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%D \module
%D [ file=pack-obj,
%D version=1998.01.15,
%D title=\CONTEXT\ Packaging Macros,
%D subtitle=Objects,
%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. See mreadme.pdf for
%C details.
\writestatus{loading}{ConTeXt Packaging Macros / Objects}
\unprotect
\let\objectreference\gobblefourarguments % catch mkii tuo stuff
\registerctxluafile{pack-obj}{1.001}
%D \macros
%D {setobject,getobject,ifinobject}
%D
%D Boxes can be considered reuable objects. Unfortunaltely once
%D passed to the \DVI\ file, such objects cannot be reused. In
%D \PDF\ however, reusing is possible and sometimes even a
%D necessity. Therefore, \CONTEXT\ supports reusable objects.
%D
%D During the \TEX\ processing run, boxes can serve the purpose
%D of objects, and the \DVI\ driver module implements objects
%D using packed boxes.
%D
%D The \PDF\ and \PDFTEX\ driver modules implement objects
%D using \PDF\ forms. There is no (real) restriction on the
%D number of objects there.
%D
%D The first application of objects in \CONTEXT\ concerned
%D \METAPOST\ graphics and fill||in form fields. The first
%D application can save lots of bytes, while the latter use is
%D more a necessity than byte saving.
%D
%D \starttyping
%D \setobject{class}{name}\somebox{}
%D \getobject{class}{name}
%D \stoptyping
%D
%D Here \type{\somebox} can be whatever box specification suits
%D \TEX. We save the dimensions of an object, although some
%D drivers will do so themselves. This means that when for
%D instance using \PDFTEX\ we could save a hash entry plus some
%D 20+ memory locations per object by delegating this
%D housekeeping to the driver. The current approach permits
%D us to keep the box characteristic too.
\newif\ifinobject
\def\objectplaceholder{NOT YET FLUSHED}%
\def\presetobject#1#2% \global added
{\ifcsname\r!object#1::#2\endcsname\else
\global\@EA\let\csname\r!object#1::#2\endcsname\objectplaceholder
\fi}
\def\dosetobject#1#2#3% \initializepaper this will move to \everyshipout
{\initializepaper
\ifcsname\r!object#2::#3\endcsname
\expandafter\gobblefivearguments
\else % tzt, overload internal referenced objects to save entries
\expandafter\dodosetobject
\fi
{#1}{#2}{#3}}
\def\resetobject#1#2%
{\letbeundefined{\r!object#1::#2}}
%D \macros
%D {finalizeobjectbox}
%D
%D This one provides a hook for last minute object box processing
%D we need this in \MKIV.
\ifx\finalizeobjectbox\undefined
\let\finalizeobjectbox\gobbleoneargument
\fi
%D Somehow there is a rounding error problem in either \PDFTEX\
%D or in viewers, or maybe it is conforming the specs. The next
%D variable compensate for it by removing the rather tight
%D clip.
\def\objectoffset{1cm}
\def\dodosetobject#1#2#3%
{\bgroup
\globalpushmacro\crossreferenceobject \objectreferenced
\inobjecttrue
\dowithnextbox
{\globalpopmacro\crossreferenceobject
\dododosetobject{#1}{#2}{#3}\egroup}}
\def\dododosetobject#1#2#3%
{\begingroup
\dontshowcomposition % rather fuzzy in \setxvalue ... \hbox
\scratchdimen\objectoffset
\@EA\xdef\csname\r!object#2::#3\endcsname
{\noexpand\dohandleobject{#2}{#3}%
{\ifhbox\nextbox\hbox\else\vbox\fi}%
{\number\nextboxwd}{\number\nextboxht}{\number\nextboxdp}%
{\number\scratchdimen}}%
\expanded % freeze the dimensions since \dostartobject may use \nextbox
{\dostartobject{#2}{#3}{\the\nextboxwd}{\the\nextboxht}{\the\nextboxdp}}%
\ifcase#1\relax\else \ifdim\objectoffset>\zeropoint
\setbox\nextbox\vbox spread 2\scratchdimen
{\forgetall \offinterlineskip
\vss\hbox spread 2\scratchdimen{\hss\flushnextbox\hss}\vss}%
\fi \fi
\flushnextbox
\dostopobject
\endgroup}
\def\getobject#1#2%
{\begingroup
\let\dohandleobject\dogetobject
\csname\r!object#1::#2\endcsname}
\def\dogetobject#1#2#3#4#5#6#7% don't change this, should work for dvi & pdf
{\initializepaper
\forgetall
\dontshowcomposition
\setbox\scratchbox\vbox
{\doinsertobject{#1}{#2}}%
\setbox\scratchbox#3%
{\vbox to #5\scaledpoint
{\ifdim\ht\scratchbox>#5\scaledpoint
\vss\hbox to #4\scaledpoint{\hss\box\scratchbox\hss}\vss
\else\ifdim\wd\scratchbox>#4\scaledpoint
\vss\hbox to #4\scaledpoint{\hss\box\scratchbox\hss}\vss
\else
%\vss\box\scratchbox
\vss\hbox to #4\scaledpoint{\box\scratchbox\hss}% fix Chof
\fi\fi}}%
\box\scratchbox
\endgroup}
%D If needed one can ask for the dimensions of an object with:
%D
%D \starttyping
%D \getobjectdimensions{class}{name}
%D \stoptyping
%D
%D The results are reported in \type {\objectwidth}, \type
%D {\objectheight} and \type {\objectdepth}.
\def\dogetobjectdimensions#1#2#3#4#5#6#7%
{\def\objectwidth {#4\s!sp}%
\def\objectheight{#5\s!sp}%
\def\objectdepth {#6\s!sp}%
\def\objectmargin{#7\s!sp}}
\def\getobjectdimensions#1#2%
{\let\dohandleobject\dogetobjectdimensions
\let\objectwidth \!!zeropoint
\let\objectheight\!!zeropoint
\let\objectdepth \!!zeropoint
\labelcsname\r!object#1::#2\endcsname}
%D Apart from this kind of objects, that have typeset content,
%D we can have low level driver specific objects. Both types
%D can have references to internal representations, hidden for
%D the user. We keep track of such references by means of a
%D dedicated cross reference mechanism. Normally, objects are
%D defined before they are used, but forward referencing
%D sometimes occurs.
%D
%D \starttyping
%D \dosetobjectreference {class} {identifier} {reference value} {page}
%D \dogetobjectreference {class} {identifier} \csname
%D \stoptyping
%D
%D These commands are to be called by the \type{\startobject},
%D \type{\stopobject} and \type{\insertobject} specials.
\def\objectreferenced{\global\chardef\crossreferenceobject\plusone}
\def\driverreferenced{\global\chardef\crossreferenceobject\zerocount}
\objectreferenced
% no undefined test ! ! ! ! (pdftex fails on undefined objects)
\def\doregisterobjectreference#1#2#3{\normalexpanded{\noexpand\ctxlatelua{jobobjects.save("#1::#2",#3,\noexpand\the\realpageno)}}}
\def\dooverloadobjectreference#1#2#3{\ctxlua{jobobjects.set("#1::#2",#3,\the\realpageno)}}
\def\dosetobjectreference
{\ifcase\crossreferenceobject
\objectreferenced
\expandafter\dooverloadobjectreference
\else
\expandafter\doregisterobjectreference
\fi}
\def\dosetdriverreference
{\driverreferenced\dosetobjectreference}
\def\defaultobjectreference#1#2{0} % driver dependent
\def\defaultobjectpage #1#2{\realfolio}
\def\dogetobjectreference #1#2#3{\xdef#3{\ctxlua{jobobjects.number("#1::#2","\defaultobjectreference{#1}{#2}")}}}
\def\dogetobjectreferencepage#1#2#3{\xdef#3{\ctxlua{jobobjects.page("#1::#2","\defaultobjectpage{#1}{#2}")}}}
\def\setobject {\driverreferenced\dosetobject1}
\def\settightobject{\driverreferenced\dosetobject0}
%D \macros
%D {doifobjectfoundelse,doifobjectreferencefoundelse}
%D
%D To prevent redundant definition of objects, one can use
%D the next tests:
%D
%D \starttyping
%D \doifobjectfoundelse{class}{object}{do then}{do else}
%D \doifobjectreferencefoundelse{class}{object}{do then}{do else}
%D \stoptyping
\def\doifobjectfoundelse#1#2%
{\ifcsname\r!object#1::#2\endcsname
\expandafter\firstoftwoarguments
\else
\expandafter\secondoftwoarguments
\fi}
\def\doifobjectreferencefoundelse#1#2{\ctxlua{jobobjects.doifelse("#1::#2")}}
\protect \endinput
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