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+%D \module
+%D [ file=supp-mul,
+%D version=1998.03.15,
+%D title=\CONTEXT\ Core Macros,
+%D subtitle=Multi Column Output,
+%D author=Hans Hagen,
+%D date=\currentdate,
+%D copyright={PRAGMA / Hans Hagen \& Ton Otten}]
+%C
+%C This module is part of the \CONTEXT\ macro||package and is
+%C therefore copyrighted by \PRAGMA. Non||commercial use is
+%C granted.
+
+\writestatus{loading}{Context Core Macros / Multi Column Output}
+
+\unprotect
+
+%D This one will become core-mul.tex!
+
+%D The following macro's implement a multi||column output
+%D routine. The original implementation was based on Donald
+%D Knuth's implementation, which was adapted by Craig Platt to
+%D support balancing of the last page. I gradually adapted
+%D Platt's version to our needs but under certain
+%D circumstances things still went wrong. I considered all
+%D calls to Platt's \type{\balancingerror} as undesirable.
+
+\startmessages dutch library: columns
+ title: kolommen
+ 1: maximaal -- kolommen
+ 2: gebruik eventueel \string\filbreak
+ 3: probleempje, probeer [balanceren=nee]
+ 4: plaatsblok boven nog niet mogelijk
+ 5: plaatsblok onder nog niet mogelijk
+ 6: -- plaatsblok(en) opgeschort
+ 7: balanceren afgebroken na 100 stappen
+ 8: gebalanceerd in -- stap(pen)
+ 9: uitlijnen controleren!
+ 10: (minder dan) 1 regel over
+ 11: plaatsblok te breed voor kolom
+ 12: plaatsblok verplaatst naar volgende kolom
+ 13: breed figuur geplaatst boven kolommen
+\stopmessages
+
+\startmessages english library: columns
+ title: columns
+ 1: only -- columns possible
+ 2: use \string\filbreak\space as alternative
+ 3: problems, disable balancing
+ 4: top float not yet supported
+ 5: bottom float not yet supported
+ 6: -- float(s) postponed
+ 7: balancing aborted after 100 steps
+ 8: balanced in -- step(s)
+ 9: check raggedness
+ 10: (less than) 1 line left
+ 11: float to wide for column
+ 12: float moved to next column
+ 13: wide float moved to top of columns
+\stopmessages
+
+\startmessages german library: columns
+ title: Spalten
+ 1: nur -- Spalten moeglich
+ 2: benutzte \string\filbreak\space als Alternative
+ 3: Problem, verwende [ausgleich=nein]
+ 4: Gleitobjekt oben ncoh nicht unterstuetzt
+ 5: Gleitobjekt unten ncoh nicht unterstuetzt
+ 6: -- Gleitobjekt(e) verschoben
+ 7: ausgleich nach 100 Schritten abgebrocheb
+ 8: ausgeglichen nach -- Schritt(en)
+ 9: Ausrichtung ueberpruefen
+ 10: (weniger als) 1 Zeile uebrig
+ 11: Gleitobjekt zu breit fuer Spalte
+ 12: Gleitobjekt in naechste Zeile verschoben
+ 13: breites Gleitobjekt an den Anfang der Spalten verschoben
+\stopmessages
+
+%D This completely new implementation can handle enough
+%D situations for everyday documents, but is still far from
+%D perfect. While at the moment the routine doesn't support
+%D all kind of floats, it does support:
+%D
+%D \startopsomming[opelkaar]
+%D \som an unlimitted number of columns
+%D \som ragged or not ragged bottoms
+%D \som optional balancing without \type{\balancingerrors}
+%D \som different \type{\baselineskips}, \type{\spacing},
+%D \type{\topskip} and \type{\maxdepth}
+%D \som left- and right indentation, e.g. within lists
+%D \som moving columns floats to the next column or page
+%D \som handling of floats that are to wide for a columns
+%D \stopopsomming
+%D
+%D One could wonder why single and multi||columns modes are
+%D still separated. One reason for this is that \TeX\ is not
+%D suited well for handling multi||columns. As a result, the
+%D single columns routines are more robust. Handling one
+%D column as a special case of multi||columns is posible but at
+%D the cost of worse float handling, worse page breaking,
+%D worse etc. Complicated multi||column page handling should
+%D be done in \kap{DTP}||systems anyway.
+%D
+%D There are three commands provided for entering and leaving
+%D multi||column mode and for going to the next column:
+%D
+%D \interface \type{\beginmulticolumns} \\ \\
+%D \interface \type{\endmulticolumns} \\ \\
+%D \interface \type{\ejectcolumn} \\ \\
+%D
+%D This routines are sort of stand||alone. They communicate
+%D with the rest of \CONTEXT\ by means of some interface
+%D macro's, which we only mention.
+%D
+%D \interface \type{\nofcolumns} \\
+%D the number of columns \\
+%D \interface \type{\betweencolumns} \\
+%D the stuff between columns \\
+%D \interface \type{\finaloutput{action}{box}} \\
+%D some kind of \type{\pagebody} and \type{\shipout} \\
+%D
+%D \interface \type{\ifbalancecolumns} \\
+%D balancing the colums or not \\
+%D \interface \type{\ifstretchcolumns} \\
+%D ragging the bottom or not \\
+%D
+%D \interface \type{\ifheightencolumns} \\
+%D fix the heigh tor not \\
+%D \interface \type{\fixedcolumnheight} \\
+%D the optional fixed height \\
+%D
+%D \interface \type{\ifinheritcolumns} \\
+%D handle ragging or not \\
+%D \interface \type{\ifr@ggedbottom} \\
+%D use ragged bottoms \\
+%D \interface \type{\ifb@selinebottom} \\
+%D put the bottom line on the baseline \\
+%D \interface \type{\ifnormalbottom} \\
+%D put the bottom line at the baseline \\
+%D
+%D \interface \type{\usercolumnwidth} \\
+%D the calculated width of a column \\
+%D \interface \type{\columntextwidth} \\
+%D the maximum width of a column \\
+%D \interface \type{\columntextheight} \\
+%D the minimum width of a column \\
+%D
+%D \interface \type{\spacingfactor} \\
+%D the spacing factor \\
+%D \interface \type{\bodyfontsize} \\
+%D the (local) bodyfontsize \\
+%D \interface \type{\openlineheight} \\
+%D the lineheight (including \type{\spacing}) \\
+%D
+%D \interface \type{\Everybodyfont} \\
+%D communication channel to font switching routines \\
+%D
+%D \interface \type{\global\settopskip} \\
+%D set \type{\topskip} \\
+%D \interface \type{\setcolumnwarnings} \\
+%D set \type{\badness} and \type{\fuzz} \\
+%D \interface \type{\setcolumninserts} \\
+%D set \type{\insert}'s \\
+%D \interface \type{\setvsize} \\
+%D set \type{\vsize} and \type{\pagegoal} \\
+%D \interface \type{\sethsize} \\
+%D set \type{\hsize} \\
+%D
+%D \interface \type{\flushcolumnfloats} \\
+%D push saved column floats (next page) \\
+%D \interface \type{\flushcolumnfloat} \\
+%D push saved column floats (next column) \\
+%D \interface \type{\setcolumnfloats} \\
+%D initialize column floats \\
+%D
+%D \interface \type{\finishcolumnbox} \\
+%D do something special (a hook) \\
+%D \interface \type{\postprocesscolumnline} \\
+%D do something with each columnline (also a hook) \\
+%D \interface \type{\currentcolumn} \\
+%D the current column \\
+%D
+%D These interface macro's are called upon or initialized
+%D by the multi||column macro's.
