Re: Hiding first stem in group hides beam

[David Kastrup]

TorbjörnBjörkman <address@hidden> writes:

> I try to hide the first stem in a beam group and expect this to keep the
> beam, just as happens if you hide any other stem in the group. However, the
> whole beam goes away.
>
> I run lilypond version 2.18.2 on a Mac.
>
> Code snippet that demonstrates the issue follows. The first two beam groups
> show the expected behaviour and the last fails. This seems to be a bug.
>
> Best regards,
> Torbjörn Björkman
>
> \score{
>   \new Staff 
>   \relative c' {
>     \cadenzaOn
>     c8[ e \once \hide Stem f] 
>     c[ \once \hide Stem e f] 
>     \once \hide Stem c[ e f] 
>   }
> }     

That's the intended consequence of issue 2866
<URL:https://code.google.com/p/lilypond/issues/detail?id=2866>.

Rereading the issue, I'm not quite sure about the exact rationale but
the main motivation appears to stem from automatic rather than manual
beams.

The report mentions a number of other issue reports.  The implementation
of the change was through

    address@hidden:/usr/local/tmp/lilypond$ git log -p bd599be12
    commit bd599be12a872b9ca95ebc78e0880e2d13c26b4f
    Author: Keith OHara <address@hidden>
    Date:   Tue May 14 21:53:25 2013 -0700

        Beams: be transparent if the first stem is transparent; issue 2866

        so that \hideNotes does not hide automatic beams that could have,
        but did not, start on a hidden note.

though I provided an initial version of the patch.

-- 
David Kastrup