Added support saving/restoring plugin bus layouts in the audio host demo

examples/audio plugin host/Source/FilterGraph.cpp

@@ -288,6 +288,67 @@ void FilterGraph::setLastDocumentOpened (const File& file)
 }
 
 //==============================================================================
+static void readBusLayoutFromXml (AudioProcessor::BusesLayout& busesLayout, AudioProcessor* plugin, const XmlElement& xml, const bool isInput)
+{
+    Array<AudioChannelSet>& targetBuses = (isInput ? busesLayout.inputBuses : busesLayout.outputBuses);
+    int maxNumBuses = 0;
+
+    if (auto* buses = xml.getChildByName (isInput ? "INPUTS" : "OUTPUTS"))
+    {
+        forEachXmlChildElementWithTagName (*buses, e, "BUS")
+        {
+            const int busIdx = e->getIntAttribute ("index");
+            maxNumBuses = jmax (maxNumBuses, busIdx + 1);
+
+            // the number of buses on busesLayout may not be in sync with the plugin after adding buses
+            // because adding an input bus could also add an output bus
+            for (int actualIdx = plugin->getBusCount (isInput) - 1; actualIdx < busIdx; ++actualIdx)
+                if (! plugin->addBus (isInput)) return;
+
+            for (int actualIdx = targetBuses.size() - 1; actualIdx < busIdx; ++actualIdx)
+                targetBuses.add (plugin->getChannelLayoutOfBus (isInput, busIdx));
+
+            const String& layout = e->getStringAttribute("layout");
+
+            if (layout.isNotEmpty())
+                targetBuses.getReference (busIdx) = AudioChannelSet::fromAbbreviatedString (layout);
+        }
+    }
+
+    // if the plugin has more buses than specified in the xml, then try to remove them!
+    while (maxNumBuses < targetBuses.size())
+    {
+        if (! plugin->removeBus (isInput))
+            return;
+
+        targetBuses.removeLast();
+    }
+}
+
+//==============================================================================
+static XmlElement* createBusLayoutXml (const AudioProcessor::BusesLayout& layout, const bool isInput)
+{
+    const Array<AudioChannelSet>& buses = (isInput ? layout.inputBuses : layout.outputBuses);
+
+    XmlElement* xml = new XmlElement (isInput ? "INPUTS" : "OUTPUTS");
+
+    const int n = buses.size();
+    for (int busIdx = 0; busIdx < n; ++busIdx)
+    {
+        XmlElement* bus = new XmlElement ("BUS");
+        bus->setAttribute ("index", busIdx);
+
+        const AudioChannelSet& set = buses.getReference (busIdx);
+        const String layoutName = set.isDisabled() ? "disabled" : set.getSpeakerArrangementAsString();
+
+        bus->setAttribute ("layout", layoutName);
+
+        xml->addChildElement (bus);
+    }
+
+    return xml;
+}
+
 static XmlElement* createNodeXml (AudioProcessorGraph::Node* const node) noexcept
 {
     AudioPluginInstance* plugin = dynamic_cast<AudioPluginInstance*> (node->getProcessor());
@@ -327,6 +388,14 @@ static XmlElement* createNodeXml (AudioProcessorGraph::Node* const node) noexcep
     state->addTextElement (m.toBase64Encoding());
     e->addChildElement (state);
 
+    XmlElement* layouts = new XmlElement ("LAYOUT");
+    const AudioProcessor::BusesLayout layout = plugin->getBusesLayout();
+
+    for (bool isInput : { true, false })
+        layouts->addChildElement (createBusLayoutXml (layout, isInput));
+
+    e->addChildElement (layouts);
+
     return e;
 }
 
@@ -347,6 +416,16 @@ void FilterGraph::createNodeFromXml (const XmlElement& xml)
     if (instance == nullptr)
         return;
 
+    if (const XmlElement* const layoutEntity = xml.getChildByName ("LAYOUT"))
+    {
+        AudioProcessor::BusesLayout layout = instance->getBusesLayout();
+
+        for (bool isInput : { true, false })
+            readBusLayoutFromXml (layout, instance, *layoutEntity, isInput);
+
+        instance->setBusesLayout (layout);
+    }
+
     AudioProcessorGraph::Node::Ptr node (graph.addNode (instance, (uint32) xml.getIntAttribute ("uid")));
 
     if (const XmlElement* const state = xml.getChildByName ("STATE"))

modules/juce_audio_basics/buffers/juce_AudioChannelSet.cpp

@@ -114,6 +114,43 @@ String AudioChannelSet::getAbbreviatedChannelTypeName (AudioChannelSet::ChannelT
     return "";
 }
 
