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Diffstat (limited to 'tex/context/base/supp-mps.tex')
| -rw-r--r-- | tex/context/base/supp-mps.tex | 1729 |
1 files changed, 865 insertions, 864 deletions
diff --git a/tex/context/base/supp-mps.tex b/tex/context/base/supp-mps.tex index 95a51991f..d3a0e2115 100644 --- a/tex/context/base/supp-mps.tex +++ b/tex/context/base/supp-mps.tex @@ -1,864 +1,865 @@ -%D \module -%D [ file=supp-mps, -%D version=1997.07.05, -%D title=\CONTEXT\ Support Macros, -%D subtitle=\METAPOST\ Inclusion, -%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. - -% E-tex : a primitive that tells us that \write18 works -% E-tex : \executeMetaPost filename -% ConTeXt : automatic flush at end of job - -% The MP generation support is still experimental. - -%D \METAPOST\ is John Hobbys alternative for \METAFONT\ and -%D produces superior \POSTSCRIPT\ code. In this module we -%D integrate \METAPOST\ support int \CONTEXT. We offer two -%D tracks: -%D -%D \startopsomming -%D \som generating \METAPOST\ code, running this program from -%D within \TEX\ using \type{\write18}, and importing the -%D result -%D \som generating \METAPOST\ code, processing the code -%D afterward, and importing the result in a second pass -%D \stopopsomming -%D -%D The first approach uses a non standard \TEX\ feature, -%D implemented in Web2c. I'm not going to discuss the pros and -%D cons of running programs from within others, but all -%D arguments against this can be overcome by implementing a -%D \TEX\ worthy primitive: -%D -%D \starttypen -%D \excuteMetaPost filename -%D \stoptypen -%D -%D Ok then, let's start: - -\ifx \undefined \writestatus \input supp-mis.tex \relax \fi - -\writestatus{loading}{Context Support Macros / MetaPost Inclusion} - -\unprotect - -%D \macros -%D {startMPgraphic} -%D -%D From within \TEX\ one can execute \METAPOST\ code by putting -%D it between the two commands -%D -%D \starttypen -%D \startMPgraphic -%D \stopMPgraphic -%D \stoptypen -%D -%D This is implemented as: - -\long\def\startMPgraphic#1\stopMPgraphic% - {\startwritingMPgraphic - \writeMPgraphic{#1}% - \stopwritingMPgraphic} - -%D \macros -%D {startMPrun} -%D -%D If we just wat to run \METAPOST\ code, that is, not to -%D explictly generate a figure in terms of \type{beginfig} and -%D \type{endfig}, we can use: -%D -%D \starttypen -%D \startMPgraphic -%D \stopMPgraphic -%D \stoptypen -%D -%D \starttypen -%D \startMPrun -%D \stopMPrun -%D \stoptypen -%D -%D The next boolean is for internal purposes only. - -\newif\ifMPrun \MPrunfalse - -\long\def\startMPrun#1\stopMPrun% geeft nog conflicten met nummer! - {\MPruntrue - \startwritingMPgraphic - \writeMPgraphic{#1}% - \stopwritingMPgraphic - \MPrunfalse} - -%D \macros -%D {startwritingMPgraphic, -%D writeMPgraphic, -%D stopwritingMPgraphic} -%D -%D If the writing process is divided into more steps, one can -%D use the components of this macro directly. -%D -%D \starttypen -%D \startwritingMPgraphic -%D ... -%D \writeMPgraphic{...} -%D ... -%D \writeMPgraphic{...} -%D ... -%D \stopwritingMPgraphic -%D \stoptypen - -%D \macros -%D {ifrunMPgraphics} -%D -%D These macros look a bit more complicated that one would -%D expect at first sight. This is due to the two ways of -%D processing these graphics, mentioned in a previous -%D paragraph. Which method is used, the direct or indirect -%D one, depends on a boolean. - -\newif\ifrunMPgraphics - -%D If set to true, one can do with a single pass, else one must -%D process the \METAPOST\ file \type{mpgraph} between two -%D succesive \TEX\ runs. - -\def\MPgraphicfile{mpgraph} - -%D \macros -%D {MPgraphic} -%D -%D When we run \METAPOST\ from within \TEX, each graphic is -%D processed at once, which means that we reuse this file many -%D times. When however the execution is delayed, all graphics -%D are saved in a separate figure. The current graphic is -%D characterized bij a \COUNTER. This counter is available -%D in \type{\MPgraphic}. - -\newcount\currentMPgraphic - -\def\MPgraphic{0} - -%D \macros -%D {ifreuseMPgraphics} -%D -%D If one want to reuse grapics, one can save much redundant -%D run time by setting the next switch to true. - -\newif\ifreuseMPgraphics - -%D The three macros responsible for writing the graphic -%D implement both schemes. - -%D \macros -%D {MPinclusions, startMPinclusions} -%D -%D One can include for instance common input commands by -%D passing them to \type{\MPinclusions}: -%D -%D \starttypen -%D \MPinclusions{input tools} -%D \stoptypen - -\let\theMPinclusions=\empty - -\long\def\startMPinclusions#1\stopMPinclusions% - {\long\def\theMPinclusions{\writeMPgraphic{#1}}} - -\long\def\MPinclusions#1% - {\startMPinclusions#1\stopMPinclusions} - -%D \macros -%D {iflongMPlines} -%D -%D When grabbing a graphic deifnition, newlines are turned -%D into spaces. By default we split the graphic definition -%D at the colon, but long lines are still possible by -%D setting the next boolean to true. - -\newif\iflongMPlines - -\long\def\writeMPgraphic#1% - {\bgroup - \iflongMPlines - \let\par=\empty - \long\def\flush##1##2\par% - {\ifx##1\relax \else - \immediate\write\scratchwrite{##1##2}% - \expandafter\flush - \fi}% - \flush#1\empty\par\relax\par - \else - \long\def\flush##1##2;% - {\ifx##1\relax \else - \dowriteMPgraphicline##1##2btex\relax etex\end - \expandafter\flush - \fi}% - \flush#1\empty;\relax;% - \fi - \egroup} - -%D The \type{;} aware method (the \type{\else} branch) also -%D takes care of \type{btex}||\type{etex} bound data. - -\def\dowriteMPgraphicline% - {\futurelet\next\dodowriteMPgraphicline} - -\long\def\dodowriteMPgraphicline#1btex#2#3etex#4\end% - {\ifx\next\empty\else\ifx\next\relax\else - \bgroup - \let\par=\empty - \ifx#2\relax - \immediate\write\scratchwrite{#1;}% - \egroup - \else - \convertargument#2#3\to\ascii - \immediate\write\scratchwrite{#1btex \ascii etex;}% - \egroup - \dowriteMPgraphicline#4btex\relax etex\end - \fi - \fi\fi} - -%D This stripper is suboptimal in the sense that more -%D \type{;}'s are output than feasible. Anyhow, \METAPOST\ -%D can handle this and users