summaryrefslogtreecommitdiff
path: root/tex/context/base/mkii/pack-lyr.mkii
diff options
context:
space:
mode:
Diffstat (limited to 'tex/context/base/mkii/pack-lyr.mkii')
-rw-r--r--tex/context/base/mkii/pack-lyr.mkii755
1 files changed, 755 insertions, 0 deletions
diff --git a/tex/context/base/mkii/pack-lyr.mkii b/tex/context/base/mkii/pack-lyr.mkii
new file mode 100644
index 000000000..1b0c0fd63
--- /dev/null
+++ b/tex/context/base/mkii/pack-lyr.mkii
@@ -0,0 +1,755 @@
+%D \module
+%D [ file=pack-lyr,
+%D version=2000.10.20,
+%D title=\CONTEXT\ Packaging Macros,
+%D subtitle=Layers,
+%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 Packaging Macros / Layers}
+
+%D This module is now etex dependent.
+
+% todo : first / last / next / +... => page key
+% test on left/right box when no doublesided option given
+% use \ifcsname instead of doifvalue
+
+\unprotect
+
+% When being backgrounds layers get the background offset
+% displacement. Should be an option, on by default
+% (compatibility).
+
+% positie=forceer == ja maar dan ook in status=herhaal
+
+%D The layering mechanism implemented here is independent of
+%D the output routine, but future extensions may depend on a
+%D more close cooperation.
+
+%D First we overload a macro from \type {core-rul}. From now on
+%D we accept a (optional) argument: the specific layer it
+%D will go in. This means that we can move an overlay from one
+%D background to the other using the dimensions of the parent.
+
+%D ! ! ! ! to be documented ! ! ! !
+
+\ifx\undefined\defineoverlay \message{loaded to early} \wait \fi
+
+\def\defineoverlay
+ {\dotripleempty\dodefineoverlay}
+
+\def\dodefineoverlay[#1][#2][#3]% overlay [layer] content
+ {\ifthirdargument
+ \writestatus{BEWARE}{This (overlay definition) has changed!}% temp
+ \def\docommand##1{\setvalue{\??ov##1}{\setlayer[#2]{\executedefinedoverlay{##1}{#3}}}}
+ \else
+ \def\docommand##1{\setvalue{\??ov##1}{\executedefinedoverlay{##1}{#2}}}%
+ \fi
+ \processcommalist[#1]\docommand}
+
+%D When tracing is turned on, a couple of boxes will
+%D show up as well as the reference point.
+
+\newif\iftracelayers % \tracelayerstrue
+
+%D This handy constant saved some string memory.
+
+\def\@@layerbox{@@layerbox}
+
+%D \macros
+%D {definelayer}
+%D
+%D Each layer gets its own (global) box. This also means that
+%D the data that goes into a layer, is typeset immediately.
+%D Each layer automatically gets an associated overlay,
+%D which can be used in any background assignment.
+
+% todo : links/rechts
+
+\def\definelayer
+ {\dodoubleargument\dodefinelayer}
+
+\def\dodefinelayer[#1][#2]% \zeropoint ipv \!!zeropoint
+ {\setuplayer
+ [#1]
+ [\c!doublesided=,\c!preset=,
+ \c!state=\v!start,\c!direction=\v!normal,\c!option=,
+ \c!x=\zeropoint,\c!y=\zeropoint,\c!position=\v!no,
+ \c!line=0,\c!column=0,
+ \c!width=\nextboxwd,\c!height=\nextboxht,
+ \c!offset=\zeropoint,\c!rotation=, % geen 0 !
+ \c!hoffset=\zeropoint,\c!voffset=\zeropoint,
+ \c!dx=\zeropoint,\c!dy=\zeropoint,
+ \c!location=rb,\c!position=\v!no,\c!page=,
+ \c!method=\v!overlay,
+ \c!sx=1,\c!sy=1,\c!corner=,#2]%
+ \doifvalue{\??ll#1\c!doublesided}\v!yes
+ {\dopresetlayerbox{\v!left #1}%
+ \dopresetlayerbox{\v!right#1}}%
+ \dopresetlayerbox{#1}%
+ \defineoverlay[#1][\composedlayer{#1}]}
+
+\def\dopresetlayerbox#1%
+ {\ifundefined{\@@layerbox#1}%
+ \expandafter\newbox\csname\@@layerbox#1\endcsname
+ \else
+ \resetlayer[#1]%
+ \fi}
+
+%D \macros
+%D {setuplayer}
+%D
+%D After a layer is defined, you can change its
+%D characteristics.