+
+%D A lot of footnote stuff added!
+
+\def\columntextwidth {\zetbreedte}
+\def\columntextheight {\teksthoogte}
+\def\usercolumnwidth {\tekstbreedte}
+
+\def\fixedcolumnheight {\teksthoogte}
+\def\betweencolumns {\hskip\bodyfontsize}
+
+\def\setcolumnwarnings {\dontcomplaincolumnboxes}
+\def\setcolumninserts {\dontpermitcolumninserts}
+
+\def\setcolumnfloats {} % in CONTEXT used for floats
+\def\flushcolumnfloats {} % in CONTEXT used for floats
+\def\flushcolumnfloat {} % in CONTEXT used for floats
+
+\def\finishcolumnbox {} % in CONTEXT used for backgrounds
+
+%D In fact, the column height and width are set by mens of
+%D two macro's. One can change their meaning if needed:
+
+\def\setcolumntextheight%
+ {\def\columntextheight{\teksthoogte}}
+
+\def\setcolumntextwidth% % pas op: geen \teksthoogte, anders steeds smaller
+ {\def\columntextwidth{\zetbreedte}}
+
+%D Both macros are redefined in \CONTEXT\ when backgrounds
+%D are applied to columns.
+
+\newcount\nofcolumns \nofcolumns=2
+
+\def\maxnofcolumns {16}
+\def\allocatednofcolumns {0}
+
+\newif\ifbalancecolumns \balancecolumnsfalse
+\newif\ifstretchcolumns \stretchcolumnsfalse
+\newif\ifinheritcolumns \inheritcolumnsfalse
+\newif\ifheightencolumns \heightencolumnsfalse
+
+\newbox\partialpage
+\newbox\restofpage
+
+\newbox\savedfloatlist
+
+\newdimen\intercolumnwidth
+\newdimen\localcolumnwidth
+\newdimen\partialpageheight
+\newdimen\savedpagetotal
+
+\newtoks\singlecolumnout
+
+%D During initialization the temporary boxes are allocated.
+%D This enables us to use as much columns as we want, without
+%D exhausting the pool of boxes too fast. We could have packed
+%D them in one box, but we've got enough boxes.
+%D
+%D Two sets of boxes are declared, the txtboxes are used for
+%D the text, the topboxes are for moved column floats.
+
+\def\@@txtcol{@@txtcol}
+\def\@@topcol{@@topcol}
+
+\def\initializemulticolumns#1%
+ {\ifnum#1>\maxnofcolumns\relax
+ \showmessage{\m!columns}{1}{\maxnofcolumns}%
+ \nofcolumns=\maxnofcolumns
+ \else
+ \nofcolumns=#1\relax
+ \fi
+ \ifnum\nofcolumns>\allocatednofcolumns\relax
+ \dorecurse
+ {#1}
+ {\ifnum\recurselevel>\allocatednofcolumns\relax
+ \newbox\next
+ \global\letvalue{\@@txtcol\recurselevel}=\next
+ \newbox\next
+ \global\letvalue{\@@topcol\recurselevel}=\next
+ \fi}%
+ \xdef\allocatednofcolumns{\the\nofcolumns}%
+ \fi
+ \edef\firstcolumnbox{\getvalue{\@@txtcol1}}%
+ \edef\firsttopcolumnbox{\getvalue{\@@topcol1}}%
+ \edef\lastcolumnbox{\getvalue{\@@txtcol\the\nofcolumns}}%
+ \edef\lasttopcolumnbox{\getvalue{\@@topcol\the\nofcolumns}}}
+
+%D Without going in details we present two macro's which
+%D handle the columns. The action which is transfered by the
+%D the first and only parameter can do something with
+%D \type{\currentcolumnbox}. In case of the mid columns,
+%D \type{\firstcolumnbox} and \type{\lastcolumnbox} are handled
+%D outside these macro's.
+
+\def\dohandlemidcolumns#1%
+ {\dorecurse
+ {\nofcolumns}
+ {\ifnum\recurselevel>1
+ \ifnum\recurselevel<\nofcolumns\relax
+ \edef\currentcolumnbox{\getvalue{\@@txtcol\recurselevel}}%
+ \edef\currenttopcolumnbox{\getvalue{\@@topcol\recurselevel}}%
+ \let\currentcolumn=\recurselevel
+ #1\relax
+ \fi
+ \fi}}
+
+\def\dohandleallcolumns#1%
+ {\dorecurse
+ {\nofcolumns}
+ {\edef\currentcolumnbox{\getvalue{\@@txtcol\recurselevel}}%
+ \edef\currenttopcolumnbox{\getvalue{\@@topcol\recurselevel}}%
+ \let\currentcolumn=\recurselevel
+ #1\relax}}
+
+%D Going to a new columns is done by means of a
+%D \type{\ejectcolumn}. The following definition does not
+%D always work.
+
+\def\ejectcolumn%
+ {\goodbreak
+ \showmessage{\m!columns}{2}{}}
+
+%D The next macro should never be called so let's deal with it.
+%D There were several solutions to these kind of errors. First
+%D we check for a good breakpoint before firing up the
+%D multi||column routine (\type{\break} or \type{\allowbreak}).
+%D We do the same at the end of the routine
+%D (\type{\allowbreak}). These allowances are definitely
+%D needed!
+%D
+%D Some on first sight redundant calls to for instance
+%D \type{\setvsize} in the flushing, splitting and balancing
+%D macro's can definitely not be omitted! Some are just there
+%D to handle situations that only few times arise. One of
+%D those can be that the output routine is invoked before
+%D everything is taken care of. This happens when we
+%D flush (part of) the current page with an \type{\unvbox}
+%D with a \type{\pagetotal}~$\approx$ \type{\pagegoal}. One
+%D simply cannot balance columns that are just balanced.
+%D
+%D I hope one never sees the following message. Because it
+%D took me a lot of time to develop the multi||columns
+%D routines, every (although seldom) warning gives me the
+%D creeps!
