[NTG-context] image across 2 page spread

[Hans Hagen]

On 4/30/2020 2:05 AM, jbf wrote:
> Hi list,
> 
> With 99% of work complete on a book, including single page images, I now 
> find myself confronted with a final problem: how to run one image across 
> facing pages or in other words, one image (plus its caption) across a 
> two-page spread, such that there is no gap.
> 
> I have tried a number of fairly crass attempts (obviously too simple) to 
> see if I could get somewhere near what I want, e.g.
> 
> \externalfigure[plate12.jpg][width=\paperwidth, height=.7\paperheight, 
> frame=none] {\tfx \sc Plates 12, 13. \tfx Twenty trucks from the 
> Netherlands setting off}
> 
> \externalfigure[plate13.jpg][width=\paperwidth, height=.7\paperheight, 
> frame=none] {\tfx for their first mission amongst the German diaspora.}
> 
> My thinking here was that \paperwidth might help extend the image to the 
> inner edge on the left-hand page, but it doesn't work that way for the 
> right-hand page, since there it extends to the outer edge, not the inner 
> edge! The .7\paperheight was to provide room for the caption. But all in 
> all, this is no solution!
> 
> If it is any help, the setup dimensions for the book are US Digest:
> 
> \definepapersize
>    [ACN][width=5.5in,height=8.5in] %  w140mm x h216mm
> 
> I then looked up how one might do it in LaTeX, and found the following 
> link: 
> https://tex.stackexchange.com/questions/23860/how-to-include-a-picture-over-two-pages-left-part-on-left-side-right-on-right
> 
> How much of that would be transferable to ConTeXt? (I am thinking 
> particularly of the |\newcommand*{\twopagepicture}[4]| bit.
> 
> There are explanations for how to do this in InDesign, and since it is 
> something someone might often want to do (e.g. in magazines), I also 
> thought it might be easier to find reference to it on Contextgarden, yet 
> haven't found anything there. But I am sure ConTeXt has a way to do this.
> 
> Could someone point me in the right direction with this please?
\setuppagenumbering
   [alternative=doublesided]

\starttext

\dorecurse{3}{\input tufte \par}

\startpostponing
     \setuppagenumbering[state=stop]
     \startspread
         \startplacefigure[location=here,title={This is a cow!}]
         \externalfigure[cow.pdf][height=\textheight]%
         \stopplacefigure
     \stopspread
     \setuppagenumbering[state=start]
\stoppostponing

\dorecurse{10}{\input tufte \par}

\stoptext

-----------------------------------------------------------------
                                           Hans Hagen | PRAGMA ADE
               Ridderstraat 27 | 8061 GH Hasselt | The Netherlands
        tel: 038 477 53 69 | www.pragma-ade.nl | www.pragma-pod.nl
-----------------------------------------------------------------