glissando stems

[Thomas Morley]

Hi,

there was a discussion on lily-devel to implement glissando stems:
http://lists.gnu.org/archive/html/lilypond-devel/2011-06/msg00810.html
but finally it was rejected.

Han-Wen's suggestion from
http://codereview.appspot.com/4661061/#ps1 (reply #16)
is beyond my knowledge.

My own work-around is very, very fragile:

\version "2.14.2"
\pointAndClickOff

gliss = #(define-music-function (parser location control)(pair?)
  (let((y-off (car control))
       (slope (cdr control)))
  #{    
   \once\override TextSpanner #'style = #'line
   \once\override TextSpanner #'extra-offset = #(cons 0 $y-off) 
   \once\override TextSpanner #'thickness = #1.5

   \override TextSpanner #'bound-details =
      #`((left . ((Y . 0)
                  (padding . 1.5)
                  ))
         (right . ((Y . ,$slope)
                   (padding . 2.5)
                   (attach-dir . ,RIGHT)
                   )))
  #}))


#(define startGliss startTextSpan)
#(define stopGliss stopTextSpan)

stemGliss = #(define-music-function (parser location control)(number?)
#{
        \once \override NoteHead #'Y-extent = #(cons 0 $control)
        \once \override NoteHead #'transparent = ##t
        \once \override Stem #'Y-extent = #'(0 . 0)
#})


\relative c' {

    \gliss #'(-3.8 . -1)
        \partial 4*1 b'\startGliss
        \stemGliss #0.3
        \once \override NoteHead #'X-extent = #'(-0.8 . 0.1)
        g
        g\stopGliss r2

        }

Is there another, better way to do the job?

Cheers,
  Harm