On 1/1/2022 11:46 AM, Youssef Cherem via ntg-context wrote:
> Dear list users,
>
> How can one go about implementing a ruler around the page/text area
> (such as a background) like the one provided by the latex package
> fgruler? https://www.ctan.org/tex-archive/macros/latex/contrib/fgruler
> <https://www.ctan.org/tex-archive/macros/latex/contrib/fgruler> or koma
> script's \layercontentsmeasure?
a good opportunity to learn some metapost

\startuniqueMPpagegraphic{ruler}
     numeric n, f, sign ;
     pair first, last;
     if OnOddPage :
         first := urcorner Page;
         last  := lrcorner Page;
         sign  := -1;
     else :
         first := ulcorner Page;
         last  := llcorner Page;
         sign  := 1;
     fi ;
     f := xpart first;
     n := 0;
     draw first -- last withpen pencircle scaled 2pt;
     for i = ypart first step -1mm until ypart last :
         if (n mod 10) == 0 :
             draw (f,i) -- (f+sign*10mm,i) ;
             if OnOddPage :
                 draw thetextext.lft(n/10,(f+sign*12mm,i)) ;
             else :
                 draw thetextext.rt (n/10,(f+sign*12mm,i)) ;
             fi
         elseif (n mod 5) == 0 :
             draw (f,i) -- (f+sign*5mm,i) ;
         else :
             draw (f,i) -- (f+sign*3mm,i) ;
         fi ;
         n := n + 1 ;
     endfor ;
     setbounds currentpicture to Page ;
\stopuniqueMPpagegraphic

\defineoverlay[ruler][\uniqueMPpagegraphic{ruler}]

\setupbackgrounds[page][background=ruler]

\setuppagenumbering[alternative=doublesided]

\starttext
     \dorecurse{10}{test \page}
\stoptext


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