may consider it being a sort -%D of error prevention bonus. - -\def\writeMPgraph% - {\immediate\write\scratchwrite{mpgraph:=\the\currentMPgraphic;}} - -\def\startwritingMPgraphic% - {\ifrunMPgraphics - \ifMPrun \else \ifreuseMPgraphics \else - \global\currentMPgraphic=0 - \fi \fi - \global\advance\currentMPgraphic by 1 - \xdef\MPgraphic{\the\currentMPgraphic}% - \immediate\openout\scratchwrite=\MPgraphicfile.mp - \writeMPgraph - \theMPinclusions - \else - \global\advance\currentMPgraphic by 1 - \xdef\MPgraphic{\the\currentMPgraphic}% - \ifnum\currentMPgraphic=1 - \immediate\openout\scratchwrite=\MPgraphicfile.mp - \writeMPgraph - \theMPinclusions - \fi - \fi - \ifMPrun \else - \immediate\write\scratchwrite{beginfig(\the\currentMPgraphic);}% - \fi - \global\let\flushMPgraphics\dodostopwritingMPgraphic - \global\let\stopwritingMPgraphic=\dostopwritingMPgraphic} - -\def\dostopwritingMPgraphic% - {\ifMPrun \else - \immediate\write\scratchwrite{endfig;}% - \fi - \ifrunMPgraphics - \dodostopwritingMPgraphic - \fi} - -\def\dodostopwritingMPgraphic% - {\ifnum\currentMPgraphic>0 - \immediate\write\scratchwrite{end.}% - \immediate\closeout\scratchwrite - \runMPgraphic{\MPgraphicfile}% - \fi - \global\let\flushMPgraphics=\relax} - -\let\stopwritingMPgraphic=\relax -\let\flushMPgraphics =\relax - -%D \macros -%D {flushMPgraphics} -%D -%D When we use the indirect method, all graphics are saved in -%D one file. This means that we cannot close this file after -%D every \type{\stopMPgraphic}. Therefore we need to say: -%D -%D \starttypen -%D \flushMPgraphic -%D \stoptypen -%D -%D else the file is closed without writing the \METAPOST\ end -%D command. One will notice this fast enough when in indirect -%D mode. When using the direct mode this command is not -%D implicitly needed, but ommiting it makes files less -%D portable. - -%D \macros -%D {loadcurrentMPgraphic, -%D placeMPgraphic} -%D -%D Once defined, we can call for this graphic by saying: -%D -%D \starttypen -%D \loadcurrentMPgraphic{setups} -%D \placeMPgraphic -%D \stoptypen -%D -%D This two stage insert permits some intermediate manipulations -%D of the graphic, which temporary saved in: - -\newbox\MPgraphicbox - -\def\loadcurrentMPgraphic#1% - {\loadMPgraphic{\MPgraphicfile.\the\currentMPgraphic}{#1}} - -\def\loadMPgraphic#1#2% - {\setbox\MPgraphicbox=\hbox{\insertMPfile{#1}{#2}}} - -\def\placeMPgraphic% - {\box\MPgraphicbox} - -%D \macros -%D {startreusableMPgraphic, reuseMPgraphic, useMPbox} -%D -%D One can use the next macro for defining graphics that are -%D to be reused. When the next switch is set, graphics are -%D cached. - -\newif\ifuseMPbox % nog eens cyclische buffer - -\def\douseMPbox#1% - {\setobject{#1} - \vbox - {\loadMPgraphic{\MPgraphicfile.\the\currentMPgraphic}{}% - \placeMPgraphic}% - \setgvalue{#1}% - {\getobject{#1}}} - -\def\nouseMPbox#1% - {\setxvalue{#1}% - {\noexpand\loadMPgraphic{\MPgraphicfile.\the\currentMPgraphic}{}% - \noexpand\placeMPgraphic}} - -\ifCONTEXT \else \let\douseMPbox=\nouseMPbox \fi - -\long\def\startreusableMPgraphic#1#2\stopreusableMPgraphic% - {\reuseMPgraphicstrue - \doifundefined{MP:#1} - {\startMPgraphic#2\stopMPgraphic - \ifuseMPbox - \douseMPbox{MP:#1}% - \else - \nouseMPbox{MP:#1}% - \fi}} - -\def\reuseMPgraphic#1% - {\getvalue{MP:#1}} - -%D \macros -%D {startuseMPgraphic,useMPgraphic} -%D -%D The every||time||it's||used original one is defined below. -%D This one makes sense when the graphic uses random numbers. - -\long\def\startuseMPgraphic#1#2\stopuseMPgraphic% - {\reuseMPgraphicstrue - \long\setgvalue{MP:#1}% - {\startMPgraphic#2\stopMPgraphic - \loadcurrentMPgraphic{}% - \placeMPgraphic}} - -\let\useMPgraphic=\reuseMPgraphic - -%D We didn't yet define the macro responsible for processing -%D the graphic from within \TEX. - -\def\runMPgraphic#1% - {\ifrunMPgraphics - \executeMETAPOST{#1}% - \else - \message{[flush and process \MPgraphicfile.mp afterwards]}% - \fi} - -%D \macros -%D {executeMetaPost, executeMETAPOST, executesystemcommand} -%D -%D With \type{\executeMETAPOST} being defined as: - -\ifx\undefined\executeMetaPost - \def\executeMETAPOST#1{\executesystemcommand{\executeMetaPost{#1}}} -\fi - -%D There are two system dependant definitions: - -\ifx\undefined\executesystemcommand - \def\executesystemcommand#1{\immediate\write18{#1}} -\fi - -\ifx\undefined\executeMetaPost - \def\executeMetaPost#1{mpost #1} -\fi - -%D \macros -%D {insertMPfile} -%D -%D One can define this command in advance or redefine it after -%D loading this module. The same goes for the forward -%D reference to the figure loading macro: - -\ifx\undefined\insertMPfile - - \def\insertMPfile#1#2% - {\ifx\undefined\externalfigure - \message{[insert file #1 here]}% - \else - \externalfigure[#1][\c!type=eps,\c!methode=mps,#2]% - \fi} - -\fi - -%D This macro takes {\em two} arguments, the second one can be -%D used to pass info to the inclusion macro. Some examples -%D of its use can be found in the modules \type{supp-tpi} and -%D \type{prag-log}. - -%D This module can be used in \PLAIN\ \TEX too. When using -%D \DVIPS, just try to process: -%D -%D \starttypen -%D \input supp-mps -%D -%D \runMPgraphicstrue -%D -%D \def\insertMPfile#1#2% -%D {\special{psfile=#1}} -%D -%D \startuseMPgraphic{1} -%D prologues := 1; -%D draw (0,0) withpen pencircle scaled 100; -%D \stopuseMPgraphic -%D -%D \useMPgraphic{1} -%D \stoptypen -%D -%D Don't forget to enable \type{\write18}. When does not say -%D \type{\runMPgraphicstrue}, the \METAPOST\ scratch file -%D must be closed by saying -%D -%D \starttypen -%D \flushMPgraphics -%D \stoptypen -%D -%D When using the indirect method, one has to process the file -%D \type{mpgraph.mp} between two successive \TEX\ runs. - -%D For some reason, \METAPOST\ needs the public domain \DVI\ to -%D \POSTSCRIPT\ converter \DVIPS. This symbiosis originates in -%D the need to include the fonts (glyphs) that \METAPOST\ uses -%D in the \POSTSCRIPT\ file. Driver independancy was one of my -%D prerequisites for using \METAPOST, so I decided to build -%D this kind of support myself. Personally I consider driver -%D dependancy a drawback for the dissemination of such a -%D package. The second part of this module more or less -%D decouples \METAPOST\ and \DVIPS. -%D -%D The macros hereafter are copied from the module -%D \type{m-metapost}. After writing module \type{supp-pdf} I -%D added this method to the module named and after a while -%D decided to hook it into module \type{spec-yy}. Therefore -%D they made it into a support module, but in a slightly -%D different way. - -%D \macros -%D {includeMPfonts, ifincludeMPfonts} -%D {} -%D -%D The method we use is both robust and simple: one can do -%D with calling the next macro with the filename as argument: -%D -%D \starttypen -%D \includeMPfonts{filename} -%D \stoptypen -%D -%D We can turn of this mechanism with: -%D -%D \starttypen -%D \includeMPfontsfalse -%D \stoptypen - -\newif\ifincludeMPfonts \includeMPfontstrue - -\def\includeMPfonts#1% - {\ifincludeMPfonts - \bgroup - \message{[MP fonts #1]}% - %\uncatcodespecials - \endlinechar=-1 - \setMPspecials - \obeyMPspecials - \setbox0=\hbox - {\hskip-\maxdimen - \doprocessfile\scratchread{#1}\handleMPfont}% - \smashbox0 - \box0 - \egroup - \fi} - -\def\UseMetaPostGraphic {\includeMPfonts} % upward compatible -\def\DontUseMetaPostGraphics {\includeMPfontsfalse} % upward compatible - -%D The characters are collected in a box and moved as far as -%D possible into the left margin. The resulting box has no -%D dimensions and can be prepended (appended) to the special -%D that handles the inclusion. The characters are in the file -%D but made invisible. - -%D We scan the graphics file for the \type{fshow} operator, -%D that is, lines that start with \type{(}. If found it -%D interprets the line, which looks like: -%D -%D \starttypen -%D (string ... string) font size fshow -%D \stoptypen -%D -%D Font definitions specified in the preamble are simply -%D ignored. Only lines starting with \type{(} are interpreted. - -\def\dohandleMPfont#1#2\relax% - {\if#1(% - \expandafter\includeMPcharacters\fileline\relax - \fi} - -\def\handleMPfont% - {\expandafter\dohandleMPfont\fileline\relax} - -%D Before we start scanning for data, we first change some -%D \CATCODES. The first set of macro's is copied from module -%D \type{supp-pdf}. This scheme is a bit overdone for this -%D module, but using the same macros saves us some memory. - -\def\octalMPcharacter#1#2#3% - {\char'#1#2#3\relax} - -\bgroup -\catcode`\|=\@@comment -\catcode`\%=\@@active -\catcode`\[=\@@active -\catcode`\]=\@@active -\catcode`\{=\@@active -\catcode`\}=\@@active -\catcode`B=\@@begingroup -\catcode`E=\@@endgroup -\gdef\ignoreMPspecials| - B\def%BE| - \def[BE| - \def]BE| - \def{BE| - \def}BEE -\gdef\obeyMPspecials| - B\def%B\char 37\relax E| - \def[B\char 91\relax E| - \def]B\char 93\relax E| - \def{B\char123\relax E| - \def}B\char125\relax EE -\gdef\setMPspecials| - B\catcode`\%=\@@active - \catcode`\[=\@@active - \catcode`\]=\@@active - \catcode`\{=\@@active - \catcode`\}=\@@active - \catcode`\$=\@@letter - \catcode`\_=\@@letter - \catcode`\#=\@@letter - \catcode`\^=\@@letter - \catcode`\&=\@@letter - \catcode`\|=\@@letter - \catcode`\~=\@@letter - \def\(B\char40\relax E| - \def\)B\char41\relax E| - \def\\B\char92\relax E| - \def\0B\octalMPcharacter0E| - \def\1B\octalMPcharacter1E| - \def\2B\octalMPcharacter2E| - \def\3B\octalMPcharacter3E| - \def\4B\octalMPcharacter4E| - \def\5B\octalMPcharacter5E| - \def\6B\octalMPcharacter6E| - \def\7B\octalMPcharacter7E| - \def\8B\octalMPcharacter8E| - \def\9B\octalMPcharacter9EE -\egroup - -%D The lines starting with \type{(} are interpreted and -%D handled by - -\def\includeMPcharacters(#1) #2 #3 #4\relax% - {\font\temp=#2 at #3bp\temp#1} - -%D This method is both robust and reasonable fast. The only -%D disadvantage is that when not embedded properly in the -%D graphics inclusion macros, one has to load all graphics by -%D hand. - -%D Now let's see if things work all right and show the example -%D files that are part of the \METAPOST\ distribution: -%D -%D \startregelcorrectie -%D \steluitlijnenin[midden] -%D \leavevmode -%D \startcombinatie[3*3] -%D {\externfiguur[mp-exa-1][methode=mps,kader=aan,breedte=.2\hsize]} {} -%D {\externfiguur[mp-exa-2][methode=mps,kader=aan,breedte=.2\hsize]} {} -%D {\externfiguur[mp-exa-3][methode=mps,kader=aan,breedte=.2\hsize]} {} -%D {\externfiguur[mp-exa-4][methode=mps,kader=aan,breedte=.2\hsize]} {} -%D {\externfiguur[mp-exa-5][methode=mps,kader=aan,breedte=.2\hsize]} {} -%D {\externfiguur[mp-exa-6][methode=mps,kader=aan,breedte=.2\hsize]} {} -%D {\externfiguur[mp-exa-7][methode=mps,kader=aan,breedte=.2\hsize]} {} -%D {\externfiguur[mp-exa-8][methode=mps,kader=aan,breedte=.2\hsize]} {} -%D {\externfiguur[mp-exa-9][methode=mps,kader=aan,breedte=.2\hsize]} {} -%D \stopcombinatie -%D \stopregelcorrectie -%D -%D Here we used calls like: -%D -%D \starttypen -%D \externfiguur[mp-exa-1][methode-mps,kader=aan,breedte=.2\hsize] -%D \stoptypen - -%D \macros -%D {convertMPcolors, -%D ifconvertMPcolors,ifreduceMPcolors,ifforceMPcolors} -%D -%D When I told the editors that I wanted to use colored -%D \METAPOST\ graphics in the color issue of the \MAPS, I was -%D asked to use the \kap{CMYK} colorspace instead of \kap{RGB} -%D one. However, \METAPOST\ only supports \kap{RGB} colors. I -%D decided to write a utility to convert the \type -%D {setrgbcolor} operators into \type {setcmykcolor} ones, and -%D some experiments showed me that I could best let \TEX\ do it -%D itself. Here it is: -%D -%D There are two booleans that control the conversion process. -%D These are false by default. - -\newif\ifconvertMPcolors -\newif\ifreduceMPcolors -\newif\ifforcegrayMPcolors - -%D The main macro is calles as: -%D -%D \starttypen -%D \convertMPcolors{filename} -%D \stoptypen -%D -%D When active, this macro returns a message saying if indeed -%D conversion took place. The old file is overwritten! This -%D saves time in a succesive passes and can't harm, simply -%D because MP can generate them anew. - -\def\convertMPcolorpath{} % {./} -\def\convertMPcolorfile{metacmyk.eps} - -\def\convertMPcolors#1% - {\bgroup - \ifforcegrayMPcolors - \donetrue - \else\ifconvertMPcolors - \donetrue - \else - \donefalse - \fi\fi - \ifdone - \message{[MP color conversion #1}% - \endlinechar=-1 - \uncatcodespecials - \donefalse - \immediate\openout\scratchwrite=\convertMPcolorpath\convertMPcolorfile - \doprocessfile\scratchread{#1}\handleMPcolor - \immediate\closeout\scratchwrite - \ifdone - \immediate\openout\scratchwrite=\convertMPcolorpath#1 - \doprocessfile\scratchread{\convertMPcolorpath \convertMPcolorfile}\handleMPcopy - \immediate\closeout\scratchwrite - \message{done]}% - \else - \message{not needed]}% - \fi - \immediate\openout\scratchwrite=\convertMPcolorpath\convertMPcolorfile - \immediate\closeout\scratchwrite - \fi - \egroup} - -%D The process is rather simple: read a line, look for the -%D \type {setrgbcolor} operator, recalculate the components and -%D check for gray reduction or black removal, write the result -%D to a temporary file, and go on. Afterwards, the file is -%D copied back. We don't have to reduce to gray scales; -%D \METAPOST\ already takes care of that. - -\def\handleMPcolor - {\expandafter\dohandleMPcolor\fileline setrgbcolor*\\} - -\def\dohandleMPcolor#1setrgbcolor#2#3\\% - {\if#2*% - \immediate\write\scratchwrite{#1}% - \else - \dodohandleMPcolor#1setrgbcolor#2#3\\% - \fi} - -\def\dodohandleMPcolor#1 #2 #3setrgbcolor#4setrgbcolor*\\% - {\bgroup - \ifforcegrayMPcolors - \convertRGBtoGRAY{#1}{#2}{#3}% - \immediate\write\scratchwrite - {\@@cl@@s \space setgray #4}% - \else - \dimen0=1pt \advance\dimen0 by -#1pt - \dimen2=1pt \advance\dimen2 by -#2pt - \dimen4=1pt \advance\dimen4 by -#3pt - \ifreduceMPcolors - \dimen6=\dimen0 - \ifdim\dimen2<\dimen6 \dimen6=\dimen2 \fi - \ifdim\dimen4<\dimen6 \dimen6=\dimen4 \fi - \advance\dimen0 by -\dimen6 - \advance\dimen2 by -\dimen6 - \advance\dimen4 by -\dimen6 - \else - \dimen6=\!!zeropoint - \fi - \immediate\write\scratchwrite - {\withoutpt{\the\dimen0} \space - \withoutpt{\the\dimen2} \space - \withoutpt{\the\dimen4} \space - \withoutpt{\the\dimen6} \space setcmykcolor #4}% - \fi - \egroup - \donetrue} % needed for message - -\def\handleMPcopy% - {\immediate\write\scratchwrite{\fileline}} - -%D The next macro is needed for forced conversion. This macro -%D is copied from \type{colo-ini}, just in case one uses this -%D module outside \CONTEXT. - -\ifx\convertRGBtoGRAY\undefined - - \def\convertRGBtoGRAY#1#2#3% - {\scratchdimen=#1\s!pt - \scratchdimen=300\scratchdimen - \scratchcounter=\scratchdimen - \scratchdimen=#2\s!pt - \scratchdimen=590\scratchdimen - \advance\scratchcounter by \scratchdimen - \scratchdimen=#3\s!pt - \scratchdimen=110\scratchdimen - \advance\scratchcounter by \scratchdimen - \advance\scratchcounter by \!!medcard - \divide\scratchcounter by \!!maxcard - \edef\@@cl@@s{\realcolorvalue\scratchcounter}} - -\fi - -%D The next examples show the color conversion macros in -%D action. These examples also demonstrate in||text \METAPOST\ -%D handling. As we will see, the conversion is hooked into the -%D \CONTEXT\ color mechanism. -%D -%D By setting both \type{rgb} and \type{cmyk} to off, we force -%D conversion to gray scales using: -%D -%D \plaatsformule[-] -%D \startformule -%D G = .30r + .59g + .11b -%D \stopformule -%D -%D By using buffers, we keep the \ASCII\ layout clean: -%D -%D \startbuffer -%D \startbuffer[rgb] -%D \stelkleurenin[rgb=ja,cmyk=nee,reductie=nee,conversie=nee] -%D \useMPgraphic{hans} -%D \stopbuffer -%D -%D \startbuffer[cmyk] -%D \stelkleurenin[rgb=nee,cmyk=ja,reductie=nee,conversie=nee] -%D \useMPgraphic{hans} -%D \stopbuffer -%D -%D \startbuffer[cmy] -%D \stelkleurenin[rgb=nee,cmyk=ja,reductie=ja,conversie=nee] -%D \useMPgraphic{hans} -%D \stopbuffer -%D -%D \startbuffer[gray] -%D \stelkleurenin[rgb=nee,cmyk=nee,reductie=nee,conversie=nee] -%D \useMPgraphic{hans} -%D \stopbuffer -%D \stopbuffer -%D -%D \typebuffer -%D \haalbuffer -%D -%D The graphic is rather simple and is generated each time -%D it's called: -%D -%D \global\runMPgraphicstrue -%D -%D \startbuffer -%D \startbuffer[graphic] -%D \startuseMPgraphic{hans} -%D width :=\the\tekstbreedte/5; -%D height := width/4; -%D fill fullcircle -%D xscaled width -%D yscaled height -%D withcolor (\RedGreenBlue); -%D \stopuseMPgraphic -%D \stopbuffer -%D \stopbuffer -%D -%D \typebuffer -%D \haalbuffer -%D -%D Next we combine the four alternative interpretations in a -%D combination: -%D -%D \startbuffer -%D \startbuffer[result] -%D \startcombinatie[4] -%D {\haalbuffer[rgb]} {\tfxx original} -%D {\haalbuffer[cmyk]} {\ttxx\string\convertMPcolorstrue} -%D {\haalbuffer[cmy]} {\ttxx\string\reduceMPcolorstrue} -%D {\haalbuffer[gray]} {\ttxx\string\forcegrayMPcolorstrue} -%D \stopcombinatie -%D \stopbuffer -%D \stopbuffer -%D -%D \typebuffer -%D \haalbuffer -%D -%D Finally we call the buffers, using different setting: -%D -%D \startbuffer -%D \plaatsfiguur -%D {\METAPOST\ color conversions} -%D {\def\RedGreenBlue{.1,.4,.6}\haalbuffer[graphic]\haalbuffer[result]\vskip6pt -%D \def\RedGreenBlue{.1,.6,.4}\haalbuffer[graphic]\haalbuffer[result]\vskip6pt -%D \def\RedGreenBlue{.4,.1,.6}\haalbuffer[graphic]\haalbuffer[result]\vskip6pt -%D \def\RedGreenBlue{.4,.6,.1}\haalbuffer[graphic]\haalbuffer[result]\vskip6pt -%D \def\RedGreenBlue{.6,.1,.4}\haalbuffer[graphic]\haalbuffer[result]\vskip6pt -%D \def\RedGreenBlue{.6,.4,.1}\haalbuffer[graphic]\haalbuffer[result]} -%D \stopbuffer -%D -%D \typebuffer -%D \haalbuffer -%D -%D By the way, when the \POSTSCRIPT\ file resulting from -%D this input is converted into \PDF\ and viewed in Acrobat -%D Reader, one can quite different colors from those -%D displayed in \GHOSTSCRIPT, which view equals the -%D \POSTSCRIPT\ originals. - -\protect - -\endinput +%D \module
+%D [ file=supp-mps,
+%D version=1997.07.05,
+%D title=\CONTEXT\ Support Macros,
+%D subtitle=\METAPOST\ Inclusion,
+%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.
+
+% E-tex : a primitive that tells us that \write18 works
+% E-tex : \executeMetaPost filename
+% ConTeXt : automatic flush at end of job
+
+% The MP generation support is still experimental.
