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%D \module
%D [ file=core-vis,
%D version=1996.06.01,
%D title=\CONTEXT\ Core Macros,
%D subtitle=Visualization,
%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.
%D This module adds some more visualization cues to the ones
%D supplied in the support module.
%D
%D %\everypar dual character, \the\everypar and \everypar=
%D %\hrule cannot be grabbed in advance, switches mode
%D %\vrule cannot be grabbed in advance, switches mode
%D %
%D %\indent only explicit ones
%D %\noindent only explicit ones
%D %\par only explicit ones
%D
%D %\leftskip only if explicit one
%D %\rightskip only if explicit one
\writestatus{loading}{Context Support Macros / Visualization}
\unprotect
%D \macros
%D {indent, noindent,
%D leavevmode,
%D par}
%D {}
%D
%D \TeX\ acts upon paragraphs. In mosts documents paragraphs
%D are separated by empty lines, which internally are handled as
%D \type{\par}. Paragraphs can be indented or not, depending on
%D the setting of \type{\parindent}, the first token of a
%D paragraph and/or user suppressed or forced indentation.
%D
%D Because the actual typesetting is based on both explicit
%D user and implicit system actions, visualization is only
%D possible for the user supplied \type{\indent},
%D \type{\noindent}, \type{\leavevmode} and \type{\par}. Other
%D 'clever' tricks will quite certainly lead to more failures
%D than successes, so we only support these three explicit
%D primitives and one macro:
\let\normalnoindent = \noindent
\let\normalindent = \indent
\let\normalpar = \par
\let\normalleavevmode = \leavevmode
\def\showparagraphcue#1#2#3#4#5%
{\bgroup
\scratchdimen#1\relax
\dontinterfere
\dontcomplain
\boxrulewidth=5\testrulewidth
#3#4\relax
\setbox0=\normalhbox to \scratchdimen
{#2{\ruledhbox to \scratchdimen
{\vrule
#5 20\testrulewidth
\!!width \!!zeropoint
\normalhss}}}%
\smashbox0
\normalpenalty\!!tenthousand
\box0
\egroup}
\def\ruledhanging%
{\ifdim\hangindent>\!!zeropoint\relax
\ifnum\hangafter<0
\normalhbox
{\boxrulewidth=5\testrulewidth
\setbox0=\ruledhbox to \hangindent
{\scratchdimen=\ht\strutbox
\advance\scratchdimen by \dp\strutbox
\vrule
\!!width\!!zeropoint
\!!height\!!zeropoint
\!!depth-\hangafter\scratchdimen}%
\normalhskip-\hangindent
\smashbox0
\raise\ht\strutbox\box0}%
\fi
\fi}
\def\ruledparagraphcues%
{\bgroup
\dontcomplain
\normalhbox to \!!zeropoint
{\ifdim\leftskip>\!!zeropoint\relax
\showparagraphcue\leftskip\llap\relax\relax\!!depth
\normalhskip-\leftskip
\fi
\ruledhanging
\normalhskip\hsize
\ifdim\rightskip>\!!zeropoint\relax
\normalhskip-\rightskip
\showparagraphcue\rightskip\relax\relax\relax\!!depth
\fi}%
\egroup}
\def\ruledpar%
{\relax
\ifhmode
\showparagraphcue{40\testrulewidth}\relax\rightrulefalse\relax\!!height
\fi
\normalpar}
\def\rulednoindent%
{\relax
\normalnoindent
\ruledparagraphcues
\showparagraphcue{40\testrulewidth}\llap\leftrulefalse\relax\!!height}
\def\ruledindent%
{\relax
\normalnoindent
\ruledparagraphcues
\ifdim\parindent>\!!zeropoint\relax
\showparagraphcue\parindent\relax\relax\relax\!!height
\else
\showparagraphcue{40\testrulewidth}\llap\relax\relax\!!height
\fi
\normalhskip\parindent}
\def\ruledleavevmode%
{\relax
\normalleavevmode
\ifdim\parindent>\!!zeropoint\relax
\normalhskip-\parindent
\ruledparagraphcues
\showparagraphcue\parindent\relax\leftrulefalse\rightrulefalse\!!height
\normalhskip\parindent
\else
\ruledparagraphcues
\showparagraphcue{40\testrulewidth}\llap\leftrulefalse\rightrulefalse\!!height
\fi}
\def\dontshowimplicits%
{\let\noindent = \normalnoindent
\let\indent = \normalindent
\let\leavevmode = \normalleavevmode
\let\par = \normalpar}
\def\showimplicits%
{\testrulewidth = \defaulttestrulewidth
\let\noindent = \rulednoindent
\let\indent = \ruledindent
\let\leavevmode = \ruledleavevmode
\let\par = \ruledpar}
%D The next few||line examples show the four cues. Keep in
%D mind that we only see them when we explicitly open or close
%D a paragraph.
