[NTG-context] help with facing page image

[śrīrāma]

On Monday, March 7, 2022 9:19 AM jbf via ntg-context wrote:
> Author wants an image on facing page to each of 10 chapters in the 
> bodypart of the document. Assume that everything else is working 
> properly for this document (double-sided etc.), but other than before 
> chapter 1, I can't seem to get my facing page image to appear where it 
> should!

>From what I understood from your explanation, I have this:

%%% SOF
  % for 'mill'
  \setupexternalfigures[location={default}]

  \setuppagenumbering[alternative=doublesided]

  \definelayer[mill][x=0mm,y=0mm,width=\paperwidth,height=\paperheight,repeat=yes]
  \setlayer[mill]{\externalfigure[mill][width=\paperwidth]}

  \startsetups chapter:before
  \doifoddpageelse{}
    {\pushbackground[page]
    \setupbackgrounds[page][background=mill]
    \page[empty]
    \popbackground}
  \stopsetups

  \startsetups chapter:after
  \doifoddpageelse{}
    {\page[empty]}
  \stopsetups

  \setuphead
    [chapter]
    [page=yes,
    before=\directsetup{chapter:before},
    aftersection=\directsetup{chapter:after}]

  \starttext
  \dorecurse{10}{
    \startchapter[title={Chapter \convertnumber{word}{\recurselevel}}]
      \input knuth
      \blank
      \input tufte
      \blank
      \input ward
      \blank
      \ifnum\recurselevel=5
        \page
        \input zapf
        \input zapf
      \fi
    \stopchapter
  }
  \stoptext
%%% EOF

[I am just using the mill picture on every facing page of chapter]
If the chapter ends on an even page then we can insert an empty page with \page[empty] with [aftersection=...] in \setuphead. The [before=...] is push, set background to mill on a new (empty) left page and then pop back (much like the example from wiki).

Sreeram