Re: scheme in \layout to produce relative dimensions

[Graham Percival]

On 16-May-06, at 11:32 AM, Nicolas Sceaux wrote:

> I don't know what exactly you're trying to do, but maybe this example 
> may
> help you:

At the moment, I'm investigating the line-width bug in lilypond-book, 
but this is good general info anyway.  :)

> \paper {
>   left-margin = 15\mm
>   right-margin = 15\mm
>   #(define line-width (- paper-width (* 30 mm)))
> }
>
> This resizes the margins (15mm left and right), and then set 
> accordingly
> the line width.

Thanks, that works.  But can this be done inside a \score{} ?   (to 
work in lilypond-book)

\score{
  \relative c'' {
    \repeat unfold 16 {a4 b c d}
  }
  \layout{
    #(define line-width (- paper-width (* 30 mm)))
  }
}

produces
----
spark:~/tmp gperciva$ lilypond fff.ly
GNU LilyPond 2.8.2
Processing `fff.ly'
Parsing...ERROR: Unbound variable: paper-width
----

(I really need to clean out my ~/tmp/ directory; I've run out of 
foo.ly, bar.ly, baz.ly, bug.ly, and baa.ly :)

I tried a few variations of the #(define...) line without success, but 
since it works in \paper{} I figure I probably need to do something 
like
#page:paper-width
to access this variable inside a \score{ \layout{}}.


> Indeed, the paper width being set when the paper size is defined (using
> set-default-paper-size for instance), the line width can be computed as
> follow:
>   line-width = paper-width - left-margin - right-margin
> that is, in scheme:
>   #(define line-width (- paper-width left-margin right-margin))

Is this working now?  There's a @refbug in 10.4.2 Page formatting that 
says that right-margin doesn't actually work yet, and that one should 
simply set left-margin and line-width.  I don't know how old this 
report is, though.

Cheers,
- Graham