Instead of a note offset (in measure) for every note, compute what the gap is between the note and the preceding note (or start of measure, if it's the first note in the voice/measure). That way most notes have the same zero gap, so we don't get a ton of spurious diffs when a gap/space is inserted in one of the two scores being diffed.

Author: gregchapman-dev

musicdiff/annotation.py

@@ -19,7 +19,7 @@
 import typing as t
 
 import music21 as m21
-from music21.common.numberTools import OffsetQL
+from music21.common.numberTools import OffsetQL, opFrac
 
 from musicdiff import M21Utils
 from musicdiff import DetailLevel
@@ -28,7 +28,7 @@ class AnnNote:
     def __init__(
         self,
         general_note: m21.note.GeneralNote,
-        offsetInMeasure: OffsetQL,
+        gap_dur: OffsetQL,
         enhanced_beam_list: list[str],
         tuplet_list: list[str],
         tuplet_info: list[str],
@@ -39,6 +39,8 @@ def __init__(
 
         Args:
             general_note (music21.note.GeneralNote): The music21 note/chord/rest to extend.
+            gap_dur (OffsetQL): gap since end of last note (or since start of measure, if
+                first note in measure).  Usually zero.
             enhanced_beam_list (list): A list of beaming information about this GeneralNote.
             tuplet_list (list): A list of tuplet info about this GeneralNote.
             detail (DetailLevel): What level of detail to use during the diff.
@@ -48,7 +50,7 @@ def __init__(
 
         """
         self.general_note: int | str = general_note.id
-        self.offsetInMeasure: OffsetQL = offsetInMeasure
+        self.gap_dur: OffsetQL = gap_dur
         self.beamings: list[str] = enhanced_beam_list
         self.tuplets: list[str] = tuplet_list
         self.tuplet_info: list[str] = tuplet_info
@@ -244,28 +246,31 @@ def __str__(self) -> str:
 
         if len(self.articulations) > 0:  # add for articulations
             for a in self.articulations:
-                string += a
+                string += ' ' + a
         if len(self.expressions) > 0:  # add for articulations
             for e in self.expressions:
-                string += e
+                string += ' ' + e
         if len(self.lyrics) > 0:  # add for lyrics
             for lyric in self.lyrics:
-                string += lyric
+                string += ' ' + lyric
 
         if self.noteshape != 'normal':
-            string += f"noteshape={self.noteshape}"
+            string += f" noteshape={self.noteshape}"
         if self.noteheadFill is not None:
-            string += f"noteheadFill={self.noteheadFill}"
+            string += f" noteheadFill={self.noteheadFill}"
         if self.noteheadParenthesis:
-            string += f"noteheadParenthesis={self.noteheadParenthesis}"
+            string += f" noteheadParenthesis={self.noteheadParenthesis}"
         if self.stemDirection != 'unspecified':
-            string += f"stemDirection={self.stemDirection}"
+            string += f" stemDirection={self.stemDirection}"
 
-        # offset
-        string += f" {self.offsetInMeasure}"
+        # gap_dur
+        if self.gap_dur != 0:
+            string += f" spaceBefore={self.gap_dur}"
 
         # and then the style fields
         for i, (k, v) in enumerate(self.styledict.items()):
+            if i == 0:
+                string += ' '
             if i > 0:
                 string += ","
             string += f"{k}={v}"
@@ -286,25 +291,6 @@ def __eq__(self, other) -> bool:
         # equality does not consider the MEI id!
         return self.precomputed_str == other.precomputed_str
 
-        # if not isinstance(other, AnnNote):
-        #     return False
-        # elif self.pitches != other.pitches:
-        #     return False
-        # elif self.note_head != other.note_head:
-        #     return False
-        # elif self.dots != other.dots:
-        #     return False
-        # elif self.beamings != other.beamings:
-        #     return False
-        # elif self.tuplets != other.tuplets:
-        #     return False
-        # elif self.articulations != other.articulations:
-        #     return False
-        # elif self.expressions != other.expressions:
-        #     return False
-        # else:
-        #     return True
-
 
 class AnnExtra:
     def __init__(
@@ -466,11 +452,21 @@ def __init__(
             # create a list of notes with beaming and tuplets information attached
             self.annot_notes = []
             for i, n in enumerate(note_list):
-                offset: OffsetQL = n.getOffsetInHierarchy(enclosingMeasure)
+                expectedOffsetInMeas: OffsetQL = 0
+                if i > 0:
+                    prevNoteStart: OffsetQL = (
+                        note_list[i - 1].getOffsetInHierarchy(enclosingMeasure)
+                    )
+                    prevNoteDurQL: OffsetQL = (
+                        note_list[i - 1].duration.quarterLength
+                    )
+                    expectedOffsetInMeas = opFrac(prevNoteStart + prevNoteDurQL)
+
+                gapDurQL: OffsetQL = n.getOffsetInHierarchy(enclosingMeasure) - expectedOffsetInMeas
                 self.annot_notes.append(
                     AnnNote(
                         n,
-                        offset,
+                        gapDurQL,
                         self.en_beam_list[i],
                         self.tuplet_list[i],
                         self.tuplet_info[i],
@@ -490,9 +486,6 @@ def __eq__(self, other) -> bool:
             return False
 
