Re: missing glissando features (bugs?)

[Neil Puttock]

2009/5/2 Marc Hohl <address@hidden>:
> I have made some observations concerning \glissando:
>
> 1) accidentals are not recognised properly; I know this is in the bug list
> and there are workarounds,
>  see http://lists.gnu.org/archive/html/bug-lilypond/2005-08/msg00235.html

This isn't at all straightforward to fix (I had a stab at it a while
ago, and it's tricky to get the positioning correct on the right hand
side because the accidental changes the anchor point for the end of
the glissando.)

> 2) the glissando line between half steps should indicate the direction;
>  e.g. a glissando line between c and c# should raise a bit and not be
> parallel to the staff lines;
>
> 3) in tablature, the glissando is always indicated upwards, but it should be
> drawn in respect to the fret number;
>  e.g. 3/5\3, not 3/5/3;
>
> Should (2) and (3) be considered as bugs? I have found a request from
> 9/2005:

Probably.

It should be quite easy to fix both problems with a callback for
'extra-dy (see below)

> http://lists.gnu.org/archive/html/bug-lilypond/2005-09/msg00112.html
>
> and it seems to me that this has been partly implemented
> (the lines betweeen fret numbers are now sloped, so there _has_ been some
> progress).
>
> Are there any hints/workarounds to solve this problem?

>From the glissando you can get the left and right noteheads using
ly:spanner-bound, from which it's possible to retrieve the pitches. A
simple comparision of pitches should allow you to set the correct
return value for 'extra-dy.

For TabVoice.Glissando, you can get the staff-positions for the
bounding notes, so it's possible to apply extra-dy only for glissandos
between tab notes on the same line.

Regards,
Neil