diff options
Diffstat (limited to 'tex/context/base/mkxl/font-otl.lmt')
| -rw-r--r-- | tex/context/base/mkxl/font-otl.lmt | 889 |
1 files changed, 889 insertions, 0 deletions
diff --git a/tex/context/base/mkxl/font-otl.lmt b/tex/context/base/mkxl/font-otl.lmt new file mode 100644 index 000000000..f493bc327 --- /dev/null +++ b/tex/context/base/mkxl/font-otl.lmt @@ -0,0 +1,889 @@ +if not modules then modules = { } end modules ['font-otl'] = { + version = 1.001, + comment = "companion to font-ini.mkiv", + author = "Hans Hagen, PRAGMA-ADE, Hasselt NL", + copyright = "PRAGMA ADE / ConTeXt Development Team", + license = "see context related readme files", +} + +-- After some experimenting with an alternative loader (one that is needed for +-- getting outlines in mp) I decided not to be compatible with the old (built-in) +-- one. The approach used in font-otn is as follows: we load the font in a compact +-- format but still very compatible with the ff data structures. From there we +-- create hashes to access the data efficiently. The implementation of feature +-- processing is mostly based on looking at the data as organized in the glyphs and +-- lookups as well as the specification. Keeping the lookup data in the glyphs is +-- very instructive and handy for tracing. On the other hand hashing is what brings +-- speed. So, the in the new approach (the old one will stay around too) we no +-- longer keep data in the glyphs which saves us a (what in retrospect looks a bit +-- like) a reconstruction step. It also means that the data format of the cached +-- files changes. What method is used depends on that format. There is no fundamental +-- change in processing, and not even in data organation. Most has to do with +-- loading and storage. + +-- todo: less tounicodes + +local lower = string.lower +local type, next, tonumber, tostring, unpack = type, next, tonumber, tostring, unpack +local abs = math.abs +local derivetable, sortedhash = table.derive, table.sortedhash +local formatters = string.formatters + +local setmetatableindex = table.setmetatableindex +local allocate = utilities.storage.allocate +local registertracker = trackers.register +local registerdirective = directives.register +local starttiming = statistics.starttiming +local stoptiming = statistics.stoptiming +local elapsedtime = statistics.elapsedtime +local findbinfile = resolvers.findbinfile + +----- trace_private = false registertracker("otf.private", function(v) trace_private = v end) +----- trace_subfonts = false registertracker("otf.subfonts", function(v) trace_subfonts = v end) +local trace_loading = false registertracker("otf.loading", function(v) trace_loading = v end) +local trace_features = false registertracker("otf.features", function(v) trace_features = v end) +----- trace_dynamics = false registertracker("otf.dynamics", function(v) trace_dynamics = v end) +----- trace_sequences = false registertracker("otf.sequences", function(v) trace_sequences = v end) +----- trace_markwidth = false registertracker("otf.markwidth", function(v) trace_markwidth = v end) +local trace_defining = false registertracker("fonts.defining", function(v) trace_defining = v end) + +local report_otf = logs.reporter("fonts","otf loading") + +local fonts = fonts +local otf = fonts.handlers.otf + +otf.version = 3.119 -- beware: also sync font-mis.lua and in mtx-fonts +otf.cache = containers.define("fonts", "otl", otf.version, true) +otf.svgcache = containers.define("fonts", "svg", otf.version, true) +otf.pngcache = containers.define("fonts", "png", otf.version, true) +otf.pdfcache = containers.define("fonts", "pdf", otf.version, true) +otf.mpscache = containers.define("fonts", "mps", otf.version, true) + +otf.svgenabled = false +otf.pngenabled = false + +local otfreaders = otf.readers + +local hashes = fonts.hashes +local definers = fonts.definers +local readers = fonts.readers +local constructors = fonts.constructors + +local otffeatures = constructors.features.otf +local registerotffeature = otffeatures.register + +local otfenhancers = constructors.enhancers.otf +local registerotfenhancer = otfenhancers.register + +local forceload = false +local cleanup = 0 -- mk: 0=885M 1=765M 2=735M (regular run 730M) +local syncspace = true +local forcenotdef = false + +local privateoffset = fonts.constructors and fonts.constructors.privateoffset or 0xF0000 -- 0x10FFFF + +local applyruntimefixes = fonts.treatments and fonts.treatments.applyfixes + +local wildcard = "*" +local default = "dflt" + +local formats = fonts.formats + +formats.otf = "opentype" +formats.ttf = "truetype" +formats.ttc = "truetype" + +registerdirective("fonts.otf.loader.cleanup", function(v) cleanup = tonumber(v) or (v and 1) or 0 end) +registerdirective("fonts.otf.loader.force", function(v) forceload = v end) +registerdirective("fonts.otf.loader.syncspace", function(v) syncspace = v end) +registerdirective("fonts.otf.loader.forcenotdef", function(v) forcenotdef = v end) + +-- otfenhancers.patch("before","migrate metadata","cambria",function() end) + +registerotfenhancer("check extra features", function() end) -- placeholder + +-- Kai has memory problems on osx so here is an experiment (I only tested on windows as +-- my test mac is old and gets no updates and is therefore rather useless.): + +local checkmemory = utilities.lua and utilities.lua.checkmemory +local threshold = 100 -- MB +local tracememory = false + +registertracker("fonts.otf.loader.memory",function(v) tracememory = v end) + +if not checkmemory then -- we need a generic plug (this code might move): + + local collectgarbage = collectgarbage + + checkmemory = function(previous,threshold) -- threshold in MB + local current = collectgarbage("count") + if previous then + local checked = (threshold or 64)*1024 + if current - previous > checked then + collectgarbage("collect") + current = collectgarbage("count") + end + end + return current + end + +end + +function otf.load(filename,sub,instance) + local base = file.basename(file.removesuffix(filename)) + local name = file.removesuffix(base) -- already no suffix + local attr = lfs.attributes(filename) + local size = attr and attr.size or 0 + local time = attr and attr.modification or 0 + -- sub can be number of string + if sub == "" then + sub = false + end + local hash = name + if sub then + hash = hash .. "-" .. sub + end + if instance then + hash = hash .. "-" .. instance + end + hash = containers.cleanname(hash) + local data = containers.read(otf.cache,hash) + local reload = not data or data.size ~= size or data.time ~= time or data.tableversion ~= otfreaders.tableversion + if forceload then + report_otf("forced reload of %a due to hard coded flag",filename) + reload = true + end + if reload then + report_otf("loading %a, hash %a",filename,hash) + -- + starttiming(otfreaders,true) + data = otfreaders.loadfont(filename,sub or 1,instance) -- we can pass the number instead (if it comes from a name search) + if data then + -- todo: make this a plugin + local used = checkmemory() + local resources = data.resources + local svgshapes = resources.svgshapes + local pngshapes = resources.pngshapes + if cleanup == 0 then + checkmemory(used,threshold,tracememory) + end + if svgshapes then + resources.svgshapes = nil + if otf.svgenabled then + local timestamp = os.date() + -- work in progress ... a bit boring to do + containers.write(otf.svgcache,hash, { + svgshapes = svgshapes, + timestamp = timestamp, + }) + data.properties.svg = { + hash = hash, + timestamp = timestamp, + } + end + if cleanup > 1 then + collectgarbage("collect") + else + checkmemory(used,threshold,tracememory) + end + end + if pngshapes then + resources.pngshapes = nil + if otf.pngenabled then + local timestamp = os.date() + -- work in progress ... a bit boring to do + containers.write(otf.pngcache,hash, { + pngshapes = pngshapes, + timestamp = timestamp, + }) + data.properties.png = { + hash = hash, + timestamp = timestamp, + } + end + if cleanup > 1 then + collectgarbage("collect") + else + checkmemory(used,threshold,tracememory) + end + end + -- + otfreaders.compact(data) + if cleanup == 0 then + checkmemory(used,threshold,tracememory) + end + otfreaders.rehash(data,"unicodes") + otfreaders.addunicodetable(data) + otfreaders.extend(data) + if cleanup == 0 then + checkmemory(used,threshold,tracememory) + end + if context then + otfreaders.condense(data) + end + otfreaders.pack(data) + report_otf("loading done") + report_otf("saving %a in cache",filename) + data = containers.write(otf.cache, hash, data) + if cleanup > 1 then + collectgarbage("collect") + else + checkmemory(used,threshold,tracememory) + end + stoptiming(otfreaders) + if elapsedtime then + report_otf("loading, optimizing, packing and caching time %s", elapsedtime(otfreaders)) + end + if cleanup > 3 then + collectgarbage("collect") + else + checkmemory(used,threshold,tracememory) + end + data = containers.read(otf.cache,hash) -- this frees the old table and load the sparse one + if cleanup > 2 then + collectgarbage("collect") + else + checkmemory(used,threshold,tracememory) + end + else + stoptiming(otfreaders) + data = nil + report_otf("loading failed due to read error") + end + end + if data then + if trace_defining then + report_otf("loading from cache using hash %a",hash) + end + -- + otfreaders.unpack(data) + otfreaders.expand(data) -- inline tables + otfreaders.addunicodetable(data) -- only when not done yet + -- + otfenhancers.apply(data,filename,data) -- in context one can also use treatments + -- + -- constructors.addcoreunicodes(data.resources.unicodes) -- still needed ? + -- + if applyruntimefixes then + applyruntimefixes(filename,data) -- e.g. see treatments.lfg + end + -- + data.metadata.math = data.resources.mathconstants + -- + -- delayed tables (experiment) + -- + local classes = data.resources.classes + if not classes then + local descriptions = data.descriptions + classes = setmetatableindex(function(t,k) + local d = descriptions[k] + local v = (d and d.class or "base") or false + t[k] = v + return v + end) + data.resources.classes = classes + end + -- + end + + return data +end + +-- modes: node, base, none + +function otf.setfeatures(tfmdata,features) + local okay = constructors.initializefeatures("otf",tfmdata,features,trace_features,report_otf) + if okay then + return constructors.collectprocessors("otf",tfmdata,features,trace_features,report_otf) + else + return { } -- will become false + end +end + +-- the first version made a top/mid/not extensible table, now we just +-- pass on the variants data and deal with it in the tfm scaler (there +-- is no longer an extensible table anyway) +-- +-- we cannot share descriptions as virtual fonts might extend them (ok, +-- we could use a cache with a hash +-- +-- we already assign an empty table to characters as we can add for +-- instance protruding info and loop over characters; one is not supposed +-- to change descriptions and if one does so one should make a copy! + +local function copytotfm(data,cache_id) + if data then + local metadata = data.metadata + local properties = derivetable(data.properties) + local descriptions = derivetable(data.descriptions) + local goodies = derivetable(data.goodies) + local characters = { } -- newtable if we knwo how many + local parameters = { } + local mathparameters = { } + -- + local resources = data.resources + local unicodes = resources.unicodes + local spaceunits = 500 + local spacer = "space" + local designsize = metadata.designsize or 100 + local minsize = metadata.minsize or designsize + local maxsize = metadata.maxsize or designsize + local mathspecs = metadata.math + -- + if designsize == 0 then + designsize = 100 + minsize = 100 + maxsize = 100 + end + if mathspecs then + for name, value in next, mathspecs do + mathparameters[name] = value + end + end + for unicode in next, data.descriptions do -- use parent table + characters[unicode] = { } + end + if mathspecs then + for unicode, character in next, characters do + local d = descriptions[unicode] -- we could use parent table here + local m = d.math + if m then + -- watch out: luatex uses hvariants for the parts + -- + local italic = m.italic + local vitalic = m.vitalic + -- + local variants = m.hvariants + local parts = m.hparts + if variants then + local c = character + for i=1,#variants do + -- local un = variants[i].glyph + local un = variants[i] + c.next = un + c = characters[un] + end -- c is now last in chain + c.hvariants = parts + elseif parts then + character.hvariants = parts + italic = m.hitalic + end + -- + local variants = m.vvariants + local parts = m.vparts + if variants then + local c = character + for i=1,#variants do + -- local un = variants[i].glyph + local un = variants[i] + c.next = un + c = characters[un] + end -- c is now last in chain + c.vvariants = parts + elseif parts then + character.vvariants = parts + end + -- + if italic and italic ~= 0 then + character.italic = italic + end + -- + if vitalic and vitalic ~= 0 then + character.vitalic = vitalic + end + -- + local accent = m.accent -- taccent? + if accent then + character.accent = accent + end + -- + local kerns = m.kerns + if kerns then + character.mathkerns = kerns + end + end + end + end + -- we need a runtime lookup because of running from cdrom or zip, brrr (shouldn't + -- we use the basename then?) + local filename = constructors.checkedfilename(resources) + local fontname = metadata.fontname + local fullname = metadata.fullname or fontname + local psname = fontname or fullname + local subfont = metadata.subfontindex + local units = metadata.units or 1000 + -- + if