+
+\def\setuplayer
+ {\dodoubleargument\dosetuplayer}
+
+\def\dosetuplayer[#1][#2]%
+ {\def\docommand##1{\getparameters[\??ll##1][#2]}%
+ \processcommalist[#1]\docommand}
+
+%D \macros
+%D {setlayer}
+%D
+%D Data is moved into a layer with the following macro. When
+%D \type {position} is set, relative positioning is used, with
+%D the current point as reference point. Otherwise the topleft
+%D corner is used as reference point.
+%D
+%D \starttyping
+%D \setlayer [identifier] [optional parameters] {data}
+%D \stoptyping
+
+\newcount\currentlayerdata
+
+\let\currentlayerwidth \!!zeropoint
+\let\currentlayerheight\!!zeropoint
+
+\def\setcurrentlayerdimensions
+ {\dodoubleempty\dosetcurrentlayerdimensions}
+
+\def\dosetcurrentlayerdimensions[#1][#2]% name left|right
+ {\edef\currentlayerwidth {\thelayerwidth {#2#1}}%
+ \edef\currentlayerheight{\thelayerheight{#2#1}}}
+
+\def\thelayerwidth #1{\the\wd\executeifdefined{\@@layerbox#1}\emptybox}
+\def\thelayerheight#1{\the\ht\executeifdefined{\@@layerbox#1}\emptybox}
+
+\def\setlayer
+ {\dotripleempty\dosetlayer}
+
+\def\dosetlayer[#1][#2][#3]% #4 == box do \fi is ok
+ {\doifelsevalue{\??ll#1\c!state}\v!stop
+ {\dowithnextbox\donothing\hbox}
+ {\ifthirdargument
+ \dodosetlayer[#1][#2][#3]%
+ \else
+ \doifassignmentelse{#2}
+ {\dodosetlayer[#1][][#2]}%
+ {\dodosetlayer[#1][#2][]}%
+ \fi}}
+
+\def\dodosetlayer[#1][#2][#3]% #2 = links/rechts
+ {\bgroup
+ \recalculatebackgrounds
+ \recalculatelogos
+ \global\advance\currentlayerdata\plusone
+ \forgetall
+ \dontcomplain
+ \doifvalue{\??ll#1\c!option}\v!test\tracelayerstrue
+ \iftracelayers\traceboxplacementtrue\fi
+ \dowithnextbox % sneller als aparte macro
+ {\ifcsname\@@layerbox#1\endcsname % nb: odd/even discard, left/right not
+ \edef\@@layerloc{#2}%
+ \ifx\@@layerloc\v!even
+ \ifodd\realpageno
+ % discard nextbox
+ \else
+ \dododosetlayer[#1][\v!left][#3]%
+ \fi
+ \else\ifx\@@layerloc\v!odd
+ \ifodd\realpageno
+ \dododosetlayer[#1][\v!right][#3]%
+ %\else
+ % discard nextbox
+ \fi
+ \else
+ \dododosetlayer[#1][#2][#3]%
+ \fi\fi
+ \else
+ \writestatus{layer}{unknown layer #1}%
+ \fi
+ \egroup}%
+ \hbox}
+
+\newbox\layerbox
+
+\newdimen\@@layerxsiz
+\newdimen\@@layerysiz
+\newdimen\@@layerxoff
+\newdimen\@@layeryoff
+\newdimen\@@layerxpos
+\newdimen\@@layerypos
+
+\let\lastlayerxpos\!!zeropoint
+\let\lastlayerypos\!!zeropoint
+\let\lastlayerwd \!!zeropoint
+\let\lastlayerht \!!zeropoint
+\let\lastlayerdp \!!zeropoint
+
+% todo left/right
+
+\def\setlastlayerpos#1%
+ {\edef\layerpage{\MPp{lyr:\the\currentlayerdata}}%
+ \xdef\lastlayerxpos{\the\dimexpr-\MPx{lyr:#1:\layerpage}+\MPx{lyr:\the\currentlayerdata}\relax}%
+ \xdef\lastlayerypos{\the\dimexpr \MPy{lyr:#1:\layerpage}-\MPy{lyr:\the\currentlayerdata}\relax}}
+
+\def\definelayerpreset
