Added an option to declare plug-in parameters as either continuous or discrete, irrespective of their number of steps

BREAKING-CHANGES.txt

@@ -6,14 +6,44 @@ Develop Branch
 
 Change
 ------
-A new FrameRateType fps23976 has been added to AudioPlayHead
+The method used to classify AudioUnit, VST3 and AAX plug-in parameters as
+either continuous or discrete has changed.
 
 Possible Issues
 ---------------
-Previously JUCE would report the FrameRateType fps24 for both 24 and
-23.976 fps. If your code uses switch statements (or similar) to handle
-all possible frame rate types, then this change may cause it to fall
-through.
+Plug-ins: DAW projects with automation data written by an AudioUnit, VST3 or
+AAX plug-in built with JUCE version 5.1.1 or earlier may load incorrectly when
+opened by an AudioUnit, VST3 or AAX plug-in built with JUCE version 5.2.0 and
+later.
+
+Hosts: The AudioPluginInstance::getParameterNumSteps method now returns correct
+values for AU and VST3 plug-ins.
+
+Workaround
+----------
+Plug-ins: Enable JUCE_FORCE_LEGACY_PARAMETER_AUTOMATION_TYPE in the
+juce_audio_plugin_client module config page in the Projucer.
+
+Hosts: Use AudioPluginInstance::getDefaultNumParameterSteps as the number of
+steps for all parameters.
+
+Rationale
+---------
+The old system for presenting plug-in parameters to a host as either continuous
+or discrete is inconsistent between plug-in types and lacks sufficient
+flexibility. This change harmonises the behaviour and allows individual
+parameters to be marked as continuous or discrete.
+
+
+Change
+------
+A new FrameRateType fps23976 has been added to AudioPlayHead,
+
+Possible Issues
+---------------
+Previously JUCE would report the FrameRateType fps24 for both 24 and 23.976
+fps. If your code uses switch statements (or similar) to handle all possible
+frame rate types, then this change may cause it to fall through.
 
 Workaround
 ----------
@@ -21,8 +51,8 @@ Add fps23976 to your switch statement and handle it appropriately.
 
 Rationale
 ---------
-JUCE should be able to handle all popular frame rate codes but was 
-missing support for 23.976.
+JUCE should be able to handle all popular frame rate codes but was missing
+support for 23.976.
 
 
 Change
@@ -120,7 +150,7 @@ or
 
 2. Override the Look&Feel method
    PopupMenu::LookAndFeelMethods::shouldPopupMenuScaleWithTargetComponent and
-   return false.  See
+   return false. See
    https://github.com/WeAreROLI/JUCE/blob/c288c94c2914af20f36c03ca9c5401fcb555e4e9/modules/juce_gui_basics/menus/juce_PopupMenu.h#725
 
 Rationale

modules/juce_audio_plugin_client/AAX/juce_AAX_Wrapper.cpp

@@ -1319,12 +1319,14 @@ namespace AAXClasses
 
             for (int parameterIndex = 0; parameterIndex < numParameters; ++parameterIndex)
             {
-                const AudioProcessorParameter::Category category = audioProcessor.getParameterCategory (parameterIndex);
+                auto* processorParam = audioProcessor.getParameters().getUnchecked (parameterIndex);
+
+                const AudioProcessorParameter::Category category = processorParam->getCategory();
 
                 aaxParamIDs.add (usingManagedParameters ? audioProcessor.getParameterID (parameterIndex)
                                                         : String (parameterIndex));
 
-                AAX_CString paramName (audioProcessor.getParameterName (parameterIndex, 31).toRawUTF8());
+                AAX_CString paramName (processorParam->getName (31).toRawUTF8());
                 AAX_CParamID paramID = aaxParamIDs.getReference (parameterIndex).getCharPointer();
 
                 paramMap.set (AAXClasses::getAAXParamHash (paramID), parameterIndex);
@@ -1339,19 +1341,25 @@ namespace AAXClasses
                 AAX_IParameter* parameter
                     = new AAX_CParameter<float> (paramID,
                                                  paramName,
-                                                 audioProcessor.getParameterDefaultValue (parameterIndex),
+                                                 processorParam->getDefaultValue(),
                                                  AAX_CLinearTaperDelegate<float, 0>(),
                                                  AAX_CNumberDisplayDelegate<float, 3>(),
                                                  audioProcessor.isParameterAutomatable (parameterIndex));
 
