Linear default knob mode in VSTGUI 4? (vs circular)

[kartalex]

Hi, guys!

VSTGUI 4
By default knobs are changed by circular mouse movements..
How to change it to linear?

[aciddose]

I'm not familiar with VSTGUI, but checking the source knob.cpp is probably a good bet:
https://github.com/steinbergmedia/vstgu ... /cknob.cpp

Seems to be bool CKnobBase::MouseEditingState::modeLinear, from line #137 cknob.cpp:

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	if (mode == kLinearMode)
	{
		if (buttons & kZoomModifier)
			mouseState.range *= zoomFactor;
		mouseState.lastPoint = where;
		mouseState.modeLinear = true;

... so we need to find where mode is defined and use the accessor such as knob->setMode(kLinearMode | knob->getMode()); or something similar. VSTGUI is one nasty bit of code and the first thing I'd do if I had to use it is a major refactor almost completely rewriting some significant portions.

Ah I see it was right there, line #125 it does some ridiculous shuffling from getFrame()->getKnobMode();

So this tells me there may not be any way to set the mode or parameters for specific widgets/controls in VSTGUI which isn't surprising really. You probably want to call getFrame()->setKnobMode(kLinearMode) or similar during construction/population of the GUI where you have access to this "frame" object which is I guess a dumb name for a window or region? I assume if the widget has a pointer or reference it must've been assigned during construction at some point.

You'll probably find that the mode you set manually is overridden elsewhere though, so even if you did set it in the constructor it might have no effect. Now you get to dig around in the VSTGUI code until you can figure out all the convoluted paths and structures and functions involved for this one simple parameter.

[kartalex]

Somehow I've done it (not sure if it's right way to do it)
Added line

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setKnobMode(Steinberg::Vst::KnobModes::kLinearMode);

in myplugincontrolller.cpp (I created project with VST3 Project Generator with VSTGUI checkbox on)

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//------------------------------------------------------------------------
IPlugView* PLUGIN_API AlexGainController::createView (FIDString name)
{
	// Here the Host wants to open your editor (if you have one)
	if (FIDStringsEqual (name, Vst::ViewType::kEditor))
	{
		// create your editor here and return a IPlugView ptr of it
		auto* view = new VSTGUI::VST3Editor (this, "view", "myplugineditor.uidesc");


		/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
		setKnobMode(Steinberg::Vst::KnobModes::kLinearMode);

		return view;
	}
	return nullptr;
}