Issue 2314 - workaround and patch

[Knut Petersen]

Hi everybody!

Werner: You reported in 2012 that lilypond emits a space glyph referencing
the century schoolbook font at the top of every page.

David: At that time you were not sure if this is a bug.

The problem is still present, and it definitely is a bug because that extra 
space glyph
has a nasty effect:

If you use ghostscript (old versions and current git master) or pdfcrop to crop 
the
output of a pdf containing multiple pages and print-page-number = ##f in the 
paper
section of the lilypond file , you can observe that there is excessive white 
space at the
top of even pages.

We could argue that ghostscript should handle that case better, but a recent gs 
bug report
http://bugs.ghostscript.com/show_bug.cgi?id=696445 was closed with a "WONTFIX".

There is a workaround within lilypond:

\paper {
    [...]
    oddHeaderMarkup = \markup \null
    evenHeaderMarkup = \markup \null
}

A look at the lilypond source code reveals that the space glyph is introduced 
by the definition
of oddHeaderMarkup and evenHeaderMarkup in ly/titling-init.ly. There we read a 
comment that
suggest that the space is necessary:

%% force the header to take some space, otherwise the
%% page layout becomes a complete mess.

Nevertheless, changing " " to "" cured the problem for me and had no negative 
side effects here ...
but that probably needs further testing.

As bounding boxes are changed this patch certainly has effects in situations 
where lilypond
snippets are used by other programs.

cu,
 Knut

0001-Dont-emit-space-glyph-as-empty-page-number.patch
Description: Text Data