%D \module
%D   [      file=s-fonts-ligatures,
%D        version=2014.12.14,
%D          title=\CONTEXT\ Style File,
%D       subtitle=Show Fonts Ligatures,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA ADE \& \CONTEXT\ Development Team}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

% begin info
%
% title   : show some ligature building in fonts
%
% comment : we trace some ligatures that have rather different implementations in fontss
% status  : experimental, used for luatex testing
%
% end info

\definefontfeature
  [otfligaturetest]
  [analyze=off,
   ccmp=yes, % brill uses that .. not really ligatures !
  %clig=yes,
   script=latn,
   language=dflt]

\hyphenation{xf-fi-a}
\hyphenation{xff-i-b}
\hyphenation{xffi-c}
\hyphenation{xffid}

\registerhyphenationexception[xf-fi-a]
\registerhyphenationexception[xff-i-b]
\registerhyphenationexception[xffi-c]
\registerhyphenationexception[xffid]

\starttexdefinition showotfligaturescaption #1
    \bTD [align={flushleft,lohi},nx=3]
        \nohyphens
        \ttbf
        #1
    \eTD
\stoptexdefinition

\starttexdefinition showotfligatureslegend #1
    \bTD [width=6em,align={flushleft,lohi}]
        \nohyphens \ttxx original
    \eTD
    \bTD [width=6em,align={flushleft,lohi}]
        \nohyphens \ttxx expanded
    \eTD
    \bTD [width=6em,align={flushleft,lohi}]
        \nohyphens \ttxx traditional
    \eTD
\stoptexdefinition

\starttexdefinition showotfligaturesline #1#2
    \bTD[toffset=.5ex,frame=off]
        \starthyphenation[#1]
            \LigatureFont
            \showfontkerns
            \showdiscretionaries
            \begstrut#2\endstrut
            \par
        \stophyphenation
    \eTD
\stoptexdefinition

\def\showotfligaturescells{3}
%def\showotfligaturesnx   {12}
%def\showotfligatureswidth{18em}
\def\showotfligaturesnx   {\the\numexpr  4*\showotfligaturescells}
\def\showotfligatureswidth{\the\dimexpr6em*\showotfligaturescells}

\starttexdefinition showotfligaturesbanner #1
    \bTR[frame=off]
        \bTD [nx=\showotfligaturesnx,width=\showotfligatureswidth,align={middle,lohi},height=4ex]
            \tttf #1
        \eTD
    \eTR
\stoptexdefinition

\starttexdefinition showotfligaturescaptions #1
    \bTR[height=3ex,align={middle,lohi},bottomframe=off]
        \processcommalist[#1]\showotfligaturescaption
    \eTR
    \bTR[height=3ex,align={middle,lohi},topframe=off]
        \processcommalist[#1]\showotfligatureslegend
    \eTR
\stoptexdefinition

\starttexdefinition showotfligatureslineset #1
    \showotfligaturesline{original}   {#1}
    \showotfligaturesline{expanded}   {#1}
    \showotfligaturesline{traditional}{#1}
\stoptexdefinition


\starttexdefinition showotfligaturesparagraphset #1
    \showotfligatureslineset {
        \hsize         \zeropoint
        \lefthyphenmin \plustwo
        \righthyphenmin\plustwo
        #1
    }
\stoptexdefinition

\starttexdefinition showotfligaturesextremeset #1
    \showotfligatureslineset {
        \hsize         \zeropoint
        \lefthyphenmin \plusone
        \righthyphenmin\plusone
        #1
    }
\stoptexdefinition

\starttexdefinition showotfligatureslines #1
    \bTR[height=4ex,bottomframe=off]
        \processcommalist[#1]\showotfligatureslineset
    \eTR
\stoptexdefinition

\starttexdefinition showotfligaturesparagraphs #1
    \bTR[topframe=off]
        \processcommalist[#1]\showotfligaturesparagraphset
    \eTR
\stoptexdefinition

\starttexdefinition showotfligaturesextremes #1
    \bTR[topframe=off]
        \processcommalist[#1]\showotfligaturesextremeset
    \eTR
\stoptexdefinition

\starttexdefinition showotfligaturesdefaults
    \bTR
        \bTD [nx=\showotfligaturesnx,width=\showotfligatureswidth,align=middle,height=4ex,frame=off]
            \start \LigatureFont fb  \stop \quad
            \start \LigatureFont ff  \stop \quad
            \start \LigatureFont fi  \stop \quad
            \start \LigatureFont fk  \stop \quad
            \start \LigatureFont fl  \stop \quad
            \start \LigatureFont ft  \stop \quad
            \start \LigatureFont ffb \stop \quad
            \start \LigatureFont fff \stop \quad
            \start \LigatureFont ffi \stop \quad
            \start \LigatureFont ffl \stop \quad
            \start \LigatureFont ffk \stop \quad
            \start \LigatureFont fft \stop
        \eTD
    \eTR
\stoptexdefinition

