Undo part 1

engine/api.py

@@ -208,6 +208,7 @@ class ClientCallbacks(Callbacks): #inherits from the templates api callbacks
         for func in self.patternLengthMultiplicatorChanged:
             func(export)
         self._patternChanged(track) #includes dataChanged
+        callbacks._dataChanged()
 
     def _swingChanged(self):
         export = session.data.swing
@@ -216,6 +217,7 @@ class ClientCallbacks(Callbacks): #inherits from the templates api callbacks
 
         for func in self.swingPercentChanged:
             func(_swingToPercent_Table[export])
+        callbacks._dataChanged()
 
 #Inject our derived Callbacks into the parent module
 template.engine.api.callbacks = ClientCallbacks()
@@ -322,6 +324,17 @@ def seek(value):
 
 ##Score
 def set_quarterNotesPerMinute(value):
+    """Transport Master is set implicitly. If value == None Patroneo will switch into
+    JackTransport Slave mode"""
+    if session.data.tempoMap.isTransportMaster:
+        oldValue = session.data.tempoMap.getQuarterNotesPerMinute()
+    else:
+        oldValue = None
+
+    if oldValue == value: return # no change
+
+    session.history.register(lambda v=oldValue: set_quarterNotesPerMinute(v), descriptionString="Tempo")
+
     if value is None:
         session.data.tempoMap.isTransportMaster = False #triggers rebuild
     elif value == "on":
@@ -338,8 +351,10 @@ def set_quarterNotesPerMinute(value):
 
 
 def set_whatTypeOfUnit(ticks):
-    """Denominator of Time Signature"""
+    """Denominator of Time Signature = Each Group produces a Quarter """
-    if session.data.whatTypeOfUnit == ticks: return
+    if session.data.whatTypeOfUnit == ticks: return #no change
+
+    session.history.register(lambda v=session.data.whatTypeOfUnit: set_whatTypeOfUnit(v), descriptionString="Group Duration")
     session.data.whatTypeOfUnit = ticks
     session.data.buildAllTracks()
     if session.inLoopMode:
@@ -348,8 +363,10 @@ def set_whatTypeOfUnit(ticks):
     callbacks._timeSignatureChanged()
 
 def set_howManyUnits(value):
-    """Numerator of Time Signature"""
+    """Numerator of Time Signature = Steps per Pattern"""
-    if session.data.howManyUnits == value: return
+    if session.data.howManyUnits == value: return #no change
+
+    session.history.register(lambda v=session.data.howManyUnits: set_howManyUnits(v), descriptionString="Steps per Pattern")
     session.data.howManyUnits = value
     session.data.buildAllTracks()
     if session.inLoopMode:
@@ -359,7 +376,9 @@ def set_howManyUnits(value):
 
 
 def set_subdivisions(value):
-    if session.data.subdivisions == value: return
+    """In groups of 1, 2, 4"""
+    if session.data.subdivisions == value: return #no change
+    session.history.register(lambda v=session.data.subdivisions: set_subdivisions(v), descriptionString="Group Size")
     session.data.subdivisions = value
     session.data.buildAllTracks()
     if session.inLoopMode:
@@ -369,9 +388,10 @@ def set_subdivisions(value):
 
 def convert_subdivisions(value, errorHandling):
     """"errorHandling can be fail, delete or merge"""
-    if session.data.subdivisions == value: return
+    oldValue = session.data.subdivisions
     result = session.data.convertSubdivisions(value, errorHandling)
-    if result:
+    if result: #bool for success
+        session.history.register(lambda v=oldValue: convert_subdivisions(v, "delete"), descriptionString="Convert Grouping") #the error handling = delete should not matter at all. We are always in a position where this is possible because we just converted to the current state.
         session.data.buildAllTracks()
         updatePlayback()
         callbacks._timeSignatureChanged() #includes subdivisions
@@ -392,6 +412,7 @@ def set_swing(value:float):
         logger.warning(f"Swing can only be between -0.5 and 0.5, not {value}")
         return
 