units == 0 then -- catch bugs in fonts + units = 1000 -- maybe 2000 when ttf + metadata.units = 1000 + report_otf("changing %a units to %a",0,units) + end + -- + local monospaced = metadata.monospaced + local charwidth = metadata.averagewidth -- or unset + local charxheight = metadata.xheight -- or unset + local italicangle = metadata.italicangle + local hasitalics = metadata.hasitalics + properties.monospaced = monospaced + properties.hasitalics = hasitalics + parameters.italicangle = italicangle + parameters.charwidth = charwidth + parameters.charxheight = charxheight + -- + local space = 0x0020 + local emdash = 0x2014 + if monospaced then + if descriptions[space] then + spaceunits, spacer = descriptions[space].width, "space" + end + if not spaceunits and descriptions[emdash] then + spaceunits, spacer = descriptions[emdash].width, "emdash" + end + if not spaceunits and charwidth then + spaceunits, spacer = charwidth, "charwidth" + end + else + if descriptions[space] then + spaceunits, spacer = descriptions[space].width, "space" + end + if not spaceunits and descriptions[emdash] then + spaceunits, spacer = descriptions[emdash].width/2, "emdash/2" + end + if not spaceunits and charwidth then + spaceunits, spacer = charwidth, "charwidth" + end + end + spaceunits = tonumber(spaceunits) or units/2 + -- + parameters.slant = 0 + parameters.space = spaceunits -- 3.333 (cmr10) + parameters.spacestretch = 1*units/2 -- 500 -- 1.666 (cmr10) + parameters.spaceshrink = 1*units/3 -- 333 -- 1.111 (cmr10) + parameters.xheight = 2*units/5 -- 400 + parameters.quad = units -- 1000 + if spaceunits < 2*units/5 then + -- todo: warning + end + if italicangle and italicangle ~= 0 then + parameters.italicangle = italicangle + parameters.italicfactor = math.cos(math.rad(90+italicangle)) + parameters.slant = - math.tan(italicangle*math.pi/180) + end + if monospaced then + parameters.spacestretch = 0 + parameters.spaceshrink = 0 + elseif syncspace then -- + parameters.spacestretch = spaceunits/2 + parameters.spaceshrink = spaceunits/3 + end + parameters.extraspace = parameters.spaceshrink -- 1.111 (cmr10) + if charxheight then + parameters.xheight = charxheight + else + local x = 0x0078 + if x then + local x = descriptions[x] + if x then + parameters.xheight = x.height + end + end + end + -- + parameters.designsize = (designsize/10)*65536 + parameters.minsize = (minsize /10)*65536 + parameters.maxsize = (maxsize /10)*65536 + parameters.ascender = abs(metadata.ascender or 0) + parameters.descender = abs(metadata.descender or 0) + parameters.units = units + parameters.vheight = metadata.defaultvheight + -- + properties.space = spacer + properties.format = data.format or formats.otf + properties.filename = filename + properties.fontname = fontname + properties.fullname = fullname + properties.psname = psname + properties.name = filename or fullname + properties.subfont = subfont + -- +if not CONTEXTLMTXMODE or CONTEXTLMTXMODE == 0 then + -- + properties.encodingbytes = 2 +elseif CONTEXTLMTXMODE then + local duplicates = resources and resources.duplicates + if duplicates then + local maxindex = data.nofglyphs or metadata.nofglyphs + if maxindex then + for u, d in sortedhash(duplicates) do + local du = descriptions[u] + if du then + for uu in sortedhash(d) do + maxindex = maxindex + 1 + descriptions[uu].dupindex = du.index + descriptions[uu].index = maxindex + end + else + -- report_otf("no %U in font %a, duplicates ignored",u,filename) + end + end + end + end + -- +end + -- + -- properties.name = specification.name + -- properties.sub = specification.sub + -- + properties.private = properties.private or data.private or privateoffset + -- + return { + characters = characters, + descriptions = descriptions, + parameters = parameters, + mathparameters = mathparameters, + resources = resources, + properties = properties, + goodies = goodies, + } + end +end + +-- These woff files are a kind of joke in a tex environment because one can simply convert +-- them to ttf/otf and use them as such (after all, we cache them too). The successor format +-- woff2 is more complex so there we can as well call an external converter which in the end +-- makes this code kind of obsolete before it's even used. Although ... it might become a +-- more general conversion plug in. + +local converters = { + woff = { + cachename = "webfonts", + action = otf.readers.woff2otf, + } +} + +-- We can get differences between daylight saving etc ... but it makes no sense to +-- mess with trickery .. so be it when you