Added callback to get number of keywaves of an on-screen seaboard view

modules/juce_blocks_basics/blocks/juce_Block.h

@@ -43,7 +43,8 @@ public:
         lightPadBlock,
         liveBlock,
         loopBlock,
-        developerControlBlock
+        developerControlBlock,
+        seaboardBlock // on-screen seaboard view
     };
 
     /** The Block class is reference-counted, so always use a Block::Ptr when

modules/juce_blocks_basics/blocks/juce_TouchSurface.h

@@ -96,6 +96,10 @@ public:
     /** Forces a touch-off message for all active touches. */
     virtual void cancelAllActiveTouches() noexcept = 0;
 
+    /** For the on-screen seaboard view, this will return the number of keys.
+        For other types of touch-surface, it will return 0. */
+    virtual int getNumberOfKeywaves() const = 0;
+
     //==============================================================================
     /** Receives callbacks when a touch moves or changes pressure. */
     struct Listener

modules/juce_blocks_basics/topology/juce_PhysicalTopologySource.cpp

@@ -1416,6 +1416,11 @@ struct PhysicalTopologySource::Internal
                 det->activeTouchSurfaces.removeFirstMatchingValue (this);
         }
 
+        int getNumberOfKeywaves() const noexcept override
+        {
+            return blockImpl.modelData.numKeywaves;
+        }
+
         void broadcastTouchChange (const TouchSurface::Touch& touchEvent)
         {
             auto& status = touches.getValue (touchEvent);