+    session.history.register(lambda v=session.data.swing: set_swing(v), descriptionString="Swing")
     session.data.swing = value
     session.data.buildAllTracks()
     updatePlayback()
@@ -409,12 +430,14 @@ def setSwingPercent(value:int):
     if value < -100 or value > 100:
         logger.warning(f"Swing in percent can only be between -100 and +100, not {value}")
         return
-    set_swing(_percentToSwing_Table[value])
+    set_swing(_percentToSwing_Table[value]) #handles undo and callbacks
 
 
 def set_numberOfMeasures(value):
     if session.data.numberOfMeasures == value:
         return
+
+    session.history.register(lambda v=session.data.numberOfMeasures: set_numberOfMeasures(v), descriptionString="Measures per Track")
     session.data.numberOfMeasures = value
     session.data.buildSongDuration()
     updatePlayback()
@@ -424,12 +447,14 @@ def set_numberOfMeasures(value):
 def set_measuresPerGroup(value):
     if session.data.measuresPerGroup == value:
         return
+    session.history.register(lambda v=session.data.measuresPerGroup: set_measuresPerGroup(v), descriptionString="Measures per Group")
     session.data.measuresPerGroup = value
     #No playback change
     callbacks._scoreChanged()
 
 def changeTrackName(trackId, name):
     track = session.data.trackById(trackId)
+    session.history.register(lambda trId=trackId, v=track.sequencerInterface.name: changeTrackName(trId,v), descriptionString="Track Name")
     track.sequencerInterface.name = " ".join(name.split())
     callbacks._trackMetaDataChanged(track)
 
@@ -437,6 +462,7 @@ def changeTrackColor(trackId, colorInHex):
     """Expects "#rrggbb"""
     track = session.data.trackById(trackId)
     assert len(colorInHex) == 7, colorInHex
+    session.history.register(lambda trId=trackId, v=track.color: changeTrackColor(trId,v), descriptionString="Track Color")
     track.color = colorInHex
     callbacks._trackMetaDataChanged(track)
 
@@ -447,6 +473,7 @@ def changeTrackMidiChannel(trackId, newChannel:int):
         logger.warning(f"Midi Channel must be between 1-16 for this function, was: {newChannel}. Doing nothing.")
         return
     track = session.data.trackById(trackId)
+    session.history.register(lambda trId=trackId, v=track.midiChannel: changeTrackMidiChannel(trId,v), descriptionString="Track Midi Channel")
     track.midiChannel = newChannel-1
     track.pattern.buildExportCache()
     track.buildTrack()
@@ -456,7 +483,10 @@ def changeTrackMidiChannel(trackId, newChannel:int):
 def addTrack(scale=None):
     if scale:
         assert type(scale) == tuple
-    session.data.addTrack(scale=scale)
+    track = session.data.addTrack(scale=scale)
+    assert track
+    trackId = id(track)
+    session.history.register(lambda trId=trackId: deleteTrack(trId), descriptionString="Add Track")
     callbacks._numberOfTracksChanged()
 
 def createSiblingTrack(trackId):
@@ -478,14 +508,30 @@ def createSiblingTrack(trackId):
     newTrackAgain = session.data.tracks.pop(newIndex)
     assert newTrackAgain is newTrack
     session.data.tracks.insert(oldIndex+1, newTrackAgain)
+    session.history.register(lambda trId=id(newTrackAgain): deleteTrack(trId), descriptionString="Clone Track")
     callbacks._numberOfTracksChanged()
     return newTrack.export()
 
+def _reinsertDeletedTrack(track, trackIndex):
+    """For undo"""
+    track.sequencerInterface.recreateThroughUndo()
+    session.data.tracks.insert(trackIndex, track)
+    session.history.register(lambda trId=id(track): deleteTrack(trId), descriptionString="Add deleted Track again")
+    updatePlayback()
+    callbacks._numberOfTracksChanged()
+
 def deleteTrack(trackId):
     track = session.data.trackById(trackId)
-    session.data.deleteTrack(track)
+    oldIndex = session.data.tracks.index(track)
+    deletedTrack = session.data.deleteTrack(track)
+
     if not session.data.tracks: #always keep at least one track
-        session.data.addTrack()
+        with session.history.sequence("Delete Track and autocreated Track"):
+            addTrack() #has it's own undo
+            session.history.register(lambda tr=deletedTrack, pos=oldIndex: _reinsertDeletedTrack(tr, pos), descriptionString="Delete Track")
+    else:
+        session.history.register(lambda tr=deletedTrack, pos=oldIndex: _reinsertDeletedTrack(tr, pos), descriptionString="Delete Track")
+
     updatePlayback()
     callbacks._numberOfTracksChanged()
 
