Mark IV
Introducing Mark IV
Mark IV is the name of the LuaTeX-aware part of ConTeXt; that is, when you use ConTeXt over the LuaTeX engine instead of PDFTeX or XeTeX. You run it with
texexec --lua filename
or
context filename
The first public beta has been released on the 6th of August, 2007. It will be available on TeX Live 2008 and MikTeX 2.8. Currently the easiest way to try it out is to install ConTeXt Minimals.
It takes advantage of the amazing capabilities of LuaTeX and opens up a whole new world of possibilities, in particular with fonts.
Troubleshooting
The environment variable TEXINPUTS has to be empty or unset. If not, you can get errors about "file.tex not found".
Sample code
Here are some examples of cool stuff you can do with Mark IV (test it!).
Lua core
The first thing you will want to test are the lua functions. Try
\ctxlua{a = 1.5 ; b = 1.8 ; c = a*b ; tex.print(c) ;}
or the equivalent:
\startlua a = 1.5 b = 1.8 c = a*b tex.print(c) \stoplua
You can also do more elaborate calculations with the lua math
library:
\ctxlua{tex.print("$\string\\sqrt{2} = " .. math.sqrt(2) .. "$")}
Note that the above works with any flavour of LuaTeX; nothing is actually ConTeXt-specific (except for \ctxlua and \startlua/\stoplua).
Fonts and typescripts
Good ol' typescripts
Of course, Mark IV allows you to use typescripts as you've always done; for example:
\usetypescript[palatino] \setupbodyfont[palatino,12pt] effe fietsen 2: \input tufte $\sqrt{2}$ \eogonek \sc effe fietsen 2: \input tufte $\sqrt{2}$ \eogonek
That's as simple as using a traditional ConTeXt typescript!
But ... how is it any different, then? Well, the difference is that in Mark IV, we can use an Opentype font directly, so that what is done here: when we want to use Palatino, the TeX Gyre equivalent (“Pagella”) is called and we can use its Opentype “features”; read on.
Opentype features
A “feature”, in the Opentype jargon, is a set of rules describing changes in the appearance of the text. Hmm, that's not very precise. Let's show some examples. First of all, you have to know that features are referred to by 4-letter tags, and you will see this a lot. One of them is ‘smcp‘, for “small caps“. Let's consider the following Mark IV-only code:
\definefontfeature[smallcaps][language=DFLT,script=latn,smcp=yes] \font\palasmallcaps=texgyrepagella-regular*smallcaps \palasmallcaps This is a text in small capitals.
Here you basically define a (Mark IV) feature with the name ”smallcaps”, and associate it with the (Opentype) feature “smcp”. You have to specify which script you want to use it with; scripts in Opentype are also tagged with four letters, and “latn” is of course Latin.
Then you define a TeX font with that feature.
You can see what features are defined in a particular font with the following bit of code
\ctxlua { fontname = 'texgyrepagella-regular.otf' --[[ First read the font data. This makes heavy use of some of the Mark IV code]] tfmdata = fonts.tfm.read_and_define("file:" .. fontname, 655360) font = tfmdata.shared.otfdata if font then gsubfeatures = fonts.otf.analyze_features(font.gsub) gposfeatures = fonts.otf.analyze_features(font.gpos) end if gsubfeatures then table.sort(gsubfeatures) % We want our list sorted alphabetically! tex.sprint("\\rm GSUB features: \\tt ") % Beware: you don't want \rm to be interpreted by lua (\rm would yield carriage return + letter m)! for _, feat in ipairs(gsubfeatures) do tex.sprint(feat) tex.sprint(' ') end else tex.sprint("\\rm No GSUB features") end tex.sprint("\\par") if gposfeatures then tex.sprint("\\rm GPOS features: \\tt ") table.sort(gposfeatures) for _, feat in ipairs(gposfeatures) do tex.sprint(feat) tex.sprint(' ') end else tex.sprint("\\rm No GPOS features") end }
It prints the list on the page. You'll notice there are two sets of features, each one of them defined in a different table of the Opentype font: the GSUB
table (for Glyph SUBstitution) gives rules for replacing glyphs in certains circumstances (think of ligatures: f + i -> fi); the GPOS
table (Glyph POSititioning) gives rules for moving glyphs (think of kerning: A + V -> A <kerning> V).
Incidentally, the above code gives some basic examples of LuaTeX programming, a mixture of both Lua and TeX programming with some special features (features in the general sense, not the Opentype one :-).
A (Complete) Typescript Example
\starttypescript [sans] [franklin] \definefontsynonym [FranklinBookRegular] [name:FranklinGothicBookITC-Regular] [features=default] \definefontsynonym [FranklinMediumRegular] [name:FranklinGothicMediumITC-Regular] [features=default] \definefontsynonym [FranklinDemiRegular] [name:FranklinGothicDemiITC-Regular] [features=default] \definefontsynonym [FranklinHeavyRegular] [name:FranklinGothicHeavyITC-Regular] [features=default] \definefontsynonym [FranklinBookItalic] [name:FranklinGothicBookITC-Italic] [features=default] \definefontsynonym [FranklinDemiItalic] [name:FranklinGothicMediumITC-Italic] [features=default] \definefontsynonym [FranklinHeavyItalic] [name:FranklinGothicDemiITC-Italic] [features=default] \definefontsynonym [FranklinMediumItalic] [name:FranklinGothicHeavyITC-Italic] [features=default] \stoptypescript \starttypescript [sans] [franklin] \definefontsynonym [Sans] [FranklinBookRegular] [features=default] \definefontsynonym [SansItalic] [FranklinBookItalic] [features=default] \definefontsynonym [SansBold] [FranklinDemiRegular] [features=default] \definefontsynonym [SansBoldItalic] [FranklinDemiItalic] [features=default] \definefontsynonym [SansSlanted] [SansItalic] [features=default] \definefontsynonym [SansBoldSlanted] [SansBoldItalic] [features=default] \definefontsynonym [SansCaps] [Sans] [features=smallcaps] \stoptypescript \definetypeface[franklin][rm][sans][franklin][default] \definetypeface[franklin][ss][sans][franklin][default] \definetypeface[franklin][tt][mono][modern] [default][rscale=1.12] \definetypeface[franklin][mm][math][iwona] [default][rscale=1.02] \setupbodyfont[franklin,ss,10pt]
Using System Fonts
LuaTeX can see system fonts if you set the OSFONTDIR
variable, for instance
set OSFONTDIR=c:/windows/fonts//
To regenerate font database you can use
mtxrun --script font --reload
More sample code
Other examples of Lua(TeX) code are to be found on Luigi's user page as well as http://luatex.bluwiki.com/