Typesetting Thai With LaTeX

Transcription

1 Typesetting Thai With LaTeX Hin-Tak Leung January 9, 2012 There are three ways of using TX (or more honestly, L A TX 2ε) to typeset Thai. They are X TX (or X L A TX), ThaiL A TX, and cjk/l A TX s Thai support. For most installations, they all use 1 fonts from the ThaiL A TX project so the end results are similar. They differ mainly in two areas: how they do word-breakings and line-wrappings, and what their preferred input encodings are. LuaTX is also unicode-capable and therefore can supposedly handle Thai; however, I have no experience with it and therefore will not mention it further. In a nutshell, X TX defaults to take UTF8 inputs while ThaiL A TX defaults to TIS620 2 but both supports the other alternative via optional directives; cjk/l A TX s Thai support is mainly TIS X TX breaks words/lines somewhat crudely on its own, while ThaiL A TX and cjk/l A TX uses external utilities (swath and emacs) to implement optimal line wrappings. Out of the box, TeXLive 2011 s X TX Thai functionality is okay; cjk/l A TX s Thai support is okay for TIS620 encoding; ThaiL A TX is not included. So I ll also describe ex-txmf-tree installation of ThaiL A TX below. 1 Thai with XeTeX Thai-style word-breakings and line-wrappings are selected via \XeTeXlinebreaklocale. Thus a typical document would include: \usepackage{fontspec} \setmainfont{norasi} \XeTeXlinebreaklocale th_th % To enable non-standard font selections % A font with Thai glyphs % Thai-style word-breakings and line-wrappings X TX defaults to assume UTF-8 inputs, but TIS620-encoded inputs can be selected via: \XeTeXinputencoding TIS620 X TX can use any platform fonts. TeXLive 2011 provides Norasi (also the default font used by cjk/l A TX s Thai support, and ThaiL A TX), but any platform fonts accessible by the fontconfig system would work. To get a list 4 : 1 X TX can use any platform fonts, while the other two are limited to what fonts TX knows about. More below. 2 TIS620 encoding is alternatively known as ISO , and LTH. ISO is the same as TIS (Thai Industrial Standard) , commonly known as TIS-620, except for the character in position a0: ISO defines this as non-breaking space, while TIS 620 leaves it undefined. 3 The first public draft of this document came into existence in the first week of December Its release for review caused a few improvements in ThaiLaTeX; I also fixed CJK s problem with emacs 23+ mentioned in the following section in Mid-December, and had the change officially incorporated; then I contributed CJK Thai support for UTF-8 inputs just before the end of year 2011, so the restriction to TIS 620 is no longer true as of end of I made Thai-style numbering and sectioning work also that feature never worked for the last 11 years. 4 Some of it are lies: fonts claim to support a language but do not have the corresponding glyphs. 1

2 fc-match -a :th X TX s word-breakings and line-wrappings uses ICU s line breaking algorithm for Thai and is less optimal than either of the other two. There is an encoding bug from the interaction of non-utf8 encodings with multiple available formats (Type 1 plus TrueType) of the same font plus style (bold face) declarations. The author has been notified (Dec 2011). Meanwhile, if one has multiple formats of the same fonts (e.g. on Fedora 16), this can be worked around by explicitly loading the Type 1 version of the bold font: \setmainfont[boldfont="[/usr/share/fonts/texlive-thailatex/norasi_b.pfb]"]{norasi} Also xdvipdfmx (X TX s dvi backend) silently drops included pdf s higher than its own. This affects cairo-based graphics and requires -output-driver="xdvipdfmx -V 5" as X L A TX s option to work. It (fontspec, possibly) also can get stuck when invalid font names are specified. 2 Thai with CJK A typical Thai document (in TIS620 encoding) with cjk/l A TX includes: \usepackage[thaicjk]{babel} Word breaks and font switching between Thai and non-thai are provided by a emacs lisp script cjk-enc.el 5 (which in turns loads thai-word.el 6 ). Thus a typical run includes running emacs to generate an intermediate input *.cjk from *.tex: run emacs creates thisfile.cjk emacs -batch -l thai-word -l cjk-enc -f batch-cjk-write-file thisfile.tex pdflatex thisfile.cjk or latex thisfile.cjk dvips thisfile.dvi Fedora s TeXLive 2011 does not bundle the emacs lisp scripts (others might do). In any case, without emacs, one can achieve font-switching alone (with bad word breaks) by: \addto\extrasthaicjk{\fontencoding{c90}\selectfont} \begin{otherlanguage}{thaicjk} % Only needed if other languages are also used...thai text... \end{otherlanguage} % cjk/l A TX itself also support UTF-8 encoded inputs via: 5 A problem of cjk-enc.el not working with emacs 23+ ( 8108), due to unicode-related changes from emacs 22 to 23, was fixed by me during the writing (Dec 2011) of this document. Be sure to get the latest cjk-enc.el. 6 A version of thai-word.el is built into emacs 22 and 23 at least, and may be even earlier. 2