+ {\dodoubleargument\dodefinelayerpreset}
+
+% \def\dodefinelayerpreset[#1][#2]%
+% {\setvalue{\??ll\??ll#1}{\dopresetlayer{#2}}}
+%
+% more fun: \definelayerpreset[whatever][lefttop]
+
+\def\dodefinelayerpreset[#1][#2]%
+ {\doifassignmentelse{#2}
+ {\setvalue{\??ll\??ll#1}{\dopresetlayer{#2}}}
+ {\setvalue{\??ll\??ll#1}{\getvalue{\??ll\??ll#2}}}}
+
+\def\dopresetlayer#1#2#3% #1=list #2=tag #3=list
+ {\getparameters[\??ll#2][#1,#3]}
+
+\letempty\currentlayer
+
+\def\layerparameter#1{\csname\??ll\currentlayer#1\endcsname}
+
+\newdimen\layerwidth
+\newdimen\layerheight
+
+\chardef\@@lacome=1 % LAyerCOnstructionMEthod / temp, will be default
+
+\def\dododosetlayer[#1][#2][#3]% will be sped up
+ {% we use the global width, never change this
+ \def\currentlayer{#1}%
+ \@@layerxsiz\layerparameter\c!width
+ \@@layerysiz\layerparameter\c!height
+ \layerwidth \@@layerxsiz
+ \layerheight\@@layerysiz
+ % preroll
+ \getparameters[\??ll\currentlayer][#3]%
+ % presets and real roll
+% maybe todo:
+% \doif{\layerparameter\c!method}\v!fit
+% {\@@layerxsiz\thelayerwidth \currentlayer
+% \@@layerysiz\thelayerheight\currentlayer
+% \layerwidth \@@layerxsiz
+% \layerheight\@@layerysiz
+% }%
+ % etc
+ \executeifdefined{\??ll\??ll\layerparameter\c!preset}\gobbletwoarguments\currentlayer{#3}%
+ % that was real slow
+ \doif{\layerparameter\c!position}\v!overlay % slow, use \dosetvalue instead
+ {\getparameters[\??ll\currentlayer][\c!width=\zeropoint,\c!height=\zeropoint,\c!position=\v!yes]}%
+ \doifsomething{\layerparameter\c!rotation}
+ {\setbox\nextbox\hbox
+ {\rotate % to be checked with new rotation
+ [\c!location=\v!high,\c!rotation=\layerparameter\c!rotation]
+ {\flushnextbox}}}%
+ % no, not local
+ % \@@layerxsiz\layerparameter\c!width
+ % \@@layerysiz\layerparameter\c!height
+ % never change that
+ \@@layerxpos\layerparameter\c!x
+ \@@layerypos\layerparameter\c!y
+ \doifelse{\layerparameter\c!hoffset}\v!max
+ {\@@layerxoff\@@layerxsiz}{\@@layerxoff\layerparameter\c!hoffset}%
+ \doifelse{\layerparameter\c!voffset}\v!max
+ {\@@layeryoff\@@layerysiz}{\@@layeryoff\layerparameter\c!voffset}%
+ % dx/dy are internal context ones and can be used in preset
+ \advance\@@layerxoff\dimexpr\layerparameter\c!offset+\layerparameter\c!dx\relax
+ \advance\@@layeryoff\dimexpr\layerparameter\c!offset+\layerparameter\c!dy\relax
+ \@@layerxpos\layerparameter\c!sx\@@layerxpos
+ \@@layerypos\layerparameter\c!sy\@@layerypos
+ \@@layerxoff\layerparameter\c!sx\@@layerxoff
+ \@@layeryoff\layerparameter\c!sy\@@layeryoff
+ \doifelse{\layerparameter\c!position}\v!yes % combine ^
+ {\setlastlayerpos{#2\currentlayer}% todo l/r %%%%%%%%%%%%
+ \@@layerxpos\lastlayerxpos
+ \@@layerypos\lastlayerypos
+ \letgvalue{\??ll\currentlayer\layerpage\c!position}\v!yes
+ \letgvalue{\??ll\currentlayer\c!state}\v!start % needed ?