+
+%D \METAPOST\ is John Hobbys alternative for \METAFONT\ and
+%D produces superior \POSTSCRIPT\ code. In this module we
+%D integrate \METAPOST\ support int \CONTEXT. We offer two
+%D tracks:
+%D
+%D \startopsomming
+%D \som generating \METAPOST\ code, running this program from
+%D within \TEX\ using \type{\write18}, and importing the
+%D result
+%D \som generating \METAPOST\ code, processing the code
+%D afterward, and importing the result in a second pass
+%D \stopopsomming
+%D
+%D The first approach uses a non standard \TEX\ feature,
+%D implemented in Web2c. I'm not going to discuss the pros and
+%D cons of running programs from within others, but all
+%D arguments against this can be overcome by implementing a
+%D \TEX\ worthy primitive:
+%D
+%D \starttypen
+%D \excuteMetaPost filename
+%D \stoptypen
+%D
+%D Ok then, let's start:
+
+\ifx \undefined \writestatus \input supp-mis.tex \relax \fi
+
+\writestatus{loading}{Context Support Macros / MetaPost Inclusion}
+
+\unprotect
+
+%D \macros
+%D {startMPgraphic}
+%D
+%D From within \TEX\ one can execute \METAPOST\ code by putting
+%D it between the two commands
+%D
+%D \starttypen
+%D \startMPgraphic
+%D \stopMPgraphic
+%D \stoptypen
+%D
+%D This is implemented as:
+
+\long\def\startMPgraphic#1\stopMPgraphic%
+ {\startwritingMPgraphic
+ \writeMPgraphic{#1}%
+ \stopwritingMPgraphic}
+
+%D \macros
+%D {startMPrun}
+%D
+%D If we just wat to run \METAPOST\ code, that is, not to
+%D explictly generate a figure in terms of \type{beginfig} and
+%D \type{endfig}, we can use:
+%D
+%D \starttypen
+%D \startMPgraphic
+%D \stopMPgraphic
+%D \stoptypen
+%D
+%D \starttypen
+%D \startMPrun
+%D \stopMPrun
+%D \stoptypen
+%D
+%D The next boolean is for internal purposes only.
+
+\newif\ifMPrun \MPrunfalse
+
+\long\def\startMPrun#1\stopMPrun% geeft nog conflicten met nummer!
+ {\MPruntrue
+ \startwritingMPgraphic
+ \writeMPgraphic{#1}%
+ \stopwritingMPgraphic
+ \MPrunfalse}
+
+%D \macros
+%D {startwritingMPgraphic,
+%D writeMPgraphic,
+%D stopwritingMPgraphic}
+%D
+%D If the writing process is divided into more steps, one can
+%D use the components of this macro directly.
+%D
+%D \starttypen
+%D \startwritingMPgraphic
+%D ...
+%D \writeMPgraphic{...}
+%D ...
+%D \writeMPgraphic{...}
+%D ...
+%D \stopwritingMPgraphic
+%D \stoptypen
+
+%D \macros
+%D {ifrunMPgraphics}
+%D
+%D These macros look a bit more complicated that one would
+%D expect at first sight. This is due to the two ways of
+%D processing these graphics, mentioned in a previous
+%D paragraph. Which method is used, the direct or indirect
+%D one, depends on a boolean.
+
+\newif\ifrunMPgraphics
+
+%D If set to true, one can do with a single pass, else one must
+%D process the \METAPOST\ file \type{mpgraph} between two
+%D succesive \TEX\ runs.
+
+\def\MPgraphicfile{mpgraph}
+
+%D \macros
+%D {MPgraphic}
+%D
+%D When we run \METAPOST\ from within \TEX, each graphic is
+%D processed at once, which means that we reuse this file many
+%D times. When however the execution is delayed, all graphics
+%D are saved in a separate figure. The current graphic is
+%D characterized bij a \COUNTER. This counter is available
+%D in \type{\MPgraphic}.
+
+\newcount\currentMPgraphic
+
+\def\MPgraphic{0}
+
+%D \macros
+%D {ifreuseMPgraphics}
+%D
+%D If one want to reuse grapics, one can save much redundant
+%D run time by setting the next switch to true.
+
+\newif\ifreuseMPgraphics
+
+%D The three macros responsible for writing the graphic
+%D implement both schemes.
+
+%D \macros
+%D {MPinclusions, startMPinclusions}
+%D
+%D One can include for instance common input commands by
+%D passing them to \type{\MPinclusions}:
+%D
+%D \starttypen
+%D \MPinclusions{input tools}
+%D \stoptypen
+
+\let\theMPinclusions=\empty
+
+\long\def\startMPinclusions#1\stopMPinclusions%
+ {\long\def\theMPinclusions{\writeMPgraphic{#1}}}
+
+\long\def\MPinclusions#1%
+ {\startMPinclusions#1\stopMPinclusions}
+
+%D \macros
+%D {iflongMPlines}
+%D
+%D When grabbing a graphic deifnition, newlines are turned
+%D into spaces. By default we split the graphic definition
+%D at the colon, but long lines are still possible by
+%D setting the next boolean to true.
+
+\newif\iflongMPlines
+
+\long\def\writeMPgraphic#1%
+ {\bgroup
+ \iflongMPlines
+ \let\par=\empty
+ \long\def\flush##1##2\par%
+ {\ifx##1\relax \else
+ \immediate\write\scratchwrite{##1##2}%
+ \expandafter\flush
+ \fi}%
+ \flush#1\empty\par\relax\par
+ \else
+ \long\def\flush##1##2;%
+ {\ifx##1\relax \else
+ \dowriteMPgraphicline##1##2btex\relax etex\end
+ \expandafter\flush
+ \fi}%
+ \flush#1\empty;\relax;%
+ \fi
+ \egroup}
+
+%D The \type{;} aware method (the \type{\else} branch) also
+%D takes care of \type{btex}||\type{etex} bound data.
+
+\def\dowriteMPgraphicline%
+ {\futurelet\next\dodowriteMPgraphicline}
+
+\long\def\dodowriteMPgraphicline#1btex#2#3etex#4\end%
+ {\ifx\next\empty\else\ifx\next\relax\else
+ \bgroup
+ \let\par=\empty
+ \ifx#2\relax
+ \immediate\write\scratchwrite{#1;}%
+ \egroup
+ \else
+ \convertargument#2#3\to\ascii
+ \immediate\write\scratchwrite{#1btex \ascii etex;}%
+ \egroup
+ \dowriteMPgraphicline#4btex\relax etex\end
+ \fi
+ \fi\fi}
+
+%D This stripper is suboptimal in the sense that more
+%D \type{;}'s are output than feasible. Anyhow, \METAPOST\
+%D can handle this and users may consider it being a sort
+%D of error prevention bonus.
+
+\def\writeMPgraph%
+ {\immediate\write\scratchwrite{mpgraph:=\the\currentMPgraphic;}}
+
+\def\startwritingMPgraphic%
+ {\ifrunMPgraphics
+ \ifMPrun \else \ifreuseMPgraphics \else
+ \global\currentMPgraphic=0
+ \fi \fi
+ \global\advance\currentMPgraphic by 1
+ \xdef\MPgraphic{\the\currentMPgraphic}%
+ \immediate\openout\scratchwrite=\MPgraphicfile.mp
+ \writeMPgraph
+ \theMPinclusions
+ \else
+ \global\advance\currentMPgraphic by 1
+ \xdef\MPgraphic{\the\currentMPgraphic}%
+ \ifnum\currentMPgraphic=1
+ \immediate\openout\scratchwrite=\MPgraphicfile.mp
+ \writeMPgraph
+ \theMPinclusions
+ \fi
+ \fi
+ \ifMPrun \else
+ \immediate\write\scratchwrite{beginfig(\the\currentMPgraphic);}%
+ \fi
+ \global\let\flushMPgraphics\dodostopwritingMPgraphic
+ \global\let\stopwritingMPgraphic=\dostopwritingMPgraphic}
+
+\def\dostopwritingMPgraphic%
+ {\ifMPrun \else
+ \immediate\write\scratchwrite{endfig;}%
+ \fi
+ \ifrunMPgraphics
+ \dodostopwritingMPgraphic
+ \fi}
+
+\def\dodostopwritingMPgraphic%
+ {\ifnum\currentMPgraphic>0
+ \immediate\write\scratchwrite{end.}%
+ \immediate\closeout\scratchwrite
+ \runMPgraphic{\MPgraphicfile}%
+ \fi
+ \global\let\flushMPgraphics=\relax}
+
+\let\stopwritingMPgraphic=\relax
+\let\flushMPgraphics =\relax
+
+%D \macros
+%D {flushMPgraphics}
+%D
+%D When we use the indirect method, all graphics are saved in
+%D one file. This means that we cannot close this file after
+%D every \type{\stopMPgraphic}. Therefore we need to say:
+%D
+%D \starttypen
+%D \flushMPgraphic
+%D \stoptypen
+%D
+%D else the file is closed without writing the \METAPOST\ end
+%D command. One will notice this fast enough when in indirect
+%D mode. When using the direct mode this command is not
+%D implicitly needed, but ommiting it makes files less
+%D portable.