%D
%D \bgroup
%D \def\voorbeeld#1%
%D {#1Visualizing some \TeX\ primitives and Plain \TeX\
%D macros can be very instructive, at least it is to me.
%D Here we see {\tt\string#1} and {\tt\string\ruledpar} in
%D action, while {\tt\string\parindent} equals
%D {\tt\the\parindent}.\ruledpar}
%D
%D \showimplicits
%D
%D \voorbeeld \indent
%D \voorbeeld \noindent
%D \voorbeeld \leavevmode
%D
%D \parindent=60pt
%D
%D \voorbeeld \indent
%D \voorbeeld \noindent
%D \voorbeeld \leavevmode
%D
%D \startsmaller
%D \voorbeeld \indent
%D \voorbeeld \noindent
%D \voorbeeld \leavevmode
%D \stopsmaller
%D \egroup
%D
%D These examples also demonstrate the visualization of
%D \type{\leftskip} and \type{\rightskip}.
\newcounter\ruledbaselines
\def\debuggertext#1%
{\ifx\ttxx\undefined
$\scriptscriptstyle#1$%
\else
{\ttxx#1}%
\fi}
\def\ruledbaseline%
{\vrule \!!width \!!zeropoint
\bgroup
\dontinterfere
\doglobal\increment\ruledbaselines
\scratchdimen=3\baselineskip
\setbox\scratchbox=\normalvbox to 2\scratchdimen
{\leaders
\normalhbox
{\strut
\vrule
\!!height \testrulewidth
\!!depth \testrulewidth
\!!width 120pt}
\normalvfill}%
\smashbox\scratchbox
\advance\scratchdimen by \strutheightfactor\baselineskip
\setbox\scratchbox=\normalhbox
{\normalhskip -48pt
\normalhbox to 24pt
{\normalhss\debuggertext\ruledbaselines\normalhskip6pt}%
\raise\scratchdimen\box\scratchbox}%
\smashbox\scratchbox
\box\scratchbox
\egroup}
\def\showbaselines%
{\testrulewidth=\defaulttestrulewidth
\EveryPar{\ruledbaseline}}
%D {\em Not yet documented!}
\def\makecutbox#1%
{\edef\ruledheight{\the\ht#1}%
\edef\ruleddepth {\the\dp#1}%
\edef\ruledwidth {\the\wd#1}%
\setbox\scratchbox=\normalvbox
{\dontcomplain
\offinterlineskip
\scratchdimen=12pt\relax
\def\verrule##1##2%
{\vrule
\!!width\boxrulewidth
\!!height##1\scratchdimen
\!!depth##2\scratchdimen}%
\def\horrule##1##2##3%
{\normalhskip##1\scratchdimen
\vrule
\!!height\boxrulewidth
\!!width##2\scratchdimen
\normalhskip##3\scratchdimen}%
\normalvskip-3\scratchdimen
\normalhbox to \ruledwidth
{\verrule{3}{-1}\normalhss\verrule{3}{-1}}%
\normalhbox to \ruledwidth
{\horrule{-3}{2}{1}\normalhss\horrule{1}{2}{-3}}%
\normalvskip-\boxrulewidth
\vskip\ruledheight
\ifdim\ruleddepth>\!!zeropoint\relax
\normalvskip-.5\boxrulewidth
\normalhbox to \ruledwidth
{\horrule{-2}{1}{1}\normalhss\horrule{1}{1}{-2}}%
\normalvskip-.5\boxrulewidth
\vskip\ruleddepth
\fi
\normalvskip-\boxrulewidth
\normalhbox to \ruledwidth
{\horrule{-3}{2}{1}\normalhss\horrule{1}{2}{-3}}%
\normalhbox to \ruledwidth
{\verrule{-1}{3}\normalhss\verrule{-1}{3}}}%
\dp\scratchbox=\ruleddepth % This re-bounding is needed and
\ht\scratchbox=\ruledheight % surfaced while typesetting continuous
\setbox\scratchbox=\normalhbox % double culumns with pagecutmark
{\lower\ruleddepth\box\scratchbox}%
\setbox#1=\ifhbox#1\normalhbox\else\normalvbox\fi
{\normalhbox
{\wd#1=\!!zeropoint
\box#1\relax
\box\scratchbox}}%
\wd#1=\ruledwidth
\ht#1=\ruledheight
\dp#1=\ruleddepth}
\def\cuthbox%
{\normalhbox\bgroup
\dowithnextbox{\makecutbox\nextbox\box\nextbox\egroup}%
\normalhbox}
\def\cutvbox%
{\normalvbox\bgroup
\dowithnextbox{\makecutbox\nextbox\box\nextbox\egroup}%
\normalvbox}
\def\cutvtop%
{\normalvtop\bgroup
\dowithnextbox{\makecutbox\nextbox\box\nextbox\egroup}%
\normalvtop}
%
% \cutvbox
% \cutvtop
% \cuthbox
%
% \cutvbox{\ruledvbox{hello\par world \par \strut ziezo}}
\protect
\endinput
|
