Re: Creating arbitrary lines (or other postscript things)

[Nick Payne]

On 16/11/10 01:08, Andrew C. Smith wrote:
> Dear users,
>
> I'm working on a piece of music where certain notes need to be connected by 
> dotted lines. I've tried a few different things: using \glissando and 
> overriding the stencil to get a different position, or just creating \markup 
> with a stencil object. I've also tried writing it in postscript (which seems to 
> be the ideal solution) but I can't figure out how to return certain values of 
> the notehead object. I'd like to avoid drawing the lines in by hand later, 
> because I want to generate scores algorithmically.
>
> What would be ideal (as far as I can tell) is to have a global variable that's a list of 
> pairs of ly:music, then at the end of the program run a function to cycle through this 
> list and draw dotted lines between all the pairs. My problem is that I can't figure out 
> how to get the x/y position of the NoteHead object from a string of text like 
> "d4", because as far as I've seen (and this may be way wrong, so forgive me) 
> the interfaces generally are built for modifying values, not returning values for use in 
> other functions. Any ideas? Or, at least places I should have already looked?
>
> Have to admit I don't know Lilypond super well, but I've googled this problem 
> pretty hard and read the manual looking specifically for it. I know mostly 
> C-related languages, so Scheme is kind of bending my brain a little. Any help 
> from more experienced users would be excellent.

This does something similar with a music function and a hidden voice:

\version "2.13.38"

guide = #(define-music-function (parser location padleft padright shift 
style) (number? number? pair? symbol?) #{
    \once \override Glissando #'style = #$style
    \once \override Glissando #'bound-details #'left #'padding = #$padleft
    \once \override Glissando #'bound-details #'right #'padding = 
#$padright
    \once \override Glissando #'extra-offset = #$shift
#})

\relative c'' {
<<
        { c8 g e g }
    \\
        { \hideNotes \guide #-0.5 #1 #'(0 . 0) #'solid-line 
c4.\glissando g8 }
>>
<<
        { c8 g e g }
    \\
        { \hideNotes \guide #-0.5 #1 #'(0 . 0) #'dashed-line 
c4.\glissando g8 }
>>
<<
        { c8 g e g }
    \\
        { \hideNotes \guide #-0.5 #1 #'(0 . 0) #'dotted-line 
c4.\glissando g8 }
>>
}

Nick

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