Re: DurationLine avoiding RehearsalMarks

[Thomas Morley]

Am Fr., 15. Apr. 2022 um 13:27 Uhr schrieb Jean Abou Samra <jean@abou-samra.fr>:
>
>
>
> Le 15/04/2022 à 13:17, Thomas Morley a écrit :
> > Am Fr., 15. Apr. 2022 um 12:52 Uhr schrieb Jean Abou Samra 
> > <jean@abou-samra.fr>:
> >>
> >>
> >> Le 15/04/2022 à 11:45, Thomas Morley a écrit :
> >>> Am Fr., 15. Apr. 2022 um 10:39 Uhr schrieb Jean Abou Samra 
> >>> <jean@abou-samra.fr>:
> >>>>
> >>>> Le 15/04/2022 à 10:13, Thomas Morley a écrit :
> >>>>> Am Mi., 13. Apr. 2022 um 17:57 Uhr schrieb Jean Abou Samra 
> >>>>> <jean@abou-samra.fr>:
> >>>>>> Le 13/04/2022 à 17:03, Thomas Morley a écrit :
> >>>>>>> Am Di., 12. Apr. 2022 um 11:54 Uhr schrieb Jean Abou Samra 
> >>>>>>> <jean@abou-samra.fr>:
> >>>>>>>> Le 12/04/2022 à 11:16, Thomas Morley a écrit :
> >>>>>>> [...]
> >>>>>>>>> In many details DurationLine was tailored after Glissando and
> >>>>>>>>> Glissando _is_ effected by the breathing sign.
> >>>>>>> [...]
> >>>>>>>
> >>>>>>>> Well, if the goal is to have DurationLine similar to Glissando,
> >>>>>>>> how about reusing line-spanner-interface code? I haven't reviewed
> >>>>>>>> the code very thoroughly, but I assumed there was a difference
> >>>>>>>> warranting a different code path. If you put
> >>>>>>>> ly:line-spanner::calc-{left,right}-bound-info in
> >>>>>>>> DurationLine.{left,righ}-bound-info, that gives you X values for free
> >>>>>>>> in the bound info properties. Would that solve the problem?
> >>>>>>> If I go for ly:line-spanner::calc-{left,right}-bound-info then
> >>>>>>>
> >>>>>>> \layout {
> >>>>>>>        \context {
> >>>>>>>          \Voice
> >>>>>>>          \consists Duration_line_engraver
> >>>>>>>        }
> >>>>>>> }
> >>>>>>>
> >>>>>>> { b1\- }
> >>>>>>>
> >>>>>>> errors with
> >>>>>>>         "programming error: extremal broken spanner's bound has no 
> >>>>>>> parent
> >>>>>>> vertical axis group"
> >>>>>>> More complex examples may add:
> >>>>>>>         "programming error: bound item has no parent vertical axis 
> >>>>>>> group"
> >>>>>>> Both coming from `ly:line-spanner::calc-right-bound-info' based upon
> >>>>>>> `Line_spanner::calc_bound_info' in /lily/line-spanner.cc
> >>>>>>>
> >>>>>>> As a mere user I'd say: "Nice error-message, but why should I 
> >>>>>>> care...?"
> >>>>>>>
> >>>>>>> As a programmer, I doubt the example above can be made working with
> >>>>>>> ly:line-spanner::calc-right-bound-info.
> >>>>>>> At least, I don't know how.
> >>>>>> Oh, I'm sorry, I missed that detail of my own code. A DurationLine will
> >>>>>> always be horizontal, thus you can and should use
> >>>>>> ly:horizontal-line-spanner::calc-{left,right}-bound-info (with 
> >>>>>> 'horizontal'
> >>>>>> in the name).  The difference is that the functions without 
> >>>>>> 'horizontal'
> >>>>>> try to compute vertical positions. This falls apart here, for 
> >>>>>> understandable
> >>>>>> reasons: the right bound of your DurationLine is a 
> >>>>>> NonMusicalPaperColumn,
> >>>>>> so how would one tell where the line should end vertically?
> >>>>> Using ly:horizontal-line-spanner::calc-{left,right}-bound-info makes
> >>>>> for huge simplifications.
> >>>>> Alas, it introduces a minor and reintroduces a major problem.
> >>>>>
> >>>>> The minor: the X-value depends now on attach-dir. For the start of the
> >>>>> DurationLine this is ofcourse RIGHT. But if starting at a skip,
> >>>>> left-bound is PaperColumn there we would want LEFT. Can be fixed by
> >>>>> accurate conditions. Count it as done.
> >>>>>
> >>>>> The major: `ly:horizontal-line-spanner::calc-right-bound-info' and
> >>>>> `unbroken-or-last-broken-spanner?' (and friends) don't agree what's
> >>>>> the last part of the spanner.
> >>>>> To illustrate:
> >>>>>
> >>>>> \version "2.23.7"
> >>>>>
> >>>>> \layout {
> >>>>>      \context {
> >>>>>        \Voice
> >>>>>        \consists "Duration_line_engraver"
> >>>>>      }
> >>>>> }
> >>>>>
> >>>>> {
> >>>>>     \override DurationLine.bound-details.right.foo =
> >>>>>       "I am last part (bound-details)"
> >>>>>     \override DurationLine.bound-details.right-broken.foo =
> >>>>>       "I am not last part (bound-details)"
> >>>>>
> >>>>>     \override DurationLine.after-line-breaking =
> >>>>>     #(lambda (grob)
> >>>>>       (pretty-print