+ \setbox\layerbox\vbox to \@@layerysiz
+ {\hbox to \@@layerxsiz{\xypos{lyr:\the\currentlayerdata}\hss}\vss}}
+ {\setbox\layerbox\emptybox
+ \globallet\lastlayerxpos\!!zeropoint
+ \globallet\lastlayerypos\!!zeropoint
+ \ExpandBothAfter\doifinset\v!bottom{\layerparameter\c!corner}
+ {\ifnum\layerparameter\c!line=\zerocount\else % can be < 0
+ \setevalue{\??ll\currentlayer\c!line}%
+ {\the\numexpr-\layerparameter\c!line+\layoutlines+\plusone\relax}%
+ \fi
+ \ifdim\@@layerysiz>\zeropoint
+ \advance\@@layerypos-\@@layerysiz
+ \@@layerypos-\@@layerypos
+ \@@layeryoff-\@@layeryoff
+ \fi}%
+ \ExpandBothAfter\doifinset\v!right{\layerparameter\c!corner}
+ {\ifnum\layerparameter\c!column=\zerocount\else % can be < 0
+ \setevalue{\??ll\currentlayer\c!column}%
+ {\the\numexpr-\layerparameter\c!column+\layoutcolumns+\plusone\relax}%
+ \fi
+ \ifdim\@@layerxsiz>\zeropoint
+ \advance\@@layerxpos-\@@layerxsiz
+ \@@layerxpos-\@@layerxpos
+ \@@layerxoff-\@@layerxoff
+ \fi}%
+ \ExpandBothAfter\doif\v!middle{\layerparameter\c!corner}
+ {\ifdim\@@layerxsiz>\zeropoint \advance\@@layerxpos.5\@@layerxsiz \fi
+ \ifdim\@@layerysiz>\zeropoint \advance\@@layerypos.5\@@layerysiz \fi}%
+ \edef\layerpage{\layerparameter\c!page}}%
+ \doifsomething\layerpage
+ {\edef\layerpage{:\layerpage}%
+ \doifundefined{\@@layerbox#2\currentlayer\layerpage}
+ {\global\expandafter\newbox\csname\@@layerbox#2\currentlayer\layerpage\endcsname}}%
+ \dontcomplain % more comfortable
+ \mathchardef\layerpagebox\csname\@@layerbox#2\currentlayer\layerpage\endcsname
+ \ifvoid\layerpagebox
+ \gsetboxllx\layerpagebox\zeropoint
+ \gsetboxlly\layerpagebox\zeropoint
+ \fi
+ \global\setbox\layerpagebox\vbox %to \layerparameter\c!height % new, otherwise no negative y possible
+ {\offinterlineskip
+ %postpone, to after nextboxwd correction % \hsize\layerparameter\c!width % new, keep box small
+ %\ifvoid\csname\@@layerbox\currentlayer\layerpage\endcsname\else % why not #2#1
+ \ifvoid\layerpagebox
+ \let\lastlayerwidth \zeropoint
+ \let\lastlayerheight\zeropoint
+ \else
+ \edef\lastlayerwidth {\the\wd\layerpagebox}%
+ \edef\lastlayerheight{\the\ht\layerpagebox}%
+ \ht\layerpagebox\zeropoint
+ \dp\layerpagebox\zeropoint
+ \wd\layerpagebox\zeropoint
+ \doifnot{\layerparameter\c!direction}\v!reverse{\box\layerpagebox}%
+ \fi
+ % don't move
+ \xdef\lastlayerwd{\the\nextboxwd}%
+ \xdef\lastlayerht{\the\nextboxht}% % not entirely ok when grid !
+ \xdef\lastlayerdp{\the\nextboxdp}% % not entirely ok when grid !