-                parameter->AddShortenedName (audioProcessor.getParameterName (parameterIndex, 4).toRawUTF8());
+                parameter->AddShortenedName (processorParam->getName (4).toRawUTF8());
 
-                const int parameterNumSteps = audioProcessor.getParameterNumSteps (parameterIndex);
+                const int parameterNumSteps = processorParam->getNumSteps();
                 parameter->SetNumberOfSteps ((uint32_t) parameterNumSteps);
+
+               #if JUCE_FORCE_LEGACY_PARAMETER_AUTOMATION_TYPE
                 parameter->SetType (parameterNumSteps > 1000 ? AAX_eParameterType_Continuous
                                                              : AAX_eParameterType_Discrete);
+               #else
+                parameter->SetType (processorParam->isDiscrete() ? AAX_eParameterType_Discrete
+                                                                 : AAX_eParameterType_Continuous);
+               #endif
 
-                parameter->SetOrientation (audioProcessor.isParameterOrientationInverted (parameterIndex)
+                parameter->SetOrientation (processorParam->isOrientationInverted()
                                             ? (AAX_eParameterOrientation_RightMinLeftMax | AAX_eParameterOrientation_TopMinBottomMax
                                                 | AAX_eParameterOrientation_RotarySingleDotMode | AAX_eParameterOrientation_RotaryRightMinLeftMax)
                                             : (AAX_eParameterOrientation_LeftMinRightMax | AAX_eParameterOrientation_BottomMinTopMax

modules/juce_audio_plugin_client/AU/juce_AU_Wrapper.mm

@@ -525,7 +525,7 @@ public:
                             const String text (String::fromCFString (pv->inString));
 
                             if (AudioProcessorParameter* param = juceFilter->getParameters() [paramID])
-                                pv->outValue = param->getValueForText (text);
+                                pv->outValue = param->getValueForText (text) * getMaximumParameterValue (param);
                             else
                                 pv->outValue = text.getFloatValue();
 
@@ -546,11 +546,12 @@ public:
                             String text;
 
                             if (AudioProcessorParameter* param = juceFilter->getParameters() [paramID])
-                                text = param->getText (value, 0);
+                                text = param->getText (value / getMaximumParameterValue (param), 0);
                             else
                                 text = String (value);
 
                             pv->outString = text.toCFString();
+
                             return noErr;
                         }
                     }
@@ -803,6 +804,17 @@ public:
     }
 
     //==============================================================================
+    // When parameters are discrete we need to use integer values.
+    static float getMaximumParameterValue (AudioProcessorParameter* param)
+    {
+       #if JUCE_FORCE_LEGACY_PARAMETER_AUTOMATION_TYPE
+        ignoreUnused (param);
+        return 1.0f;
+       #else
+        return param->isDiscrete() ? (float) (param->getNumSteps() - 1) : 1.0f;
+       #endif
+    }
+
     ComponentResult GetParameterInfo (AudioUnitScope inScope,
                                       AudioUnitParameterID inParameterID,
                                       AudioUnitParameterInfo& outParameterInfo) override
@@ -811,7 +823,7 @@ public:
 
         if (inScope == kAudioUnitScope_Global
              && juceFilter != nullptr
-             && index < juceFilter->getNumParameters())
+             && isPositiveAndBelow (index, juceFilter->getNumParameters()))
         {
             outParameterInfo.unit = kAudioUnitParameterUnit_Generic;
             outParameterInfo.flags = (UInt32) (kAudioUnitParameterFlag_IsWritable
@@ -823,28 +835,40 @@ public:
             outParameterInfo.flags |= (UInt32) kAudioUnitParameterFlag_IsHighResolution;
            #endif
 