+
+\def\balancingerror%
+ {\showmessage{\m!columns}{3}{}%
+ \finaloutput\unvbox\normalpagebox}
+
+%D Here we present the two \type{\dont...} macro's, which are
+%D of course \CONTEXT||specific ones.
+
+\def\dontcomplaincolumnboxes%
+ {\mindermeldingen}
+
+\def\dontpermitcolumninserts%
+ {\def\dotopfloat%
+ {\showmessage{\m!columns}{4}{}%
+ \doexecfloat}%
+ \def\dobotfloat%
+ {\showmessage{\m!columns}{5}{}%
+ \doexecfloat}}
+
+\def\getinsertionheights\to#1\\% \relax'm
+ {#1=\!!zeropoint
+ \def\doaddinsertionheight##1%
+ {\ifvoid##1\else
+ \advance#1 by \skip##1
+ \advance#1 by \ht##1
+ \fi}%
+ \doaddinsertionheight\topins
+ \doaddinsertionheight\botins
+ \ifcleverfootnotes
+ \doaddinsertionheight\savedfootins
+ \else
+ \doaddinsertionheight\footins
+ \fi}
+
+%D The local column width is available in the dimension
+%D register \type{\localcolumnwidth}, which is calculated as:
+
+\def\setcolumnhsize%
+ {\setbox0=\hbox
+ {\parindent\!!zeropoint\betweencolumns}%
+ \intercolumnwidth=\wd0
+ \localcolumnwidth=\columntextwidth
+ \edef\globalcolumnwidth{\the\localcolumnwidth}%
+ \advance\localcolumnwidth by -\leftskip
+ \advance\localcolumnwidth by -\rightskip
+ \advance\localcolumnwidth by -\nofcolumns\intercolumnwidth
+ \advance\localcolumnwidth by \intercolumnwidth
+ \divide\localcolumnwidth by \nofcolumns
+ \usercolumnwidth=\localcolumnwidth
+ \hsize=\localcolumnwidth} % we don't do it \global
+
+%D One should be aware that when font related dimensions are
+%D used in typesetting the in||between material, these
+%D dimensions are influenced by bodyfont switches inside
+%D multi||column mode.
+
+%D The global width is saved in \type {\globalcolumnwidth}.
+%D This value is used when we pack the columns in a \type
+%D {\hbox}.
+
+\def\setcolumnvsize%
+ {\global\vsize=\columntextheight
+ \ifdim\partialpageheight>\!!zeropoint
+ \global\advance\vsize by -\partialpageheight
+ \fi
+ \getinsertionheights\to\dimen0\\%
+ \global\advance\vsize by -\dimen0
+\ifgridsnapping % evt altijd, nog testen
+ \getnoflines\vsize
+ \vsize=\noflines\openlineheight
+ \advance\vsize by .5\openlineheight % collect enough data
+\fi
+ \global\vsize=\nofcolumns\vsize
+ \global\pagegoal=\vsize} % let's do it only here
+
+%D It really starts here. After some checks and initializations
+%D we change the output routine to continous multi||column
+%D mode. This mode handles columns that fill the current and
+%D next full pages. The method used is (more or less)
+%D multiplying \type{\vsize} and dividing \type{\hsize} by
+%D \type{\nofcolumns}. More on this can be found in the
+%D \TeX book. We save the top of the current page in box
+%D \type{\partialpage}.
+%D
+%D We manipulate \type{\topskip} a bit, just to be shure that
+%D is has no flexibility. This has te be done every time a
+%D font switch takles place, because \type{\topskip} can depend
+%D on this.
+%D
+%D Watch the trick with the \type{\vbox}. This way we get the
+%D right interlining and white space.
+
+\def\beginmulticolumns%
+ {\par
+ \flushfootnotes
+ \begingroup
+ \dontshowcomposition
+ \setcolumntextwidth\relax
+ \setcolumntextheight\relax
+ \widowpenalty=0 % is gewoon beter
+ \clubpenalty=0 % zeker bij grids
+ \ifsomefloatwaiting
+ \showmessage{\m!columns}{6}{\the\savednoffloats}%
+ \global\setbox\savedfloatlist=\box\floatlist
+ \xdef\restoresavedfloats%
+ {\global\savednoffloats=\the\savednoffloats
+ \global\setbox\floatlist=\box\savedfloatlist
+ \global\noexpand\somefloatwaitingtrue}%
+ \global\savednoffloats=0
+ \global\somefloatwaitingfalse
+ \else
+ \global\let\restoresavedfloats=\relax
+ \fi
+ \dimen0=\pagetotal
+ \advance\dimen0 by \parskip
+ \advance\dimen0 by \openlineheight
+ \ifdim\dimen0<\pagegoal
+ \allowbreak
+ \else
+ % \break Werkt in veel gevallen averechts!
+ \fi
+ \appendtoks\topskip=1\topskip\to\everybodyfont
+ \the\everybodyfont
+ \initializemulticolumns\nofcolumns
+ \setcolumninserts
+ \hangafter=0
+ \hangindent=\!!zeropoint
+ \everypar{}%
+ \ifdim\pagetotal=\!!zeropoint \else
+ \vbox{\strut}%
+ \vskip-\openlineheight
+ \fi
+ \global\savedpagetotal=\pagetotal
+ \global\singlecolumnout=\output
+ \global\output={\global\setbox\partialpage=\vbox{\unvbox\normalpagebox}}%
+ \eject
+ \global\partialpageheight=\ht\partialpage
+ \global\output={\continuousmulticolumnsout}%
+ \setcolumnfloats
+ \dohandleallcolumns
+ {\global\setbox\currenttopcolumnbox=\box\voidb@x}%
+ \checkbegincolumnfootnotes
+ \let\sethsize=\setcolumnhsize
+ \let\setvsize=\setcolumnvsize
+ \sethsize
+ \setvsize
+ \showcomposition}
+
+%D When we leave the multi||column mode, we have to process the
+%D not yet shipped out part of the columns. When we don't
+%D balance, we simply force a continuous output, but a balanced
+%D output is more tricky.
+%D
+
+%D First we try to fill up the page and when all or something
+%D is left we try to balance things. This is another useful
+%D adaption of the ancesters of these macro's. It takes some
+%D reasoning to find out what happens and maybe I'm making
+%D some mistake, but it works.
+%D
+%D Unvoiding box \type{\partialpage} is sometimes necessary,
+%D e.g. when there is no text given between \type{\begin..}
+%D and \type{\end..}. The \type{\par} is needed!