+ % this code
+ \doifelse{\layerparameter\c!location}\v!grid\donetrue\donefalse
+ \ifdone
+ \nextboxht\strutheight
+ \nextboxdp\strutdepth
+ \else
+ \setbox\nextbox\hbox{\alignedbox[\layerparameter\c!location]\vbox{\flushnextbox}}%
+ \fi
+ \ifnum\layerparameter\c!line=\zerocount\else % no \ifcase, can be negative
+ \advance\@@layerypos\dimexpr\layerparameter\c!line\lineheight+\topskip-\lineheight-\nextboxht\relax
+ \fi
+ \ifnum\layerparameter\c!column=\zerocount\else % no \ifcase, can be negative
+ \advance\@@layerxpos\layoutcolumnoffset{\layerparameter\c!column}%
+ \fi
+ \ifdone
+ \setbox\nextbox\hbox{\alignedbox[rb]\vbox{\flushnextbox}}%
+ \fi
+ % ll registration
+ \scratchdimen\@@layerxpos
+ \advance\scratchdimen\@@layerxoff
+ \ifdim\scratchdimen<\getboxllx\layerpagebox
+ \gsetboxllx\layerpagebox\scratchdimen
+ \fi
+ \ifcase\@@lacome\or % this test will become obsolete
+ \advance\scratchdimen\nextboxwd
+ \nextboxwd\ifdim\scratchdimen>\lastlayerwidth \scratchdimen \else \lastlayerwidth \fi
+ \fi
+ \scratchdimen\@@layerypos
+ \advance\scratchdimen\@@layeryoff
+ \ifdim\scratchdimen<\getboxlly\layerpagebox
+ \gsetboxlly\layerpagebox\scratchdimen
+ \fi
+ % ll compensation
+ \ifcase\@@lacome\or % this test will become obsolete
+ \advance\scratchdimen\dimexpr\nextboxht+\nextboxdp\relax
+ \nextboxht\ifdim\scratchdimen>\lastlayerheight \scratchdimen \else \lastlayerheight \fi
+ \nextboxdp\zeropoint
+ \fi
+ % placement
+ \hsize\layerparameter\c!width % new, keep box small
+ \vbox to \layerparameter\c!height \bgroup
+ \smashbox\nextbox
+ \vskip\dimexpr\@@layerypos+\@@layeryoff\relax
+ \hskip\dimexpr\@@layerxpos+\@@layerxoff\relax
+ \flushnextbox
+ \ifvoid\layerpagebox
+ % already flushed
+ \else
+ % the reverse case % check !
+ \vskip-\dimexpr\@@layerypos+\@@layeryoff\relax
+ \box\layerpagebox
+ \fi
+ \egroup}%
+ % when position is true, the layerbox holds the compensation and needs
+ % to be placed; never change this !
+ \ifvoid\layerbox\else\box\layerbox\fi}
+
+%D Given the task to be accomplished, the previous macro is
+%D not even that complicated. It mainly comes down to skipping
+%D to the right place and placing a box on top of or below the
+%D existing content. In the case of position tracking, another
+%D reference point is chosen.
+
+%D \macros
+%D {doifelselayerdata}
+%D
+
+\def\doifelselayerdata#1%
+ {\ifundefined{\@@layerbox#1}%
+ \@EA\secondoftwoarguments
+ \else\ifvoid\csname\@@layerbox#1\endcsname
+ \@EAEAEA\secondoftwoarguments
+ \else
+ \@EAEAEA\firstoftwoarguments
+ \fi\fi}
+
+%D \macros
+%D {flushlayer}
+%D
+%D When we flush a layer, we flush both the main one and the
+%D page dependent one (when defined). This feature is more
+%D efficient in \ETEX\ since there testing for an undefined
+%D macro does not takes hash space.
+
+% todo: setups before flush, handy hook
+
+\unexpanded\def\flushlayer[#1]%
+ {\doifelsevalue{\??ll#1\c!state}\v!next
+ {\global\letvalue{\??ll#1\c!state}\v!start} % dangerous, stack-built-up
+ {\doifelsevalue{\??ll#1\c!state}\v!continue
+ {\global\letvalue{\??ll#1\c!state}\v!repeat} % dangerous, stack-built-up
+ {\doifelsevalue{\??ll#1\c!doublesided}\v!yes
+ {\doifundefinedelse{\@@layerbox#1}%
+ {\dodoflushlayerA[#1]}
+ {\doifbothsidesoverruled
+ {\dodoflushlayerB\v!left [#1]}% left
