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ConTeXT provides a tight integration of TeX and [[MetapostMetaPost]]. Metapost MetaPost can used behind the scenes for some graphic trickery. This integration is also helpful for drawing figures in metapost MetaPost and use them in the document. Some This page is a brief overview of some of the commonly used commands for this are.

==<{{cmd>startMPenvironment</|defineMPinstance}} and {{cmd>==This is |setupMPinstance}} can be used to change the body set up MetaPost invocations with particular features. One use case could be to select a sans serif font for metapost graphicsall MetaPostlabels. For example, to get the text in metapost graphics in times, use

<texcode>=== \startMPenvironment\usetypescript[times][texnansi]\switchtobodyfont[times,10pt]\stopMPenvironment</texcode>===

An MPenvironment {{cmd|startMPenvironment}} is sort of like <b>verbatimtex..etex</b> a '''deprecated''' evironment in which one could place settings that one only wanted to apply in regular (standalone) the MetaPost figures. Here is an example of using verbatimtex environment, but not in a regular MetaPost figure:<texcode>verbatimtex% center-align and stack the two arguments\def\2#1#2document itself. One should use {{\vboxcmd|defineMPinstance}} and {\halign{\hfil##\hfil\cr #1\cr #2\crcmd|setupMPinstance}}}etex, instead.

beginfig(1) z0 = (2in,0); draw fullcircle scaled 3cm; label(btex = \2{sun}{mass $M$} etex, origin); draw fullcircle scaled 1.5cm shifted z0; label(btex \2{earth}{mass $m$} etex, z0);endfig;end</texcode>startMPinclusions ==

To integrate such a graphic into a ConTeXt source fileInside {{cmd|startMPinclusions}} one can specify MetaPost files to ''input'', there are several choicesand also define MetaPost functions.

1. Place the definition of <b>== \2</b> in the MPenvironment. However, that fails (as of the 2006.09.28 beta but it's likely to work soon, knowing Hans) because the definition is stored as a macro itself, startuseMPgraphic and then the parameters #1 and #2 become ##1 and ##2, alas. There is a <b>\startbuffer</b> trick that Hans posted on the mailing list. But perhaps the easiest is:useMPgraphic ==

2. Place the definition {{cmd|startuseMPgraphic}}defines a piece of <b>\2</b> in graphics code that is processed anew every time the ConTeXt environment, and change <b>btex..etex</b> to <b>\sometxt</b>graphic is placed with {{cmd|useMPgraphic}}. Here's an example:

<texcode>== \startreusableMPgraphic and \reuseMPgraphic ==% in a large documentFor graphics that are the same every time, put this def in an environment\def\2#1#2it is better to use {{\vboxcmd|startreusableMPgraphic}}: the graphic is compiled only once, and the one resulting picture can be placed at various points with {\halign{\hfil##\hfil\cr #1\cr #2\cr}cmd|reuseMPgraphic}}.

== \starttextstartMPcode ==

% earth and sun\startreusableMPgraphic{fig} z0 = (2inWhen reusing a graphic is not important,0); draw fullcircle scaled 3cm; label(\sometxt{\2you can simply use {sun}{mass $M$cmd|startMPcode}}, origin); draw fullcircle scaled 1.5cm shifted z0; label(\sometxt{\2{earth}{mass $m$}}, z0);\stopreusableMPgraphic

== \reuseMPgraphic{fig}startMPpage ==

Warning: <b>== \sometxt</b> cannot be used in loops. Instead use <b>\textext</b>. [Someone who understands why should expand this statement!]startstaticMPfigure ==

==The {{cmd|startuseMPgraphic}} series of commands were designed for using MetaPost for drawing fancy frames and backgrounds and not for using <cmdi>startMPinclusionsstand-alone</i> graphics for a document. {{cmd>==|startstaticMPfigure}} creates a separate pdf file containing the graphic. This pdf can be used for specifying metapost files included in the document using {{cmd|usestaticMPfigure}}. ConTeXt is clever enough to ''input'' and also to define metapost functionsrecompile the resulting MetaPost file only if something inside the {{cmd|startstaticMPfigure}} has changed.For example<texcode>\startMPinclusions input boxes ; vardef my_metapost_fun(expr var)= ... enddef ;\stopMPinclusions</texcode>