-            const String name (juceFilter->getParameterName (index));
+            auto* param = juceFilter->getParameters().getUnchecked (index);
+
+            const String name (param->getName (512));
 
-            // set whether the param is automatable (unnamed parameters aren't allowed to be automated)
-            if (name.isEmpty() || ! juceFilter->isParameterAutomatable (index))
+            // Set whether the param is automatable (unnamed parameters aren't allowed to be automated)
+            if (name.isEmpty() || ! param->isAutomatable())
                 outParameterInfo.flags |= kAudioUnitParameterFlag_NonRealTime;
 
-            if (juceFilter->isMetaParameter (index))
+            if (! param->isDiscrete())
+                outParameterInfo.flags |= kAudioUnitParameterFlag_CanRamp;
+
+            if (param->isMetaParameter())
                 outParameterInfo.flags |= kAudioUnitParameterFlag_IsGlobalMeta;
 
-            // is this a meter?
-            if (((juceFilter->getParameterCategory (index) & 0xffff0000) >> 16) == 2)
+            // Is this a meter?
+            if (((param->getCategory() & 0xffff0000) >> 16) == 2)
             {
                 outParameterInfo.flags &= ~kAudioUnitParameterFlag_IsWritable;
                 outParameterInfo.flags |= kAudioUnitParameterFlag_MeterReadOnly | kAudioUnitParameterFlag_DisplayLogarithmic;
                 outParameterInfo.unit = kAudioUnitParameterUnit_LinearGain;
             }
+            else
+            {
+               #if ! JUCE_FORCE_LEGACY_PARAMETER_AUTOMATION_TYPE
+                outParameterInfo.unit = param->isDiscrete() ? kAudioUnitParameterUnit_Indexed
+                                                            : kAudioUnitParameterUnit_Generic;
+               #endif
+            }
 
             MusicDeviceBase::FillInParameterName (outParameterInfo, name.toCFString(), true);
 
             outParameterInfo.minValue = 0.0f;
-            outParameterInfo.maxValue = 1.0f;
-            outParameterInfo.defaultValue = juceFilter->getParameterDefaultValue (index);
+            outParameterInfo.maxValue = getMaximumParameterValue (param);
+            outParameterInfo.defaultValue = param->getDefaultValue();
             jassert (outParameterInfo.defaultValue >= outParameterInfo.minValue
                       && outParameterInfo.defaultValue <= outParameterInfo.maxValue);
 
@@ -861,9 +885,9 @@ public:
     {
         if (inScope == kAudioUnitScope_Global && juceFilter != nullptr)
         {
-            const int index = getJuceIndexForAUParameterID (inID);
+            auto* param = juceFilter->getParameters().getUnchecked (getJuceIndexForAUParameterID (inID));
 
-            outValue = juceFilter->getParameter (index);
+            outValue = param->getValue() * getMaximumParameterValue (param);
             return noErr;
         }
 
@@ -878,9 +902,9 @@ public:
     {
         if (inScope == kAudioUnitScope_Global && juceFilter != nullptr)
         {
-            const int index = getJuceIndexForAUParameterID (inID);
+            auto* param = juceFilter->getParameters().getUnchecked (getJuceIndexForAUParameterID (inID));
 
-            juceFilter->setParameter (index, inValue);
+            param->setValue (inValue / getMaximumParameterValue (param));
             return noErr;
         }
 
@@ -1727,6 +1751,14 @@ private:
         {
             Globals()->UseIndexedParameters (numParams);
         }
+
+       #if JUCE_DEBUG
+        // Some hosts can't handle the huge numbers of discrete parameter values created when
+        // using the default number of steps.
+        for (auto* param : juceFilter->getParameters())
+            if (param->isDiscrete())
+                jassert (param->getNumSteps() != juceFilter->getDefaultNumParameterSteps());
+       #endif
     }
 