         return self.precomputed_str == other.precomputed_str
-        # return all(
-        #     [an[0] == an[1] for an in zip(self.annot_notes, other.annot_notes)]
-        # )
 
     def notation_size(self) -> int:
         """

musicdiff/comparison.py

@@ -938,10 +938,17 @@ def _annotated_note_diff(annNote1: AnnNote, annNote2: AnnNote):
             op_list.extend(lyr_op_list)
             cost += lyr_cost
 
-        # add for offset in quarter notes from start of measure (i.e. horizontal position)
-        if annNote1.offsetInMeasure != annNote2.offsetInMeasure:
+        # add for gap from previous note or start of measure if first note in measure
+        # (i.e. horizontal position shift)
+        if annNote1.gap_dur != annNote2.gap_dur:
             cost += 1
-            op_list.append(("editnoteoffset", annNote1, annNote2, 1))
+            if annNote1.gap_dur == 0:
+                op_list.append(("insspace", annNote1, annNote2, 1))
+            elif annNote2.gap_dur == 0:
+                op_list.append(("delspace", annNote1, annNote2, 1))
+            else:
+                # neither is zero
+                op_list.append(("editspace", annNote1, annNote2, 1))
 
         # add for noteshape
         if annNote1.noteshape != annNote2.noteshape:

musicdiff/visualization.py

@@ -785,22 +785,60 @@ def mark_diffs(
                 textExp.style.color = Visualization.CHANGED_COLOR
                 note2.activeSite.insert(note2.offset, textExp)
 
-            elif op[0] == "editnoteoffset":
+            elif op[0] == "editspace":
                 assert isinstance(op[1], AnnNote)
                 assert isinstance(op[2], AnnNote)
                 note1 = score1.recurse().getElementById(op[1].general_note)  # type: ignore
                 if t.TYPE_CHECKING:
                     assert note1 is not None
                 note1.style.color = Visualization.CHANGED_COLOR
-                textExp = m21.expressions.TextExpression("changed note offset")
+                textExp = m21.expressions.TextExpression("changed space before")
                 textExp.style.color = Visualization.CHANGED_COLOR
                 note1.activeSite.insert(note1.offset, textExp)
 
                 note2 = score2.recurse().getElementById(op[2].general_note)  # type: ignore
                 if t.TYPE_CHECKING:
                     assert note2 is not None
                 note2.style.color = Visualization.CHANGED_COLOR
-                textExp = m21.expressions.TextExpression("changed note offset")
+                textExp = m21.expressions.TextExpression("changed space before")
+                textExp.style.color = Visualization.CHANGED_COLOR
+                note2.activeSite.insert(note2.offset, textExp)
+
+            elif op[0] == "insspace":
+                assert isinstance(op[1], AnnNote)
+                assert isinstance(op[2], AnnNote)
+                note1 = score1.recurse().getElementById(op[1].general_note)  # type: ignore
+                if t.TYPE_CHECKING:
+                    assert note1 is not None
+                note1.style.color = Visualization.CHANGED_COLOR
+                textExp = m21.expressions.TextExpression("inserted space before")
+                textExp.style.color = Visualization.CHANGED_COLOR
+                note1.activeSite.insert(note1.offset, textExp)
+
+                note2 = score2.recurse().getElementById(op[2].general_note)  # type: ignore
+                if t.TYPE_CHECKING:
+                    assert note2 is not None
+                note2.style.color = Visualization.CHANGED_COLOR
+                textExp = m21.expressions.TextExpression("inserted space before")
+                textExp.style.color = Visualization.CHANGED_COLOR
+                note2.activeSite.insert(note2.offset, textExp)
+
+            elif op[0] == "delspace":
+                assert isinstance(op[1], AnnNote)
+                assert isinstance(op[2], AnnNote)
+                note1 = score1.recurse().getElementById(op[1].general_note)  # type: ignore
+                if t.TYPE_CHECKING:
+                    assert note1 is not None
+                note1.style.color = Visualization.CHANGED_COLOR
+                textExp = m21.expressions.TextExpression("deleted space before")
+                textExp.style.color = Visualization.CHANGED_COLOR
+                note1.activeSite.insert(note1.offset, textExp)
+
+                note2 = score2.recurse().getElementById(op[2].general_note)  # type: ignore
+                if t.TYPE_CHECKING:
+                    assert note2 is not None
+                note2.style.color = Visualization.CHANGED_COLOR
+                textExp = m21.expressions.TextExpression("deleted space before")
                 textExp.style.color = Visualization.CHANGED_COLOR
                 note2.activeSite.insert(note2.offset, textExp)