+
+%D \macros
+%D {loadcurrentMPgraphic,
+%D placeMPgraphic}
+%D
+%D Once defined, we can call for this graphic by saying:
+%D
+%D \starttypen
+%D \loadcurrentMPgraphic{setups}
+%D \placeMPgraphic
+%D \stoptypen
+%D
+%D This two stage insert permits some intermediate manipulations
+%D of the graphic, which temporary saved in:
+
+\newbox\MPgraphicbox
+
+\def\loadcurrentMPgraphic#1%
+ {\loadMPgraphic{\MPgraphicfile.\the\currentMPgraphic}{#1}}
+
+\def\loadMPgraphic#1#2%
+ {\setbox\MPgraphicbox=\hbox{\insertMPfile{#1}{#2}}}
+
+\def\placeMPgraphic%
+ {\box\MPgraphicbox}
+
+%D \macros
+%D {startreusableMPgraphic, reuseMPgraphic, useMPbox}
+%D
+%D One can use the next macro for defining graphics that are
+%D to be reused. When the next switch is set, graphics are
+%D cached.
+
+\newif\ifuseMPbox % nog eens cyclische buffer
+
+\def\douseMPbox#1%
+ {\setobject{#1}
+ \vbox
+ {\loadMPgraphic{\MPgraphicfile.\the\currentMPgraphic}{}%
+ \placeMPgraphic}%
+ \setgvalue{#1}%
+ {\getobject{#1}}}
+
+\def\nouseMPbox#1%
+ {\setxvalue{#1}%
+ {\noexpand\loadMPgraphic{\MPgraphicfile.\the\currentMPgraphic}{}%
+ \noexpand\placeMPgraphic}}
+
+\ifCONTEXT \else \let\douseMPbox=\nouseMPbox \fi
+
+\long\def\startreusableMPgraphic#1#2\stopreusableMPgraphic%
+ {\reuseMPgraphicstrue
+ \doifundefined{MP:#1}
+ {\startMPgraphic#2\stopMPgraphic
+ \ifuseMPbox
+ \douseMPbox{MP:#1}%
+ \else
+ \nouseMPbox{MP:#1}%
+ \fi}}
+
+\def\reuseMPgraphic#1%
+ {\getvalue{MP:#1}}
+
+%D \macros
+%D {startuseMPgraphic,useMPgraphic}
+%D
+%D The every||time||it's||used original one is defined below.
+%D This one makes sense when the graphic uses random numbers.
+
+\long\def\startuseMPgraphic#1#2\stopuseMPgraphic%
+ {\reuseMPgraphicstrue
+ \long\setgvalue{MP:#1}%
+ {\startMPgraphic#2\stopMPgraphic
+ \loadcurrentMPgraphic{}%
+ \placeMPgraphic}}
+
+\let\useMPgraphic=\reuseMPgraphic
+
+%D We didn't yet define the macro responsible for processing
+%D the graphic from within \TEX.
+
+\def\runMPgraphic#1%
+ {\ifrunMPgraphics
+ \executeMETAPOST{#1}%
+ \else
+ \message{[flush and process \MPgraphicfile.mp afterwards]}%
+ \fi}
+
+%D \macros
+%D {executeMetaPost, executeMETAPOST, executesystemcommand}
+%D
+%D With \type{\executeMETAPOST} being defined as:
+
+\ifx\undefined\executeMetaPost
+ \def\executeMETAPOST#1{\executesystemcommand{\executeMetaPost{#1}}}
+\fi
+
+%D There are two system dependant definitions:
+
+\ifx\undefined\executesystemcommand
+ \def\executesystemcommand#1{\immediate\write18{#1}}
+\fi
+
+\ifx\undefined\executeMetaPost
+ \def\executeMetaPost#1{mpost #1}
+\fi
+
+%D \macros
+%D {insertMPfile}
+%D
+%D One can define this command in advance or redefine it after
+%D loading this module. The same goes for the forward
+%D reference to the figure loading macro:
+
+\ifx\undefined\insertMPfile
+
+ \def\insertMPfile#1#2%
+ {\ifx\undefined\externalfigure
+ \message{[insert file #1 here]}%
+ \else
+ \externalfigure[#1][\c!type=eps,\c!methode=mps,#2]%
+ \fi}
+
+\fi
+
+%D This macro takes {\em two} arguments, the second one can be
+%D used to pass info to the inclusion macro. Some examples
+%D of its use can be found in the modules \type{supp-tpi} and
+%D \type{prag-log}.
+
+%D This module can be used in \PLAIN\ \TEX too. When using
+%D \DVIPS, just try to process:
+%D
+%D \starttypen
+%D \input supp-mps
+%D
+%D \runMPgraphicstrue
+%D
+%D \def\insertMPfile#1#2%
+%D {\special{psfile=#1}}
+%D
+%D \startuseMPgraphic{1}
+%D prologues := 1;
+%D draw (0,0) withpen pencircle scaled 100;
+%D \stopuseMPgraphic
+%D
+%D \useMPgraphic{1}
+%D \stoptypen
+%D
+%D Don't forget to enable \type{\write18}. When does not say
+%D \type{\runMPgraphicstrue}, the \METAPOST\ scratch file
+%D must be closed by saying
+%D
+%D \starttypen
+%D \flushMPgraphics
+%D \stoptypen
+%D
+%D When using the indirect method, one has to process the file
+%D \type{mpgraph.mp} between two successive \TEX\ runs.
+
+%D For some reason, \METAPOST\ needs the public domain \DVI\ to
+%D \POSTSCRIPT\ converter \DVIPS. This symbiosis originates in
+%D the need to include the fonts (glyphs) that \METAPOST\ uses
+%D in the \POSTSCRIPT\ file. Driver independancy was one of my
+%D prerequisites for using \METAPOST, so I decided to build
+%D this kind of support myself. Personally I consider driver
+%D dependancy a drawback for the dissemination of such a
+%D package. The second part of this module more or less
+%D decouples \METAPOST\ and \DVIPS.
+%D
+%D The macros hereafter are copied from the module
+%D \type{m-metapost}. After writing module \type{supp-pdf} I
+%D added this method to the module named and after a while
+%D decided to hook it into module \type{spec-yy}. Therefore
+%D they made it into a support module, but in a slightly
+%D different way.