     //==============================================================================

modules/juce_audio_plugin_client/VST3/juce_VST3_Wrapper.cpp

@@ -204,21 +204,32 @@ public:
         Param (AudioProcessor& p, int index, Vst::ParamID paramID)  : owner (p), paramIndex (index)
         {
             info.id = paramID;
-            toString128 (info.title, p.getParameterName (index));
-            toString128 (info.shortTitle, p.getParameterName (index, 8));
-            toString128 (info.units, p.getParameterLabel (index));
 
-            const int numSteps = p.getParameterNumSteps (index);
-            info.stepCount = (Steinberg::int32) (numSteps > 0 && numSteps < 0x7fffffff ? numSteps - 1 : 0);
-            info.defaultNormalizedValue = p.getParameterDefaultValue (index);
+            auto* param = p.getParameters().getUnchecked (index);
+
+            toString128 (info.title,      param->getName (128));
+            toString128 (info.shortTitle, param->getName (8));
+            toString128 (info.units,      param->getLabel());
+
+            info.stepCount = (Steinberg::int32) 0;
+
+           #if ! JUCE_FORCE_LEGACY_PARAMETER_AUTOMATION_TYPE
+            if (param->isDiscrete())
+           #endif
+            {
+                const int numSteps = param->getNumSteps();
+                info.stepCount = (Steinberg::int32) (numSteps > 0 && numSteps < 0x7fffffff ? numSteps - 1 : 0);
+            }
+
+            info.defaultNormalizedValue = param->getDefaultValue();
             jassert (info.defaultNormalizedValue >= 0 && info.defaultNormalizedValue <= 1.0f);
             info.unitId = Vst::kRootUnitId;
 
-            // is this a meter?
-            if (((p.getParameterCategory (index) & 0xffff0000) >> 16) == 2)
+            // Is this a meter?
+            if (((param->getCategory() & 0xffff0000) >> 16) == 2)
                 info.flags = Vst::ParameterInfo::kIsReadOnly;
             else
-                info.flags = p.isParameterAutomatable (index) ? Vst::ParameterInfo::kCanAutomate : 0;
+                info.flags = param->isAutomatable() ? Vst::ParameterInfo::kCanAutomate : 0;
 
             valueNormalized = info.defaultNormalizedValue;
         }

modules/juce_audio_plugin_client/juce_audio_plugin_client.h

@@ -65,15 +65,28 @@
  #define JUCE_FORCE_USE_LEGACY_PARAM_IDS 0
 #endif
 
+/** Config: JUCE_FORCE_LEGACY_PARAMETER_AUTOMATION_TYPE
+
+    Enable this if you want to force JUCE to use a legacy scheme for
+    identifying plug-in parameters as either continuous or discrete.
+    DAW projects with automation data written by an AudioUnit, VST3 or
+    AAX plug-in built with JUCE version 5.1.1 or earlier may load
+    incorrectly when opened by an AudioUnit, VST3 or AAX plug-in built
+    with JUCE version 5.2.0 and later.
+*/
+#ifndef JUCE_FORCE_LEGACY_PARAMETER_AUTOMATION_TYPE
+ #define JUCE_FORCE_LEGACY_PARAMETER_AUTOMATION_TYPE 0
+#endif
+
 /** Config: JUCE_USE_STUDIO_ONE_COMPATIBLE_PARAMETERS
 
     Enable this if you want JUCE to use parameter ids which are compatible
-    to Studio One. Studio One ignores any parameter ids which are negative.
+    with Studio One. Studio One ignores any parameter ids which are negative.
     Enabling this option will make JUCE generate only positive parameter ids.
-    Note that if you have already released a plug-in prio to JUCE 4.3.0 then
+    Note that if you have already released a plug-in prior to JUCE 4.3.0 then
     enabling this will change your parameter ids making your plug-in
     incompatible to old automation data.
- */
+*/
 #ifndef JUCE_USE_STUDIO_ONE_COMPATIBLE_PARAMETERS
  #define JUCE_USE_STUDIO_ONE_COMPATIBLE_PARAMETERS 1
 #endif

modules/juce_audio_processors/format_types/juce_AudioUnitPluginFormat.mm

@@ -986,6 +986,22 @@ public:
 
     const String getParameterText (int index) override   { return String (getParameter (index)); }
 
