MusicXML: Apply Attributes and Direction only to the staves/voices they apply to

When extracting the voices of a part, first detect all different voices so that
we can assign dynamics to all voices right from the beginning.
Also, assign the dynamics and attributes only to those voices they really apply
to (in particular, if they have a <staff> element, only assign them to the voices
that use that particular staff). For this, I also need to keep a dict for
staff=>[voiceids,...] around. To be able to assign attributes only to the
correct voices, I need to copy the attributes object and erase all clefs, times
and keys that do not apply to the staff (and keep only those objects that either
have no number attribute or have the correct number attribute). This copying
(shallow copying of the relevant parts of the Attributes object) gave me some
major headache, but it should work fine now.

Signed-off-by: Reinhold Kainhofer <reinhold@kainhofer.com>

diff --git a/python/musicxml.py b/python/musicxml.py
index 9788d9745dd9fda26d898660bb13af0634bd168e..7281a129f3921a49c95bc860dde67acf8b8ecd6f 100644 (file)
--- a/python/musicxml.py
+++ b/python/musicxml.py
@@ -1,8 +1,10 @@
+# -*- coding: utf-8 -*-
 import new
 import string
 from rational import *
 import re
 import sys
+import copy
 
 def escape_ly_output_string (input_string):
     return_string = input_string
@@ -518,12 +520,51 @@ class Part (Music_xml_node):
 
                 now = new_now
 
+    # modify attributes so that only those applying to the given staff remain
+    def extract_attributes_for_staff (part, attr, staff):
+        attributes = copy.copy (attr)
+        attributes._children = copy.copy (attr._children)
+        attributes._dict = attr._dict.copy ()
+        for c in attributes._children:
+            if hasattr (c, 'number') and c.number != staff:
+                attributes._children.remove (c)
+        return attributes
+
     def extract_voices (part):
        voices = {}
        measures = part.get_typed_children (Measure)
        elements = []
        for m in measures:
            elements.extend (m.get_all_children ())
+        # make sure we know all voices already so that dynamics, clefs, etc.
+        # can be assigned to the correct voices
+        voice_to_staff_dict = {}
+        for n in elements:
+            voice_id = n.get_maybe_exist_named_child (u'voice')
+            vid = None
+            if voice_id:
+                vid = voice_id.get_text ()
+
+            staff_id = n.get_maybe_exist_named_child (u'staff')
+            sid = None
+            if staff_id:
+                sid = staff_id.get_text ()
+            if vid and not voices.has_key (vid):
+                voices[vid] = Musicxml_voice()
+            if vid and sid and not n.get_maybe_exist_typed_child (Grace):
+                if not voice_to_staff_dict.has_key (vid):
+                    voice_to_staff_dict[vid] = sid
+        # invert the voice_to_staff_dict into a staff_to_voice_dict (since we
+        # need to assign staff-assigned objects like clefs, times, etc. to
+        # all the correct voices. This will never work entirely correct due
+        # to staff-switches, but that's the best we can do!
+        staff_to_voice_dict = {}
+        for (v,s) in voice_to_staff_dict.items ():
+            if not staff_to_voice_dict.has_key (s):
+                staff_to_voice_dict[s] = [v]
+            else:
+                staff_to_voice_dict[s].append (v)
+
 
        start_attr = None
        for n in elements:
@@ -538,22 +579,38 @@ class Part (Music_xml_node):
                start_attr = n
                continue
 
-           if isinstance (n, Attributes) or isinstance (n, Direction):
-               for v in voices.values ():
-                   v.add_element (n)
-               continue
+            if isinstance (n, Attributes):
+                # assign these only to the voices they really belongs to!
+                for (s, vids) in staff_to_voice_dict.items ():
+                    staff_attributes = part.extract_attributes_for_staff (n, s)
+                    for v in vids:
+                        voices[v].add_element (staff_attributes)
+                continue
+
+            if isinstance (n, Direction):
+                staff_id = n.get_maybe_exist_named_child (u'staff')
+                if staff_id:
+                    staff_id = staff_id.get_text ()
+                if staff_id:
+                    dir_voices = staff_to_voice_dict[staff_id]
+                else:
+                    dir_voices = voices.keys ()
+                for v in dir_voices:
+                    voices[v].add_element (n)
+                continue
 
            id = voice_id.get_text ()
-           if not voices.has_key (id):
-               voices[id] = Musicxml_voice()
-
            voices[id].add_element (n)
 
        if start_attr:
-           for (k,v) in voices.items ():
-               v.insert (0, start_attr)
-
-       part._voices = voices
+            for (s, vids) in staff_to_voice_dict.items ():
+                staff_attributes = part.extract_attributes_for_staff (start_attr, s)
+                staff_attributes.read_self ()
+                for v in vids:
+                    voices[v].insert (0, staff_attributes)
+                    voices[v]._elements[0].read_self()
+
+        part._voices = voices
 
     def get_voices (self):
        return self._voices