+AudioChannelSet::ChannelType AudioChannelSet::getChannelTypeFromAbbreviation (const String& abbr)
+{
+    if (abbr.length() > 0 && (abbr[0] >= '0' && abbr[0] <= '9'))
+        return static_cast<AudioChannelSet::ChannelType> (static_cast<int> (discreteChannel0)
+                                                               + abbr.getIntValue() + 1);
+
+    if      (abbr == "L")    return left;
+    else if (abbr == "R")    return right;
+    else if (abbr == "C")    return centre;
+    else if (abbr == "Lfe")  return LFE;
+    else if (abbr == "Ls")   return leftSurround;
+    else if (abbr == "Rs")   return rightSurround;
+    else if (abbr == "Lc")   return leftCentre;
+    else if (abbr == "Rc")   return rightCentre;
+    else if (abbr == "Cs")   return centreSurround;
+    else if (abbr == "Lrs")  return leftSurroundRear;
+    else if (abbr == "Rrs")  return rightSurroundRear;
+    else if (abbr == "Tm")   return topMiddle;
+    else if (abbr == "Tfl")  return topFrontLeft;
+    else if (abbr == "Tfc")  return topFrontCentre;
+    else if (abbr == "Tfr")  return topFrontRight;
+    else if (abbr == "Trl")  return topRearLeft;
+    else if (abbr == "Trc")  return topRearCentre;
+    else if (abbr == "Trr")  return topRearRight;
+    else if (abbr == "Wl")   return wideLeft;
+    else if (abbr == "Wr")   return wideRight;
+    else if (abbr == "Lfe2") return LFE2;
+    else if (abbr == "Lss")  return leftSurroundSide;
+    else if (abbr == "Rss")  return rightSurroundSide;
+    else if (abbr == "W")    return ambisonicW;
+    else if (abbr == "X")    return ambisonicX;
+    else if (abbr == "Y")    return ambisonicY;
+    else if (abbr == "Z")    return ambisonicZ;
+
+    return unknown;
+}
+
 String AudioChannelSet::getSpeakerArrangementAsString() const
 {
     StringArray speakerTypes;
@@ -130,6 +167,22 @@ String AudioChannelSet::getSpeakerArrangementAsString() const
     return speakerTypes.joinIntoString (" ");
 }
 
+AudioChannelSet AudioChannelSet::fromAbbreviatedString (const String& str)
+{
+    StringArray abbr = StringArray::fromTokens(str, true);
+    AudioChannelSet set;
+
+    for (int i = 0; i < abbr.size(); ++i)
+    {
+        AudioChannelSet::ChannelType type = getChannelTypeFromAbbreviation (abbr[i]);
+
+        if (type != unknown)
+            set.addChannel (type);
+    }
+
+    return set;
+}
+
 String AudioChannelSet::getDescription() const
 {
     if (isDiscreteLayout())            return String ("Discrete #") + String (size());

modules/juce_audio_basics/buffers/juce_AudioChannelSet.h

@@ -308,6 +308,9 @@ public:
     /** Returns the abbreviated name of a channel type. For example, this method may return "Ls". */
     static String getAbbreviatedChannelTypeName (ChannelType);
 
+    /** Returns the channel type from an abbreviated name. */
+    static ChannelType getChannelTypeFromAbbreviation (const String& abbreviation);
+
     //==============================================================================
     enum
     {
@@ -342,6 +345,11 @@ public:
         the returned string will be empty.*/
     String getSpeakerArrangementAsString() const;
 
+    /** Returns an AudioChannelSet from a string returned by getSpeakerArrangementAsString
+
+        @see getSpeakerArrangementAsString */
+    static AudioChannelSet fromAbbreviatedString (const String& set);
+
     /** Returns the description of the current layout. For example, this method may return
         "Quadraphonic". Note that the returned string may not be unique. */
     String getDescription() const;