+    int getParameterNumSteps (int index) override
+    {
+        if (auto* p = parameters[index])
+            return p->numSteps;
+
+        return AudioProcessor::getDefaultNumParameterSteps();
+    }
+
+    bool isParameterDiscrete (int index) const override
+    {
+        if (auto* p = parameters[index])
+            return p->discrete;
+
+        return false;
+    }
+
     bool isParameterAutomatable (int index) const override
     {
         if (auto* p = parameters[index])
@@ -1178,6 +1194,8 @@ public:
                         param->minValue = info.minValue;
                         param->maxValue = info.maxValue;
                         param->automatable = (info.flags & kAudioUnitParameterFlag_NonRealTime) == 0;
+                        param->discrete = (info.unit == kAudioUnitParameterUnit_Indexed);
+                        param->numSteps = param->discrete ? (int) (info.maxValue + 1.0f) : AudioProcessor::getDefaultNumParameterSteps();
 
                         if ((info.flags & kAudioUnitParameterFlag_HasCFNameString) != 0)
                         {
@@ -1263,7 +1281,8 @@ private:
         UInt32 paramID;
         String name;
         AudioUnitParameterValue minValue, maxValue;
-        bool automatable;
+        bool automatable, discrete;
+        int numSteps;
     };
 
     OwnedArray<ParamInfo> parameters;

modules/juce_audio_processors/format_types/juce_VST3PluginFormat.cpp

@@ -2247,30 +2247,54 @@ struct VST3PluginInstance : public AudioPluginInstance
         return toString (getParameterInfoForIndex (parameterIndex).title);
     }
 
-    float getParameter (int parameterIndex) override
+    const String getParameterText (int parameterIndex) override
     {
         if (editController != nullptr)
         {
             auto id = getParameterInfoForIndex (parameterIndex).id;
-            return (float) editController->getParamNormalized (id);
+
+            Vst::String128 result;
+            warnOnFailure (editController->getParamStringByValue (id, editController->getParamNormalized (id), result));
+
+            return toString (result);
         }
 
-        return 0.0f;
+        return {};
     }
 
-    const String getParameterText (int parameterIndex) override
+    int getParameterNumSteps (int parameterIndex) override
     {
         if (editController != nullptr)
         {
-            auto id = getParameterInfoForIndex (parameterIndex).id;
+            const auto numSteps = getParameterInfoForIndex (parameterIndex).stepCount;
 
-            Vst::String128 result;
-            warnOnFailure (editController->getParamStringByValue (id, editController->getParamNormalized (id), result));
+            if (numSteps > 0)
+                return numSteps;
+        }
 
-            return toString (result);
+        return AudioProcessor::getDefaultNumParameterSteps();
+    }
+
+    bool isParameterDiscrete (int parameterIndex) const override
+    {
+        if (editController != nullptr)
+        {
+            const auto numSteps = getParameterInfoForIndex (parameterIndex).stepCount;
+            return numSteps > 0;
         }
 
-        return {};
+        return false;
+    }
+
+    float getParameter (int parameterIndex) override
+    {
+        if (editController != nullptr)
+        {
+            auto id = getParameterInfoForIndex (parameterIndex).id;
+            return (float) editController->getParamNormalized (id);
+        }
+
+        return 0.0f;
     }
 
     void setParameter (int parameterIndex, float newValue) override

modules/juce_audio_processors/juce_audio_processors.h

@@ -56,6 +56,18 @@
 #include <juce_gui_basics/juce_gui_basics.h>
 #include <juce_audio_basics/juce_audio_basics.h>
 
