APVTS: Fixed an inconsistency between ComboBoxAttachment IDs and parameter values

modules/juce_audio_processors/utilities/juce_AudioProcessorValueTreeState.cpp

@@ -217,19 +217,19 @@ AudioProcessorParameterWithID* AudioProcessorValueTreeState::createAndAddParamet
 
 void AudioProcessorValueTreeState::addParameterListener (StringRef paramID, Listener* listener)
 {
-    if (Parameter* p = Parameter::getParameterForID (processor, paramID))
+    if (auto* p = Parameter::getParameterForID (processor, paramID))
         p->listeners.add (listener);
 }
 
 void AudioProcessorValueTreeState::removeParameterListener (StringRef paramID, Listener* listener)
 {
-    if (Parameter* p = Parameter::getParameterForID (processor, paramID))
+    if (auto* p = Parameter::getParameterForID (processor, paramID))
         p->listeners.remove (listener);
 }
 
 Value AudioProcessorValueTreeState::getParameterAsValue (StringRef paramID) const
 {
-    if (Parameter* p = Parameter::getParameterForID (processor, paramID))
+    if (auto* p = Parameter::getParameterForID (processor, paramID))
         return p->state.getPropertyAsValue (valuePropertyID, undoManager);
 
     return {};
@@ -237,7 +237,7 @@ Value AudioProcessorValueTreeState::getParameterAsValue (StringRef paramID) cons
 
 NormalisableRange<float> AudioProcessorValueTreeState::getParameterRange (StringRef paramID) const noexcept
 {
-    if (Parameter* p = Parameter::getParameterForID (processor, paramID))
+    if (auto* p = Parameter::getParameterForID (processor, paramID))
         return p->range;
 
     return NormalisableRange<float>();
@@ -250,7 +250,7 @@ AudioProcessorParameterWithID* AudioProcessorValueTreeState::getParameter (Strin
 
 float* AudioProcessorValueTreeState::getRawParameterValue (StringRef paramID) const noexcept
 {
-    if (Parameter* p = Parameter::getParameterForID (processor, paramID))
+    if (auto* p = Parameter::getParameterForID (processor, paramID))
         return &(p->value);
 
     return nullptr;
@@ -382,7 +382,7 @@ struct AttachedControlBase  : public AudioProcessorValueTreeState::Listener,
 
     void setNewUnnormalisedValue (float newUnnormalisedValue)
     {
-        if (AudioProcessorParameter* p = state.getParameter (paramID))
+        if (auto* p = state.getParameter (paramID))
         {
             const float newValue = state.getParameterRange (paramID)
                                         .convertTo0to1 (newUnnormalisedValue);
@@ -394,7 +394,7 @@ struct AttachedControlBase  : public AudioProcessorValueTreeState::Listener,
 
     void sendInitialUpdate()
     {
-        if (float* v = state.getRawParameterValue (paramID))
+        if (auto* v = state.getRawParameterValue (paramID))
             parameterChanged (paramID, *v);
     }
 
@@ -415,7 +415,7 @@ struct AttachedControlBase  : public AudioProcessorValueTreeState::Listener,
 
     void beginParameterChange()
     {
-        if (AudioProcessorParameter* p = state.getParameter (paramID))
+        if (auto* p = state.getParameter (paramID))
         {
             if (state.undoManager != nullptr)
                 state.undoManager->beginNewTransaction();
@@ -570,21 +570,37 @@ struct AudioProcessorValueTreeState::ComboBoxAttachment::Pimpl  : private Attach
     {
         const ScopedLock selfCallbackLock (selfCallbackMutex);
 
+        if (state.getParameter (paramID) != nullptr)
         {
-            ScopedValueSetter<bool> svs (ignoreCallbacks, true);
-            combo.setSelectedItemIndex (roundToInt (newValue), sendNotificationSync);
+            auto normValue = state.getParameterRange (paramID)
+                                  .convertTo0to1 (newValue);
+            auto index = roundToInt (normValue * (combo.getNumItems() - 1));
+
+            if (index != combo.getSelectedItemIndex())
+            {
+                ScopedValueSetter<bool> svs (ignoreCallbacks, true);
+                combo.setSelectedItemIndex (index, sendNotificationSync);
+            }
         }
     }
 
-    void comboBoxChanged (ComboBox* comboBox) override
+    void comboBoxChanged (ComboBox*) override
     {
         const ScopedLock selfCallbackLock (selfCallbackMutex);
 
         if (! ignoreCallbacks)
         {
-            beginParameterChange();
-            setNewUnnormalisedValue ((float) comboBox->getSelectedId() - 1.0f);
-            endParameterChange();
+            if (auto* p = state.getParameter (paramID))
+            {
+                auto newValue = (float) combo.getSelectedItemIndex() / (combo.getNumItems() - 1);
+
+                if (p->getValue() != newValue)
+                {
+                    beginParameterChange();
+                    p->setValueNotifyingHost (newValue);
+                    endParameterChange();
+                }
+            }
         }
     }
 

modules/juce_audio_processors/utilities/juce_AudioProcessorValueTreeState.h

@@ -206,6 +206,11 @@ public:
     /** An object of this class maintains a connection between a ComboBox and a parameter
         in an AudioProcessorValueTreeState.
 
+        Combobox items will be spaced linearly across the range of the parameter. For
+        example if the range is specified by NormalisableRange<float> (-0.5f, 0.5f, 0.5f)
+        and you add three items then the first will be mapped to a value of -0.5, the
+        second to 0, and the third to 0.5.
+
         During the lifetime of this ComboBoxAttachment object, it keeps the two things in
         sync, making it easy to connect a combo box to a parameter. When this object is
         deleted, the connection is broken. Make sure that your AudioProcessorValueTreeState