Re: musicxml2ly bar-line support

[Reinhold Kainhofer]

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Am Sonntag, 12. Oktober 2008 schrieb Valentin Villenave:
> a French user has asked about musixml2ly's support for
> hiding/modifying bar lines; it seems that this is not fully supported
> yet, as (reportedly) demonstrated by the attached files.

Actually, this not a problem with bar line styles. The 

      <barline location="right">
        <bar-style>none</bar-style>
      </barline>

elements of the MusicXML file are correctly converted to 
   \bar ""
in Lilypond... 
This can also be seen in the hidden bar lines at the beginning of each stanza.


The issue is rather the different handling of measure length of lilypond and 
MusicXML. The MusicXML file uses one measure (of variable length) for each 
stanza. 

Now, the issue is as following: In MusicXML a measure consists of everything 
between <measure ...> ... </measure>, no matter how long/short the timing of 
the contents is and how many beats this measure contains. The first file 
(Psalm_bar-lines_1.xml) for example contains 10 double beats (quartes and 
half notes summing up to 10 half notes) in the first measure, and 9 double 
beats in the remaining measures.
However, it does NOT contain any time signatures. MusicXML treats those 9 or 
10 double beats as one long measure, but LilyPond uses a default time 
signature of 4/4 if no time signature is given (the .xml file does not 
contain any time signature, of course).
So when processing the .ly file, LilyPond internally splits a stanza like

    g2 a4 b4 c2 r2 c2 b4 a4 b4 c4 a2 g2 r2 \bar "" % 0

up into 5 measures with 4 beats when processing the file, while MusicXML 
treats it as one large measure and does not keep track of any timing 
information...
It's these additional bar lines that make it look like musicxml2ly would not 
support barline styles.

The file Psalm_bar-lines_2.xml inserts the correct time signatures, so that 
lilypond uses the same measure lengths as the .xml file and no measures are 
split internally in lilypond. If you look at the .pdf file, you'll see that 
now there are really no bar lines present.


Unfortunately, i don't see any way to work around this different understanding 
of how measure work in MusicXML and LilyPond...

You might want to take a look at cadenzas, though, in the LilyPond 
Documentation:
http://kainhofer.com/~lilypond/Documentation/user/lilypond/Displaying-rhythms.html#Unmetered-music


If you add \cadenzaOn at the beginning of the music defined in the 
PartPOneVoiceOne variable, you'll get exactly what you want. (Actually, 
musicxml2ly writes out an additional bar number check (the "|" characters on 
a line on their own), which does not make sense inside a cadenza, so either 
you delete those pipe symbols or you live with the warnings that LilyPond 
generates for them.

Also note that things like line or page breaks are NOT converted from MusicXML 
to LilyPond, since LilyPond will do the page layout itself, so trying to 
force the same line breaks as the file in Finale will in most cases simply 
lead to badly spaced output...

I hope this clears up a little bit...

Cheers,
Reinhold

- -- 
- ------------------------------------------------------------------
Reinhold Kainhofer, Vienna University of Technology, Austria
email: address@hidden, http://reinhold.kainhofer.com/
 * Financial and Actuarial Mathematics, TU Wien, http://www.fam.tuwien.ac.at/
 * K Desktop Environment, http://www.kde.org, KOrganizer maintainer
 * Chorvereinigung "Jung-Wien", http://www.jung-wien.at/
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