+/** Config: JUCE_FORCE_LEGACY_PARAMETER_AUTOMATION_TYPE
+
+    Enable this if you want to force JUCE to use an old scheme for selecting
+    when parameters are classified as discrete or continuous in a host. If this
+    is not enabled then DAW projects with automation data written by an
+    AudioUnit, VST3 or AAX plug-in built with JUCE version 5.1.1 or earlier may
+    load incorrectly when opened by an AudioUnit, VST3 or AAX plug-in built
+    with JUCE version 5.2.0 and later.
+*/
+#ifndef JUCE_FORCE_LEGACY_PARAMETER_AUTOMATION_TYPE
+ #define JUCE_FORCE_LEGACY_PARAMETER_AUTOMATION_TYPE 0
+#endif
 
 //==============================================================================
 /** Config: JUCE_PLUGINHOST_VST

modules/juce_audio_processors/processors/juce_AudioProcessor.cpp

@@ -625,6 +625,14 @@ int AudioProcessor::getDefaultNumParameterSteps() noexcept
     return 0x7fffffff;
 }
 
+bool AudioProcessor::isParameterDiscrete (int index) const
+{
+    if (auto* p = managedParameters[index])
+        return p->isDiscrete();
+
+    return false;
+}
+
 String AudioProcessor::getParameterLabel (int index) const
 {
     if (auto* p = managedParameters[index])
@@ -1401,11 +1409,12 @@ void AudioProcessorParameter::endChangeGesture()
     processor->endParameterChangeGesture (parameterIndex);
 }
 
-bool AudioProcessorParameter::isOrientationInverted() const                    { return false; }
-bool AudioProcessorParameter::isAutomatable() const                            { return true; }
-bool AudioProcessorParameter::isMetaParameter() const                          { return false; }
-AudioProcessorParameter::Category AudioProcessorParameter::getCategory() const { return genericParameter; }
-int AudioProcessorParameter::getNumSteps() const            { return AudioProcessor::getDefaultNumParameterSteps(); }
+bool AudioProcessorParameter::isOrientationInverted() const                      { return false; }
+bool AudioProcessorParameter::isAutomatable() const                              { return true; }
+bool AudioProcessorParameter::isMetaParameter() const                            { return false; }
+AudioProcessorParameter::Category AudioProcessorParameter::getCategory() const   { return genericParameter; }
+int AudioProcessorParameter::getNumSteps() const                                 { return AudioProcessor::getDefaultNumParameterSteps(); }
+bool AudioProcessorParameter::isDiscrete() const                                 { return false; }
 
 String AudioProcessorParameter::getText (float value, int /*maximumStringLength*/) const
 {

modules/juce_audio_processors/processors/juce_AudioProcessor.h

@@ -1020,13 +1020,22 @@ public:
     virtual String getParameterText (int parameterIndex, int maximumStringLength);
 
     /** Returns the number of discrete steps that this parameter can represent.
+
         The default return value if you don't implement this method is
         AudioProcessor::getDefaultNumParameterSteps().
+
         If your parameter is boolean, then you may want to make this return 2.
+
+        If you want the host to display stepped automation values, rather than a
+        continuous interpolation between successive values, you should ensure that
+        isParameterDiscrete returns true.
+
         The value that is returned may or may not be used, depending on the host.
 
         NOTE! This method will eventually be deprecated! It's recommended that you use
         AudioProcessorParameter::getNumSteps() instead.
+
+        @see isParameterDiscrete
     */
     virtual int getParameterNumSteps (int parameterIndex);
 
@@ -1034,10 +1043,26 @@ public:
 
         NOTE! This method will eventually be deprecated! It's recommended that you use
         AudioProcessorParameter::getNumSteps() instead.
+
         @see getParameterNumSteps
     */
     static int getDefaultNumParameterSteps() noexcept;
 
