Re: Adjusting parameters for a single page

[Hans Hagen <j.hagen@xs4all.nl>]

On 5/10/2021 5:15 PM, denis.maier@ub.unibe.ch wrote:
> Hi everyone,
> 
> I know it is possible to make local changes by enclosing text in \start 
> \stop pairs to make local changes. Then, there are also commands that 
> only affect the next/current paragraph, such as \looseness.
> 
> But is there a similar mechanism for page-layout changes? For example 
> your penalty settings allow widows and orphans, but on one particular 
> page you want to change the penalties. Or, you use \setupalign[height], 
> but on one page you want to use \setupalign[bottom] instead. Is there a 
> way to do this ?
it works per paragraph so then you need to adapt it for a specific 
paragraph

when the par starts, the properties are stored (in lmtx it's configured 
that way); you can change properties in the middle of a paragraph but 
then you need to explicitly freeze them, as demonstrated in the examples 
below; tracing will show you all stored properties

(default tex behaviour is that the last setting counts which can be 
somewhat unexpected)

\starttext
     \tracingoutput1 \tracingonline1
     \pretolerance9000 test \pretolerance8000 test \par
     \pretolerance9000 test \pretolerance7000 \updateparagraphproperties 
test \par
     \pretolerance9000 test \pretolerance6000 
\snapshotpar\frozentolerancecode test \par
\stoptext

the log shows ...

\par[newgraf][16=1,17=1], .... pretolerance 9000, ....
\par[newgraf][16=1,17=1], .... pretolerance 7000, ....
\par[newgraf][16=1,17=1], .... pretolerance 6000, ....

now, as you probably don't want to be persistent you can group:

\def\MyHack
   {\bgroup
    \pretolerance5000
    \snapshotpar\frozentolerancecode
    \egroup}

test \MyHack test

works ok because the snapshotting applies to the current paragraph (it's 
actually described in some manual)

so, basically, you have a lot of control, all together some 36 
parameters (pablo probably loves the somewhat secret on the fly 
adjustspacing step, stretch and shrink tweakability)

Hans

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                                           Hans Hagen | PRAGMA ADE
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