Hi Hans,

I implemented my changing navigation bar like you proposed, i.e. using a 
layer that is "refreshed" by the footer text:

\definelayer[navbar]
\setupbackgrounds[text][leftmargin][background=navbar]
\startsetups NavBar
... some quite complicated code setting up the navigation bar layer ...
\stopsetups

\setupfootertexts[\setups{NavBar}]

Everything works now, but I was not able to use the \goto makro inside 
the navigation layer setup code. It seems that the \goto makro somehow 
interferes with the output routine. Therefore I had to replace the \goto 
makro in the setup code with my self written \PrevOrNextPage makro. This 
makro writes a "raw" pdftex link. (Sometime ago you hinted me to replace 
my \PrevOrNextPage makro by the \goto makro.)

Using the \goto makro I get the following error message:

! Missing } inserted.
<inserted text>
                 }
<to be read again>
                    \endgroup
\dosingletexts ...atetexts {#1#2#5}{#6{}{}{}}}}}}}
                                                   \egroup
<argument> ...tk \v!voet \v!tekst \c!middentekst }
                                                   \hss }\hskip 
-\zetbreedte ...

\dododoplacelayouttextline ...#2 #3}\hbox to #1{#4
                                                   }\stoplayoutcomponent 
\get...

\dodoplacelayouttextline ... \c!kantlijntekst }}}}
                                                   \fi \ifdim 
\rechtermargebr...
...
l.211 ...t\crlf{} Die Landesregierung\blank[small]

Can you please have a look on the example? I attach a file that when it 
is texexecuted produces the above error. When you comment out line 150 
in the file and use line 148 instead, then the example works fine.

Thanks,
--Stefan


Hans Hagen wrote:
> Stefan Wachter wrote:
> 
>> Hi all,
>>
>> I use an overlay to implement a navigation bar in the left margin of a 
>> document. It seems to me that the processing of the overlay is done 
>> only once and not for every page again. In addition, the \lastpage is 
>> not available.
> 
> 
> page, paper and text backgrounda are calculated each page, unless you 
> say \setupbackgrounds[state=repeat], in which case all are recalculated; 
> if you put something in a layer it happens directly (but the layer may 
> be flushed later)
> 
>> Does anyone know a solution? Maybe headers/footers are a solution. But 
>> how is absolute positioning accomplished with them?
>>
> you can put a layer in the background of the header area and that do 
> something:
> 
> \startsetups whatever
> 
>  \setlayer[thatlayer][....positioning...]{\the\pageno}
> 
> \stopsetups
> 
> \setupheadertexts[\setups{whatever}]
> 
>> PS: Here is my current implementation:
>>
>> \definelayer[navbar]
>> \setupbackgrounds[text][leftmargin][background=navbar]
>> \setlayer[navbar][x=0cm,y=10cm]{\the\pageno}
> 
> 
> lastpage etc only make sense in the output routine (during page 
> building) since one does not know where tex will break the page.
> H
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>                                          Hans Hagen | PRAGMA ADE
>              Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
>     tel: 038 477 53 69 | fax: 038 477 53 74 | www.pragma-ade.com
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