+
+%D \macros
+%D {includeMPfonts, ifincludeMPfonts}
+%D {}
+%D
+%D The method we use is both robust and simple: one can do
+%D with calling the next macro with the filename as argument:
+%D
+%D \starttypen
+%D \includeMPfonts{filename}
+%D \stoptypen
+%D
+%D We can turn of this mechanism with:
+%D
+%D \starttypen
+%D \includeMPfontsfalse
+%D \stoptypen
+
+\newif\ifincludeMPfonts \includeMPfontstrue
+
+\def\includeMPfonts#1%
+ {\ifincludeMPfonts
+ \bgroup
+ \message{[MP fonts #1]}%
+ %\uncatcodespecials
+ \endlinechar=-1
+ \setMPspecials
+ \obeyMPspecials
+ \setbox0=\hbox
+ {\hskip-\maxdimen
+ \doprocessfile\scratchread{#1}\handleMPfont}%
+ \smashbox0
+ \box0
+ \egroup
+ \fi}
+
+\def\UseMetaPostGraphic {\includeMPfonts} % upward compatible
+\def\DontUseMetaPostGraphics {\includeMPfontsfalse} % upward compatible
+
+%D The characters are collected in a box and moved as far as
+%D possible into the left margin. The resulting box has no
+%D dimensions and can be prepended (appended) to the special
+%D that handles the inclusion. The characters are in the file
+%D but made invisible.
+
+%D We scan the graphics file for the \type{fshow} operator,
+%D that is, lines that start with \type{(}. If found it
+%D interprets the line, which looks like:
+%D
+%D \starttypen
+%D (string ... string) font size fshow
+%D \stoptypen
+%D
+%D Font definitions specified in the preamble are simply
+%D ignored. Only lines starting with \type{(} are interpreted.
+
+\def\dohandleMPfont#1#2\relax%
+ {\if#1(%
+ \expandafter\includeMPcharacters\fileline\relax
+ \fi}
+
+\def\handleMPfont%
+ {\expandafter\dohandleMPfont\fileline\relax}
+
+%D Before we start scanning for data, we first change some
+%D \CATCODES. The first set of macro's is copied from module
+%D \type{supp-pdf}. This scheme is a bit overdone for this
+%D module, but using the same macros saves us some memory.
+
+\def\octalMPcharacter#1#2#3%
+ {\char'#1#2#3\relax}
+
+\bgroup
+\catcode`\|=\@@comment
+\catcode`\%=\@@active
+\catcode`\[=\@@active
+\catcode`\]=\@@active
+\catcode`\{=\@@active
+\catcode`\}=\@@active
+\catcode`B=\@@begingroup
+\catcode`E=\@@endgroup
+\gdef\ignoreMPspecials|
+ B\def%BE|
+ \def[BE|
+ \def]BE|
+ \def{BE|
+ \def}BEE
+\gdef\obeyMPspecials|
+ B\def%B\char 37\relax E|
+ \def[B\char 91\relax E|
+ \def]B\char 93\relax E|
+ \def{B\char123\relax E|
+ \def}B\char125\relax EE
+\gdef\setMPspecials|
+ B\catcode`\%=\@@active
+ \catcode`\[=\@@active
+ \catcode`\]=\@@active
+ \catcode`\{=\@@active
+ \catcode`\}=\@@active
+ \catcode`\$=\@@letter
+ \catcode`\_=\@@letter
+ \catcode`\#=\@@letter
+ \catcode`\^=\@@letter
+ \catcode`\&=\@@letter
+ \catcode`\|=\@@letter
+ \catcode`\~=\@@letter
+ \def\(B\char40\relax E|
+ \def\)B\char41\relax E|
+ \def\\B\char92\relax E|
+ \def\0B\octalMPcharacter0E|
+ \def\1B\octalMPcharacter1E|
+ \def\2B\octalMPcharacter2E|
+ \def\3B\octalMPcharacter3E|
+ \def\4B\octalMPcharacter4E|
+ \def\5B\octalMPcharacter5E|
+ \def\6B\octalMPcharacter6E|
+ \def\7B\octalMPcharacter7E|
+ \def\8B\octalMPcharacter8E|
+ \def\9B\octalMPcharacter9EE
+\egroup
+
+%D The lines starting with \type{(} are interpreted and
+%D handled by
+
+\def\includeMPcharacters(#1) #2 #3 #4\relax%
+ {\font\temp=#2 at #3bp\temp#1}
+
+%D This method is both robust and reasonable fast. The only
+%D disadvantage is that when not embedded properly in the
+%D graphics inclusion macros, one has to load all graphics by
+%D hand.
+
+%D Now let's see if things work all right and show the example
+%D files that are part of the \METAPOST\ distribution:
+%D
+%D \startregelcorrectie
+%D \steluitlijnenin[midden]
+%D \leavevmode
+%D \startcombinatie[3*3]
+%D {\externfiguur[mp-exa-1][methode=mps,kader=aan,breedte=.2\hsize]} {}
+%D {\externfiguur[mp-exa-2][methode=mps,kader=aan,breedte=.2\hsize]} {}
+%D {\externfiguur[mp-exa-3][methode=mps,kader=aan,breedte=.2\hsize]} {}
+%D {\externfiguur[mp-exa-4][methode=mps,kader=aan,breedte=.2\hsize]} {}
+%D {\externfiguur[mp-exa-5][methode=mps,kader=aan,breedte=.2\hsize]} {}
+%D {\externfiguur[mp-exa-6][methode=mps,kader=aan,breedte=.2\hsize]} {}
+%D {\externfiguur[mp-exa-7][methode=mps,kader=aan,breedte=.2\hsize]} {}
+%D {\externfiguur[mp-exa-8][methode=mps,kader=aan,breedte=.2\hsize]} {}
+%D {\externfiguur[mp-exa-9][methode=mps,kader=aan,breedte=.2\hsize]} {}
+%D \stopcombinatie
+%D \stopregelcorrectie
+%D
+%D Here we used calls like:
+%D
+%D \starttypen
+%D \externfiguur[mp-exa-1][methode-mps,kader=aan,breedte=.2\hsize]
+%D \stoptypen
+
+%D \macros
+%D {convertMPcolors,
+%D ifconvertMPcolors,ifreduceMPcolors,ifforceMPcolors}
+%D
+%D When I told the editors that I wanted to use colored
+%D \METAPOST\ graphics in the color issue of the \MAPS, I was
+%D asked to use the \kap{CMYK} colorspace instead of \kap{RGB}
+%D one. However, \METAPOST\ only supports \kap{RGB} colors. I
+%D decided to write a utility to convert the \type
+%D {setrgbcolor} operators into \type {setcmykcolor} ones, and
+%D some experiments showed me that I could best let \TEX\ do it
+%D itself. Here it is:
+%D
+%D There are two booleans that control the conversion process.
+%D These are false by default.
+
+\newif\ifconvertMPcolors
+\newif\ifreduceMPcolors
+\newif\ifforcegrayMPcolors
+
+%D The main macro is calles as:
+%D
+%D \starttypen
+%D \convertMPcolors{filename}
+%D \stoptypen
+%D
+%D When active, this macro returns a message saying if indeed
+%D conversion took place. The old file is overwritten! This
+%D saves time in a succesive passes and can't harm, simply
+%D because MP can generate them anew.
+
+\def\convertMPcolorpath{} % {./}
+\def\convertMPcolorfile{metacmyk.eps}
+
+\def\convertMPcolors#1%
+ {\bgroup
+ \ifforcegrayMPcolors
+ \donetrue
+ \else\ifconvertMPcolors
+ \donetrue
+ \else
+ \donefalse
+ \fi\fi
+ \ifdone
+ \message{[MP color conversion #1}%
+ \endlinechar=-1
+ \uncatcodespecials
+ \donefalse
+ \immediate\openout\scratchwrite=\convertMPcolorpath\convertMPcolorfile
+ \doprocessfile\scratchread{#1}\handleMPcolor
+ \immediate\closeout\scratchwrite
+ \ifdone
+ \immediate\openout\scratchwrite=\convertMPcolorpath#1
+ \doprocessfile\scratchread{\convertMPcolorpath \convertMPcolorfile}\handleMPcopy
+ \immediate\closeout\scratchwrite
+ \message{done]}%
+ \else
+ \message{not needed]}%
+ \fi
+ \immediate\openout\scratchwrite=\convertMPcolorpath\convertMPcolorfile
+ \immediate\closeout\scratchwrite
+ \fi
+ \egroup}
+
+%D The process is rather simple: read a line, look for the
+%D \type {setrgbcolor} operator, recalculate the components and
+%D check for gray reduction or black removal, write the result
+%D to a temporary file, and go on. Afterwards, the file is
+%D copied back. We don't have to reduce to gray scales;
+%D \METAPOST\ already takes care of that.