==<cmd>startMPpage</cmd>See also ==This produces a page containing metapost graphic. The resulting pdf is self contained (it has all the fonts embedded) This is useful if you want to send the figure to a coauthor or a journal. For example, one can have <texcode>\starttext\startMPpage draw fullcircle scaled 2cm ; dotlabel.bot(textext("(0,0)"),origin) ;\stopMPpage \startMPpage draw fullcircle scaled 2cm ; drawarrow (0,0)--(1cm,0) ; label.bot(textext("$r$"),(5mm,0)) ;\stopMPpage \stoptext</texcode> Processing this file using<texcode> texmfstart texexec --pdf filename</texcode>gives a pdf with two pages of graphics. ==<cmd>startstaticMPfigure</cmd>==<cmd>startuseMPgraphic</cmd> series of commands were designed for using metapost for drawing fancy frames and backgrounds and not for using <i>stand-alone</i> graphics for a document. <cmd>startstaticMPfigure</cmd> creates a separate pdf file containing the graphic. This pdf can be included in the document using <cmd>usestaticMPfigure</cmd>. Context is clever enough to recompile the resulting metapost file, only if something inside the start stop staticMPgraphic has changed. For example,<texcode>\startstaticMPfigure{center} draw fullcircle scaled 2cm ; dotlabel.bot(textext("(0,0)"),origin) ;\stopstaticMPfigure \startstaticMPfigure{radiusMetaPost see also} draw fullcircle scaled 2cm ; drawarrow (0,0)--(1cm,0) ; label.bot(textext("$r$"),(5mm,0)) ;\stopstaticMPfigure \starttext Circle centered \usestaticMPfigure[center][width=1cm] at origin with radius\usestaticMPfigure[radius][width=1cm] $r=1\,\text{cm}$. \stoptext</texcode> * '''center''' and '''radius''' above are ''labels'' that are used to access the figuresection 3.* <cmd>usestaticMPfigure</cmd> takes the first argument as the ''label'' 3 of the figure to be inserted[[manual:metafun-s. The second argument has the same options as the second argument of <cmd>externalfigure</cmd>* To force the figure files to be regenerated, remove all the <code>*.mp.md5</code> files from the current directory.==Transparent colors in figures== You can use transparent colors! For example: <texcode>\runMPgraphicstrue\setupcolors[state=startpdf|MetaFun manual]]\starttext\startreusableMPgraphic{a}fill unitsquare scaled 1cm withcolor yellow;fill unitsquare shifted (0.5,0.5) scaled 1cm withcolor transparent(1,0.5,red);\stopreusableMPgraphic \placefigure[force,none]{}{\reuseMPgraphic{a}}\stoptext</texcode>

If you see black squares rather than a yellow one underneath a partially transparent red one, then you probably hit the 'missing specials' problem diagnosed by Taco (ntg-context list, 23 Sep 2006 22:00:42 +0200): <pre>This all sounds like the 'missing specials' problem that is causedby conflicting -progname= arguments when using the web2c versionof metapost. Make sure you do not have conflicting memory settings for both main_memory.mpostas well as main_memory.metafun The best is to remove all trace of '.mpost' and '.metafun' memorysettings from your texmf.cnf, but at least make sure all the'.mpost' and 'metafun' values are the same . Then regenerate metafun using texexec --make, and all should bewell again.</pre> And indeed it fixed it for me (Sanjoy). These were the memory setting in the ''/etc/texmf/texmf.d/95NonPath.cnf''configlet that is part of Debian and Ubuntu distributions of TeX: <pre>main_memory = 1000000 % words of inimemory available; also applies to inimf&mpmain_memory.context = 1500000main_memory.mpost = 1500000</pre> I commented out the .mpost line (there was no separate metafun line,which I guess instead used the main_memory value of 1000000),regenerated ''/etc/texmf/texmf.cnf'' with ''update-texmf'' (as root), then regenerated metafun with ''texexec --make metafun'' (as me) and transparency worked. [[Category:Graphics]][[Category:{{Metapost]]navbox}}