@@ -494,6 +540,7 @@ def moveTrack(trackId, newIndex):
     track = session.data.trackById(trackId)
     oldIndex = session.data.tracks.index(track)
     if not oldIndex == newIndex:
+        session.history.register(lambda tr=trackId, pos=oldIndex: moveTrack(trackId, pos), descriptionString="Move Track")
         session.data.tracks.pop(oldIndex)
         session.data.tracks.insert(newIndex, track)
         callbacks._numberOfTracksChanged()
@@ -503,6 +550,7 @@ def setTrackPatternLengthMultiplicator(trackId, newMultiplicator:int):
         return #Invalid input
 
     track = session.data.trackById(trackId)
+    session.history.register(lambda tr=trackId, v=track.patternLengthMultiplicator: setTrackPatternLengthMultiplicator(trackId, v), descriptionString="Pattern Multiplier")
     track.patternLengthMultiplicator = newMultiplicator
     track.pattern.buildExportCache()
     track.buildTrack()
@@ -513,22 +561,37 @@ def setTrackPatternLengthMultiplicator(trackId, newMultiplicator:int):
     callbacks._patternChanged(track)
 
 
+#Track Switches
+#Aka measures
+
+def _setTrackStructure(trackId, structure):
+    """For undo. Used by all functions as entry point, then calls itself for undo/redo.
+    structure is a set of integers which we can copy with .copy()"""
+    track = session.data.trackById(trackId)
 
+    session.history.register(lambda tr=trackId, v=track.structure.copy(): _setTrackStructure(trackId, v), descriptionString="Set Measures")
+
+    track.structure = structure #restore data
+    track.buildTrack()
+    updatePlayback()
+    callbacks._trackStructureChanged(track)
 
-#Track Switches
 
 def setSwitches(trackId, setOfPositions, newBool):
+    """Used in the GUI to select multiple switches in a row by dragging the mouse"""
     track = session.data.trackById(trackId)
+    session.history.register(lambda tr=trackId, v=track.structure.copy(): _setTrackStructure(trackId, v), descriptionString="Set Measures")
     if newBool:
-        track.structure = track.structure.union(setOfPositions) #add setOfPositions to the existing one
+        track.structure = track.structure.union(setOfPositions) #merge: add setOfPositions to the existing one
     else:
-        track.structure = track.structure.difference(setOfPositions) #remove everything from setOfPositions that is in the existing one, ignore entries from setOfPositions not in existing.
+        track.structure = track.structure.difference(setOfPositions) #replace: remove everything from setOfPositions that is in the existing one, ignore entries from setOfPositions not in existing.
     track.buildTrack()
     updatePlayback()
     callbacks._trackStructureChanged(track)
 
 def setSwitch(trackId, position, newBool):
     track = session.data.trackById(trackId)
+    session.history.register(lambda trId=trackId, v=track.structure.copy(): _setTrackStructure(trId, v), descriptionString="Set Measures")
     if newBool:
         if position in track.structure: return
         track.structure.add(position)
@@ -542,6 +605,7 @@ def setSwitch(trackId, position, newBool):
 
 def trackInvertSwitches(trackId):
     track = session.data.trackById(trackId)
+    session.history.register(lambda trId=trackId, v=track.structure.copy(): _setTrackStructure(trId, v), descriptionString="Set Measures")
     """
     if track.structure:
         new = set(i for i in range(max(track.structure)))
@@ -557,6 +621,7 @@ def trackInvertSwitches(trackId):
 
 def trackOffAllSwitches(trackId):
     track = session.data.trackById(trackId)
+    session.history.register(lambda trId=trackId, v=track.structure.copy(): _setTrackStructure(trId, v), descriptionString="Set Measures")
     track.structure = set()
     track.buildTrack()
     updatePlayback()
@@ -564,6 +629,7 @@ def trackOffAllSwitches(trackId):
 
