Engraving essay questions and RFC

[Andrew Hawryluk]

Hi everyone, I'm working on the LilyPond essay, and I'm ready to ask
you some questions.

You can read my current draft at http://www.musicbyandrew.ca/essay.pdf
(this is identical to a doc build with my latest patch, except that I
have only updated the pages containing the new essay, leaving out the
original, the GPL stuff, and the index.) The source file in question
is Documentation/essay/engraving.itely

Questions:

1. Multiple staff sizes and optical line weights. I have a piano +
violin excerpt on page 4 (PDF page 6). If I modify the staff-space and
thickness by the same number then I don't get the relatively heavier
lines that I would naturally get using "set-global-staff-size". I am
currently using this:

  \new Staff \with {
      fontSize = #-4
      \override StaffSymbol #'staff-space = #(magstep -4)
      \override StaffSymbol #'thickness = #(magstep -3)
    }

This gives me staff lines that I like, but they may not match the
carefully tunes weights of "set-global-staff-size". Also, I think I
should be thickening up the barlines and stems as well.
- Any suggestions on the tweaks I should do to match the
"set-global-staff-size" appearance?

(A previous discussion suggested magstep = 3.5 for these cases, but I
am trying to increase the contrast a bit.)

2. Something is wrong with my beaming on page 6 (PDF 8). Any guesses?
The source is
\relative c {
  \clef "bass"
  \key d \minor
  \time 3/4
  \mergeDifferentlyDottedOn
  << {\slurDashed d8.-\flageolet( e16) e4.-\trill( d16 e)}
     \\ {d4_2 a2}
  >>
  \slurDashed
  <f' a, d,>4. e8( d c)
  \slurSolid
  bes g' f e16( f g_1 a_2 bes_3 d,_2)
  \slurDashed
  cis4.-\trill b8_3( a g)
  << {\slurDashed d'8.( e16) e4.-\trill( d16 e)}
     \\ {<f, a>4 a2}
  >>
}

3. As you can see, I have started a comparison of Finale / LilyPond /
real engravings. The scores are on the last 3 pages. (Note that the
Finale example has been clipped just a bit to close on the right hand
side. I will fix this.) My preliminary observations are

- Finale rests are always at the same heights (in v1/v2 situations).
- Finale doesn’t interlock notes nicely (mm. 28–29).
- Finale misses the B-flat in mm. 33!
- Finale’s beamed stems are almost always too long when they extend
off the staff.
- LilyPond 2.13.5 currently has a vertical spacing problem (no padding
between staves).
- LilyPond could use a little more space before the first note of mm. 30, 33–34.
- LilyPond’s ties to beat 1 of mm. 31 are shorter than any of the
reference scores, and Finale’s are even worse.
- LilyPond’s stems are often shorter than any of the references,
especially RH mm. 31.

Have I missed anything?
Please discuss?
Maybe a couple of those items should be bug reports? Although I want
to be fair in this essay, I also don't want to

4. I believe that I have now incorporated the most valuable elements
of the original essay into the nicer structure that Trevor began. Do
you agree or did I miss something? (There are probably still things to
add, but I don't think they will come from the old essay.)

5. Any other thoughts? The essay has been a prominent piece of
LilyPond 'marketing' and I want to know that community is getting the
upgraded essay that they want.

Thanks,
Andrew