Re: [NTG-context] \centerline vs. \midaligned vs. \startalignment[middle]

26 Jun 2013

      Hello,

thanks for explanation.

I also wrote a sample code which should typeset a midaligned table via Lua using "tabulate".

But I'm not able to achieve the goal - what am I doing wrong?

----
\starttext
   T

   \startluacode
     local f = function()
       context.starttabulate{"|rw(2cm)|rw(2cm)|"}
         context.NC()
         context("A")
         context.NC()
         context("B")
         context.NC()
         context.NR()
       context.stoptabulate()
     end

     f()

     context("U\\par")

     context.startalignment{"middle"}
       context("V") -- OK, "V" is successfully midaligned
     context.stopalignment()

     context.startalignment{"middle"}
       f() -- Wrong, table is not midaligned
     context.stopalignment()

     context.startalignment{"middle"}
       context.dontleavehmode()
       f() -- Wrong, too, table is still not midaligned (?!)
     context.stopalignment()

     -- context.midaligned(f) -- This breaks Ctx!
   \stopluacode
\stoptext
----

Best regards,

Lukas

On Wed, 26 Jun 2013 14:46:32 +0200, Wolfgang Schuster  wrote:
...
Am 26.06.2013 um 14:07 schrieb Procházka Lukáš Ing. - Pontex s. r. o. :
...
Hello,
there are several similar commands to produce text (or another object) to be centered on the line.
What are differences (or intended usage) among \centerline, \midaligned, \startalignment[middle]?
(NB: \centerline has no its-own page on wiki, but it is used at several places in wiki samples.
\centerline was also mentioned here in the mailing list, when I was trying to center "tabulate" - and neither \midaligned nor \startalignment[middle] combined with \dontleavehmode worked.)
The three commands
- \leftline,
  - \rightline and
  - \centerline
are copied from plain TeX and allow you to center short text which fits on a single line but it isn’t recommended to use them because ConTeXt has it’s own alternative for them. The replacement commands are
- \leftaligned,
  - \rightaligned and
  - \midaligned.
Even though each command is only meant for short text you use the \\ command to put text into several lines, e.g.
\starttext
  \midaligned{One\\Two\\Three}
  \stoptext
creates three lines for the input. In recent installations you can write
\startlinealignment[left|middle|right]
  …
  \stopalignment
as a alternative to \leftaligned etc.
With the alignment environment you can change the alignment of the text for a certain region. Unlike the line alignment environment you can use text which covers more than a single line.
\starttext
  \input knuth\par
  \startalignment[middle]
  \input knuth\par
  \stopalignment
  \stoptext
Wolfgang
-- 
Ing. Lukáš Procházka [mailto:LPr@pontex.cz]
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