add color property to MIDISceneChange

libs/ardour/ardour/midi_scene_change.h

@@ -22,6 +22,8 @@
 
 #include "evoral/PatchChange.hpp"
 
+#include "pbd/signals.h"
+
 #include "ardour/scene_change.h"
 
 namespace ARDOUR
@@ -53,10 +55,15 @@ class MIDISceneChange : public SceneChange
 
         bool operator==(const MIDISceneChange& other) const;
 
+        uint32_t color() const;
+        void set_color (uint32_t);
+        PBD::Signal0<void> ColorChanged;
+
   private:
 	int _bank;
 	int _program;
 	uint8_t _channel;
+        uint32_t _color;
 };
 
 } /* namespace */

libs/ardour/midi_scene_change.cc

@@ -32,6 +32,7 @@ MIDISceneChange::MIDISceneChange (int c, int b, int p)
 	: _bank (b)
 	, _program (p)
 	, _channel (c & 0xf)
+        , _color (0x00000000) /* note: zero alpha means invisible, which acts as out-of-bound signal */
 {
 	if (_bank > 16384) {
 		_bank = -1;
@@ -148,3 +149,16 @@ MIDISceneChange::operator==(const MIDISceneChange& other) const
                 _bank == other._bank &&
                 _channel == other._channel;
 }
+
+void
+MIDISceneChange::set_color (uint32_t c) 
+{
+        _color = c;
+        ColorChanged (); /* EMIT SIGNAL */
+}
+
+uint32_t
+MIDISceneChange::color() const
+{
+        return _color;
+}