Re: [NTG-context] optical centering...

17 Dec 2011

      On 16-12-2011 19:26, Wolfgang Schuster wrote:
...
Am 16.12.2011 um 18:37 schrieb Chris Lott:
...
On Fri, Dec 16, 2011 at 8:26 AM, Wolfgang Schuster
  wrote:
...
Centered text based on the longest line is simple but when it’s
better to make this a feature of the lines environment.
Yeah, but it *isn't* based on the longest line, but on an average of
line length. I guess that's why it is call...well, except for the
first example in the doc provided, which is what I think your code
does.
Though the code you provided is very useful, so thanks!
I showed only it’s not so hard to achieve this feature
but with a more complex solution where you check
the width of each line you can use different values
for the margins.
A teaser for Wolfgang (a few more status dimens in the latest):

\definesystemvariable{zv}

\def\startverse[#1]%
   {\begingroup
    \getparameters[\??zv][\c!align=,#1]%
    \dostartbuffer[versecontent][startverse][stopverse]}

\setvalue{\??zv:\v!flushleft }{\raggedright}
\setvalue{\??zv:\v!flushright}{\raggedleft}
\setvalue{\??zv:\v!left      }{\raggedleft}
\setvalue{\??zv:\v!right     }{\raggedright}
\setvalue{\??zv:\v!middle    }{\raggedcenter}
\setvalue{\??zv:\v!min 
}{\leftskip\the\dimexpr(\textwidth-\framedminwidth)/2\relax}
\setvalue{\??zv:\v!max 
}{\leftskip\the\dimexpr(\textwidth-\framedmaxwidth)/2\relax}
\setvalue{\??zv:\v!medium 
}{\leftskip\the\dimexpr(\textwidth-\framedaveragewidth)/2\relax}

\def\stopverse
   {\setbox\scratchbox\hbox\bgroup\framed[width=fit,align=right]\bgroup
      \startlines
      \getbuffer[versecontent]
      \stoplines
    \egroup\egroup
    \getvalue{\??zv:\@@zvalign}%
    \startlines
    \getbuffer[versecontent]
    \stoplines
    \endgroup}

% \protect

\starttext \showframe

\startverse[align=flushleft]
ASM rządzi
dioda świeci miodowo
chrząszcz chrzęści w czcionkach.
\stopverse

\startverse[align=flushright]
ASM rządzi
dioda świeci miodowo
chrząszcz chrzęści w czcionkach.
\stopverse

\startverse[align=middle]
ASM rządzi
dioda świeci miodowo
chrząszcz chrzęści w czcionkach.
\stopverse

\startverse[align=min]
ASM rządzi
dioda świeci miodowo
chrząszcz chrzęści w czcionkach.
\stopverse

\startverse[align=max]
ASM rządzi
dioda świeci miodowo
chrząszcz chrzęści w czcionkach.
\stopverse

\startverse[align=medium]
ASM rządzi
dioda świeci miodowo
chrząszcz chrzęści w czcionkach.
\stopverse

\stoptext

I'll think about a pluggable special line alignment in th emain text 
stream (would be multipass).

Hans

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