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diff --git a/doc/context/sources/general/manuals/mk/mk-arabic.tex b/doc/context/sources/general/manuals/mk/mk-arabic.tex new file mode 100644 index 000000000..a9f9e52d9 --- /dev/null +++ b/doc/context/sources/general/manuals/mk/mk-arabic.tex @@ -0,0 +1,324 @@ +% language=uk + +\startcomponent mk-arabic + +\environment mk-environment + +\disablemode[dynamic-arabic] % to be checked, we loose colors + +\definefontfeature + [arab-none] + [mode=node,language=dflt,script=arab] + +\definefontfeature + [arab-compose] + [mode=node,language=dflt,script=arab, + ccmp=yes] + +\definefontfeature + [arab-replace] + [mode=node,language=dflt,script=arab, + ccmp=yes, + init=yes,medi=yes,fina=yes,isol=yes] + +\definefontfeature + [arab-mark] + [mode=node,language=dflt,script=arab, + ccmp=yes, + init=yes,medi=yes,fina=yes,isol=yes, + mark=yes] + +\definefontfeature + [arab-mkmk] + [mode=node,language=dflt,script=arab, + ccmp=yes, + init=yes,medi=yes,fina=yes,isol=yes, + mark=yes,mkmk=yes] + +\definefontfeature + [arab-kern] + [mode=node,language=dflt,script=arab, + ccmp=yes, + init=yes,medi=yes,fina=yes,isol=yes, + mark=yes,mkmk=yes, + kern=yes] + +\definefontfeature[arab-context] + [mode=node,language=dflt,script=arab, + ccmp=yes, + init=yes,medi=yes,fina=yes,isol=yes, + mark=yes,mkmk=yes, + kern=yes, + calt=yes] + +\definefontfeature + [arab-ligs] + [mode=node,language=dflt,script=arab, + ccmp=yes, + init=yes,medi=yes,fina=yes,isol=yes, + liga=yes,dlig=yes,rlig=yes,clig=yes, + mkmk=yes,mark=yes, + kern=yes] + +\definefontfeature + [arab-curs] + [mode=node,language=dflt,script=arab, + ccmp=yes, + init=yes,medi=yes,fina=yes,isol=yes, + liga=yes,dlig=yes,rlig=yes,clig=yes, + mark=yes,mkmk=yes, + kern=yes,curs=yes] + +\definefontfeature + [arab-urdu] + [mode=node,language=urd,script=arab, + ccmp=yes, + init=yes,medi=yes,fina=yes,isol=yes, + liga=yes,dlig=yes,rlig=yes,clig=yes, + mark=yes,mkmk=yes, + kern=yes,curs=yes] + +\definefontfeature + [arab-default] + [mode=node,language=dflt,script=arab, + ccmp=yes, + init=yes,medi=yes,fina=yes,isol=yes, + liga=yes,dlig=yes,rlig=yes,clig=yes, + mark=yes,mkmk=yes,kern=yes,curs=yes] + +% \font \ArabNone = arabtype*arab-none at 48pt +% \font \ArabCompose = arabtype*arab-compose at 48pt +% \font \ArabReplace = arabtype*arab-replace at 48pt +% \font \ArabMark = arabtype*arab-mark at 48pt +% \font \ArabMkmk = arabtype*arab-mkmk at 48pt +% \font \ArabKern = arabtype*arab-kern at 48pt +% \font \ArabContext = arabtype*arab-context at 48pt +% \font \ArabLigs = arabtype*arab-ligs at 48pt +% \font \ArabCurs = arabtype*arab-curs at 48pt +% \font \ArabUrdu = arabtype*arab-urdu at 48pt + +% \startbuffer[word] +% \char1604\char1616\char1604\char1617\char1648\char1607\char1616 % لِلّٰهِ +% \stopbuffer + +\startbuffer[split-word] + \def\somechar #1{ \char#1\relax}% + \def\somevowel#1{ \char#1\relax}% + \dontleavehmode\ignorespaces\getbuffer[word]\removeunwantedspaces +\stopbuffer + +\startbuffer[normal-word] + \def\somechar #1{\char#1\relax}% + \def\somevowel#1{\char#1\relax}% + \ignorespaces\getbuffer[word]\removeunwantedspaces +\stopbuffer + +\startbuffer[word] + \somechar {1604}% + \somevowel{1616}% + \somechar {1604}% + \somevowel{1617}% + \somevowel{1648}% + \somechar {1607}% + \somevowel{1616}% + % لِلّٰهِ +\stopbuffer + +\startbuffer[word] + \somechar {"644}% + \somevowel{"650}% + \somechar {"644}% + \somevowel{"651}% + \somevowel{"670}% + \somechar {"647}% + \somevowel{"650}% + % لِلّٰهِ +\stopbuffer + +\startbuffer[paragraph] +اَلْحَمْدُ لِلّٰهِ حَمْدَ مُعْتَرِفٍ بِحَمْدِهٖ، مُغْتَرِفٌ مِنْ بِحَارِ مَجْدِهٖ، بِلِسَانِ +الثَّنَاۤءِ شَاكِرًا، وَلِحُسْنِ اٰلاۤئِهٖ نَاشِرًا؛ اَلَّذِيْ خَلَقَ الْمَوْتَ وَالْحَيٰوةَ، وَالْخَيْرَ +وَالشَّرَّ، وَالنَّفْعَ وَالضَّرَّ، وَالسُّكُوْنَ وَالْحَرَكَةَ، وَالْأَرْوَاحَ +وَالْأَجْسَامَ، وَالذِّكْرَ وَالنِّسْيَانَ. +\stopbuffer + +\def\ArabSampleFont{arabtype} + +\def\ShowArabSample#1% + {\begingroup + \blank + \enabletrackers[otf.analyzing] + \doifmodeelse{dynamic-arabic}{ + \font\ArabFont = \ArabSampleFont\space at 48pt + }{ + \font\ArabFont = \ArabSampleFont*#1 at 48pt + } + \font\ArabFontX = \ArabSampleFont\space at 24pt + \startlinecorrection + \bTABLE[framecolor=red,rulethickness=1pt,offset=1ex] + \bTR + \bTD[width=.8\textwidth] % [ny=2] + \tttf\fontfeatureslist[#1][, ]% + \eTD + \bTD[width=.2\textwidth,align={lohi,middle},offset=0pt]% + \ArabFont\doifmode{dynamic-arabic}{\setfontfeature{#1}}\textdir TRT\relax + \getbuffer[normal-word]% + \eTD + \eTR +% \bTR +% \bTD[width=9em,align={lohi,middle},offset=0pt]% +% \ArabFontX\textdir TRT\relax +% \getbuffer[split-word]% +% \eTD +% \eTR + \eTABLE + \stoplinecorrection + \blank + \doifmodeelse{dynamic-arabic}{ + \font\ArabFont = \ArabSampleFont\space at 24pt + \setfontfeature{#1}% + }{ + \font\ArabFont = \ArabSampleFont*#1 at 24pt + } + \ArabFont + \pardir TRT\relax\textdir TRT\relax\getbuffer[paragraph]\endgraf + \disabletrackers[otf.analyzing] + \pardir TRT\relax\textdir TRT\relax\getbuffer[paragraph]\endgraf + \endgroup} + +\chapter{Arabic} + +Let's start with admitting that I don't speak or read Arabic, and the sample +texts used here are part of what we use in the Oriental \TEX\ project for +exploring advanced Arabic typesetting. This chapter will not discuss arab +typesetting in much detail, but should be seen as complementing the \quote +{Onthology on Arabic Typesetting} written by Idris. Here I will only show what +the consequences are of applying features. Because we see glyphs but often still +deal with characters when analyzing what to do, we will use these terms mixed. + +The font that we use here is the \quote {arabtype} font by MicroSoft. This font +covers Latin scripts and Arabic and has a rich set of features. It's also a rather +big font, so it is a nice torture test for \LUATEX. + +First we show what \MKIV\ does with a sequence of characters when no features +are enabled by the user. We have turn on color tracing. This gives us some +feedback about the how the analyze worked out. Analyzing for Arabic boils down +to marking the initial, mid, final and isolated forms. We don't need to +explicitly enable analyzing, it's on by default. The \type {mode} flag is set +to \type {node} because we cannot use \TEX's default mechanism. When \LUATEX\ +and \MKIV\ are beyond beta stage, we will use that mode by default. + +\ShowArabSample {arab-none} + +Once these forms are identified, the \type {init}, \type {medi}, \type {fina} +and \type {isol} features can be applied since they need this information. As +you can see, different shapes show up. The vowels (marks in \OPENTYPE\ speak) +are not affected. It may not be entirely clear here, but these vowels don't have +width. + +\ShowArabSample {arab-compose} + +We start with some preparations with regards to combinations of marks. This +is really needed in order to get the right output. + +\ShowArabSample {arab-replace} + +The order in which features are applied is dictated by the