+ {\dodoflushlayerB\v!right[#1]}% right
+ {\dodoflushlayerB\v!left [#1]}}}% left
+ {\dodoflushlayerA[#1]}}}}
+
+\def\dodoflushlayerA[#1]%
+ {\doifnotvalue{\??ll#1\c!state}\v!stop
+ {\startoverlay
+ {\dodoflushlayer1{#1}{#1}}
+ {\dodoflushlayer0{#1}{#1:\realfolio}}
+ \stopoverlay}}
+
+\def\dodoflushlayerB#1[#2]%
+ {\doifnotvalue{\??ll#2\c!state}\v!stop
+ {\startoverlay
+ {\dodoflushlayer1{#2}{#2}}
+ {\dodoflushlayer0{#2}{#2:\realfolio}}
+ {\dodoflushlayer1{#2}{#1#2}}
+ {\dodoflushlayer0{#2}{#1#2:\realfolio}}
+ \stopoverlay}}
+
+\def\dodoflushlayer#1#2#3%
+ {\ifundefined{\@@layerbox#3}%
+ \ifcase#1\else\writestatus{layer}{unknown layer #3}\fi
+ \else
+ \bgroup
+ \forgetall
+ \offinterlineskip
+ % needed because we need to handle method
+ \executeifdefined{\??ll\??ll\getvalue{\??ll#2\c!preset}}\gobbletwoarguments{#2}{}%
+ %
+ \doifvalue{\??ll#2\c!option}\v!test\tracelayerstrue
+ \iftracelayers\traceboxplacementtrue\fi
+ \!!doneafalse
+ \!!donebfalse
+ \doifvalue{\??ll#2\c!method}\v!overlay\!!doneatrue
+ \doifvalue{\??ll#2\c!method}\v!fit\!!donebtrue
+ \!!donectrue
+ \ifcase#1\else
+ \doifnotvalue{\??ll#2\c!position}\v!yes
+ {\doifvalue{\??ll#2\c!repeat}\v!yes\!!donecfalse
+ \doifvalue{\??ll#2\c!state}\v!repeat\!!donecfalse}%
+ \fi
+ \mathchardef\layerbox\csname\@@layerbox#3\endcsname
+ % we need to copy in order to retain the negative offsets for a next
+ % stage of additions, i.e. llx/lly accumulate in repeat mode and the
+ % compensation may differ each flush depending on added content
+ \setbox\nextbox \if!!doneb
+% \vbox
+% {\scratchdimen\getboxlly\layerbox
+% \vskip-\scratchdimen
+% \scratchdimen\getboxllx\layerbox
+% \hskip-\scratchdimen
+% \advance\scratchdimen-\wd\layerbox
+% \hsize-\scratchdimen
+% \if!!donec\box\else\copy\fi\layerbox}%
+ \vbox
+ {\vskip-\getboxlly\layerbox
+ \hskip-\getboxllx\layerbox
+ \hsize-\dimexpr\getboxllx\layerbox-\wd\layerbox\relax
+ \if!!donec\box\else\copy\fi\layerbox}%
+ \else
+ \if!!donec\box\else\copy\fi\layerbox % sorry for the delay due to copying
+ \fi
+ % todo: method=offset => overlayoffset right/down (handy for backgrounds with offset)
+ \iftracelayers \ruledvbox \else \vbox \fi \if!!donea to \overlayheight \fi
+ {\hbox \if!!donea to \overlaywidth \fi
+ {% klopt dit? #3 en niet #2 ?
+ \doifvalue{\??ll#3\realfolio\c!position}\v!yes{\xypos{lyr:#3:\realfolio}}%
+ \doifoverlayelse{#3}
+ {\box\nextbox}
+ {\startlayoutcomponent{l:#3}{layer #3}\box\nextbox\stoplayoutcomponent}%
+ \hss}%
+ \vss}%
+ \if!!donec
+ \gsetboxllx\layerbox\zeropoint
+ \gsetboxlly\layerbox\zeropoint
+ \fi
+ \egroup
+ \fi}
+
+% \definelayer[test][method=fit] \setupcolors[state=start] \tracelayerstrue
+%
+% \framed[framecolor=red,offset=overlay]{\setlayer[test]{aa}\setlayer[test][x=10pt]{g}\flushlayer[test]}
+% \framed[framecolor=red,offset=overlay]{\setlayer[test]{aa}\setlayer[test][x=-10pt]{bb}\flushlayer[test]}
+% \framed[framecolor=red,offset=overlay]{\setlayer[test][x=-20pt]{cccccc}\flushlayer[test]}
+% \framed[framecolor=red,offset=overlay]{\setlayer[test]{dd}\setlayer[test][x=-20pt,y=-3pt]{eeeeee}\flushlayer[test]}
+
+%D \macros
+%D {composedlayer,placelayer,tightlayer}
+%D
+%D This is a handy shortcut, which saves a couple of braces
+%D when we use it as parameter. This name also suits better
+%D to other layering commands.