+
+\def\endmulticolumns%
+ {\dontshowcomposition
+ \doflushcolumnfloats % added recently
+ \par
+ \ifbalancecolumns
+ \global\output={\continuousmulticolumnsout}%
+ \goodbreak
+ \global\output={\balancedmulticolumnsout}%
+ \else
+ \goodbreak
+ \fi
+ \eject % the prevdepth is important, try e.g. toclist in
+ \prevdepth\!!zeropoint % columns before some noncolumned text text
+ \global\output=\singlecolumnout
+ \ifvoid\partialpage\else
+ \unvbox\partialpage
+ \fi
+ \global\partialpageheight=\!!zeropoint
+ \endgroup % here
+ \nofcolumns=1
+ \setvsize % the outer one!
+ \checkendcolumnfootnotes
+ \dosomebreak\allowbreak
+ \restoresavedfloats}
+
+%D NEW: still to be documented!
+
+\newinsert\savedfootins
+
+\def\checkbegincolumnfootnotes%
+ {\ifcleverfootnotes
+ \doflushfootnotes
+ \ifdim\ht\footins>\!!zeropoint
+ \global\setbox\savedfootins=\box\footins
+ \else
+ \global\setbox\savedfootins=\box\voidb@x
+ \fi
+ \global\skip\savedfootins=\skip\footins
+ \global\count\savedfootins=\count\footins
+ \setupfootnotes
+ \else
+ \global\skip\savedfootins=\skip\footins
+ \global\setbox\savedfootins=\box\voidb@x
+ \global\count\savedfootins=\count\footins
+ \setupfootnotes
+\global\multiply\count\footins by \nofcolumns % gaat mis bij lokale
+ \fi}
+
+\def\checkendcolumnfootnotes%
+ {\ifcleverfootnotes\ifvoid\savedfootins\else
+ \global\setbox\footins=\box\savedfootins
+ \fi\fi
+ \global\skip\footins=\skip\savedfootins
+ \global\count\footins=\count\savedfootins}
+
+%D Because some initializations happen three times, we
+%D defined a macro for them. The \type{\everypar{}} is
+%D needed because we don't want anything to interfere.
+
+\def\setmulticolumnsout%
+ {\everypar{}%
+ \setcolumnwarnings
+ \settopskip
+ \setmaxdepth
+ \topskip=1\topskip
+ \splittopskip=\topskip
+ \splitmaxdepth=\maxdepth
+ \boxmaxdepth=\maxdepth
+ \emergencystretch=\!!zeropoint\relax} % sometimes needed !
+
+%D Flushing the page comes to pasting the columns together and
+%D appending the result to box \type{\partialpage}, if not
+%D void. I've seen a lot of implementations in which some skip
+%D was put between normal text and multi||column text. When we
+%D don't want this, the baselines can be messed up. I hope the
+%D seemingly complicated calculation of a correction
+%D \type{\kern} is adequate to overcome this. Although not
+%D watertight, spacing is taken into account and even multiple
+%D mode changes on one page go well. But cross your fingers and
+%D don't blame me.
+%D
+%D One of the complications of flushing out the boxes is that
+%D \type{\partialpage} needs to be \type{\unvbox}'ed, otherwise
+%D there is too less flexibility in the page when using
+%D \type{\r@ggedbottom}. It took a lot of time before these
+%D kind of problems were overcome. Using \type{\unvbox} at the
+%D wrong moment can generate \type{\balancingerror}'s.
+%D
+%D One can use the macros \type {\maxcolumnheight} and \type
+%D {\maxcolumndepth} when generating material between columns
+%D as well as postprocessing column lines.
+
+\let\maxcolumnheight=\!!zeropoint
+\let\maxcolumndepth =\!!zeropoint
+
+\def\setmaxcolumndimensions%
+ {\let\maxcolumnheight=\!!zeropoint
+ \let\maxcolumndepth =\!!zeropoint
+ \dohandleallcolumns
+ {\ifdim\ht\currentcolumnbox>\maxcolumnheight
+ \edef\maxcolumnheight{\the\ht\currentcolumnbox}%
+ \fi
+ \ifdim\dp\currentcolumnbox>\maxcolumndepth
+ \edef\maxcolumndepth{\the\dp\currentcolumnbox}%
+ \fi}}
+
+\def\flushcolumnedpage%
+ {\bgroup
+ \forgetall
+ \setmulticolumnsout
+ \showcomposition
+ \setmaxcolumndimensions
+ \postprocesscolumns
+ \dohandleallcolumns % \hbox i.v.m. \showcomposition
+ {\global\setbox\currentcolumnbox=\hbox to \localcolumnwidth
+ {\box\currentcolumnbox
+ \global\wd\currentcolumnbox=\localcolumnwidth
+ \ifheightencolumns
+ \global\ht\currentcolumnbox=\fixedcolumnheight
+ \fi}}%
+ \setmaxcolumndimensions
+ \overlaycolumnfootnotes
+ \setbox0=\vbox
+ {\hbox to \globalcolumnwidth
+ {\dohandleallcolumns
+ {\finishcolumnbox{\hbox{\box\currentcolumnbox}}%
+ \ifnum\currentcolumn<\nofcolumns
+ \hfil\betweencolumns\hfil
+ \fi}}}%
+ \dohandleallcolumns
+ {\global\setbox\currenttopcolumnbox=\box\voidb@x}%
+ \ifvoid\partialpage \else
+ \ifgridsnapping % do you believe this junk?
+ \scratchdimen=\savedpagetotal
+ \advance\scratchdimen by -\ht\partialpage
+ \advance\scratchdimen by -\dp\partialpage
+ \advance\scratchdimen by -\topskip
+ \box\partialpage
+ \kern\scratchdimen
+ \else
+ \unvbox\partialpage
+ \fi
+ \fi
+ \global\partialpageheight=\!!zeropoint
+ \setvsize
+ \dosomebreak\nobreak
+ \dp0=\!!zeropoint
+ \prevdepth\openstrutdepth % \dp\strutbox
+ \nointerlineskip
+ \box0
+ \egroup}
+
+%D In case one didn't notice, finaly \type{\finishcolumnbox} is
+%D applied to all boxes. One can use this hook for special
+%D purposes. But there is more:
+%D
+%D Once upon a time I wanted to manipulate the individual lines
+%D in a column. This feature is demonstrated in the two examples
+%D below.
+%D
+%D \startbuffer
+%D \def\postprocesscolumnline#1%
+%D {\ruledhbox{#1}\hss}
+%D
+%D \startkolommen[n=4]
+%D \dorecurse{25}{line: \recurselevel\par}
+%D \stopkolommen
+%D \stopbuffer
+%D
+%D \typebuffer
+%D
+%D Here we show the natural width of the lines:
+%D
+%D {\haalbuffer}
+%D
+%D The next example does a bit more advanced manipulation:
+%D
+%D \startbuffer
+%D \def\postprocesscolumnline#1%
+%D {\ifodd\currentcolumn
+%D \hfill#1\relax
+%D \else
+%D \relax#1\hfill
+%D \fi}
+%D
+%D \startkolommen[n=4]
+%D \dorecurse{25}{line \recurselevel\par}
+%D \stopkolommen
+%D \stopbuffer
+%D
+%D \typebuffer
+%D
+%D Here we also see an application of \type{\currentcolumn}:
+%D
+%D {\haalbuffer}
+%D
+%D This feature is implemented using the reshape macros
+%D presented in \type{supp-box}.