\starttexdefinition showotfligaturesexample #1#2
    \showotfligaturescaptions  {#1}
    \showotfligatureslines     {#2}
    \showotfligaturesparagraphs{#2}
    \showotfligaturesextremes  {#2}
\stoptexdefinition

% todo: n -> and split in lua

\starttexdefinition showotfligaturesexamples
    \showotfligaturesexample
        {leafing,baffling,efficient,shifffahrt}
        {leafing,baffling,efficient,shifffahrt}
    \showotfligaturesexample
        {offbeat,effect,ef-fective,ef\-fective}
        {offbeat,effect,ef-fective,ef\-fective}
    \showotfligaturesexample
        {xf+fi+a,xff+i+b,xffi+c,xffid}
        {xffia,  xffib,  xffic, xffid}
\stoptexdefinition

\starttexdefinition showotfligatures [#1]
    \begingroup
        \getdummyparameters[font=Regular,features=default,#1]
        \definefont[LigatureFont][\dummyparameter{font}*\dummyparameter{features},otfligaturetest ht 2ex]
        \bTABLE[leftframe=off,rightframe=off]
            \showotfligaturesbanner{\dummyparameter{font} * \dummyparameter{features}}
            \showotfligaturesdefaults
            \showotfligaturesexamples
        \eTABLE
    \endgroup
\stoptexdefinition

\continueifinputfile{s-fonts-ligatures.mkiv}

\starttext

    \startTEXpage[offset=10pt] \showotfligatures[font=lmroman10-regular.otf, features=default]   \stopTEXpage
    \startTEXpage[offset=10pt] \showotfligatures[font=dejavu-serif.ttf,      features=default]   \stopTEXpage
    \startTEXpage[offset=10pt] \showotfligatures[font=minionpro.otf,         features=default]   \stopTEXpage
    \startTEXpage[offset=10pt] \showotfligatures[font=minionpro.otf,         features=smallcaps] \stopTEXpage
    \startTEXpage[offset=10pt] \showotfligatures[font=brill.otf,             features=default]   \stopTEXpage
    \startTEXpage[offset=10pt] \showotfligatures[font=gentiumplus-r.ttf,     features=default]   \stopTEXpage
    \startTEXpage[offset=10pt] \showotfligatures[font=cambria,               features=default]   \stopTEXpage

\stoptext

% \startluacode
%
%     local f = fonts.hashes.identifiers[true]
%
%     local sequences    = f.resources.sequences
%     local descriptions = f.shared.rawdata.descriptions
%     local lookuptypes  = f.resources.lookuptypes
%     local lookups      = f.resources.lookups
%
%     local ligatures = { "liga", "dlig", "rlig", "clig", "tlig", "ccmp" }
%     local found     = { }
%
%     for i=1,#sequences do
%         local sequence = sequences[i]
%         local features = sequence.features
%         for i=1,#ligatures do
%             local l = ligatures[i]
%             if features[l] then
%                 local subtables = sequence.subtables
%                 if subtables then
%                     for i=1,#subtables do
%                         local subtable = subtables[i]
%                         local lookup   = found[subtable]
%                         if lookup then
%                             lookup[l] = true
%                         else
%                             found[subtable] = { [l] = true }
%                         end
%                     end
%                 end
%             end
%         end
%     end
%
%     context.starttabulate { "|||T|T|T|" }
%
%     local function flush(l,v,start,unicode,data,done)
%         local features = found[l]
%         if features then
%             local lookuptype = lookuptypes[l]
%             if lookuptype == "ligature" then
%                 local t = { }
%                 for i=1,#v do
%                     t[i] = utf.char(v[i])
%                 end
%                 t = table.concat(t," ")
%                 if not done[t] then
%                     context.NC()
%                         context(t)
%                     context.NC()
%                         context(utf.char(unicode))
%                     context.NC()
%                         context(" %t",table.sortedkeys(features))
%                     context.NC()
%                         local name = data.name
%                         if name then
%                             context(name)
%                         end
%                     context.NC()
%                         context("%U",unicode)
%                     context.NC()
%                     context.NR()
%                     done[t] = true
%                 end
%             end
%         end
%     end
%
%     for unicode, data in table.sortedhash(descriptions) do
%         local slookups = data.slookups
%         local mlookups = data.mlookups
%         local done     = { }
%         if slookups then
%             for l, v in next, slookups do
%                 flush(l,v,1,unicode,data,done)
%             end
%         end
%         if mlookups then
%             for i=1,#mlookups do
%                 local v = mlookups[i]
%                 flush(v[1],v,2,unicode,data,done)
%             end
%         end
%     end
%
%     context.stoptabulate()
%
% \stopluacode