+
+\def\composedlayer#1{\flushlayer[#1]}
+
+\let\placelayer\flushlayer
+
+\def\tightlayer[#1]%
+ {\hbox
+ {\def\currentlayer{#1}% todo: left/right
+ \setbox\nextbox\emptybox % hoogte/breedte are \wd\nextbox/\ht\nextbox
+ \hsize\layerparameter\c!width % \overlaywidth = \hsize
+ \vsize\layerparameter\c!height % \overlaywheight = \vsize
+ \composedlayer{#1}}}
+
+%D \macros
+%D {resetlayer}
+%D
+%D This macro hardly needs an explanation (and is seldom
+%D needed as well).
+
+\def\doresetlayer#1%
+ {\ifundefined{\@@layerbox#1}\else
+ \global\setbox\csname\@@layerbox#1\endcsname\emptybox
+ \fi}
+
+\def\resetlayer[#1]%
+ {\doresetlayer{#1}%
+ \doifvalue{\??ll#1\c!doublesided}\v!yes % kind of redundant test
+ {\doresetlayer{\v!left #1}%
+ \doresetlayer{\v!right#1}}%
+ \doresetlayer{#1:\realfolio}}
+
+%D \macros
+%D {setMPlayer}
+%D
+%D The following layer macro uses the positions that are
+%D registered by \METAPOST.
+%D
+%D \starttyping
+%D \definelayer[test]
+%D
+%D \setMPlayer [test] [somepos-1] {Whatever we want here!}
+%D \setMPlayer [test] [somepos-2] {Whatever we need there!}
+%D \setMPlayer [test] [somepos-3] {\externalfigure[cow.mps][width=2cm]}
+%D
+%D \startuseMPgraphic{oeps}
+%D draw fullcircle scaled 10cm withcolor red ;
+%D register ("somepos-1",2cm,3cm,center currentpicture) ;
+%D register ("somepos-2",8cm,5cm,(-1cm,-2cm)) ;
+%D register ("somepos-3",0cm,0cm,(-2cm,2cm)) ;
+%D \stopuseMPgraphic
+%D
+%D \getMPlayer[test]{\useMPgraphic{oeps}}
+%D \stoptyping
+%D
+%D The last line is equivalent to
+%D
+%D \starttyping
+%D \framed
+%D [background={foreground,test},offset=overlay]
+%D {\useMPgraphic{oeps}}
+%D \stoptyping
+
+\def\setMPlayer
+ {\dotripleempty\dosetMPlayer}
+
+\def\MPlayerwidth {\hsize}
+\def\MPlayerheight{\vsize}
+
+\def\dosetMPlayer[#1][#2][#3]%
+ {\checkpositions % new, else only support after \starttext
+ \edef\MPlayerwidth {\MPw{#2}}%
+ \edef\MPlayerheight{\MPh{#2}}%
+ \setlayer[#1][\c!x=\MPx{#2},\c!y=\MPy{#2},\c!position=\v!no,#3]}
+
+\def\getMPlayer
+ {\dodoubleempty\dogetMPlayer}
+
+\def\dogetMPlayer[#1][#2]%
+ {\framed
+ [\c!background={\v!foreground,#1},
+ \c!frame=\v!off,
+ \c!offset=\v!overlay,#2]}
+
+% Some day this (old) mechanism will be combined/integrated
+% in overlays
+
+\newskip\xposition \newskip\yposition
+\newskip\xdimension \newskip\ydimension
+\newskip\xoffset \newskip\yoffset
+
+% already defined \newbox\positionbox
+
+\def\startpositioning
+ {\bgroup
+ \xposition \zeropoint \yposition \zeropoint
+ \xdimension\zeropoint \ydimension\zeropoint
+ \xoffset \zeropoint \yoffset \zeropoint
+ \hfuzz \paperwidth \vfuzz \paperheight
+ \setbox\positionbox\hbox\bgroup}
+
+\def\stoppositioning
+ {\doifnot\@@psoffset\v!yes
+ {\global\xoffset\zeropoint
+ \global\yoffset\zeropoint}%
+ \global\advance\xdimension \xoffset
+ \global\advance\ydimension \yoffset
