Support for minAngle maxAngle for knobs

[hemmer]

I'm updating the Befaco modules for recent updates on VCV side. All going well, but for one case, the knob has a custom range for the knob:

auto p = createParamCentered<Davies1900hLargeLightGreyKnob>(mm2px(Vec(15.0, 67.275)), module, Voltio::SEMITONES_PARAM);
p->minAngle = -0.83 * M_PI;
p->maxAngle = M_PI; 
addParam(p);

Is this or can this be supported on the metamodule side? I can try to implement if you point me in the right direction. If not I can make the Befaco metamodule branch remove these lines.

[danngreen]

I think it could be done easily. The minAngle/maxAngle fields of rack::app::Knob could be captured and stored in the MetaModule Element type. Then the element draw/redraw functions would use this instead of their default angles. At least, this is easy in the dynamic_loader branch. The main branch would be a bit more tricky since I'm assuming that bit of code is in the ModuleWidget constructor so we'd need to capture the min/max values in ModuleWidget::addParam.

More specifically:

• [ ] Add min_angle and max_angle fields to MetaModule::Knob in base_element.hh, with default values (300 degrees total sweep, centered at noon is how it's drawn now). This might trigger some warnings about missing braces wherever a Knob is constructed with an initializer list
• [ ] Use these fields in redraw_element(const &knob, ...) in gui/elements/redraw.hh (note that LVGL natively uses integers for angles such that 3600 = 2*PI)
• [ ] In the dynamic_loader branch: In make_element(rack::app::SvgKnob *, ...) and make_element(rack::componentlibrary::Rogan*, ...) in vcv_plugin/src/make_element.cc add the minAngle and maxAngle fields of the widget to the Knob's initializer list
• [ ] In the main branch: in VCV_adaptor/app/ModuleWidget.hpp we'd need a new overload for addParam like addParam(app::Knob *widget). Then in this function we could do a std::visit on the widget->element that sets the min_angle and max_angle fields if the variant type is MetaModule::Knob, and does nothing otherwise. Then the same stuff that happens in the other addParam() would need to happen.

I think that's all it will take

[hemmer]

Thanks I'll try and take a look

[danngreen]

@hemmer Is this still relevant? I was thinking of doing it unless you've made any progress.

Since it would be an API change for plugins, we would need to roll it into SDK API v1.1.

[hemmer]

Ah sorry I don't think I still have those changes, and it'll be a little while before I get the chance to look at it properly. It may be easiest (and faster with your understanding) if you do it - sorry I never got round to it!

[danngreen]

Note: while adding fields to Knob, we might want to add snap (boolean), units (string), base, multiplier, and offset to ParamElement.