 def trackOnAllSwitches(trackId):
     track = session.data.trackById(trackId)
+    session.history.register(lambda trId=trackId, v=track.structure.copy(): _setTrackStructure(trId, v), descriptionString="Set Measures")
     track.structure = set(i for i in range(session.data.numberOfMeasures))
     track.buildTrack()
     updatePlayback()
@@ -573,6 +639,7 @@ def trackMergeCopyFrom(sourceTrackId, targetTrackId):
     if not sourceTrackId == targetTrackId:
         sourceTrack = session.data.trackById(sourceTrackId)
         targetTrack = session.data.trackById(targetTrackId)
+        session.history.register(lambda trId=id(targetTrack), v=targetTrack.structure.copy(): _setTrackStructure(trId, v), descriptionString="Set Measures")
         targetTrack.structure = targetTrack.structure.union(sourceTrack.structure)
         targetTrack.whichPatternsAreScaleTransposed.update(sourceTrack.whichPatternsAreScaleTransposed)
         targetTrack.whichPatternsAreHalftoneTransposed.update(sourceTrack.whichPatternsAreHalftoneTransposed)
@@ -584,6 +651,7 @@ def trackPatternReplaceFrom(sourceTrackId, targetTrackId):
     if not sourceTrackId == targetTrackId:
         sourceTrack = session.data.trackById(sourceTrackId)
         targetTrack = session.data.trackById(targetTrackId)
+        session.history.register(lambda trId=id(targetTrack), v=targetTrack.structure.copy(): _setTrackStructure(trId, v), descriptionString="Set Measures")
 
         copyPattern = sourceTrack.pattern.copy(newParentTrack = targetTrack)
         targetTrack.pattern = copyPattern
@@ -592,24 +660,66 @@ def trackPatternReplaceFrom(sourceTrackId, targetTrackId):
         updatePlayback()
         callbacks._patternChanged(targetTrack)
 
+#Transpositions and Modal Shifts
+
+def _setSwitchesScaleTranspose(trackId, whichPatternsAreScaleTransposed):
+    """For undo. Used by all functions as entry point, then calls itself for undo/redo.
+    whichPatternsAreScaleTransposed is a dicts of int:int which we can copy with .copy()"""
+    track = session.data.trackById(trackId)
+
+    session.history.register(lambda tr=trackId, v=track.whichPatternsAreScaleTransposed.copy(): _setSwitchesScaleTranspose(trackId, v), descriptionString="Set Modal Shift")
+
+    track.whichPatternsAreScaleTransposed = whichPatternsAreScaleTransposed #restore data
+    track.buildTrack()
+    updatePlayback()
+    callbacks._trackStructureChanged(track)
+
+
 def setSwitchScaleTranspose(trackId, position, transpose):
     """Scale transposition is flipped. lower value means higher pitch"""
     track = session.data.trackById(trackId)
+    session.history.register(lambda tr=trackId, v=track.whichPatternsAreScaleTransposed.copy(): _setSwitchesScaleTranspose(trackId, v), descriptionString="Set Modal Shift")
     track.whichPatternsAreScaleTransposed[position] = transpose
     track.buildTrack()
     updatePlayback()
     callbacks._trackStructureChanged(track)
     return True
 
+
+def _setSwitchHalftoneTranspose(trackId, whichPatternsAreHalftoneTransposed):
+    """For undo. Used by all functions as entry point, then calls itself for undo/redo.
+    whichPatternsAreScaleTransposed is a dicts of int:int which we can copy with .copy()"""
+    track = session.data.trackById(trackId)
+
+    session.history.register(lambda tr=trackId, v=track.whichPatternsAreHalftoneTransposed.copy(): _setSwitchHalftoneTranspose(trackId, v), descriptionString="Set Half Tone Shift")
+
+    track.whichPatternsAreHalftoneTransposed = whichPatternsAreHalftoneTransposed #restore data
+    track.buildTrack()
+    updatePlayback()
+    callbacks._trackStructureChanged(track)
+
 def setSwitchHalftoneTranspose(trackId, position, transpose):
     """Halftone transposition is not flipped. Higher value means higher pitch"""
     track = session.data.trackById(trackId)
+    session.history.register(lambda tr=trackId, v=track.whichPatternsAreHalftoneTransposed.copy(): _setSwitchHalftoneTranspose(trackId, v), descriptionString="Set Half Tone Shift")
     track.whichPatternsAreHalftoneTransposed[position] = transpose
     track.buildTrack()
     updatePlayback()
     callbacks._trackStructureChanged(track)
     return True
 