use a different binary. + +local function checkconversion(specification) + local filename = specification.filename + local converter = converters[lower(file.suffix(filename))] + if converter then + local base = file.basename(filename) + local name = file.removesuffix(base) + local attr = lfs.attributes(filename) + local size = attr and attr.size or 0 + local time = attr and attr.modification or 0 + if size > 0 then + local cleanname = containers.cleanname(name) + local cachename = caches.setfirstwritablefile(cleanname,converter.cachename) + if not io.exists(cachename) or (time ~= lfs.attributes(cachename).modification) then + report_otf("caching font %a in %a",filename,cachename) + converter.action(filename,cachename) -- todo infoonly + lfs.touch(cachename,time,time) + end + specification.filename = cachename + end + end +end + +local function otftotfm(specification) + local cache_id = specification.hash + local tfmdata = containers.read(constructors.cache,cache_id) + if not tfmdata then + + checkconversion(specification) -- for the moment here + + local name = specification.name + local sub = specification.sub + local subindex = specification.subindex + local filename = specification.filename + local features = specification.features.normal + local instance = specification.instance or (features and features.axis) + local rawdata = otf.load(filename,sub,instance) + if rawdata and next(rawdata) then + local descriptions = rawdata.descriptions + rawdata.lookuphash = { } -- to be done + tfmdata = copytotfm(rawdata,cache_id) + if tfmdata and next(tfmdata) then + -- at this moment no characters are assigned yet, only empty slots + local features = constructors.checkedfeatures("otf",features) + local shared = tfmdata.shared + if not shared then + shared = { } + tfmdata.shared = shared + end + shared.rawdata = rawdata + -- shared.features = features -- default + shared.dynamics = { } + -- shared.processes = { } + tfmdata.changed = { } + shared.features = features + shared.processes = otf.setfeatures(tfmdata,features) + end + end + containers.write(constructors.cache,cache_id,tfmdata) + end + return tfmdata +end + +local function read_from_otf(specification) + local tfmdata = otftotfm(specification) + if tfmdata then + -- this late ? .. needs checking + tfmdata.properties.name = specification.name + tfmdata.properties.sub = specification.sub + tfmdata.properties.id = specification.id + -- + tfmdata = constructors.scale(tfmdata,specification) + local allfeatures = tfmdata.shared.features or specification.features.normal + constructors.applymanipulators("otf",tfmdata,allfeatures,trace_features,report_otf) + constructors.setname(tfmdata,specification) -- only otf? + fonts.loggers.register(tfmdata,file.suffix(specification.filename),specification) + end + return tfmdata +end + +local function checkmathsize(tfmdata,mathsize) + local mathdata = tfmdata.shared.rawdata.metadata.math + local mathsize = tonumber(mathsize) + if mathdata then -- we cannot use mathparameters as luatex will complain + local parameters = tfmdata.parameters + parameters.scriptpercentage = mathdata.ScriptPercentScaleDown + parameters.scriptscriptpercentage = mathdata.ScriptScriptPercentScaleDown + parameters.mathsize = mathsize -- only when a number ! + end +end + +registerotffeature { + name = "mathsize", + description = "apply mathsize specified in the font", + initializers = { + base = checkmathsize, + node = checkmathsize, + } +} + +-- readers + +function otf.collectlookups(rawdata,kind,script,language) + if not kind then + return + end + if not script then + script = default + end + if not language then + language = default + end + local lookupcache = rawdata.lookupcache + if not lookupcache then + lookupcache = { } + rawdata.lookupcache = lookupcache + end + local kindlookup = lookupcache[kind] + if not kindlookup then + kindlookup = { } + lookupcache[kind] = kindlookup + end + local scriptlookup = kindlookup[script] + if not scriptlookup then + scriptlookup = { } + kindlookup[script] = scriptlookup + end + local languagelookup = scriptlookup[language] + if not languagelookup then + local sequences = rawdata.resources.sequences + local featuremap = { } + local featurelist = { } + if sequences then + for s=1,#sequences do + local sequence = sequences[s] + local features = sequence.features + if features then + features = features[kind] + if features then + -- features = features[script] or features[default] or features[wildcard] + features = features[script] or features[wildcard] + if