%D \module
%D   [       file=anch-loc,
%D        version=2021.05.27,
%D          title=\CONTEXT\ Anchoring Macros,
%D       subtitle=Local Positioning Support,
%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 Anchoring Macros / Local Positioning}

%D This is a typical \LMTX\ feature that could have been provided in \MKIV\ but I
%D never finished it there. In \LMTX\ we have already a bit better infrastructure
%D for it.
%D
%D When watching the brilliant positive yt videos of Yoyoka Soma (よよか) drum
%D performances one realizes that a covers can improve the original. Let's see if
%D this module can improve some of the position related mechanisms. (Btw, quite
%D often covers impress me more than originals I'd never list too anyway.)

% todo:
%
% - make box fit and inject glue
% - set height / depth or just insert something between

\registerctxluafile{anch-loc}{autosuffix}

\unprotect

\aliased\let\syncanchor \gobblethreearguments
\aliased\let\alignanchor\gobblefourarguments
\aliased\let\markanchor \gobblethreearguments

\permanent\protected\def\anch_local_withanchor_s  #1#2#3{\leftboundary\setlocalsyncanchor {#1} #2 #3\rightboundary}
\permanent\protected\def\anch_local_withanchor_a#1#2#3#4{\leftboundary\setlocalalignanchor{#1} #2 #3{#4}\rightboundary}
\permanent\protected\def\anch_local_withanchor_n  #1#2#3{\leftboundary\setlocalmarkanchor {#1} #2 #3\rightboundary}
\permanent\protected\def\anch_local_withanchor_t  #1#2#3{\anch_local_withanchor_n{#1}{#2}{#3}\smash[whd]{\smallinfofont\number#2-\number#3}}

\permanent\protected\def\setlocalanchoring
  {\enforced\let\syncanchor \anch_local_withanchor_s
   \enforced\let\alignanchor\anch_local_withanchor_a
   \enforced\let\markanchor \anch_local_withanchor_m}

\let\anch_local_withanchor_m\anch_local_withanchor_n

\installtextracker{localanchor}
  {\let\anch_local_withanchor_m\anch_local_withanchor_t}
  {\let\anch_local_withanchor_m\anch_local_withanchor_n}

\permanent\protected\lettonothing\stopanchoring

\permanent\protected\def\startanchoring#1\stopanchoring % todo: boundary
  {\begingroup
   \pushlocalanchors
   \setlocalanchoring
   \setbox\scratchbox\vbox{\settrialtypesetting#1}%
   \analyzelocalanchors\scratchbox
   \vbox{#1}%
   \poplocalanchors
   \endgroup}

\permanent\protected\lettonothing\stopsynchronizing

\permanent\protected\def\startsynchronizing#1\stopsynchronizing % todo: boundary
  {\begingroup
   \pushlocalanchors
   \setlocalanchoring
   \setbox\scratchbox\vbox{#1}%
   \synchronizelocalanchors\scratchbox
   \unvbox\scratchbox
   \poplocalanchors
   \endgroup}

% variant on \sync (defined at the lua end)

\permanent\protected\def\autosync#1#2{\leftboundary\sync{#1}{#2}\rightboundary}

% \startsynchronizing
%     $a            = a            + a        $\par
%     $a \mathsnc{1}= a            + a        $\par
%     $  \mordsnc{1}= a            + a + a    $\par
%     $  \mordsnc{1}= a \mathsnc{2}+ a + a + a$\par
%     $  \mordsnc{1}    \mordsnc{2}+ a + a + a$
% \stopsynchronizing

\permanent\protected\def\mathsync#1{\sync{m}{#1}}
\permanent\protected\def\mordsync#1{\mathord{}\sync{m}{#1}}
\permanent\protected\def\mrelsync#1{\mathrel{}\sync{m}{#1}}
\permanent\protected\def\mbinsync#1{\mathbin{}\sync{m}{#1}}

\setlocalanchoring

%D These are defined at the \LUA\ end.
%D
%D \starttyping
%D \pushlocalanchors
%D \poplocalanchors
%D \analyzelocalanchors
%D \synchronizelocalanchors
%D \setlocalsyncanchor  {name} x y | {name} {x} {y}
%D \setlocalmarkanchor  {name} x y | {name} {x} {y}
%D \localanchorx        {name} x y | {name} {x} {y}
%D \localanchory        {name} x y | {name} {x} {y}
%D \sync                {name} x   | {name} {x}
%D \stoptyping

% \permanent\def\anchorxy#1#2#3{(\todimension\localanchorx{#1} #2 #3,\todimension\localanchory{#1} #2 #3)}

\protect \endinput

% Musical timestamp: Nightwish Decades bluray in loop mode.