Re: kAudioUnitParameterUnit_Indexed value range
Re: kAudioUnitParameterUnit_Indexed value range
- Subject: Re: kAudioUnitParameterUnit_Indexed value range
- From: Bill Stewart <email@hidden>
- Date: Tue, 29 Oct 2002 11:24:07 -0800
There's no limitation on the value range of these parameter types - then can
be from any number to any number (and we do expect that the steps between
them are integral steps)
We'll take a look at the problems with the generic view
Bill
on 29/10/02 10:53 AM, Marc Poirier wrote:
>
Hi. I have some questions about the kAudioUnitParameterUnit_Indexed
>
parameter unit and how it is expected that a parameter of that unit type
>
will behave. Well, my main question is: Are the values of the parameter
>
expected to correspond to actual array indices? In other words, should
>
the value range always be from zero to some positive number?
>
>
My understanding is that using the Indexed unit type indicates a couple of
>
things: (1) that the parameter values should be treated like integer
>
values, not decimal values, and (2) that ValueStrings may exist for the
>
parameter's value displays (and if not, then the values are displayed as
>
integers). All that it says for a description in AudioUnitProperties.h
>
is: "takes an integer value (good for menu selections)." From this, I
>
would think that any value range, including negative values, would be
>
okay.
>
>
I have an Indexed parameter whose range is -5 to 0. Logic doesn't seem to
>
dig this. The generic Logic plugin interface shows parameter value
>
integers for -5 to -1 and then shows the first ValueString for 0 (the
>
ValueString that actually corresponds to -5). So I am guessing that Logic
>
is assuming that the values of this parameter are exactly the indices of
>
the ValueStrings array, and is therefore not attempting to index with the
>
negative values (which is a good save, certainly better than crashing).
>
But I would think that what should happen is that the host should derive
>
the index as something like currentValue-parameterMinValue.
>
>
Am I right about this or should I just be using 0 to n_positive value
>
ranges?
>
>
In other news, the Apple GenericAUView has its own problems with my
>
ValueStrings... A number of the strings are negative numbers (like "-3"
>
"-2" etc.). The Apple GenericAUView can't display these, it just displays
>
blank menu items. If I insert a space or something at the beginning of
>
one of those strings (like " -3"), then it works fine. Logic, on the
>
other hand, has no problems with the strings that start with hyphens (but
>
has the other indexing problem). Oh yeah, the GenericAUView does, on the
>
other hand, show all of my negative value indexed strings, as I would
>
hope.
>
>
Thanks for any help,
>
Marc
>
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