%D \module
%D   [       file=pack-fen,
%D        version=2011.07.21,
%D          title=\CONTEXT\ Packaging Macros,
%D       subtitle= Fences for Ruled Content,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA ADE \& \CONTEXT\ Development Team}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

\writestatus{loading}{ConTeXt Packaging Macros / Fences for Ruled Content}

% we can move the main fences here too

\unprotect

\def\installleftframerenderer#1#2%
  {\setvalue{l\@@frame@@\v!on#1}{\whateverleftframe{#2}}%
   \expandafter\let\csname l\@@frame@@\v!off#1\expandafter\endcsname\csname l\@@frame@@\v!on#1\endcsname}

\def\installrightframerenderer#1#2%
  {\setvalue{r\@@frame@@\v!on#1}{\whateverrightframe{#2}}%
   \expandafter\let\csname r\@@frame@@\v!off#1\expandafter\endcsname\csname r\@@frame@@\v!on#1\endcsname}

\def\installtopframerenderer#1#2%
  {\setvalue{t\@@frame@@\v!on#1}{\whatevertopframe{#2}}%
   \expandafter\let\csname t\@@frame@@\v!off#1\expandafter\endcsname\csname t\@@frame@@\v!on#1\endcsname}

\def\installbottomframerenderer#1#2%
  {\setvalue{b\@@frame@@\v!on#1}{\whateverbottomframe{#2}}%
   \expandafter\let\csname b\@@frame@@\v!off#1\expandafter\endcsname\csname b\@@frame@@\v!on#1\endcsname}

\def\setinstalledframedimensions
  {\edef\overlayheight{\the\dimexpr\frameddimenht+\frameddimendp}%
   \edef\overlaywidth {\the\frameddimenwd}}

\newbox\specialframebox

\def\whateverleftframe#1%
  {\setinstalledframedimensions
   \setbox\specialframebox\vbox to \overlayheight{\vss#1\vss}%
   \setbox\specialframebox\hbox to \zeropoint{\box\specialframebox\hss}%
   \ht\specialframebox\zeropoint
   \dp\specialframebox\zeropoint
   \box\specialframebox}

\def\whateverrightframe#1%
  {\setinstalledframedimensions
   \setbox\specialframebox\vbox to \overlayheight{\vss#1\vss}%
   \setbox\specialframebox\hbox to \zeropoint{\hss\box\specialframebox}%
   \ht\specialframebox\zeropoint
   \dp\specialframebox\zeropoint
   \box\specialframebox}

\def\whatevertopframe#1%
  {\setinstalledframedimensions
   \setbox\specialframebox\hbox to \overlaywidth{\hss#1\hss}%
   \setbox\specialframebox\vbox to \zeropoint{\box\specialframebox\vss}%
   \ht\specialframebox\zeropoint
   \dp\specialframebox\zeropoint
   \box\specialframebox
   \nointerlineskip}

\def\whateverbottomframe#1%
  {\setinstalledframedimensions
   \setbox\specialframebox\hbox to \overlaywidth{\hss#1\hss}%
   \setbox\specialframebox\vbox to \zeropoint{\vss\box\specialframebox}%
   \ht\specialframebox\zeropoint
   \dp\specialframebox\zeropoint
   \box\specialframebox}

\protect \endinput