+
+\def\handleMPcolor
+ {\expandafter\dohandleMPcolor\fileline setrgbcolor*\\}
+
+\def\dohandleMPcolor#1setrgbcolor#2#3\\%
+ {\if#2*%
+ \immediate\write\scratchwrite{#1}%
+ \else
+ \dodohandleMPcolor#1setrgbcolor#2#3\\%
+ \fi}
+
+\def\dodohandleMPcolor#1 #2 #3setrgbcolor#4setrgbcolor*\\%
+ {\bgroup
+ \ifforcegrayMPcolors
+ \convertRGBtoGRAY{#1}{#2}{#3}%
+ \immediate\write\scratchwrite
+ {\@@cl@@s \space setgray #4}%
+ \else
+ \dimen0=1pt \advance\dimen0 by -#1pt
+ \dimen2=1pt \advance\dimen2 by -#2pt
+ \dimen4=1pt \advance\dimen4 by -#3pt
+ \ifreduceMPcolors
+ \dimen6=\dimen0
+ \ifdim\dimen2<\dimen6 \dimen6=\dimen2 \fi
+ \ifdim\dimen4<\dimen6 \dimen6=\dimen4 \fi
+ \advance\dimen0 by -\dimen6
+ \advance\dimen2 by -\dimen6
+ \advance\dimen4 by -\dimen6
+ \else
+ \dimen6=\!!zeropoint
+ \fi
+ \immediate\write\scratchwrite
+ {\withoutpt{\the\dimen0} \space
+ \withoutpt{\the\dimen2} \space
+ \withoutpt{\the\dimen4} \space
+ \withoutpt{\the\dimen6} \space setcmykcolor #4}%
+ \fi
+ \egroup
+ \donetrue} % needed for message
+
+\def\handleMPcopy%
+ {\immediate\write\scratchwrite{\fileline}}
+
+%D The next macro is needed for forced conversion. This macro
+%D is copied from \type{colo-ini}, just in case one uses this
+%D module outside \CONTEXT.
+
+\ifx\convertRGBtoGRAY\undefined
+
+ \def\convertRGBtoGRAY#1#2#3%
+ {\scratchdimen=#1\s!pt
+ \scratchdimen=300\scratchdimen
+ \scratchcounter=\scratchdimen
+ \scratchdimen=#2\s!pt
+ \scratchdimen=590\scratchdimen
+ \advance\scratchcounter by \scratchdimen
+ \scratchdimen=#3\s!pt
+ \scratchdimen=110\scratchdimen
+ \advance\scratchcounter by \scratchdimen
+ \advance\scratchcounter by \!!medcard
+ \divide\scratchcounter by \!!maxcard
+ \edef\@@cl@@s{\realcolorvalue\scratchcounter}}
+
+\fi
+
+%D The next examples show the color conversion macros in
+%D action. These examples also demonstrate in||text \METAPOST\
+%D handling. As we will see, the conversion is hooked into the
+%D \CONTEXT\ color mechanism.
+%D
+%D By setting both \type{rgb} and \type{cmyk} to off, we force
+%D conversion to gray scales using:
+%D
+%D \plaatsformule[-]
+%D \startformule
+%D G = .30r + .59g + .11b
+%D \stopformule
+%D
+%D By using buffers, we keep the \ASCII\ layout clean:
+%D
+%D \startbuffer
+%D \startbuffer[rgb]
+%D \stelkleurenin[rgb=ja,cmyk=nee,reductie=nee,conversie=nee]
+%D \useMPgraphic{hans}
+%D \stopbuffer
+%D
+%D \startbuffer[cmyk]
+%D \stelkleurenin[rgb=nee,cmyk=ja,reductie=nee,conversie=nee]
+%D \useMPgraphic{hans}
+%D \stopbuffer
+%D
+%D \startbuffer[cmy]
+%D \stelkleurenin[rgb=nee,cmyk=ja,reductie=ja,conversie=nee]
+%D \useMPgraphic{hans}
+%D \stopbuffer
+%D
+%D \startbuffer[gray]
+%D \stelkleurenin[rgb=nee,cmyk=nee,reductie=nee,conversie=nee]
+%D \useMPgraphic{hans}
+%D \stopbuffer
+%D \stopbuffer
+%D
+%D \typebuffer
+%D \haalbuffer
+%D
+%D The graphic is rather simple and is generated each time
+%D it's called:
+%D
+%D \global\runMPgraphicstrue
+%D
+%D \startbuffer
+%D \startbuffer[graphic]
+%D \startuseMPgraphic{hans}
+%D width :=\the\tekstbreedte/5;
+%D height := width/4;
+%D fill fullcircle
+%D xscaled width
+%D yscaled height
+%D withcolor (\RedGreenBlue);
+%D \stopuseMPgraphic
+%D \stopbuffer
+%D \stopbuffer
+%D
+%D \typebuffer
+%D \haalbuffer
+%D
+%D Next we combine the four alternative interpretations in a
+%D combination:
+%D
+%D \startbuffer
+%D \startbuffer[result]
+%D \startcombinatie[4]
+%D {\haalbuffer[rgb]} {\tfxx original}
+%D {\haalbuffer[cmyk]} {\ttxx\string\convertMPcolorstrue}
+%D {\haalbuffer[cmy]} {\ttxx\string\reduceMPcolorstrue}
+%D {\haalbuffer[gray]} {\ttxx\string\forcegrayMPcolorstrue}
+%D \stopcombinatie
+%D \stopbuffer
+%D \stopbuffer
+%D
+%D \typebuffer
+%D \haalbuffer
+%D
+%D Finally we call the buffers, using different setting:
+%D
+%D \startbuffer
+%D \plaatsfiguur
+%D {\METAPOST\ color conversions}
+%D {\def\RedGreenBlue{.1,.4,.6}\haalbuffer[graphic]\haalbuffer[result]\vskip6pt
+%D \def\RedGreenBlue{.1,.6,.4}\haalbuffer[graphic]\haalbuffer[result]\vskip6pt
+%D \def\RedGreenBlue{.4,.1,.6}\haalbuffer[graphic]\haalbuffer[result]\vskip6pt
+%D \def\RedGreenBlue{.4,.6,.1}\haalbuffer[graphic]\haalbuffer[result]\vskip6pt
+%D \def\RedGreenBlue{.6,.1,.4}\haalbuffer[graphic]\haalbuffer[result]\vskip6pt
+%D \def\RedGreenBlue{.6,.4,.1}\haalbuffer[graphic]\haalbuffer[result]}
+%D \stopbuffer
+%D
+%D \typebuffer
+%D \haalbuffer
+%D
+%D By the way, when the \POSTSCRIPT\ file resulting from
+%D this input is converted into \PDF\ and viewed in Acrobat
+%D Reader, one can quite different colors from those
+%D displayed in \GHOSTSCRIPT, which view equals the
+%D \POSTSCRIPT\ originals.
+
+\protect
+
+\endinput
+
\ No newline at end of file |