+def _registerHistoryWholeTrackSwitches(track):
+    """This is used by insertSilence, clearSwitchGroupTranspositions etc.
+    It assumes to run inside the context:
+        with session.history.sequence(""):
+    """
+    trackId = id(track)
+    session.history.register(lambda trId=trackId, v=track.patternLengthMultiplicator: setTrackPatternLengthMultiplicator(trId, v), descriptionString="Pattern Multiplier")
+    session.history.register(lambda trId=trackId, v=track.structure.copy(): _setTrackStructure(trId, v), descriptionString="Set Measures")
+    session.history.register(lambda trId=trackId, v=track.whichPatternsAreScaleTransposed.copy(): _setSwitchesScaleTranspose(trId, v), descriptionString="Set Modal Shift")
+    session.history.register(lambda trId=trackId, v=track.whichPatternsAreHalftoneTransposed.copy(): _setSwitchHalftoneTranspose(trId, v), descriptionString="Set Half Tone Shift")
+
+
 def insertSilence(howMany:int, beforeMeasureNumber:int):
     """Insert empty measures into all tracks.
     Parameters are un-multiplied."""
@@ -617,13 +727,18 @@ def insertSilence(howMany:int, beforeMeasureNumber:int):
     #In each track shift every switch to the right if it is before the dividing measure number
     #Keep the concept of a "group" even if there are multiplicators in the track.
     #If you insert 4 normal measures then a multiplicator-track of two gets only 2 new ones.
-    for track in session.data.tracks:
+    with session.history.sequence("Insert/Duplicate Group"):  #this actually handles duplicateSwitchGroup undo as well!!!
-        thisTrackWhere = beforeMeasureNumber // track.patternLengthMultiplicator #integer division
+        for track in session.data.tracks:
-        thisTrackHowMany = howMany // track.patternLengthMultiplicator #integer division
+            _registerHistoryWholeTrackSwitches(track)
-        track.structure = set( (switch + thisTrackHowMany if switch >= thisTrackWhere else switch) for switch in track.structure )
+
-        track.whichPatternsAreScaleTransposed = { (k+thisTrackHowMany if k >= thisTrackWhere else k):v for k,v in track.whichPatternsAreScaleTransposed.items() }
+            thisTrackWhere = beforeMeasureNumber // track.patternLengthMultiplicator #integer division
-        track.whichPatternsAreHalftoneTransposed = { (k+thisTrackHowMany if k >= thisTrackWhere else k):v for k,v in track.whichPatternsAreHalftoneTransposed.items() }
+            thisTrackHowMany = howMany // track.patternLengthMultiplicator #integer division
-        callbacks._trackStructureChanged(track)
+            track.structure = set( (switch + thisTrackHowMany if switch >= thisTrackWhere else switch) for switch in track.structure )
+            track.whichPatternsAreScaleTransposed = { (k+thisTrackHowMany if k >= thisTrackWhere else k):v for k,v in track.whichPatternsAreScaleTransposed.items() }
+            track.whichPatternsAreHalftoneTransposed = { (k+thisTrackHowMany if k >= thisTrackWhere else k):v for k,v in track.whichPatternsAreHalftoneTransposed.items() }
+            callbacks._trackStructureChanged(track)
+
+    callbacks._dataChanged() #register undo
     session.data.buildAllTracks()
     updatePlayback()
 
@@ -632,8 +747,9 @@ def duplicateSwitchGroup(startMeasureForGroup:int, endMeasureExclusive:int):
     format."""
 
     groupSize = endMeasureExclusive-startMeasureForGroup
-    insertSilence(groupSize, endMeasureExclusive) #insert silence handles multiplicator-tracks on its own
 
