Re: Issue 1015 in lilypond: doc line width

[lilypond]

Comment #7 on issue 1015 by percival.music.ca: doc line width
http://code.google.com/p/lilypond/issues/detail?id=1015

Some initial info:
- the docs current set the line width to be 160mm in:
    python/book_texinfo.py
  (all our manuals use @afourpaper)
This seems very reasonable.  A4 paper is narrower (210.0mm) than usletter  
(215.9mm), so we should use the narrower version.  If we have a 25mm  
left+right margin, then this leaves 160mm for the width.
NB: this leaves no space for a gutter.  I'm comfortable with that, but I'm  
prepared to listen to arguments in favour of gutters.

However, the lilypond line-width is *not* 160mm.

- currently, 3mm is subtracted from this figure.  I believe this is to  
reserve space for bar numbers.

- we SHOULD (but currently do not) reserve space for instrument names, or  
make lilypond automatically shift the music to the right.  (this is issue  
766 and 1093, which on a quick reading are duplicates?  and 766 is lacking  
an image)

- we SHOULD (but currently do not) reserve space for [quote].


A clear demonstration of these problems is the snippet  
heavily-customized-polymetric-time-signatures.ly.  In snippets.pdf, the  
music extends into the right-hand page margins.  In the HTML output, this  
image is 683 pixels wide, whereas other "full-width" images are 639  
pixels.  (this number must have been chosen deliberately, and IMO is quite  
appropriate)


So I think this issue is blocked on the instrument name and (maybe) the bar  
number shifting.  But the overall effect is that the amount of horizontal  
space will be reduced; probably to about 150mm.