stable 1997.10.28

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+%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

+ 

+%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:

+

+\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:

+

+\def\startMPgraphic#1\stopMPgraphic%

+  {\startwritingMPgraphic

+   \writeMPgraphic{#1}%

+   \stopwritingMPgraphic}

+

+%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 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 number:

+

+\newcounter\currentMPgraphic

+

+%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 \macro

+%D   {MPinclusions}

+%D

+%D One can include for instance common input commands by 

+%D assigning those to the token register:

+

+\newtoks\MPinclusions

+

+\def\writeMPgraphic%

+  {\immediate\write\scratchwrite}

+

+\def\startwritingMPgraphic%

+  {\ifrunMPgraphics

+     \ifreuseMPgraphics \else

+       \doglobal\newcounter\currentMPgraphic 

+     \fi

+     \doglobal\increment\currentMPgraphic 

+     \immediate\openout\scratchwrite=\MPgraphicfile.mp

+     \immediate\write\scratchwrite{\the\MPinclusions}%

+   \else

+     \doglobal\increment\currentMPgraphic 

+     \ifnum\currentMPgraphic=1

+       \immediate\openout\scratchwrite=\MPgraphicfile.mp

+       \immediate\write\scratchwrite{\the\MPinclusions}%

+     \fi

+   \fi

+   \immediate\write\scratchwrite{beginfig(\currentMPgraphic);}%

+   \global\let\flushMPgraphics\dodostopwritingMPgraphic

+   \global\let\stopwritingMPgraphic=\dostopwritingMPgraphic}

+

+\def\dostopwritingMPgraphic%

+  {\immediate\write\scratchwrite{endfig;}%

+   \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\MPgraphic

+

+\def\loadcurrentMPgraphic#1%

+  {\loadMPgraphic{\MPgraphicfile.\currentMPgraphic}{#1}}

+

+\def\loadMPgraphic#1#2%

+  {\setbox\MPgraphic=\hbox{\insertMPfile{#1}{#2}}}

+

+\def\placeMPgraphic%

+  {\box\MPgraphic}

+

+%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

+

+\long\def\startreusableMPgraphic#1#2\stopreusableMPgraphic%

+  {\reuseMPgraphicstrue

+   \doifundefined{MP:#1}

+     {\startMPgraphic#2\stopMPgraphic

+      \ifuseMPbox

+        \ifx\setobject\undefined

+          \newbox\somebox

+          \global\setbox\somebox=\vbox

+            {\loadMPgraphic{\MPgraphicfile.\currentMPgraphic}{}%

+             \placeMPgraphic}%

+          \global\setevalue{MP:#1}%

+            {\copy\the\somebox\relax}%

+        \else

+          \setobject{MP:#1}

+            \vbox

+              {\loadMPgraphic{\MPgraphicfile.\currentMPgraphic}{}%

+               \placeMPgraphic}%

+          \global\setvalue{MP:#1}%

+            {\getobject{MP:#1}}%

+        \fi

+      \else

+        \global\setevalue{MP:#1}%

+          {\noexpand\loadMPgraphic{\MPgraphicfile.\currentMPgraphic}{}%

+           \noexpand\placeMPgraphic}%

+      \fi}}

+

+\def\reuseMPgraphic#1%

+  {\getvalue{MP:#1}}

+

+%D \macro

+%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.

+

+\def\startuseMPgraphic#1#2\stopuseMPgraphic%

+  {\reuseMPgraphicstrue 

+   \long\setvalue{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 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   {UseMetaPostGraphic, DontUseMetaPostGraphics}

+%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 \UseMetaPostGraphic{filename}

+%D \stoptypen

+%D

+%D We can turn of this mechanism with: 

+%D

+%D \starttypen

+%D \DontUseMetaPostGraphics

+%D \stoptypen

+

+\def\UseMetaPostGraphic#1%

+  {\bgroup

+   \message{[MP fonts #1]}%

+   %\uncatcodespecials

+   \endlinechar=-1

+   \setMPspecials

+   \obeyMPspecials

+   \setbox0=\hbox

+     {\hskip-\maxdimen

+      \doprocessfile\scratchread{#1}\handleMPSline}%

+   \smashbox0 

+   \box0

+   \egroup}

+

+\def\DontUseMetaPostGraphics%

+  {\let\UseMetaPostGraphic=\gobbleoneargument}

+

+%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\dohandleMPSline#1#2\relax%

+  {\if#1(%

+     \expandafter\includeMPcharacters\fileline\relax

+   \fi}

+

+\def\handleMPSline%

+  {\expandafter\dohandleMPSline\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

+

+\protect 

+

+\endinput