add option to change midi channel of tracks

CHANGELOG

@@ -1,3 +1,6 @@
+2021-04-15 Version 2.1.0
+Add option to change the midi channel for a track in the tracks context menu.
+
 2021-01-15 Version 2.0.0
 Big new features increase the MAJOR version. Old save files can still be loaded.
 The new features integrate seamlessly into the existing workflow:

engine/api.py

@@ -440,6 +440,19 @@ def changeTrackColor(trackId, colorInHex):
     track.color = colorInHex
     callbacks._trackMetaDataChanged(track)
 
+def changeTrackMidiChannel(trackId, newChannel:int):
+    """newChannel is 1-16, we convert here to internal format 0-15.
+    Callbacks export data sends 1-16 again"""
+    if newChannel < 1 or newChannel > 16:
+        logger.warning(f"Midi Channel must be between 1-16 for this function, was: {newChannel}. Doing nothing.")
+        return
+    track = session.data.trackById(trackId)
+    track.midiChannel = newChannel-1
+    track.pattern.buildExportCache()
+    track.buildTrack()
+    updatePlayback()
+    callbacks._trackMetaDataChanged(track)
+
 def addTrack(scale=None):
     if scale:
         assert type(scale) == tuple
@@ -455,6 +468,7 @@ def createSiblingTrack(trackId):
     newTrack = session.data.addTrack(name=track.sequencerInterface.name, scale=track.pattern.scale, color=track.color, simpleNoteNames=track.pattern.simpleNoteNames) #track name increments itself from "Track A" to "Track B" or "Track 1" -> "Track 2"
     newTrack.pattern.averageVelocity = track.pattern.averageVelocity
     newTrack.patternLengthMultiplicator = track.patternLengthMultiplicator
+    newTrack.midiChannel = track.midiChannel
     jackConnections = cbox.JackIO.get_connected_ports(track.sequencerInterface.cboxPortName())
     for port in jackConnections:
         cbox.JackIO.port_connect(newTrack.sequencerInterface.cboxPortName(), port)
@@ -498,6 +512,9 @@ def setTrackPatternLengthMultiplicator(trackId, newMultiplicator:int):
     callbacks._patternLengthMultiplicatorChanged(track)
     callbacks._patternChanged(track)
 
+
+
+
 #Track Switches
 
 def setSwitches(trackId, setOfPositions, newBool):
@@ -956,11 +973,11 @@ def resizePatternWithoutScale(trackId, steps):
 def noteOn(trackId, row):
     track = session.data.trackById(trackId)
     midipitch = track.pattern.scale[row]
-    cbox.send_midi_event(0x90, midipitch, track.pattern.averageVelocity, output=track.sequencerInterface.cboxMidiOutUuid)
+    cbox.send_midi_event(0x90+track.midiChannel, midipitch, track.pattern.averageVelocity, output=track.sequencerInterface.cboxMidiOutUuid)
 
 def noteOff(trackId, row):
     track = session.data.trackById(trackId)
     midipitch = track.pattern.scale[row]
-    cbox.send_midi_event(0x80, midipitch, track.pattern.averageVelocity, output=track.sequencerInterface.cboxMidiOutUuid)
+    cbox.send_midi_event(0x80+track.midiChannel, midipitch, track.pattern.averageVelocity, output=track.sequencerInterface.cboxMidiOutUuid)
 
 

engine/pattern.py

@@ -354,8 +354,8 @@ class Pattern(object):
 
             velocity = noteDict["velocity"]
             pitch = self._cachedTransposedScale[noteDict["pitch"] + scaleTransposition] + halftoneTransposition
-            exportPattern += cbox.Pattern.serialize_event(startTick, 0x90, pitch, velocity) # note on
-            exportPattern += cbox.Pattern.serialize_event(endTick-1, 0x80, pitch, velocity) # note off  #-1 ticks to create a small logical gap. Does not affect next note on.
+            exportPattern += cbox.Pattern.serialize_event(startTick, 0x90 + self.parentTrack.midiChannel, pitch, velocity) # note on
+            exportPattern += cbox.Pattern.serialize_event(endTick-1, 0x80 + self.parentTrack.midiChannel, pitch, velocity) # note off  #-1 ticks to create a small logical gap. Does not affect next note on.
 