+
+\def\postprocesscolumns% recent extension
+ {\ifx\postprocesscolumnline\undefined \else
+ \dohandleallcolumns
+ {\global\setbox\currentcolumnbox=\vtop
+ {\beginofshapebox
+ \unvbox\currentcolumnbox
+ \unskip\unskip
+ \endofshapebox
+ \reshapebox
+ {\dimen0=\ht\shapebox
+ \dimen2=\dp\shapebox
+ \setbox\shapebox=\hbox to \hsize
+ {\postprocesscolumnline{\unhbox\shapebox}}%
+ \ht\shapebox=\dimen0
+ \dp\shapebox=\dimen2
+ \box\shapebox}%
+ \flushshapebox
+ \everypar{}\parskip\!!zeropoint % = \forgetall
+ \strut\endgraf
+ \vskip-\lineheight
+ \vfil}}%
+ \fi}
+
+%D We default to doing nothing!
+
+\let\postprocesscolumnline=\undefined
+
+%D Here comes the simple splitting routine. It's a bit
+%D longer than expected because of ragging bottoms or not.
+%D This part can be a bit shorter but I suppose that I will
+%D forget what happens. The splitting takes some already
+%D present material (think of floats) into account!
+%D
+%D First we present some auxiliary routines. Any material,
+%D like for instance floats, that is already present in the
+%D boxes is preserved.
+
+% \def\splitcolumn#1from \box#2to \dimen#3 top \box#4%
+% {\bgroup
+% \ifdim\ht#4>\!!zeropoint
+% \dimen0=\dimen#3\relax
+% \dimen2=\dimen#3\relax
+% \advance\dimen0 by -\ht#4
+% \setbox0=\vsplit#2 to \dimen0
+% \global\setbox#1=\vbox to \dimen2{\unvcopy#4\unvbox0}%
+% \else
+% \global\setbox#1=\vsplit#2 to \dimen#3
+% \fi
+% \egroup}
+
+\def\splitcolumn#1from \box#2to \dimen#3 top \box#4%
+ {\bgroup
+ \ifdim\ht#4>\!!zeropoint
+ \dimen0=\dimen#3\relax
+ \dimen2=\dimen2
+ \advance\dimen0 by -\ht#4%
+ \columnfootnotecorrection{#1}{\dimen0}%
+ \setbox0=\vsplit#2 to \dimen0
+ \global\setbox#1=\vbox to \dimen2
+ {\ifgridsnapping
+ \dimen0=-\openstrutheight\advance\dimen0 by \topskip
+ \vskip\dimen0\copy#4\vskip-\dimen0
+ \else
+ \unvcopy#4%
+ \fi
+ \unvbox0\fakecolumnfootnotes{#1}}%
+ \else
+ \ifcleverfootnotes
+ \columnfootnotecorrection{#1}{\dimen#3}%
+ \setbox0=\vsplit#2 to \dimen#3%
+ \global\setbox#1=\vbox to \dimen#3{\unvbox0\fakecolumnfootnotes{#1}}%
+ \else
+ \global\setbox#1=\vsplit#2 to \dimen#3%
+ \fi
+ \fi
+ \egroup}
+
+\def\splitcurrentcolumn from \box#1to \dimen#2%
+ {\splitcolumn\currentcolumnbox from \box#1 to \dimen#2 top \box\currenttopcolumnbox}
+
+\def\splitfirstcolumn from \box#1to \dimen#2%
+ {\splitcolumn\firstcolumnbox from \box#1 to \dimen#2 top \box\firsttopcolumnbox}
+
+% \def\splitlastcolumn from \box#1to \dimen#2%
+% {\global\setbox\lastcolumnbox=\vbox
+% {\unvcopy\lasttopcolumnbox
+% \unvbox#1}}
+
+\def\splitlastcolumn from \box#1to \dimen#2%
+ {\global\setbox\lastcolumnbox=\vbox
+ {\unvcopy\lasttopcolumnbox
+ \unvbox#1
+ \fakecolumnfootnotes\lastcolumnbox}}
+
+%D NEW: still to be documented.
+
+\def\fakecolumnfootnotes#1%
+ {\relax
+ \ifcleverfootnotes
+ \ifnum#1=\lastcolumnbox
+ \ifdim\ht\footins>\!!zeropoint
+ \vskip\skip\footins
+ \vskip\ht\footins
+ \fi
+ \fi
+ \fi}
+
+\def\columnfootnotecorrection#1#2%
+ {\relax
+ \ifcleverfootnotes
+ \ifnum#1=\lastcolumnbox\relax
+ \ifdim\ht\footins>\!!zeropoint
+ \advance#2 by -\ht\footins
+ \advance#2 by -\skip\footins
+ \fi
+ \fi
+ \fi}
+
+\def\overlaycolumnfootnotes% VERVANGEN !!!
+ {\relax
+ \ifcleverfootnotes\ifdim\ht\footins>\!!zeropoint
+ \bgroup
+ %\ifgridsnapping
+ \scratchdimen=\ht\firstcolumnbox
+ \advance\scratchdimen by -\openstrutdepth % \dp\strutbox
+ \getnoflines\scratchdimen
+ \advance\noflines by -2
+ \scratchdimen=\noflines\lineheight
+ \advance\scratchdimen by \topskip
+ \setbox0=\hbox
+ {\lower\scratchdimen\vbox{\placefootnoteinserts}}%
+ \ht0=\openstrutheight % \ht\strutbox
+ \dp0=\openstrutdepth % \dp\strutbox
+ \scratchdimen=\ht\lastcolumnbox
+ \global\setbox\lastcolumnbox=\vbox to \scratchdimen
+ {\box\lastcolumnbox
+ \vskip-\scratchdimen
+ \box0}%
+ %\else
+ % \setbox0=\vbox to \ht\lastcolumnbox
+ % {\vfill\placefootnoteinserts}%
+ % \scratchdimen=\wd\lastcolumnbox
+ % \wd0=\wd\lastcolumnbox
+ % \wd\lastcolumnbox=\!!zeropoint
+ % \global\setbox\lastcolumnbox=\hbox
+ % {\box\lastcolumnbox\box0}%
+ %\fi
+ \egroup
+ \fi\fi}
+
+
+%D Here comes the routine that splits the long box in columns.
+%D The macro \type{\flushcolumnfloats} can be used to flush
+%D either floats that were present before the multi||column
+%D mode was entered, or floats that migrate to next columns.