3 \usepackage{cjkutf8} \begin{cjk}{utf8}{bsmi}...utf8 text... \end{cjk} Unfortunately TeXLive 2011 does not ship any suitable font definitions for UTF8-encoded Thai text. 7 (UTF8-encoded Chinese is supported in TexLive 2011 by the Arphic fonts, and UTF8-encoded Japanese by the Wadalab fonts, Korean by UHC fonts. None of them have Thai glyphs). 8 3 Thai with ThaiLaTeX ThaiL A TX documents default to contain TIS620-encoded texts, and typically include these lines 9 : \usepackage[thai]{babel} \usepackage{fonts-tlwg} % Alternative: \usepackage{fonts-arundina} UTF8-encoded texts can be indicated by the additional: \usepackage[utf8x]{inputenc} Word breaks are achieved by an additional external C++-based command-line utility swath. Thus a typical run includes: swath -d swathdic.tri -u UTF-8 -f latex < thisfile.tex > thisfile_new.tex pdflatex thisfile_new.tex or latex thisfile_new.tex dvips thisfile_new.dvi Without swath, ThaiL A TX still works to some extent, with non-ideal word/line breaks. TexLive 2011 ships enough of ThaiL A TX fonts to allow cjk/l A TX to work, but not ThaiL A TX itself. So I shall describe an out-of-tree installation below. 3.1 Installing ThaiLaTeX outside TeXLive s TXMF Building swath is non-trivial (even on Linux or other GNU-base systems) with additional dependencies of libdatrie. The latter is available from ftp://linux.thai.net/pub/thailinux/ software/libthai/. unpack the two sources in parallel: cd libdatrie-0.2.5/ --disable-shared, so swath does not need it afterwards 7 I added the UTF8-encoded Thai capability to cjk-enc.el before end of 2011 so it does work, although the change has not been accepted and officially incorporated yet. 8 This paragraph is strictly true only as of early December 2011: before the end of 2011, I contributed CJK s adaption for coping with UTF8-encoded Thai text. See also footnote in the first page. 9 See also the next footnote regarding fonts-tlwg.sty vs thswitch.sty. 3

4 ./configure --enable-static --disable-shared make cd../swath-0.4.1/ swath build needs one of the datrie-tools export PATH= pwd /../libdatrie-0.2.5/tools/:$path The /.libs/ below is a libtool quirk: DATRI_LIBS="-L pwd /../libdatrie-0.2.5/datrie/.libs/ -ldatrie" \ PKG_CONFIG_PATH= pwd /../libdatrie-0.2.5/ \ DATRI_CFLAGS=-I pwd /../libdatrie-0.2.5/./configure make ThaiL A TX support for L A TX 2ε consists of a babel extension and some font-agnostic and some per-font support files. To build the per-font support files, extract thailatex (version at the time of writing 10 ) and copy the two thailatex/fonts/*.enc files to both the top level of thaifonts-scalable (0.4.17) and thaifonts-arundina (0.1.3) as well as a few of their inner directories: cp thailatex/fonts/*.enc thaifonts-scalable/ cp thailatex/fonts/*.enc thaifonts-scalable/nectec/ cp thailatex/fonts/*.enc thaifonts-scalable/tlwg/ cp thailatex/fonts/*.enc thaifonts-scalable/nf/ cp thailatex/fonts/*.enc thaifonts-arundina/ cp thailatex/fonts/*.enc thaifonts-arundina/arundina/ The copying to top-level is to allow --enable-latex to work, thaifonts-scalable./configure --enable-pfb --enable-otf --enable-testfont \ --enable-xfontsdir --enable-latex thaifonts-arundina./configure --enable-pfb --enable-latex Running make after./configure uses the inner copies. Afterwards, many new files are generated. One should also run./configure; make in thailatex. That s for the relatively trivial task of building one needed file new, thai.ldf. Set up a set of directories, and set your environment variables as below: NV variables File types Move from TFMFONTS *.tfm thaifonts-*/*/*.tfm NCFONTS *.enc thailatex/fonts/*.enc TXPSHADRS *.enc thailatex/fonts/*.enc TXFONTMAPS *.map thaifonts-*/*/*.map AFMFONTS *.afm VFFONTS *.vf thaifonts-*/*/*.vf TXINPUTS *.fd, *.sty, *.def, *.ldf thaifonts-*/*/*.{fd,sty} TXINPUTS (cont) *.fd, *.sty, *.def, *.ldf thailatex/babel/*.{def,sty,ldf} T1FONTS *.pfb 10 It is a bit higher than 0.4.6, and one of the post changes is renaming thswitch.sty to fonts-tlwg.sty, which is important to this discussion. 4

5 TexLive 2011 already ships the *.afm files and the *.pfb files, so those two entries are listed above only for completeness. Both dvips and pdflatex needs the *.enc files, but access them through different variables, hence both NCFONTS and TXPSHADRS above. At this point, run updmap as follows: updmap --enable Map=arundina.map updmap --enable Map=nectec.map updmap --enable Map=nf.map updmap --enable Map=tlwg.map This creates or updates ${HOM}/.texlive2011/texmf-config/web2c/updmap.cfg as well as ${HOM}/.texlive2011/texmf-var/fonts/map/*/updmap/*, and one should be able to run thailatex s or thaifonts-* s examples, without modifying the system s TeXLive 2011 installation. System-wide installation can be achieved by copying the files to location of similar files under TeXLive s TXMF, run texhash to update the file location database, and updmap-sys. That doesn t work well with system-wide upgrades and is messy though. 3.2 Installing ThaiLaTeX on Windows or MikTeX Apparently TexLive 2011 also runs on windows. Presumably one can simply copy all the files mentioned above (obtained from a ready-made source) into the relevant directories. MikTeX also seems to have a updmap utility which works in a similar role. More information needed here. 5