From 28f104e641e84d484a22266d87536ef7d765b223 Mon Sep 17 00:00:00 2001
From: Hans Hagen <pragma@wxs.nl>
Date: Tue, 25 Sep 2018 15:11:00 +0200
Subject: 2018-09-25 14:23:00

---
 tex/context/base/mkiv/page-pcl.mkiv | 77 +++++++++++++++++++++++++++++--------
 1 file changed, 62 insertions(+), 15 deletions(-)

(limited to 'tex/context/base/mkiv/page-pcl.mkiv')

diff --git a/tex/context/base/mkiv/page-pcl.mkiv b/tex/context/base/mkiv/page-pcl.mkiv
index 5b7d0ae8a..140444fc2 100644
--- a/tex/context/base/mkiv/page-pcl.mkiv
+++ b/tex/context/base/mkiv/page-pcl.mkiv
@@ -30,19 +30,18 @@
 \definemeasure[threecolumns][\dimexpr\plusthree\columnwidth+\plustwo  \columndistance\relax]
 \definemeasure[fourcolumns] [\dimexpr\plusfour \columnwidth+\plusthree\columndistance\relax]
 
-\newcount\c_page_col_n_of_columns \c_page_col_n_of_columns\plusone
-\newcount\c_page_col_current      \c_page_col_current     \plusone
-\newdimen\d_page_col_distance
-\newdimen\d_page_col_max_height
-\newdimen\d_page_col_max_width
-%newdimen\d_page_col_balance_step
-\newdimen\d_page_col_column_width
-
-\newdimen\d_page_col_top_height
-\newdimen\d_page_col_top_width
-
-\newdimen\d_page_col_available
-\newdimen\d_page_col_sofar
+\newcount      \c_page_col_n_of_columns \c_page_col_n_of_columns\plusone
+\newcount      \c_page_col_current      \c_page_col_current     \plusone
+\newdimen      \d_page_col_distance
+\newdimen      \d_page_col_max_height
+\newdimen      \d_page_col_max_width
+%newdimen      \d_page_col_balance_step
+\newdimen      \d_page_col_column_width
+\newdimen      \d_page_col_top_height
+\newdimen      \d_page_col_top_width
+\newdimen      \d_page_col_available
+\newdimen      \d_page_col_sofar
+\newconditional\c_page_col_page
 
 %D We need to step over empty columns.
 
@@ -700,6 +699,7 @@
 \setuppagecolumns
   [\c!distance=1.5\bodyfontsize,
    \c!n=\plustwo,
+   \c!page=\v!yes,
   %\c!align=, % inherit (also replaces tolerance)
   %\c!before=,
   %\c!after=,
@@ -727,9 +727,39 @@
 \ifdefined \columnwidth    \else \newdimen\columnwidth    \fi
 \ifdefined \columndistance \else \newdimen\columndistance \fi
 
+\def\page_col_pickup_preceding
+  {\begingroup
+   \setupoutputroutine[\s!mixedcolumn]%
+   \c_page_mix_routine\c_page_mix_routine_intercept
+   \page_otr_trigger_output_routine
+   \ifvoid\b_page_mix_preceding \else
+     % moved here, before the packaging
+     \page_postprocessors_linenumbers_deepbox\b_page_mix_preceding
+     % we need to avoid unvboxing with successive balanced on one page
+     \global\setbox\b_page_mix_preceding\vbox\bgroup
+       % yes or no: \forcestrutdepth
+       \unvbox\b_page_mix_preceding
+       \forcestrutdepth
+     \egroup
+     \wd\b_page_mix_preceding\makeupwidth
+     \global\d_page_mix_preceding_height\ht\b_page_mix_preceding
+   \fi
+   \endgroup}
+
+\def\page_col_flush_preceding
+  {\ifvoid\b_page_mix_preceding \else
+     % this is just one method but ok for now
+     \begingroup
+     % we might need more but for now this is ok
+     \setupfloat[\c!spacebefore=,\c!spaceafter=]%
+     \startplacefigure[\c!location={\v!top,\v!none}]%
+       \box\b_page_mix_preceding
+     \stopplacefigure
+     \endgroup
+   \fi}
+
 \unexpanded\def\startpagecolumns
-  {\page
-   \begingroup
+  {\begingroup
    \begingroup
    \dosingleempty\page_col_start}
 
@@ -738,6 +768,15 @@
      {\let\currentpagecolumns\empty
       \setuppagecolumns[#1]}%
      {\edef\currentpagecolumns{#1}}%
+   \edef\p_page{\pagecolumnsparameter\c!page}%
+   \ifx\p_page\empty
+     \setfalse\c_page_col_page
+   \else\ifx\p_page\v!no
+     \setfalse\c_page_col_page
+   \else
+     \settrue\c_page_col_page
+     \page[\p_page]%
+   \fi\fi
    \c_page_col_n_of_columns\pagecolumnsparameter\c!n\relax
    \ifnum\c_page_col_n_of_columns>\plusone
      \expandafter\page_col_start_yes
@@ -775,7 +814,15 @@
    %
    \usesetupsparameter\pagecolumnsparameter
    %
+   % This will become a method but for now it's good enough
+   %
+   \ifconditional\c_page_col_page\else
+     \page_col_pickup_preceding
+   \fi
    \setupoutputroutine[\s!pagecolumn]%
+   \ifconditional\c_page_col_page\else
+     \page_col_flush_preceding
+   \fi
    %
    \setupfloats[\c!ntop=\plusthousand]%
  % \setupfloats[\c!nbottom=\plusthousand]%
-- 
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