+%D Flushing floats is a delicate process.
+
+\def\continuousmulticolumnsout%
+ {\bgroup
+ \setmulticolumnsout
+ \dontshowcomposition
+% \dimen0=\columntextheight
+% \advance\dimen0 by -\partialpageheight
+% \getinsertionheights\to\dimen2\\% toegevoegd ivm voetnoten
+% \ifgridsnapping
+% \getnoflines{\dimen2}%
+% \advance\dimen0 by -\noflines\openlineheight
+%\getnoflines{\dimen0}\dimen0=\noflines\openlineheight
+% \else
+% \advance\dimen0 by -\dimen2
+% \fi
+%
+ \dimen0=\columntextheight
+ \getinsertionheights\to\dimen2\\% toegevoegd ivm voetnoten
+ \advance\dimen2 by \partialpageheight
+ \ifgridsnapping
+ \getnoflines{\dimen2}%
+ \advance\dimen0 by -\noflines\openlineheight
+ \getnoflines{\dimen0}%
+ \dimen0=\noflines\openlineheight
+ \else
+ \advance\dimen0 by -\dimen2
+ \fi
+%
+ \dohandleallcolumns
+ {\splitcurrentcolumn from \box\normalpagebox to \dimen0}
+ \setbox\restofpage=\vbox{\unvbox\normalpagebox}%
+ \ifinheritcolumns
+ \ifr@ggedbottom
+ \dohandleallcolumns
+ {\global\setbox\currentcolumnbox=\vbox to \dimen0
+ {\dimen0=\dp\currentcolumnbox
+ \unvbox\currentcolumnbox
+ \vskip-\dimen0
+ \vskip\openstrutdepth % \dp\strutbox
+ \prevdepth\openstrutdepth % \dp\strutbox
+ \vfill}}%
+ \fi
+ \ifn@rmalbottom
+ \advance\dimen0 by \maxdepth
+ \dohandleallcolumns
+ {\global\setbox\currentcolumnbox=\vbox to \dimen0
+ {\unvbox\currentcolumnbox}}%
+ \fi
+ \ifb@selinebottom
+ % the columns are on top of the baseline
+ \fi
+ \else
+ \dohandleallcolumns
+ {\global\setbox\currentcolumnbox=\vbox to \dimen0
+ {\ifstretchcolumns
+ \unvbox\currentcolumnbox
+ \else
+ \unvbox\currentcolumnbox % wel of niet \unvbox ?
+ \vfill
+ \fi}}%
+ \dohandleallcolumns
+ {\global\ht\currentcolumnbox=\dimen0}%
+ \fi
+ \setbox\partialpage=\vbox{\flushcolumnedpage}%
+ \finaloutput\box\partialpage
+ \sethsize
+ \setvsize
+ \flushcolumnfloats
+ \unvbox\restofpage
+ % \penalty\outputpenalty % gaat gruwelijk mis in opsommingen
+ \egroup}
+
+%D And this is the balancing stuff. Again, part of the routine
+%D is dedicated to handling ragged bottoms, but here we also
+%D see some handling concerning the stretching of columns.
+%D We set \type{\widowpenalty} at~0, which enables us to
+%D balance columns with few lines. The use of \type{\box2} and
+%D \type{\box4} garantees a more robust check when skips are
+%D used.
+
+\def\balancedmulticolumnsout%
+ {\bgroup
+ \setmulticolumnsout
+ \dontshowcomposition
+ \widowpenalty=0
+ \setbox0=\vbox{\unvbox\normalpagebox}%
+ \ifdim\ht0>\openlineheight
+ \dimen0=\ht0
+ \advance\dimen0 by \topskip
+ \advance\dimen0 by -\baselineskip
+ \divide\dimen0 by \nofcolumns
+ \vbadness=\!!tenthousand\relax
+ \count255=0
+ \bgroup
+ \ifgridsnapping
+ \dimen2=\lineheight
+ \else
+ \dimen2=\!!onepoint % RUBISH
+ \dimen2=\spacingfactor\dimen2
+ \fi
+ \loop
+ \advance\count255 by 1
+ \global\setbox\restofpage=\copy0\relax
+ \splitfirstcolumn from \box\restofpage to \dimen0
+ \dohandlemidcolumns
+ {\splitcurrentcolumn from \box\restofpage to \dimen0}%
+ \splitlastcolumn from \box\restofpage to \dimen0
+ \setbox2=\vbox{\unvcopy\firstcolumnbox}%
+ \dimen4=\!!zeropoint
+ \dohandleallcolumns
+ {\setbox4=\vbox{\unvcopy\currentcolumnbox}%
+ \dimen6=\ht4
+ \ifdim\dimen6>\dimen4 \dimen4=\dimen6\fi}%
+ \ifnum\count255>100\relax
+ \donefalse
+ \else\ifdim\dimen4>\ht2
+ \donetrue
+ \else
+ \donefalse
+ \fi\fi
+ \ifdone
+ \advance\dimen0 by \dimen2\relax
+ \repeat
+ \dohandleallcolumns
+ {\global\setbox\currentcolumnbox=\vbox{\unvcopy\currentcolumnbox}}% NIEUW
+ \ifnum\count255>100\relax
+ \showmessage{\m!columns}{7}{}%
+ \else
+ \showmessage{\m!columns}{8}{\the\count255\space}%
+ \fi
+ \egroup
+ \ifinheritcolumns
+ \dimen0=\ht\firstcolumnbox
+ \dimen2=\ht\firstcolumnbox
+ \advance\dimen2 by -\openlineheight
+ \dohandleallcolumns
+ {\dimen4=\ht\currentcolumnbox
+ \dimen6=10\openlineheight
+ \global\setbox\currentcolumnbox=\vbox to \dimen0
+ {\unvbox\currentcolumnbox
+ \ifdim\dimen4>\dimen6
+ \ifdim\dimen4<\dimen0
+ \ifdim\dimen4>\dimen2
+ \vskip\!!zeropoint % !!