font and users don't +need to bother about it. In the next example we enable the \type {mark} and +\type {mkmk} features. As with other positioning related features, these are +normally applied late in the feature chain. + +\ShowArabSample {arab-mark} + +The \type {mark} feature positions marks (vowels) relative to characters, also +known as mark to base. The \type {mkmk} feature positions marks to basemarks. + +\ShowArabSample {arab-mkmk} + +Kerning depends on the font. Some fonts don't need kerning, others may need +extensive relative positioning of characters (by now glyphs). + +\ShowArabSample {arab-kern} + +So far we only had rather straightforward replacements. More sophisticated +replacements are those driven by the context. In principle all replacements +can be context driven, but the \type {calt} and \type {clig} features are +normally dedicated to the real complex ones that take preceding and following +characters into account. + +\ShowArabSample {arab-context} + +Ligatures are often used to beautify Arabic typeset documents. Here we enable the +whole lot. + +\ShowArabSample {arab-ligs} + +Kerning deals with horizontal displacements, but \type {curs} (cursive) goes one +step further. As with marks, positioning is based on anchor points and resolving +them involves a bit of trickery because one needs to take into account that +characters may have vowels attached to them. + +\ShowArabSample {arab-curs} + +One script can serve multiple languages so let's see what happens when we switch to +Urdu. + +\ShowArabSample {arab-urdu} + +In practice one will enable most of the features. In \MKIV\ one can define feature +sets as follows: + +\starttyping +\definefontfeature + [arab-default] + [mode=node,language=dflt,script=arab, + init=yes,medi=yes,fina=yes,isol=yes, + liga=yes,dlig=yes,rlig=yes,clig=yes, + mark=yes,mkmk=yes,kern=yes,curs=yes] +\stoptyping + +Applying these features to fonts can be done in several ways, with as most basic +one: + +\starttyping +\font\ArabFont=arabtype*arab-default at 18pt +\stoptyping + +Normally one will do something like + +\starttyping +\definefont[ArabFont][arabtype*arab-default at 18pt] +\stoptyping + +or use typescripts to set up ap proper font collection, in which case we end +up with definitions that look like: + +\starttyping +\definefontsynonym[ArabType][name:arabtype][features=arab-default] +\definefontsynonym[Serif][ArabType] +\stoptyping + +More information about typescripts can be found in manuals and on the +\CONTEXT\ wiki. + +We end this chapter with showing two arabic fonts so that you can get a taste +if the differences: arabtype by MicroSoft and Palatino which is designed by +Herman Zapf for Linotype. + +\def\ArabSampleFont{arabtype} \ShowArabSample {arab-default} + +\def\ArabSampleFont{name:palatinoltarabic} \ShowArabSample {arab-default} + +These fonts are quite different in designsize: + +\def\Test{test} % (\the\dimexpr1em\relax)} + +\starttabulate[|r|c|c|c|] +\NC \NC \bf arabtype \NC \bf palatino \NC \NR +\NC \bf 10pt \NC \definedfont[arabtype at 10pt]\Test \NC \definedfont[name:palatinoltarabic at 10pt]\Test \NC \NR +\NC \bf 12pt \NC \definedfont[arabtype at 12pt]\Test \NC \definedfont[name:palatinoltarabic at 12pt]\Test \NC \NR +\NC \bf 18pt \NC \definedfont[arabtype at 18pt]\Test \NC \definedfont[name:palatinoltarabic at 18pt]\Test \NC \NR +\NC \bf 24pt \NC \definedfont[arabtype at 24pt]\Test \NC \definedfont[name:palatinoltarabic at 24pt]\Test \NC \NR +\stoptabulate + +\stopcomponent |