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IParameterFunctionName Class Referenceabstract

Edit controller component interface extension: Vst::IParameterFunctionName. More...

#include <ivstparameterfunctionname.h>

+ Inheritance diagram for IParameterFunctionName:

Public Member Functions

virtual tresult getParameterIDFromFunctionName (UnitID unitID, FIDString functionName, ParamID &paramID)=0
 Gets for the given unitID the associated paramID to a function Name.
- Public Member Functions inherited from FUnknown
virtual tresult queryInterface (const TUID _iid, void **obj)=0
virtual uint32 addRef ()=0
virtual uint32 release ()=0

Static Public Attributes

static const FUID iid
- Static Public Attributes inherited from FUnknown
static const FUID iid

Detailed Description

Edit controller component interface extension: Vst::IParameterFunctionName.

This interface allows the host to get a parameter associated to a specific meaning (a functionName) for a given unit. The host can use this information, for example, for drawing a Gain Reduction meter in its own UI. In order to get the plain value of this parameter, the host should use the IEditController::normalizedParamToPlain. The host can automatically map parameters to dedicated UI controls, such as the wet-dry mix knob or Randomize button.


// here an example of how a VST3 plug-in could support this IParameterFunctionName interface.
// we need to define somewhere the iids:
in MyController class declaration
class MyController : public Vst::EditController, public Vst::IParameterFunctionName
tresult PLUGIN_API getParameterIDFromFunctionName (UnitID unitID, FIDString functionName,
Vst::ParamID& paramID) override;
OBJ_METHODS (MyController, Vst::EditController)
DEF_INTERFACE (Vst::IParameterFunctionName)
DELEGATE_REFCOUNT (Vst::EditController)
#include "ivstparameterfunctionname.h"
namespace Steinberg {
namespace Vst {
DEF_CLASS_IID (IParameterFunctionName)
tresult PLUGIN_API MyController::getParameterIDFromFunctionName (UnitID unitID, FIDString
functionName, Vst::ParamID& paramID)
using namespace Vst;
paramID = kNoParamId;
if (unitID == kRootUnitId && FIDStringsEqual (functionName, kCompGainReduction))
paramID = kMyGainReductionId;
return (paramID != kNoParamId) ? kResultOk : kResultFalse;
//--- a host implementation example: --------------------
FUnknownPtr<Vst::IParameterFunctionName> functionName (mEditController->getIEditController ());
if (functionName)
Vst::ParamID paramID;
if (functionName->getParameterIDFromFunctionName (kRootUnitId,
// paramID could be cached for performance issue
ParamValue norm = mEditController->getIEditController ()->getParamNormalized (paramID);
ParamValue plain = mEditController->getIEditController ()->normalizedParamToPlain (paramID, norm);
// plain is something like -6 (-6dB)

Member Function Documentation

virtual tresult getParameterIDFromFunctionName ( UnitID  unitID,
FIDString  functionName,
ParamID paramID 
pure virtual

Gets for the given unitID the associated paramID to a function Name.

Returns kResultFalse when no found parameter (paramID is set to kNoParamId in this case).

Member Data Documentation

const FUID iid

Copyright ©2022 Steinberg Media Technologies GmbH. All Rights Reserved. This documentation is under this license.