features then + -- features = features[language] or features[default] or features[wildcard] + features = features[language] or features[wildcard] + if features then + if not featuremap[sequence] then + featuremap[sequence] = true + featurelist[#featurelist+1] = sequence + end + end + end + end + end + end + if #featurelist == 0 then + featuremap, featurelist = false, false + end + else + featuremap, featurelist = false, false + end + languagelookup = { featuremap, featurelist } + scriptlookup[language] = languagelookup + end + return unpack(languagelookup) +end + +-- moved from font-oth.lua, todo: also afm + +local function getgsub(tfmdata,k,kind,value) + local shared = tfmdata.shared + local rawdata = shared and shared.rawdata + if rawdata then + local sequences = rawdata.resources.sequences + if sequences then + local properties = tfmdata.properties + local validlookups, lookuplist = otf.collectlookups(rawdata,kind,properties.script,properties.language) + if validlookups then + -- local choice = tonumber(value) or 1 -- no random here (yet) + for i=1,#lookuplist do + local lookup = lookuplist[i] + local steps = lookup.steps + local nofsteps = lookup.nofsteps + for i=1,nofsteps do + local coverage = steps[i].coverage + if coverage then + local found = coverage[k] + if found then + return found, lookup.type + end + end + end + end + end + end + end +end + +otf.getgsub = getgsub -- returns value, gsub_kind + +function otf.getsubstitution(tfmdata,k,kind,value) + local found, kind = getgsub(tfmdata,k,kind,value) + if not found then + -- + elseif kind == "gsub_single" then + return found + elseif kind == "gsub_alternate" then + local choice = tonumber(value) or 1 -- no random here (yet) + return found[choice] or found[1] or k + end + return k +end + +otf.getalternate = otf.getsubstitution + +function otf.getmultiple(tfmdata,k,kind) + local found, kind = getgsub(tfmdata,k,kind) + if found and kind == "gsub_multiple" then + return found + end + return { k } +end + +function otf.getkern(tfmdata,left,right,kind) + local kerns = getgsub(tfmdata,left,kind or "kern",true) -- for now we use getsub + if kerns then + local found = kerns[right] + local kind = type(found) + if kind == "table" then + found = found[1][3] -- can be more clever + elseif kind ~= "number" then + found = false + end + if found then + return found * tfmdata.parameters.factor + end + end + return 0 +end + +local function check_otf(forced,specification,suffix) + local name = specification.name + if forced then + name = specification.forcedname -- messy + end + local fullname = findbinfile(name,suffix) or "" + if fullname == "" then + fullname = fonts.names.getfilename(name,suffix) or "" + end + if fullname ~= "" and not fonts.names.ignoredfile(fullname) then + specification.filename = fullname + return read_from_otf(specification) + end +end + +local function opentypereader(specification,suffix) + local forced = specification.forced or "" + if formats[forced] then + return check_otf(true,specification,forced) + else + return check_otf(false,specification,suffix) + end +end + +readers.opentype = opentypereader -- kind of useless and obsolete + +function readers.otf(specification) return opentypereader(specification,"otf") end +function readers.ttf(specification) return opentypereader(specification,"ttf") end +function readers.ttc(specification) return opentypereader(specification,"ttf") end + +function readers.woff(specification) + checkconversion(specification) + opentypereader(specification,"") +end + +-- this will be overloaded + +function otf.scriptandlanguage(tfmdata,attr) + local properties = tfmdata.properties + return properties.script or "dflt", properties.language or "dflt" +end + +-- a little bit of abstraction + +local function justset(coverage,unicode,replacement) + coverage[unicode] = replacement +end + +otf.coverup = { + stepkey = "steps", + actions = { + chainsubstitution = justset, + chainposition = justset, + substitution = justset, + alternate = justset, + multiple = justset, + kern = justset, + pair = justset, + single = justset, + ligature = function(coverage,unicode,ligature) + local first = ligature[1] + local tree = coverage[first] + if not tree then + tree = { } + coverage[first] = tree + end + for i=2,#ligature do + local l = ligature[i] + local t = tree[l] + if not t then + t = { } + tree[l] = t + end + tree = t + end + tree.ligature = unicode + end, + }, + register = function(coverage,featuretype,format) + return { + format = format, + coverage = coverage, + } + end +} |