+    /** Returns true if the parameter should take discrete, rather than continuous
+        values.
+
+        If the parameter is boolean, this should return true (with getParameterNumSteps
+        returning 2).
+
+        The value that is returned may or may not be used, depending on the host.
+
+        NOTE! This method will eventually be deprecated! It's recommended that you use
+        AudioProcessorParameter::isDiscrete() instead.
+
+        @see getParameterNumSteps
+    */
+    virtual bool isParameterDiscrete (int parameterIndex) const;
+
     /** Returns the default value for the parameter.
         By default, this just returns 0.
         The value that is returned may or may not be used, depending on the host.

modules/juce_audio_processors/processors/juce_AudioProcessorParameter.h

@@ -106,16 +106,32 @@ public:
     */
     virtual String getLabel() const = 0;
 
-    /** Returns the number of discrete interval steps that this parameter's range
-        should be quantised into.
+    /** Returns the number of steps that this parameter's range should be quantised into.
 
         If you want a continuous range of values, don't override this method, and allow
         the default implementation to return AudioProcessor::getDefaultNumParameterSteps().
+
         If your parameter is boolean, then you may want to make this return 2.
-        The value that is returned may or may not be used, depending on the host.
+
+        The value that is returned may or may not be used, depending on the host. If you
+        want the host to display stepped automation values, rather than a continuous
+        interpolation between successive values, you should override isDiscrete to return true.
+
+        @see isDiscrete
     */
     virtual int getNumSteps() const;
 
+    /** Returns whether the parameter uses discrete values, based on the result of
+        getNumSteps, or allows the host to select values continuously.
+
+        This information may or may not be used, depending on the host. If you
+        want the host to display stepped automation values, rather than a continuous
+        interpolation between successive values, override this method to return true.
+
+        @see getNumSteps
+    */
+    virtual bool isDiscrete() const;
+
     /** Returns a textual version of the supplied parameter value.
         The default implementation just returns the floating point value
         as a string, but this could do anything you need for a custom type

modules/juce_audio_processors/utilities/juce_AudioParameterBool.h

@@ -58,6 +58,7 @@ private:
     void setValue (float newValue) override;
     float getDefaultValue() const override;
     int getNumSteps() const override;
+    bool isDiscrete() const override;
     String getText (float, int) const override;
     float getValueForText (const String&) const override;
 

modules/juce_audio_processors/utilities/juce_AudioParameterChoice.h

@@ -69,6 +69,7 @@ private:
     void setValue (float newValue) override;
     float getDefaultValue() const override;
     int getNumSteps() const override;
+    bool isDiscrete() const override;
     String getText (float, int) const override;
     float getValueForText (const String&) const override;
 

modules/juce_audio_processors/utilities/juce_AudioProcessorParameters.cpp

@@ -124,6 +124,7 @@ float AudioParameterBool::getValue() const                               { retur
 void AudioParameterBool::setValue (float newValue)                       { value = newValue; }
 float AudioParameterBool::getDefaultValue() const                        { return defaultValue; }
 int AudioParameterBool::getNumSteps() const                              { return 2; }
+bool AudioParameterBool::isDiscrete() const                              { return true; }
 float AudioParameterBool::getValueForText (const String& text) const     { return text.getIntValue() != 0 ? 1.0f : 0.0f; }
 String AudioParameterBool::getText (float v, int /*length*/) const       { return String ((int) (v > 0.5f ? 1 : 0)); }
 
@@ -156,6 +157,7 @@ float AudioParameterChoice::getValue() const                             { retur
 void AudioParameterChoice::setValue (float newValue)                     { value = (float) convertFrom0to1 (newValue); }
 float AudioParameterChoice::getDefaultValue() const                      { return defaultValue; }
 int AudioParameterChoice::getNumSteps() const                            { return choices.size(); }
+bool AudioParameterChoice::isDiscrete() const                            { return true; }
 float AudioParameterChoice::getValueForText (const String& text) const   { return convertTo0to1 (choices.indexOf (text)); }
 String AudioParameterChoice::getText (float v, int /*length*/) const     { return choices [convertFrom0to1 (v)]; }
 

