Add option to define left-margin

[uliska]

With a defined left-margin option in the lilypond-score it will be possible to explicitly align the first barline to the text margin, which is something I'd greatly prefer.

Any value set here should be added to line-width. So a left margin of 0.5cm should add 0.5cm to the line width.

[jperon]

I'm not sure I understand very well, but I've no objection !

[uliska]

OK, I see now that it's not that simple and that I need some help from the lilypond-user list, but I can fake an example.

By default LaTeX aligns an image with the left margin of the surrounding text. When suppressing parindent this looks like this:

However, I would prefer giving users the possibility (because I would usually do it like this) not to align the border of the image but the first barline and have the system bracket (or whatever brackets are used, maybe even short instrument names) protrude in the left margin like this:

For this we have to know (set) the exact width of the left margin of the score and offset the position in the LaTeX file accordingly.

Unfortunately the cropped layout always crops the left margin, so we can't easily retrieve the necessary information (because the actual value dependes on the actual staff organization (a PianoStaff brace over three staves is wider than over two etc.). I'll have to see if there's a way to make LilyPond produce a usable score for this use case.

[uliska]

A clearer description of the problem in the attached PDF.

I think this problem is already touched in the code by defaulting the line width to the text's line width minus 10 pt. But as the elements to the left are of arbitrary width this is not a real solution.

[uliska]

Having asked on lilypond-user I found an answer myself. The solution consists of a number of steps, and I would like to give it a try myself:

• Add a left-margin option to the score definition
  This must be sufficient to handle all protruding elements and small enough to allow line-width to fit on the paper size.
  It must be given in points (\pt => bp/big points in LaTeX)
• compile using eps backend (as it already is done)
• read the first value from the BoundingBox line from the main eps file:
  %%BoundingBox: 27 -209 532 -18 means a value of 27 points
  head -n 3 my-file.eps | tail -n 1 | cut -d " " -f 2 does that
  [Edit: I have implemented it in Lua instead]
• calculate the offset as left-margin minus that bounding box value
• When copying the value from the -systems.tex file prepend each entry with \hspace*{-<bb-value>}
• Make sure there is no parindent. Store the current value in a local variable and restore it after the music