+    #Undo:   InsertSilence has a complete undo already registered. We chose a neutral undo description so it handles both duplicate and insert silence.
+    insertSilence(groupSize, endMeasureExclusive) #insert silence handles multiplicator-tracks on its own
     for track in session.data.tracks:
         thisTrackStartMeasure = startMeasureForGroup // track.patternLengthMultiplicator #integer division
         thisTrackEndMeasure = endMeasureExclusive // track.patternLengthMultiplicator
@@ -647,59 +763,69 @@ def duplicateSwitchGroup(startMeasureForGroup:int, endMeasureExclusive:int):
             if switch-thisGroupSize in track.whichPatternsAreHalftoneTransposed:
                 track.whichPatternsAreHalftoneTransposed[switch] = track.whichPatternsAreHalftoneTransposed[switch-thisGroupSize]
             callbacks._trackStructureChanged(track)
+
     session.data.buildAllTracks()
     updatePlayback()
 
 def clearSwitchGroupTranspositions(startMeasureForGroup:int, endMeasureExclusive:int):
     """startMeasureForGroup and endMeasureExclusive are in the global, un-multiplied measure counting
     format."""
-    for track in session.data.tracks:
+    with session.history.sequence("Clear all Group Transpositions"):
-        thisTrackStartMeasure = startMeasureForGroup // track.patternLengthMultiplicator #integer division
+        for track in session.data.tracks:
-        thisTrackEndMeasure = endMeasureExclusive // track.patternLengthMultiplicator
+            _registerHistoryWholeTrackSwitches(track)
-        for switch in range(thisTrackStartMeasure, thisTrackEndMeasure):
+            thisTrackStartMeasure = startMeasureForGroup // track.patternLengthMultiplicator #integer division
-            if switch in track.whichPatternsAreScaleTransposed:
+            thisTrackEndMeasure = endMeasureExclusive // track.patternLengthMultiplicator
-                del track.whichPatternsAreScaleTransposed[switch]
+            for switch in range(thisTrackStartMeasure, thisTrackEndMeasure):
-            if switch in track.whichPatternsAreHalftoneTransposed:
+                if switch in track.whichPatternsAreScaleTransposed:
-                del track.whichPatternsAreHalftoneTransposed[switch]
+                    del track.whichPatternsAreScaleTransposed[switch]
-        callbacks._trackStructureChanged(track)
+                if switch in track.whichPatternsAreHalftoneTransposed:
+                    del track.whichPatternsAreHalftoneTransposed[switch]
+            callbacks._trackStructureChanged(track)
+    callbacks._dataChanged() #register undo
     session.data.buildAllTracks()
     updatePlayback()
 
