AUv3: Improved the host-provided parameter views

modules/juce_audio_plugin_client/AU/juce_AU_Wrapper.mm

@@ -525,11 +525,11 @@ public:
                     {
                         if (juceFilter != nullptr)
                         {
-                            const int paramID = getJuceIndexForAUParameterID (pv->inParamID);
+                            const int i = getJuceIndexForAUParameterID (pv->inParamID);
                             const String text (String::fromCFString (pv->inString));
 
-                            if (AudioProcessorParameter* param = juceFilter->getParameters() [paramID])
-                                pv->outValue = param->getValueForText (text) * getMaximumParameterValue (paramID);
+                            if (AudioProcessorParameter* param = juceFilter->getParameters()[i])
+                                pv->outValue = param->getValueForText (text) * getMaximumParameterValue (i);
                             else
                                 pv->outValue = text.getFloatValue();
 
@@ -545,12 +545,12 @@ public:
                     {
                         if (juceFilter != nullptr)
                         {
-                            const int paramID = getJuceIndexForAUParameterID (pv->inParamID);
+                            const int i = getJuceIndexForAUParameterID (pv->inParamID);
                             const float value = (float) *(pv->inValue);
                             String text;
 
-                            if (AudioProcessorParameter* param = juceFilter->getParameters() [paramID])
-                                text = param->getText (value / getMaximumParameterValue (paramID), 0);
+                            if (AudioProcessorParameter* param = juceFilter->getParameters()[i])
+                                text = param->getText (value / getMaximumParameterValue (i), 0);
                             else
                                 text = String (value);
 
@@ -776,7 +776,7 @@ public:
         return (UInt32) layouts.size();
     }
 
-    OSStatus SetAudioChannelLayout(AudioUnitScope scope, AudioUnitElement element, const AudioChannelLayout* inLayout) override
+    OSStatus SetAudioChannelLayout (AudioUnitScope scope, AudioUnitElement element, const AudioChannelLayout* inLayout) override
     {
         bool isInput;
         int busNr;
@@ -877,8 +877,8 @@ public:
             else
             {
                #if ! JUCE_FORCE_LEGACY_PARAMETER_AUTOMATION_TYPE
-                outParameterInfo.unit = isParameterDiscrete ? kAudioUnitParameterUnit_Indexed
-                                                            : kAudioUnitParameterUnit_Generic;
+                if (isParameterDiscrete)
+                    outParameterInfo.unit = kAudioUnitParameterUnit_Indexed;
                #endif
             }
 

modules/juce_audio_plugin_client/AU/juce_AUv3_Wrapper.mm

@@ -1082,13 +1082,22 @@ private:
                                                                                          busses: array];
     }
 
+    // When parameters are discrete we need to use integer values.
+    float getMaximumParameterValue (int parameterIndex)
+    {
+       #if JUCE_FORCE_LEGACY_PARAMETER_AUTOMATION_TYPE
+        ignoreUnused (parameterIndex);
+        return 1.0f;
+       #else
+        auto& processor = getAudioProcessor();
+        return processor.isParameterDiscrete (parameterIndex) ? (float) (processor.getParameterNumSteps (parameterIndex) - 1) : 1.0f;
+       #endif
+    }
+
     void addParameters()
     {
         ScopedPointer<NSMutableArray<AUParameterNode*>> params = [[NSMutableArray<AUParameterNode*> alloc] init];
 
-        paramObserver = CreateObjCBlock (this, &JuceAudioUnitv3::valueChangedFromHost);
-        paramProvider = CreateObjCBlock (this, &JuceAudioUnitv3::getValue);
-
         overviewParams = [[NSMutableArray<NSNumber*> alloc] init];
 
         auto& processor = getAudioProcessor();
@@ -1118,9 +1127,17 @@ private:
             if (name.isEmpty() || ! processor.isParameterAutomatable (idx))
                 flags |= kAudioUnitParameterFlag_NonRealTime;
 
+            const bool isParameterDiscrete = processor.isParameterDiscrete (idx);
+
+            if (! isParameterDiscrete)
+                flags |= kAudioUnitParameterFlag_CanRamp;
+
             if (processor.isMetaParameter (idx))
                 flags |= kAudioUnitParameterFlag_IsGlobalMeta;
 
+            auto deleter = [](NSMutableArray* arr) { [arr release]; };
+            std::unique_ptr<NSMutableArray, decltype (deleter)> valueStrings (nullptr, deleter);
+
             // is this a meter?
             if (((processor.getParameterCategory (idx) & 0xffff0000) >> 16) == 2)
             {
@@ -1128,13 +1145,36 @@ private:
                 flags |= kAudioUnitParameterFlag_MeterReadOnly | kAudioUnitParameterFlag_DisplayLogarithmic;
                 unit = kAudioUnitParameterUnit_LinearGain;
             }
+            else
+            {
+               #if ! JUCE_FORCE_LEGACY_PARAMETER_AUTOMATION_TYPE
+                if (auto* param = processor.getParameters()[idx])
+                {
+                    if (param->isDiscrete())
+                    {
+                        unit = kAudioUnitParameterUnit_Indexed;
+                        auto maxValue = getMaximumParameterValue (idx);
+                        auto numSteps = param->getNumSteps();
+
+                        // Some hosts can't handle the huge numbers of discrete parameter values created when
+                        // using the default number of steps.
+                        jassert (numSteps != AudioProcessor::getDefaultNumParameterSteps());
+
+                        valueStrings.reset ([NSMutableArray new]);
+
+                        for (int i = 0; i < numSteps; ++i)
+                            [valueStrings.get() addObject: juceStringToNS (param->getText ((float) i / maxValue, 0))];
+                    }
+                }
+               #endif
+            }
 
