Fix channel change ly export. Better GUI text

engine/items.py

@@ -2167,7 +2167,6 @@ class KeySignature(Item):
             lyKeysignature = subtextRoot +  "\\set Staff.keyAlterations = #`(( 0 . ,NATURAL))" #TODO: subtextRoot position is broken                    
         return lyKeysignature                
         
-
 class Clef(Item):
     """A clef has no direct musical logical meaning. But it gives some hints:
     Voice range. A typical musical voice in a polyphonic setup has between one and two octaves range
@@ -2741,7 +2740,7 @@ class ChannelChange(Item):
             "tickindex" : trackState.tickindex - duration, #we parse the tickindex after we stepped over the item.
              "midiBytes" : [],
             "text" : self.text,
-             "UIstring" : "ch{}".format(self.value), #this is for a UI, possibly a text UI, maybe for simple items of a GUI. Make it as short and unambigious as possible.
+            "UIstring" : f"{self.text}(ch{self.value})" if self.text else f"ch{self.value}", #this is for a UI, possibly a text UI, maybe for simple items of a GUI. Make it as short and unambigious as possible.
         }
 
     def _lilypond(self):
@@ -2749,8 +2748,7 @@ class ChannelChange(Item):
         Don't create white-spaces yourself, this is done by the structures.
         When in doubt prefer functionality and robustness over 'beautiful' lilypond syntax."""
         if self.text:            
-            raise NotImplementedError("Implement _lilypond() with correct instrument change syntax")
-            return self.text
+            return f'\\mark \\markup {{\\small "{self.text}"}}'
         else:
             return ""
 
@@ -2847,6 +2845,7 @@ class LilypondText(Item):
         When in doubt prefer functionality and robustness over 'beautiful' lilypond syntax."""         
         return self.text 
         
+
     @classmethod
     def instanceFromSerializedData(cls, serializedObject, parentObject):
         """see Score.instanceFromSerializedData"""        

engine/track.py

@@ -986,7 +986,8 @@ class Track(object):
         #TODO: However, it is even less elegant to put this call in all rhythm editing methods and functions. inserts, block duplicate, content links, augment, tuplets undo etc.
         #Taken out an placed in tempo Export. #self.score.tempoTrack.expandLastBlockToScoreDuration() #we guarantee that the tempo track is always at least as long as the music tracks.
 
-        patternBlob = bytes() # Create a binary blob that contains the MIDI events
+        midiNotesBinaryCoxData = bytes() # Create a binary blob that contains the MIDI events        
+        instrumentChangesBinaryCoxData = bytes() # same as above, but only for instrument changes.
         
         originalPosition = self.state.position()
         self.getPreliminaryData()
@@ -1005,9 +1006,9 @@ class Track(object):
         assert self.initialMidiBankMsb == initialProgamChange.msb
         assert self.initialMidiBankLsb == initialProgamChange.lsb
         if initialProgamChange.program >= 0: #-1 is off.
-            patternBlob += cbox.Pattern.serialize_event(0, 0xC0 + self.initialMidiChannel, initialProgamChange.program, 0)
-            patternBlob += cbox.Pattern.serialize_event(0, 0xB0 + self.initialMidiChannel, 0, self.initialMidiBankMsb) #position, status byte+channel, controller number, controller value
-            patternBlob += cbox.Pattern.serialize_event(0, 0xB0 + self.initialMidiChannel, 32, self.initialMidiBankLsb) #position, status byte+channel, controller number, controller value
+            instrumentChangesBinaryCoxData += cbox.Pattern.serialize_event(0, 0xC0 + self.initialMidiChannel, initialProgamChange.program, 0)
+            instrumentChangesBinaryCoxData += cbox.Pattern.serialize_event(0, 0xB0 + self.initialMidiChannel, 0, self.initialMidiBankMsb) #position, status byte+channel, controller number, controller value
+            instrumentChangesBinaryCoxData += cbox.Pattern.serialize_event(0, 0xB0 + self.initialMidiChannel, 32, self.initialMidiBankLsb) #position, status byte+channel, controller number, controller value
 
         localRight = self.right #performance
         resultAppend = result.append #performance
@@ -1024,10 +1025,14 @@ class Track(object):
                 expObj = previousItem.exportObject(self.state) #yes, it is correct that the state in the parameter is ahead by one position. Why is it that way? Because everything that matters, like new dynamics will only be parsed afterwards. The trackState is always correct except for the tickindex when exporting after parsing. Thats why exportObject sometimes substracts its own duration for finding its starting tick.
                 resultAppend(expObj)
                 dur = expObj["completeDuration"]
-                for blob in expObj["midiBytes"]: #a list of
-                    patternBlob += blob
-                if expObj["type"] == "Chord" or expObj["type"] == "Rest": #save for later when we create Beams. No other use.
-                    _allExportedChordsAppend(expObj)
+                if expObj["type"] != "InstrumentChange":
+                    for blob in expObj["midiBytes"]: #a list of
+                        midiNotesBinaryCoxData += blob
+                    if expObj["type"] == "Chord" or expObj["type"] == "Rest": #save for later when we create Beams. No other use.
+                        _allExportedChordsAppend(expObj)                
+                else:                
+                    for blob in expObj["midiBytes"]: #a list of
+                        instrumentChangesBinaryCoxData += blob
                         
             elif r == 2: #block end. Again, this is already the previous state. right now we are in the next block already.
                 lastBlock = self.blocks[self.state.blockindex-1] #why -1? see comment above
@@ -1155,9 +1160,14 @@ class Track(object):
         metaData["duration"] = self.state.tickindex #tickindex is now at the end, so this is the end duration. This includes Blocks minimumDuration as well since it is included in left/right
         metaData["beams"] = resultBeamGroups                
         
-        t = (patternBlob, 0, self.state.tickindex)
+        #Notes
+        t = (midiNotesBinaryCoxData, 0, self.state.tickindex)
         self.sequencerInterface.setTrack([t])  #(bytes-blob, position, length) #tickindex is still on the last position, which means the second parameter is the length
         
+        #Instrument Changes
+        self.sequencerInterface.setSubtrack(key="instrumentChanges", blobs=[(instrumentChangesBinaryCoxData, 0, self.state.tickindex),]) #(bytes-blob, position, length) 
+        
+        
         self.toPosition(originalPosition, strict = False) #has head() in it
         return result