+ \else
+ \vskip\openlineheight
+ \vfill
+ \fi
+ \else
+ \vskip\!!zeropoint
+ \fi
+ \else
+ \vskip\openlineheight
+ \vfill
+ \fi}}%
+ \else
+ \bgroup
+ \ifstretchcolumns
+ \dimen0=\ht\firstcolumnbox
+ \dimen2=\bottomtolerance\ht\firstcolumnbox
+ \setbox0=\vbox{\unvcopy\lastcolumnbox}%
+ \advance\dimen0 by -\ht0\relax
+ \advance\dimen0 by -\dp0\relax
+ \ifdim\dimen0>\openlineheight\relax
+ \ifdim\dimen0>\dimen2\relax
+ % \stretchcolumnsfalse % beter goed slecht dan slecht goed
+ \showmessage{\m!columns}{9}{}%
+ \fi
+ \fi
+ \fi
+ \dohandleallcolumns
+ {\global\setbox\currentcolumnbox=\vbox to \ht\firstcolumnbox
+ {\ifstretchcolumns
+ \unvbox\currentcolumnbox
+ \else
+ \box\currentcolumnbox
+ \vfill
+ \fi}}%
+ \egroup
+ \fi
+ \else
+ \showmessage{\m!columns}{10}{}%
+ \global\setbox\firstcolumnbox=\vbox{\unvbox0}%
+ \fi
+ \global\output={\balancingerror}%
+ \b@selinebottomtrue % forces depth in separation rule
+ \flushcolumnedpage
+ \allowbreak
+ \egroup}
+
+%D The multicolumn mechanism is incorporated in a \CONTEXT\
+%D interface, which acts like:
+%D
+%D \starttypen
+%D \startcolumns[n=4,balance=no,stretch=no,line=on]
+%D some text
+%D \stopcolumns
+%D \stoptypen
+%D
+%D The setup is optional. The default behaviour of columns
+%D can be set up with:
+%D
+%D \starttypen
+%D \setupcolumns
+%D [n=2,
+%D balance=yes,
+%D stretch=text,
+%D line=off]
+%D \stoptypen
+%D
+%D In this case, stretching is according to the way it's
+%D done outside columns (\type{\inheritcolumnstrue}). Also
+%D we can setup the \type{tolerance} within a column, the
+%D \type{distance} between columns and the fixed
+%D \type{height} of a column.
+
+%D Multi||column output: the float routines
+%D
+%D Here come the routines that handle the placement of column
+%D floats. Floats that are to big migrate to the next
+%D column. Floats that are too wide, migrate to the top of the
+%D next page, where they span as much columns as needed.
+%D Floats that are left over from outside the multi||column
+%D mode are flushed first. In macro \type{\finaloutput} the
+%D topfloats that are left from previous text should be set.
+%D
+%D When there are some floats in the queue, we inhibit the
+%D flushing of floats on top of columns. The number of
+%D waiting floats is preswent in \type{\savednoftopfloats} and
+%D is saved. As long as there are floats waiting, the topfloats
+%D are places as if we are outside multi||column mode. This is
+%D neccessary for e.g. multicolumn lists.
+%D
+%D When all those floats are flushed, we switch to the local
+%D flushing routine.
+
+\def\setcolumnfloats%
+ {\xdef\globalsavednoffloats{\the\savednoffloats}%
+ \ifnum\globalsavednoffloats>0
+ \setglobalcolumnfloats
+ \else
+ \setlocalcolumnfloats
+ \fi}
+
+\def\setglobalcolumnfloats%
+ {\everypar={}%
+ \let\flushcolumnfloat=\relax
+ \let\doroomfloat=\relax
+ \let\flushcolumnfloats=\noflushcolumnfloats}
+
+\def\setlocalcolumnfloats%
+ {\everypar={\flushfootnotes\flushcolumnfloat\flushmargincontents\checkindentation}
+ \let\flushcolumnfloat=\doflushcolumnfloat
+ \let\doroomfloat=\docolumnroomfloat
+ \let\flushcolumnfloats=\doflushcolumnfloats
+ \let\dosetbothinserts=\relax
+ \let\dotopinsertions=\relax}
+
+\def\noflushcolumnfloats%
+ {\bgroup
+ \xdef\localsavednoffloats{\the\savednoffloats}%
+ \global\savednoffloats=\globalsavednoffloats
+ \dotopinsertions
+ \xdef\globalsavenoffloats{\the\savednoffloats}%
+ \ifnum\globalsavednoffloats=0
+ \setlocalcolumnfloats
+ \fi
+ \global\savednoffloats=\localsavednoffloats
+ \egroup}
+
+%D We need to calculate the amount of free space in a columns.
+%D When there is not enough room, we migrate the float to the
+%D next column. These macro's are alternatives (and
+%D look||alikes) of \type{\doroomfloat}. When a float is to
+%D wide, for one column, it is moved to the top of the next
+%D page. Of course such moved floats have to be taken into
+%D account when we calculate the available space. It's a pitty
+%D that such things are no integral part of \TEX.
+
+% \def\getcolumnstatus\column#1\total#2\goal#3\\%
+% {\ifdim\pagegoal<\maxdimen
+% \dimen0=\pagegoal
+% \divide\dimen0 by \nofcolumns
+% \dimen2=\!!zeropoint
+% \count255=0\relax
+% \dimen8=\columntextheight
+% \advance\dimen8 by -\partialpageheight
+% %\advance\dimen8 by -\maxdepth % recently deleted
+% \def\dogetcolumnstatus%
+% {\advance\count255 by 1\relax
+% \advance\dimen2 by \ht\currenttopcolumnbox
+% \advance\dimen2 by \dp\currenttopcolumnbox
+% \dimen4=\dimen2\relax
+% \advance\dimen4 by \pagetotal
+% \dimen6=\count255\dimen8
+% \ifdim\dimen4>\dimen6
+% \else
+% \let\dogetcolumnstatus=\relax
+% \fi}%
+% \dohandleallcolumns{\dogetcolumnstatus}%
+% \ifdim\dimen4=\dimen6
+% \dimen4=\!!zeropoint
+% \advance\count255 by 1
+% \fi
+% #1=\count255
+% #2=\dimen4
+% #3=\dimen6
+% \else
+% #1=1
+% #2=\!!zeropoint
+% #3=\teksthoogte
+% \advance#3 by -\partialpageheight
+% \fi}
+
+\def\getcolumnstatus\column#1\total#2\goal#3\\%
+ {\ifdim\pagegoal<\maxdimen
+ \dimen0=\pagetotal
+ \else
+ \dimen0=\!!zeropoint
+ \fi
+ \dimen2=\!!zeropoint
+ \count255=0
+ \dimen8=\columntextheight
+ \advance\dimen8 by -\partialpageheight
+ \def\dogetcolumnstatus%
+ {\advance\count255 by 1
+ \advance\dimen2 by \ht\currenttopcolumnbox
+ \advance\dimen2 by \dp\currenttopcolumnbox
+ \dimen4=\dimen2
+ \advance\dimen4 by \dimen0
+ \dimen6=\count255\dimen8
+ \ifdim\dimen4>\dimen6
+ \else
+ \let\dogetcolumnstatus=\relax
+ \fi}%
+ \dohandleallcolumns{\dogetcolumnstatus}%
+ \ifnum\count255=0 \count255=1 \fi
+ #1=\count255
+ #2=\dimen4
+ #3=\dimen6 }
+
+\def\docolumnroomfloat%
+ {\ifnofloatpermitted
+ \global\roomforfloatfalse
+ \else
+ \bgroup
+ \getcolumnstatus\column\count255\total\dimen0\goal\dimen2\\%
+\ifgridsnapping\ifnum\count255=\nofcolumns\ifvoid\footins\else
+ \advance\dimen0 by 1.5\openlineheight % nog nodig ?
