Is it possible to have thin lines or crop marks to help cut the pages with \setuparranging?

Question

I have something like this:

\setuppagenumbering[state=stop]
\setuppapersize[A5,landscape][A4]
\setuplayout[topspace=1cm,backspace=1cm,
  header=0mm,footer=0mm,
  width=middle,height=middle]
\setuparranging[2TOP]

I'd like to have a thin line in the middle of the page so that I know where to cut the paper. Alternatively, kind of "crop marks" with the same purpose would do. Is there an option for that? marking=on in \setuplayout didn't help (probably because the "classical" crop marks fall outside of the paper with these settings - am I right?).

I'm using ConTeXt MkIV.

Note: please retag this question as appropriate, I didn't know what tags would be best.

Answer 1

Marking are usually shown in a way so that they do no show when the page is cut. One way to see what is happening is to set the print paer size to A3. For example,

\setuppapersize[A5,landscape][A3]
\setuparranging[2TOP]

\setuplayout
  [
    topspace=1cm,
    backspace=1cm,
    header=0mm,
    footer=0mm,
    width=middle,
    height=middle,
    marking=on,
    location=middle,
  ]

  \showframe

However, you can easily add a background image to show your own marks.

\setuppapersize[A5,landscape][A4]
\setuparranging[2TOP]

\setuplayout
  [
    topspace=1cm,
    backspace=1cm,
    header=0mm,
    footer=0mm,
    width=middle,
    height=middle,
    marking=on,
    location=middle,
  ]

\startuseMPgraphic{cropmarks}
  StartPage;
  begingroup;
  drawoptions(withpen pencircle scaled 1bp withcolor red);
  if odd(\the\realpageno) :
    draw (0,0) -- (1cm, 0);
    draw (PaperWidth,1mm) -- (PaperWidth-1cm, 1mm);
  fi ;
  endgroup;
  StopPage;
\stopuseMPgraphic

\defineoverlay[cropmarks][\useMPgraphic{cropmarks}]

\setupbackgrounds[page][background=cropmarks]

Answer 2

I had the same idea as Aditya, however with a different approach. Adityas solution resorts to MetaPost, the most flexible solution you can get. The following solution uses a version of ConTeXts \framed command to draw a thin line between the pages without direct use of MetaPost.

\setuppagenumbering [state=stop]
\setuparranging     [2TOP]
\setuppapersize     [A5,landscape] [A4]
\setuplayout
  [
     topspace=1cm,
    backspace=1cm,
       header=0mm,
       footer=0mm,
        width=middle,
       height=middle,
  ]

\setupbackgrounds [page] [background=cropmarks, setups=cropmarks]
\definelayer      [cropmarks]

\startsetups cropmarks
  \doifoddpageelse{}{%
    \setlayerframed [cropmarks]
      [
           frame=off,
        topframe=on,
           width=\paperwidth,
          height=\paperheight,
      ]{}}
\stopsetups

\starttext
  \dorecurse{20}{
    \input knuth\par}
\stoptext

The result:

EDIT: The code above is way too complicated, much easier:

\setuppagenumbering [state=stop]
\setuparranging     [2TOP]
\setuppapersize     [A5,landscape] [A4]
\setupbackgrounds   [page] [topframe=on]
\setuplayout
  [  topspace=1cm,
    backspace=1cm,
       header=0mm,
       footer=0mm,
        width=middle,
       height=middle]

\starttext
  \dorecurse{20}{
    \input knuth\par}
\stoptext