Re: [NTG-context] Adjusting column width dynamically to get rid of orphans and widows

23 Jun 2017

      On 20 June 2017 at 20:33, Hans Hagen  wrote:
...
On 6/20/2017 11:53 AM, Thomas Widmann wrote:
...
On 20 June 2017 at 10:41, Henri Menke  wrote:
...
On Tue, 2017-06-20 at 09:22 +0100, Thomas Widmann wrote:
...
I recently started experimenting with using ConTeXt (mkiv) for
dictionary typesetting. It's a much
more attractive option than plain TeX or LaTeX because of the support
for typesetting on a grid.
However, grid typesetting can easily result in a large number of orphans
and widows, which really
doesn't look good in a dictionary.
In an ideal world, I'd want to alter the column width slightly to
prevent them (because most
dictionaries aren't justified, this wouldn't be very noticeable).
Would it be possible to use LuaTeX to achieve this?  I.e., could one
write some code that gets
triggered by orphans and widows and then alters the current column width
slightly until the
problem disappears?  Has somebody already done this?  Or have the
relevant TeX internals not been
Luafied yet?
I'd also be interested in other ways to solve this issue – for instance
changing the looseness
dynamically instead of the column width.
Have a look at \widowpenalty and \clubpenalty.  Also use margin kerning
and font expansion.
\widowpenalty and \clubpenalty are almost useless in this context –
believe me, I've tried! (I'm typesetting on a grid, with a fixed
number of lines per page.) Which is why I'm looking for alternatives.
Margin kerning and font expansion are definitely options, but again,
my real query would be how to trigger them dynamically to avoid a
widow or an orphan.
can you make a small example showing the problem
Sorry about the delay – here you go!

On my computer, the first column goes on for two lines more than the
following column, and it still produces a widow:

%%% document starts here

\mainlanguage[en]

\definefontfeature
  [default][default]
  [
    protrusion=quality,
    expansion=quality,
    onum=yes,
  ]

\definestartstop [negindent] [
  before={%
    \startnarrower[left]%
    \setupindenting[-.5em,yes,first]%
    \setuphead[subject][indentnext=yes]%
  },
  after=\stopnarrower,
]

\setupbodyfont[palatino]

\setupalign[hz,hanging,tolerant]

\startsetups[grid][mypenalties]
    \setdefaultpenalties
    \setpenalties\widowpenalties{2}{10000}
    \setpenalties\clubpenalties {2}{10000}
\stopsetups

\setuplayout[grid=yes, setups=mypenalties]

\righthyphenmin=60
\lefthyphenmin=60

\def\Sblackbold#1{{\bf #1}}
\def\Sdef#1{{#1}}
\def\Sdefrf#1{{\bf #1}}
\def\ShwJNR#1{{\blue\bf #1}}
\def\Spospsmallcaps#1{{\sc #1}}
\def\Spunctuation#1{{#1}}
\def\Sxrefxrhw#1{{\bf #1}}
\def\Sgroupintro#1{{\it #1}}

\def\threeentries{\ShwJNR{headphones}\page[no]\par\-\hskip
.5em\Spospsmallcaps{noun}\Spunctuation{ }\Sdef{a pair of small
speakers that you wear over your
ears}\par\ShwJNR{heard}\page[no]\par\-\hskip
.5em\Spospsmallcaps{verb}\Spunctuation{ }\Sgroupintro{the past tense
and past participle of}\Spunctuation{
}\Sxrefxrhw{hear}\par\ShwJNR{hearing}\page[no]\par\-\hskip
.5em\Spospsmallcaps{noun}\Spunctuation{ }\Sblackbold{2}\Spunctuation{
}\Sdef{If someone gives you a }\Sdefrf{hearing}\Sdef{, they let you
give your point of view and listen to you.\par}}

\def\thirtyentries{\threeentries\threeentries\threeentries\threeentries\threeentries\threeentries\threeentries\threeentries\threeentries\threeentries}

\startdocument

\startmixedcolumns[balance=yes]
\raggedright
\startnegindent

\thirtyentries

\stopnegindent
\stopmixedcolumns
\placefloats
\stopdocument

%%% document ends here

The thing is that there simply isn't a good way to break up a
three-line dictionary entry, and it would be much better to play
around with the column width, the looseness, margin kerning or other
tools rather than having to do so.  Doing it manually is easy enough,
but it would be much nicer if the one or more of these tools could get
triggered automatically.

Regards,

Thomas
-- 
Thomas Widmann
Director
Complexli Limited
+44 789 444 3009