+ \egroup
+ \vbox to \ydimension
+ {\vskip\yoffset
+ \hbox to \xdimension
+ {\hskip\xoffset
+ \box\positionbox
+ \hfill}
+ \vfill}%
+ \egroup}
+
+\def\resetpositioning
+ {\getparameters[\??ps]
+ [\c!state=\v!start,%
+ \c!unit=\s!cm,%
+ \c!factor=1,%
+ \c!scale=1,%
+ \c!xfactor=\@@psfactor,%
+ \c!yfactor=\@@psfactor,%
+ \c!xscale=\@@psscale,%
+ \c!yscale=\@@psscale,%
+ \c!xstep=\v!absolute,%
+ \c!ystep=\v!absolute,%
+ \c!xoffset=\!!zeropoint,%
+ \c!yoffset=\!!zeropoint]}
+
+\def\setuppositioning
+ {\resetpositioning
+ \dodoubleargument\getparameters[\??ps]}
+
+\def\calculateposition#1#2#3#4#5#6#7#8#9%
+ {\setdimensionwithunit\scratchskip{#1}\@@psunit
+ \scratchskip#8\scratchskip
+ \scratchskip#9\scratchskip
+ \advance\scratchskip #4\relax
+ \doif{#2}\v!relative
+ {\advance\scratchskip #3%
+ \let#4\!!zeropoint}%
+ #3\scratchskip\relax
+ \doifnot\@@psstate\v!overlay
+ {\scratchskip#5\relax
+ \advance\scratchskip #3\relax
+ \ifdim#3<-#7\relax \global#7-#3\relax \fi
+ \ifdim\scratchskip>#6\relax \global#6\scratchskip\relax \fi}}
+
+\def\position
+ {\dosingleempty\doposition}
+
+\def\doposition[#1]#2(#3,#4)%
+ {\dowithnextbox
+ {\bgroup
+ \getparameters[\??ps][#1]%
+ \dontcomplain
+ \calculateposition{#3}\@@psxstep\xposition
+ \@@psxoffset{\nextboxwd}\xdimension\xoffset
+ \@@psxscale\@@psxfactor
+ \scratchdimen\nextboxht \advance\scratchdimen \nextboxdp
+ \calculateposition{#4}\@@psystep\yposition
+ \@@psyoffset\scratchdimen\ydimension\yoffset
+ \@@psyscale\@@psyfactor
+ \vbox to \zeropoint % kan beter.
+ {\vskip\yposition
+ \hbox to \zeropoint
+ {\hskip\xposition
+ \flushnextbox
+ \hss}
+ \vss}%
+ \xdef\dopoppositioning
+ {\xposition\the\xposition
+ \yposition\the\yposition
+ \noexpand\def\noexpand\@@psxoffset{\@@psxoffset}%
+ \noexpand\def\noexpand\@@psyoffset{\@@psyoffset}}%
+ \egroup
+ \dopoppositioning
+ \ignorespaces}
+ \hbox}
+
+\resetpositioning
+
+\setuppositioning
+ [\c!unit=\s!cm,
+ \c!factor=1,
+ \c!scale=1,
+ \c!xstep=\v!absolute,
+ \c!ystep=\v!absolute,
+ \c!offset=\v!yes,
+ \c!xoffset=\!!zeropoint,
+ \c!yoffset=\!!zeropoint]
+
+%D Watch out, a redefinition:
+
+\ifx\settextpagecontent\undefined \writestatus\m!systems{error in page-lyr.tex} \wait \fi
+
+\let\normalsettextpagecontent\settextpagecontent
+
+\definelayer
+ [OTRTEXT]
+
+\setuplayer
+ [OTRTEXT]
+ [\c!width=\innermakeupwidth,
+ \c!height=\textheight]
+
+% will be overloaded in page-spr
+
+\def\settextpagecontent#1#2#3% #2 and #3 will disappear
+ {\doifelselayerdata{OTRTEXT}
+ {\setbox#1\hbox to \makeupwidth
+ {\startoverlay
+ {\tightlayer[OTRTEXT]} % first, otherwise problems with toc
+ {\normalsettextpagecontent{#1}{#2}{#3}\box#1}
+ \stopoverlay}%
+ \dp#1\zeropoint}%
+ {\normalsettextpagecontent{#1}{#2}{#3}}}
+
+\protect \endinput
generated by cgit v1.2.3 (git 2.25.1) at 2024-05-23 16:28:51 +0000