            #if JUCE_FORCE_USE_LEGACY_PARAM_IDS
             AUParameterAddress address = static_cast<AUParameterAddress> (idx);
            #else
             AUParameterAddress address = generateAUParameterAddressForIndex (idx);
 
-            // Consider yourself very unlucky if you hit this assertion. The hash code of your
+            // Consider yourself very unlucky if you hit this assertion. The hash codes of your
             // parameter ids are not unique.
             jassert (! paramMap.contains (static_cast<int64> (address)));
 
@@ -1148,13 +1188,15 @@ private:
                                                                                           name: juceStringToNS (name)
                                                                                        address: address
                                                                                            min: 0.0f
-                                                                                           max: 1.0f
+                                                                                           max: getMaximumParameterValue (idx)
                                                                                           unit: unit
                                                                                       unitName: nullptr
                                                                                          flags: flags
-                                                                                  valueStrings: nullptr
+                                                                                  valueStrings: valueStrings.get()
                                                                            dependentParameters: nullptr] retain];
 
+            [param.get() setValue: processor.getParameterDefaultValue (idx)];
+
             [params addObject: param];
             [overviewParams addObject: [NSNumber numberWithUnsignedLongLong:address]];
         }
@@ -1162,8 +1204,15 @@ private:
         // create methods in AUParameterTree return unretained objects (!) -> see Apple header AUAudioUnitImplementation.h
         paramTree = [[AUParameterTree createTreeWithChildren: params] retain];
 
+        paramObserver           = CreateObjCBlock (this, &JuceAudioUnitv3::valueChangedFromHost);
+        paramProvider           = CreateObjCBlock (this, &JuceAudioUnitv3::getValue);
+        stringFromValueProvider = CreateObjCBlock (this, &JuceAudioUnitv3::stringFromValue);
+        valueFromStringProvider = CreateObjCBlock (this, &JuceAudioUnitv3::valueFromString);
+
         [paramTree setImplementorValueObserver: paramObserver];
         [paramTree setImplementorValueProvider: paramProvider];
+        [paramTree setImplementorStringFromValueCallback: stringFromValueProvider];
+        [paramTree setImplementorValueFromStringCallback: valueFromStringProvider];
 
         if (processor.hasEditor())
         {
@@ -1375,7 +1424,7 @@ private:
             auto& processor = getAudioProcessor();
 
             if (isPositiveAndBelow (idx, processor.getNumParameters()))
-                processor.setParameter (idx, value);
+                processor.setParameter (idx, value / getMaximumParameterValue (idx));
         }
     }
 
@@ -1387,7 +1436,7 @@ private:
             auto& processor = getAudioProcessor();
 
             if (isPositiveAndBelow (idx, processor.getNumParameters()))
-                return processor.getParameter (idx);
+                return processor.getParameter (idx) * getMaximumParameterValue (idx);
         }
 
         return 0;
@@ -1398,6 +1447,41 @@ private:
         // this will have already been handled by valueChangedFromHost
     }
 
+    NSString* stringFromValue (AUParameter* param, const AUValue* value)
+    {
+        String text;
+
+        if (param != nullptr && value != nullptr)
+        {
+            const int idx = getJuceParameterIndexForAUAddress ([param address]);
+            auto& processor = getAudioProcessor();
+
+            if (auto* p = processor.getParameters()[idx])
+                text = p->getText (*value / getMaximumParameterValue (idx), 0);
+            else
+                text = String (*value);
+        }
+
+        return juceStringToNS (text);
+    }
+
+    AUValue valueFromString (AUParameter* param, NSString* str)
+    {
+        if (param != nullptr && str != nullptr)
+        {
+            const int idx = getJuceParameterIndexForAUAddress ([param address]);
+            auto& processor = getAudioProcessor();
+            const String text (nsStringToJuce (str));
+
+            if (auto* p = processor.getParameters()[idx])
+                return p->getValueForText (text) * getMaximumParameterValue (idx);
+            else
+                return text.getFloatValue();
+        }
+
+        return 0;
+    }
+
     //==============================================================================
    #if JUCE_FORCE_USE_LEGACY_PARAM_IDS
     inline AUParameterAddress getAUParameterAddressForIndex (int paramIndex) const noexcept     { return static_cast<AUParameterAddress> (paramIndex); }
@@ -1443,6 +1527,8 @@ private:
 
     ObjCBlock<AUImplementorValueObserver> paramObserver;
     ObjCBlock<AUImplementorValueProvider> paramProvider;
+    ObjCBlock<AUImplementorStringFromValueCallback> stringFromValueProvider;
+    ObjCBlock<AUImplementorValueFromStringCallback> valueFromStringProvider;
 
    #if ! JUCE_FORCE_USE_LEGACY_PARAM_IDS
     bool usingManagedParameter;