 def deleteSwitches(howMany, fromMeasureNumber):
     """Parameters are un-multiplied measures."""
-    for track in session.data.tracks:
+
-        thisTrackHowMany = howMany // track.patternLengthMultiplicator #integer division
+    with session.history.sequence("Delete whole Group"):
-        thisTrackWhere = fromMeasureNumber // track.patternLengthMultiplicator #integer division
+        for track in session.data.tracks:
-
+            _registerHistoryWholeTrackSwitches(track)
-        new_structure = set()
+
-
+            thisTrackHowMany = howMany // track.patternLengthMultiplicator #integer division
-        for switch in track.structure:
+            thisTrackWhere = fromMeasureNumber // track.patternLengthMultiplicator #integer division
-            if switch < thisTrackWhere:
+
-                new_structure.add(switch)
+            new_structure = set()
-            elif switch >= thisTrackWhere+thisTrackHowMany: #like a text editor let gravitate left into the hole left by the deleted range
+
-                new_structure.add(switch-thisTrackHowMany)
+            for switch in track.structure:
-            #else: #discard all in range to delete
+                if switch < thisTrackWhere:
-        track.structure = new_structure
+                    new_structure.add(switch)
-
+                elif switch >= thisTrackWhere+thisTrackHowMany: #like a text editor let gravitate left into the hole left by the deleted range
-        new_scaleTransposed = dict()
+                    new_structure.add(switch-thisTrackHowMany)
-        for k,v in track.whichPatternsAreScaleTransposed.items():
+                #else: #discard all in range to delete
-            if k < thisTrackWhere:
+            track.structure = new_structure
-                new_scaleTransposed[k] = v
+
-            elif k >= thisTrackWhere+thisTrackHowMany: #like a text editor let gravitate left into the hole left by the deleted range
+            new_scaleTransposed = dict()
-                new_scaleTransposed[k-thisTrackHowMany] = v
+            for k,v in track.whichPatternsAreScaleTransposed.items():
-            #else: #discard all in range to delete
+                if k < thisTrackWhere:
-        track.whichPatternsAreScaleTransposed = new_scaleTransposed
+                    new_scaleTransposed[k] = v
-
+                elif k >= thisTrackWhere+thisTrackHowMany: #like a text editor let gravitate left into the hole left by the deleted range
-        new_halftoneTransposed = dict()
+                    new_scaleTransposed[k-thisTrackHowMany] = v
-        for k,v in track.whichPatternsAreHalftoneTransposed.items():
+                #else: #discard all in range to delete
-            if k < thisTrackWhere:
+            track.whichPatternsAreScaleTransposed = new_scaleTransposed
-                new_halftoneTransposed[k] = v
+
-            elif k >= thisTrackWhere+thisTrackHowMany: #like a text editor let gravitate left into the hole left by the deleted range
+            new_halftoneTransposed = dict()
-                new_halftoneTransposed[k-thisTrackHowMany] = v
+            for k,v in track.whichPatternsAreHalftoneTransposed.items():
-            #else: #discard all in range to delete
+                if k < thisTrackWhere:
-        track.whichPatternsAreHalftoneTransposed = new_halftoneTransposed
+                    new_halftoneTransposed[k] = v
-
+                elif k >= thisTrackWhere+thisTrackHowMany: #like a text editor let gravitate left into the hole left by the deleted range
-        callbacks._trackStructureChanged(track)
+                    new_halftoneTransposed[k-thisTrackHowMany] = v
+                #else: #discard all in range to delete
+            track.whichPatternsAreHalftoneTransposed = new_halftoneTransposed
+
+            callbacks._trackStructureChanged(track)
+
+    callbacks._dataChanged() #register undo
     session.data.buildAllTracks()
     updatePlayback()
 

qtgui/mainwindow.py

@@ -75,8 +75,8 @@ class MainWindow(TemplateMainWindow):
             tooltip=QtCore.QCoreApplication.translate("Menu", "Change step-grouping but keep your music the same"),
             )
 
-        self.ui.actionUndo.setVisible(False)
+        #self.ui.actionUndo.setVisible(False)
-        self.ui.actionRedo.setVisible(False)
+        #self.ui.actionRedo.setVisible(False)
 
         #Playback Controls
 

template/engine/api.py

@@ -78,7 +78,7 @@ class Callbacks(object):
 
 
     def _dataChanged(self):
-        """Only called from within the callbacks.
+        """Only called from within the callbacks or template api.
         This is about data the user cares about. In other words this is the indicator if you need
         to save again.
 
@@ -136,6 +136,7 @@ class Callbacks(object):
         status = playbackStatus()
         for func in self.setPlaybackTicks:
             func(ppqn, status)
+        self._dataChanged() #includes _historyChanged
 
     def _playbackStatusChanged(self):
         """Returns a bool if the playback is running.
@@ -243,6 +244,8 @@ class Callbacks(object):
         lst = [track.export() for track in session.data.tracks]
         for func in self.numberOfTracksChanged:
             func(lst)
+        self._dataChanged() #includes _historyChanged
+
 
     def _metronomeChanged(self):
         """returns a dictionary with meta data such as the mute-state and the track name"""

template/engine/sequencer.py

@@ -88,6 +88,7 @@ class Score(Data):
 
     #Tracks
     def addTrack(self, name:str=""):
+        """Create and add a new track. Not an existing one"""
         track = Score.TrackClass(parentData=self, name=name)
         assert track.sequencerInterface
         self.tracks.append(track)
@@ -96,6 +97,7 @@ class Score(Data):
     def deleteTrack(self, track):
         track.sequencerInterface.prepareForDeletion()
         self.tracks.remove(track)
+        return track #for undo
 
     def updateJackMetadataSorting(self):
         """Add this to you  "tracksChanged" or "numberOfTracksChanged" callback.