Re: Images centered on page

["Wolfgang Schuster" <schuster.wolfgang@googlemail.com>]

2007/11/23, Vyatcheslav Yatskovsky <yatskovsky@gmail.com>:
> Hello,
>
> How can I center the image on a page? I want images to cover the page completely, and since they have proper size (roughly A4), I only need them to be centered. Now they are stuck to the top, leaving a gap on bottom (and same for left-right).
>
> I have the following script (note my Lua trick to process images in a batch). Image names are "Image00001.png" and so on.
>
>
> %engine=luatex
> \setuplayout
>   [footer=0mm, header=0mm,
>   topspace=0mm, backspace=0mm,
>   leftmargin=0mm, rightmargin=0mm,
>   location=middle,
>   height=fit, width=fit]
>
> \starttext
>
> \startluacode
>   for n = 1, 9 do
>     tex.print(string.format("\\externalfigure[Image%05d.png]", n));
>   end
> \stopluacode
>
> \stoptext

your mail remind me to something I wanted a long time ago but I was now
motivated enough to write it. Below is solution to fit a given image to
a page with the normal width and height but remove parts at the top and
bottom or left and right if the width height relation is different from
the one of the document.

I think Hans would be ablo to write a better solution but this all I
can do by myself at the moment.

\unprotect

\def\fullpagebox
  {\bgroup
   \dowithnextbox
     {\!!widtha\dimexpr\paperwidth/\nextboxwd\relax
      \!!widthb\dimexpr\paperheight/\nextboxht\relax
      \ifdim\!!widtha>\!!widthb
        \setbox\nextbox\vbox\!!to\paperheight{\vss\expanded{\scale[\c!width=\paperwidth]{\flushnextbox}}\vss}%
      \else
        \setbox\nextbox\hbox\!!to\paperwidth{\hss\expanded{\scale[\c!height=\paperheight]{\flushnextbox}}\hss}%
      \fi \setbox\nextbox\hbox{\clip[\c!width=\paperwidth,\c!height=\paperheight]{\flushnextbox}}%
      \startTEXpage
      \flushnextbox
      \stopTEXpage
      \egroup}
   \hbox}

\protect

\starttext

\fullpagebox{\externalfigure[image]}

\stoptext

Wolfgang
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