# [NTG-context] help with facing page image

śrīrāma citturs at gmail.com
Mon Mar 7 08:01:33 CET 2022

```On Monday, March 7, 2022 11:50 AM jbf wrote:
> All ten images are different, though, in my case (Chapter1.jpg,
> Chapter2.jpg... Chapter10.jpg all in a pics directory, so I'd point
> \setupexternalfigures to that). I wonder if there is a way to list them
> so that they get called in order as chapters proceed. A kind of "if such
> and such then \setlayer 1,2,3...."

I think that should be easy. Suppose you have images
{chap-cover-1.jpg, chap-cover-2.jpg,  ... chap-cover-10.jpg}
each of which appear at the ends of their respective chapters, then the following achieves what you want (once you point ConTeXt to the right directory for figures of course):

% kate: hl ctx
%%% SOF
\setuppagenumbering[alternative=doublesided]

\definelayer
[chapCover]
[x=0mm,
y=0mm,
width=\paperwidth,
height=\paperheight,repeat=yes]

\startsetups chapter:before
\doifoddpageelse{}
{\pushbackground[page]
\resetlayer[chapCover]
\setlayer
[chapCover]
\externalfigure
[width=\paperwidth]}
\setupbackgrounds[page][background=chapCover]
\page[empty]
\popbackground}
\stopsetups

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

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

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

So we figure out which chapter we are in and then set the layer to the corresponding picture. Personally, I much prefer to collect all the images into a separate PDF with:

%%% chap-covers.tex
\starttext
\dorecurse{10}{\startTEXpage
\externalfigure[chap-cover-\recurselevel]
\stopTEXpage}
\stoptext
%%% EOF

[and get 'chap-covers.pdf' from context]

... and then modify the 'before' setup to read as below

%%%
\startsetups chapter:before
\doifoddpageelse{}
{\pushbackground[page]
\resetlayer[chapCover]
\setlayer
[chapCover]
\externalfigure
[chap-covers]