Re: Set indent based on instrument name (issue 6457049)

[Phil Holmes]

----- Original Message ----- 
From: "David Kastrup" <address@hidden>
To: "Phil Holmes" <address@hidden>
Cc: <address@hidden>
Sent: Tuesday, July 31, 2012 3:40 PM
Subject: Re: Set indent based on instrument name (issue 6457049)


> "Phil Holmes" <address@hidden> writes:
>
> > > I can't actually help here since either problem description or what the
> > > patch is trying to achieve is utterly absent from the issue.
> > >
> > > <URL:http://code.google.com/p/lilypond/issues/detail?id=2703>
> > >
> > > "Set indent based on instrument name" is all that is described
> > > anywhere.  _How_ the indent is supposed to be based on instrument names,
> > > _when_ it is supposed to be based on instrument names, _what_ instrument
> > > names it is supposed to be base on, _which_ indent is supposed to be
> > > based on instrument names, _what_ problem this is trying to solve:
> > >
> > > I draw a blank.  I can't even suggest what variables and organization to
> > > use here since I have no clue what the problem is, and what the solution
> > > tries to achieve.
> >
> > Apologies - I intended to link to
> > http://code.google.com/p/lilypond/issues/detail?id=766 but clearly
> > omitted to do so.
> >
> > The problem is that the left indent of staves is fixed with no
> > consideration of whether there is an instrument name to fit into that
> > indent.  So we can just about get away with "Violin", but any name
> > like "Baroque violin with horse hair strings" simply falls off the
> > left of the paper unless indent is manually adjusted.  The same is
> > true of short indent/short instrument name. In the same way that
> > lilypond moves music to avoid clashes and overlaps, it should
> > automatically adjust indent to accommodate the instrument names
> > used. IMHO it's the current worst example of poor typesetting that
> > lilypond provides.
>
> So _how_ are you trying to accommodate?  Increase indent until the
> instrument name fits wholly in the text width?  Let it stick out
> somewhat?  How much?

Increase the indent until it accommodates the instrument name.  That's the 
_only_ sensible option (and it's what Sibelius does, FWIW).  If the user 
then discovers they have only one note per line because of a stupidly long 
name, they have the option of changing the name, putting it in a column, 
changing the font, etc.  But they don't need to keep experimenting with 
indents.

> > What's worse is that the images used in the documentation _do_ shift
> > right to accommodate instrument names, with the result that the image
> > pushes off the left of the page, and black bars result.
>
> They probably also shift left, basically ignoring indent completely.
> Cropping images based on contents rather than extent is always asking
> for problems.

It's how our documentation system works.

> > I'm not trying to take a shortcut - I'm wandering down the only road I
> > can find.  I first asked for some pointers as to how to do this a week
> > ago, and since then I've been trying to work out a solution.  It took
> > me all day on Sunday to get the version that counted letters, and all
> > day yesterday to work out how to go from
> > markup->SCM->stencil->interval->length.  I actually think that's a
> > fair improvement and I'm pretty pleased with progress so far.
> >
> > I now understand I need to either store the indent length in something
> > to do with a score context, or re-initialise it whenever a new score
> > is created. I'll have a go at working out how to do that, but I don't
> > even understand how to access contexts from c++, so it seems like it
> > would be a continuing number of days of poring over the code to find
> > out.
> >
> > Any pointers (pun not intended) you could give to help me on my way
> > would be appreciated.
>
> Where do indent and shortindent end up being used?  That's where the
> results of your calculations likely need to be available.  And what kind
> of variables you need to use depends on how the results from your
> calculation are supposed to travel to the site of use.


There are 2 activities at work here.  The first is lilypond detecting and 
acting upon instrumentName/shortInstrumentName (I'll call this name in 
future) changes.  It does this with the Instrument_name_engraver and 
processes all the name changes before the indent is used to set the music. 
line_dimensions_int is then called by constrained-breaking.cc and 
page-layout-problem.cc to calculate where the music will be placed and then 
to place it on the stave.

--
Phil Holmes