modules/juce_audio_processors/utilities/juce_AudioProcessorValueTreeState.cpp

@@ -34,13 +34,15 @@ struct AudioProcessorValueTreeState::Parameter   : public AudioProcessorParamete
                std::function<String (float)> valueToText,
                std::function<float (const String&)> textToValue,
                bool meta,
-               bool automatable)
+               bool automatable,
+               bool discrete)
         : AudioProcessorParameterWithID (parameterID, paramName, labelText),
           owner (s), valueToTextFunction (valueToText), textToValueFunction (textToValue),
           range (r), value (defaultVal), defaultValue (defaultVal),
           listenersNeedCalling (true),
           isMetaParam (meta),
-          isAutomatableParam (automatable)
+          isAutomatableParam (automatable),
+          isDiscreteParam (discrete)
     {
         state.addListener (this);
         needsUpdate.set (1);
@@ -150,6 +152,7 @@ struct AudioProcessorValueTreeState::Parameter   : public AudioProcessorParamete
 
     bool isMetaParameter() const override      { return isMetaParam; }
     bool isAutomatable() const override        { return isAutomatableParam; }
+    bool isDiscrete() const override           { return isDiscreteParam; }
 
     AudioProcessorValueTreeState& owner;
     ValueTree state;
@@ -160,7 +163,7 @@ struct AudioProcessorValueTreeState::Parameter   : public AudioProcessorParamete
     float value, defaultValue;
     Atomic<int> needsUpdate;
     bool listenersNeedCalling;
-    const bool isMetaParam, isAutomatableParam;
+    const bool isMetaParam, isAutomatableParam, isDiscreteParam;
 
     JUCE_DECLARE_NON_COPYABLE_WITH_LEAK_DETECTOR (Parameter)
 };
@@ -185,7 +188,8 @@ AudioProcessorParameterWithID* AudioProcessorValueTreeState::createAndAddParamet
                                                                                     float defaultVal, std::function<String (float)> valueToTextFunction,
                                                                                     std::function<float (const String&)> textToValueFunction,
                                                                                     bool isMetaParameter,
-                                                                                    bool isAutomatableParameter)
+                                                                                    bool isAutomatableParameter,
+                                                                                    bool isDiscreteParameter)
 {
     // All parameters must be created before giving this manager a ValueTree state!
     jassert (! state.isValid());
@@ -195,7 +199,8 @@ AudioProcessorParameterWithID* AudioProcessorValueTreeState::createAndAddParamet
 
     Parameter* p = new Parameter (*this, paramID, paramName, labelText, r,
                                   defaultVal, valueToTextFunction, textToValueFunction,
-                                  isMetaParameter, isAutomatableParameter);
+                                  isMetaParameter, isAutomatableParameter,
+                                  isDiscreteParameter);
     processor.addParameter (p);
     return p;
 }

modules/juce_audio_processors/utilities/juce_AudioProcessorValueTreeState.h

@@ -77,6 +77,8 @@ public:
         @param textToValueFunction      The inverse of valueToTextFunction
         @param isMetaParameter          Set this value to true if this should be a meta parameter
         @param isAutomatableParameter   Set this value to false if this parameter should not be automatable
+        @param isDiscrete               Set this value to true to make this parameter take discrete values in a host.
+                                        @see AudioProcessorParameter::isDiscrete
 
         @returns the parameter object that was created
     */
@@ -88,7 +90,8 @@ public:
                                                           std::function<String (float)> valueToTextFunction,
                                                           std::function<float (const String&)> textToValueFunction,
                                                           bool isMetaParameter = false,
-                                                          bool isAutomatableParameter = true);
+                                                          bool isAutomatableParameter = true,
+                                                          bool isDiscrete = false);
 
     /** Returns a parameter by its ID string. */
     AudioProcessorParameterWithID* getParameter (StringRef parameterID) const noexcept;