know) the value of all parameters.
>
>
However I cannot find the exact specification of this in
>
the current AU standard.
>
>
Is it specified ? (please redirect me to the revelant info)
>
Will it be specified ?
>
>
Many thanks,
>
>
--
>
========================================+===================
>
Raphael Dinge | Ohm Force
>
DSP developer & Software designer | DA Software
>
mailto:email@hidden | www.ohmforce.com
>
========================================+===================
>
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