Configuring custom parameter display in v1

Development
1

I quite like the new param config mechanism.

Some of the knobs in my modules use custom tapers. For example, when the user turns a DURATION knob, my modules apply a custom taper to compute the duration.

The custom taper means that I can’t use the param configurations’ built-in linear/exponential mappings.

I would like to make sure the knob rotation and the display value always correspond. Given the knob rotation, I can compute the corresponding duration. Given a duration, I can compute the corresponding rotation.

When the user turns the knob, how can I set its display value to reflect the computed duration?

When the user enters a duration via the keyboard, how can I set the knob’s rotation to reflect the computed rotation?

It’s not obvious to me how to do this. If it’s possible, I’m sure I can figure it out eventually. I’m not sure I can figure it out before v1 launches.

2

You could make your own ParamQuantity subclass, override

	float getDisplayValue() override {...}
	void setDisplayValue(float displayValue) override {...}

and use

configParam<MyParamQuantity>(...);
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3

Got it. The remaining thing for me to figure out is what event is generated when the user types a value. But you’ve narrowed the search enough that I think I can find that on my own.

Thanks!

4

When a user types a value for a ParamWidget? No event is generated. But setDisplayValue is called which allows you to call setValue after transforming the value.

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5

Okay. That helps. Thanks!

6

This seems related enough to not warrant a new thread: is there a graceful way to remove the value entry field from a ParamWidget’s context menu?

7

No

8

Hi @Vortico,

thanks for this suggestion!

But… what if I want to have a custom subclass that return values due to a range? I mean, I have my configParam<Division>(...); param knob that display division on this range:

 "1/2d", "1/2", "1/2t", "1/4d", "1/4", "1/4t"

Another time, I just need different ranges, such as:

 "4", "3", "2", "1", "1/2d", "1/2", "1/2t", "1/4d", "1/4", "1/4t", "1/8d", "1/8", "1/8t", "1/16d", "1/16", "1/16t"

For the same subclass, of course. How could I pass a custom “array” to my subclass by template?

I don’t see any way. Also, configParam is void, doesn’t return TParamQuantity (which could be used to point to my array).

Any clue? Thanks

9

In Rack v2, configParam returns the TParamQuantity. In Rack v1, you can use

dynamic_cast<TParamQuantity*>(paramQuantities[PARAM])

Rack v2 also has SwitchQuantity (Rack development blog) but in Rack v1 you have to write your own ParamQuantity subclass.

1 Like