> Procházka Lukáš Ing. <mailto:LPr@pontex.cz>
> 18. Juli 2016 um 16:41
> Hello,
>
> thank you for the patch.
>
> A solution which would not require named page sizes might be better as 
> we don't necessary need to know the name of the "previous" (or 
> "pushed") paper size (mostly we use "anonymous" page sizes, set up 
> once in the document preamble).
>
> Thus push/pop way would be a bit more flexible (like 
> \pushpagebackground / \poppagebackground);
> or making paper size local (enclosing paper setup into group - \start 
> \setupppapersize ... \stop\page) would restore the previous paper size.
A normal environment should be enough (push and pop are used to save and 
restore states etc.) which inserts are the necessary page breaks.

\unprotect

\def\startpapersize
   {\page
    \pushmacro\page_paper_restore
    \setuppapersize}

\def\stoppapersize
   {\page
    \popmacro\page_paper_restore
    \setuppapersize}

\protect

\starttext
     Page 1. \page
     Page 2. \page
     \startpapersize[A4,landscape]
     Page 3. \page
     Page 4. \page
     \stoppapersize
     Page 5. \page
     Page 6. \page
\stoptext

Wolfgang