         pattern = cbox.Document.get_song().pattern_from_blob(exportPattern, oneMeasureInTicks)
         self._builtPatternCache[cacheHash] = pattern

engine/track.py

@@ -56,6 +56,7 @@ class Track(object): #injection at the bottom of this file!
         #we take inspiration from the GUI that presents the Track on its own.
         #The following setting is most likely to be found in the track sub-window:
         self.patternLengthMultiplicator = 1 #int. >= 1   the multiplicator is added after all other calculations, like subdivions.  We can't integrate this into howManyUnits because that is the global score value
+        self.midiChannel = 0 # 0-15 midi channel is always set.
 
         self.pattern = Pattern(parentTrack=self, scale=scale, simpleNoteNames=simpleNoteNames)
         self.structure = structure if structure else set() #see buildTrack(). This is the main track data structure besides the pattern. Just integers (starts at 0) as switches which are positions where to play the patterns. In between are automatic rests.
@@ -109,6 +110,7 @@ class Track(object): #injection at the bottom of this file!
             "whichPatternsAreScaleTransposed" : self.whichPatternsAreScaleTransposed,
             "whichPatternsAreHalftoneTransposed" : self.whichPatternsAreHalftoneTransposed,
             "patternLengthMultiplicator" : self.patternLengthMultiplicator,
+            "midiChannel" : self.midiChannel,
         }
 
     @classmethod
@@ -116,11 +118,18 @@ class Track(object): #injection at the bottom of this file!
         self = cls.__new__(cls)
         self.parentData = parentData
         self.sequencerInterface = template.engine.sequencer.SequencerInterface.instanceFromSerializedData(self, serializedData["sequencerInterface"])
-        if "patternLengthMultiplicator" in serializedData: #Version 1.8
+
+        #Version 2.0+ changes
+        if "patternLengthMultiplicator" in serializedData:
             self.patternLengthMultiplicator = serializedData["patternLengthMultiplicator"]
         else:
             self.patternLengthMultiplicator = 1
 
+        if "midiChannel" in serializedData:
+            self.midiChannel = serializedData["midiChannel"]
+        else:
+            self.midiChannel = 0
+
         self.color = serializedData["color"]
         self.structure = set(serializedData["structure"])
         self.whichPatternsAreHalftoneTransposed = {int(k):int(v)  for k,v in serializedData["whichPatternsAreHalftoneTransposed"].items()} #json saves dict keys as strings
@@ -144,6 +153,7 @@ class Track(object): #injection at the bottom of this file!
             "numberOfMeasures": self.parentData.numberOfMeasures,
             "whichPatternsAreScaleTransposed": self.whichPatternsAreScaleTransposed,
             "whichPatternsAreHalftoneTransposed": self.whichPatternsAreHalftoneTransposed,
+            "midiChannel" : self.midiChannel+1, #1-16
         }
 
 #Dependency Injections.

qtgui/songeditor.py

@@ -762,6 +762,16 @@ class TrackLabelEditor(QtWidgets.QGraphicsScene):
                 a.setEnabled(False)
             a.triggered.connect(mergeCommand)
 
+        #Add a submenu to set the midi channel of this track. Highlight the current one
+        midiChannelMenu = menu.addMenu(QtCore.QCoreApplication.translate("TrackLabelContext", "Send on MIDI Channel"))
+        for mch in range(1, 17):
+            mchAction =  QtWidgets.QAction(str(mch), midiChannelMenu)
+            midiChannelMenu.addAction(mchAction)
+            midiChannelCommand = lambda discard, chArg=mch: api.changeTrackMidiChannel(exportDict["id"], chArg) #discard parameter given by QAction
+            if exportDict["midiChannel"] == mch:
+                mchAction.setEnabled(False)
+            mchAction.triggered.connect(midiChannelCommand)
+
         pos = QtGui.QCursor.pos()
         pos.setY(pos.y() + 5)
         self.parentView.parentMainWindow.setFocus()

template/documentation/readme.template

@@ -4,6 +4,7 @@
 #<name>
 Program version <version>
 
+
 ![Screenshot](https://git.laborejo.org/lss/<name>/raw/branch/master/documentation/screenshot.png "Screenshot")