> >>>>>         (if (unbroken-or-last-broken-spanner? grob)
> >>>>>             "I am last part (unbroken-or-last-broken-spanner?)"
> >>>>>             "I am not last part (unbroken-or-last-broken-spanner?)"))
> >>>>>       (pretty-print
> >>>>>         (assoc-get 'foo 
> >>>>> (ly:horizontal-line-spanner::calc-right-bound-info grob))))
> >>>>>
> >>>>>     b1\-
> >>>>> }
> >>>>>
> >>>>> =>
> >>>>> "I am last part (unbroken-or-last-broken-spanner?)"
> >>>>> "I am not last part (bound-details)"
> >>>>>
> >>>>> The problem occurs if we have a broken DurationLine with end-items
> >>>>> running to the very end of the score.
> >>>>> To fix it one would again need something like:
> >>>>>
> >>>>> {
> >>>>>      \override DurationLine.bound-details =
> >>>>>      #(grob-transformer 'bound-details
> >>>>>        (lambda (grob orig)
> >>>>>         (if (end-broken-spanner? grob)
> >>>>>             (cons
> >>>>>               (cons 'right-broken
> >>>>>                 (cons '(end-style . arrow) (assoc-get 'right-broken 
> >>>>> orig)))
> >>>>>               orig)
> >>>>>             orig)))
> >>>>>      b1\-
> >>>>>      \break
> >>>>>      s1
> >>>>>      \break
> >>>>>      s1
> >>>>>      \bar "|."
> >>>>> }
> >>>>>
> >>>>> Or like \lastEndStyle which you cleared with
> >>>>>
> >>>>> commit 46671d13257f6ad68d1778a1cc850e59116c856a
> >>>>> Author: Jean Abou Samra <jean@abou-samra.fr>
> >>>>> Date:   Wed Dec 29 00:16:46 2021 +0100
> >>>>>
> >>>>>        Fix broken spanner functions
> >>>>>
> >>>>>        They were broken (pun intended) on spanners of which one bound 
> >>>>> is a
> >>>>>        non-musical column at a system boundary.  For example,
> >>>>>        unbroken-or-last-broken-spanner? would return false on a spanner
> >>>>>        running to the NonMusicalPaperColumn at the end of a score.  This
> >>>>>        fixes the known issue with duration lines running to the end of 
> >>>>> the
> >>>>>        piece, and will be needed in a refactoring of spanner-placement
> >>>>>        treatment for balloon-interface.
> >>>>>
> >>>>>        While at it, document these functions.
> >>>>>
> >>>>> This is unfortunate. Any chance making
> >>>>> `ly:horizontal-line-spanner::calc-right-bound-info' and friends
> >>>>> identify the last spanner-part correctly, i.e. like
> >>>>> `unbroken-or-last-broken-spanner?'
> >>>>> ?
> >>>>
> >>>> Ah, this one is showing up again. Yes, this is not too hard to
> >>>> fix (but please allow me some time).
> >>>>
> >>> No problem.
> >>> If you don't mind I'll open an issue for it with the code-example above.
> >>> Meanwhile I found a different workaround, without the need to have the
> >>> apply an extra override.
> >>> If testings suceed, I'll upload a patch with the new code for 
> >>> DurationLine.
> >>> The workaround could be removed later easily.
> >>
> >> The attached patch fixes it for me.
> >>
> >> Thanks,
> >> Jean
> > Will test in the evening, real life will occupy me the afternoon.
> > Though, at first glance:
> > I fear using "unbroken-or-first-broken-spanner?" will not cover middle
> > part(s) of a multiple broken spanner.
> > Shouldn't it be "unbroken-or-not-last-broken-spanner?"
> > ?
> > To be defined as:
> > (define-public (unbroken-or-not-last-broken-spanner? spanner)
> >    "Is @var{spanner} either unbroken or not the last of its broken
> > siblings?"
> >    (check-broken-spanner
> >     #t
> >     (lambda (siblings)
> >       (not (eq? spanner (last siblings))))
> >     spanner))
> >
> > Though, not tested.
>
>
>
> Are you sure? unbroken-or-first-broken-spanner? is used to decide
> between left and left-broken. Only the first broken spanner should
> use left and not left-broken, all the others need left-broken on
> top of left.

My concern at first glance was for the right side: Only the last
broken spanner should use right, all the others right-broken.
Though, I've tested it now, doing a full regtest-comparison with your
patch on top of my own (patch attached).
All works nicely, afaict.

Now, how should we upload our work?
I.e. in which sequence and who does it?
I'd volunteer to upload both, although I'm not sure how gitlab deals
with patches from different authors in one MR (or doing it
separately?)

Cheers,
  Harm

0001-Simplify-duration-line-calc.patch
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