+\fi\fi\fi
+ \setbox\scratchbox=\vbox
+ {\blanko[\@@bkvoorwit]
+ \snaptogrid\vbox{\copy\floatbox}}
+ \advance\dimen0 by \ht\scratchbox
+ \advance\dimen0 by .5\lineheight % needed because goal a bit higher
+ \ifdim\dimen0>\dimen2
+ \global\roomforfloatfalse
+ \else
+ \global\roomforfloattrue
+ \fi
+ \egroup
+ \ifdim\wd\floatbox>\hsize
+ \showmessage{\m!columns}{11}{}%
+ \global\roomforfloatfalse
+ \fi
+ \fi}
+
+%D Flushing one float is done as soon as possible, i.e.
+%D \type{\everypar}. This means that (at the moment)
+%D sidefloats are not supported (overulled)!
+
+\newif\ifflushingcolumnfloats \flushingcolumnfloatstrue
+
+\def\doflushcolumnfloat%
+ {\ifflushingcolumnfloats\ifprocessingverbatim\else\ifsomefloatwaiting
+ \bgroup
+ \forgetall
+ \let\doflushcolumnfloat=\relax
+ \getcolumnstatus\column\count255\total\dimen0\goal\dimen2\\%
+ \ifdim\dimen0>\!!zeropoint
+ \dogetfloat
+ \ifdim\wd\floatbox>\hsize
+ \doresavefloat
+ \else
+ \setbox2=\vbox
+ {\blanko[\@@bkvoorwit]
+ \snaptogrid\vbox{\copy\floatbox}%
+ \blanko[\@@bknawit]}%
+ \advance\dimen0 by \ht2
+ \ifdim\dimen0>\dimen2
+ \showmessage{\m!columns}{12}{}%
+ \ifnum\count255<\nofcolumns
+ \advance\count255 by 1
+ \edef\currenttopcolumnbox{\getvalue{\@@topcol\the\count255}}%
+ \ifdim\ht\currenttopcolumnbox=\!!zeropoint
+ \global\setbox\currenttopcolumnbox=\vbox
+ {\snaptogrid\vbox{\copy\floatbox}
+ \witruimte % nodig ?
+ \blanko[\@@bknawit]}%
+ \dimen4=\ht\currenttopcolumnbox
+ \advance\dimen4 by \dp\currenttopcolumnbox
+ \global\advance\vsize by -\dimen4
+ \advance\dimen4 by -\pagegoal
+ \global\pagegoal=-\dimen4
+ \else
+ \doresavefloat
+ \fi
+ \else
+ \doresavefloat
+ \fi
+ \else
+ \ifhmode{\setbox0=\lastbox}\fi% waar is die er in geslopen
+ \par
+ \ifdim\prevdepth<\!!zeropoint\relax % anders bovenaan kolom witruimte
+ \else
+ \blanko[\@@bkvoorwit]
+ \fi
+ \flushfloatbox
+ \blanko[\@@bknawit]
+ \fi
+ \fi
+ \fi
+ \egroup
+ \fi\fi\fi}
+
+%D This one looks complicated. Upto \type{\nofcolumns} floats
+%D are placed, taking the width of a float into account. This
+%D routine can be improved on different ways:
+%D
+%D \startopsomming[intro,opelkaar]
+%D \som taking into account some imaginary baseline, just to
+%D get the captions in line
+%D \som multipass flushing until as many floats are displaced
+%D as possible
+%D \stopopsomming
+%D
+%D When handling lots of (small) floats spacing can get worse
+%D because of lining out the columns.
+
+\def\doflushcolumnfloats%
+ {\bgroup
+ \forgetall
+% \ifnum\savednoffloats>1\relax % no \ifsomefloatwaiting
+% \ifnum\savednoffloats>0\relax % no
+ \ifsomefloatwaiting
+ \dimen8=\!!zeropoint
+ \dimen4=\!!zeropoint
+ \count0=0 % count0 can be used local
+ \count2=\nofcolumns % count2 can be used local
+ \dohandleallcolumns
+ {\ifnum\count0>0\relax % the wide one's reserved space
+ \global\setbox\currenttopcolumnbox=\vbox
+ {\snaptogrid\hbox{\vphantom{\copy\floatbox}}%
+ \witruimte
+ \blanko[\@@bknawit]}%
+ \else
+ \dogetfloat
+ \ifdim\wd\floatbox>\hsize
+ \dimen0=\wd\floatbox
+ \advance\dimen0 by \intercolumnwidth
+ \dimen2=\hsize
+ \advance\dimen2 by \intercolumnwidth
+ \divide\dimen0 by \dimen2
+ \count0=\dimen0
+ \advance\count0 by 1
+ \ifnum\count0>\count2
+ \doresavefloat
+ \count0=0
+ \else
+ \dimen0=\count0\hsize
+ \advance\dimen0 by \count0\intercolumnwidth
+ \advance\dimen0 by -\intercolumnwidth
+ \global\setbox\floatbox=\hbox to \dimen0
+ {\hss\hbox{\copy\floatbox}\hss}%
+ \fi
+ \showmessage{\m!columns}{13}{}%
+ \else
+ % \showmessage{\m!columns}{13}{}%
+ \fi
+ \ifdim\ht\floatbox>\!!zeropoint\relax
+ \global\setbox\currenttopcolumnbox=\vbox
+ {\snaptogrid\vbox{\copy\floatbox}
+ \witruimte % nodig ?
+ \blanko[\@@bknawit]}%
+ \fi
+ \dimen6=\ht\currenttopcolumnbox
+ \advance\dimen6 by \dp\currenttopcolumnbox
+ \fi
+ \ifdim\dimen4<\ht\currenttopcolumnbox
+ \dimen4=\ht\currenttopcolumnbox
+ \fi
+ \advance\dimen8 by \dimen6
+ \advance\count2 by -1
+ \advance\count0 by -1\relax}%
+ \setvsize
+ \global\advance\vsize by -\dimen8
+ \global\pagegoal=\vsize
+ \else
+ \doflushfloats
+ \fi
+ \egroup}
+
+%D This were the multi||column routines. They can and need to
+%D be improved but at the moment their behaviour is acceptable.
+%D
+%D One inprovement can be to normalize the height of floats
+%D to $n\times$\type{\lineheight} with a macro like:
+%D
+%D \starttypen
+%D \normalizevbox{...}
+%D \stoptypen
+
+\protect
+
+\endinput
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-16 13:00:20 +0000