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|
if not modules then modules = { } end modules ['typo-krn'] = {
version = 1.001,
comment = "companion to typo-krn.mkiv",
author = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
copyright = "PRAGMA ADE / ConTeXt Development Team",
license = "see context related readme files"
}
-- glue is still somewhat suboptimal
local next, type, tonumber = next, type, tonumber
local utfchar = utf.char
local nodes, node, fonts = nodes, node, fonts
local tasks = nodes.tasks
local nuts = nodes.nuts
local nodepool = nuts.pool
local tonode = nuts.tonode
local tonut = nuts.tonut
local find_node_tail = nuts.tail
local free_node = nuts.free
local free_nodelist = nuts.flush_list
local copy_node = nuts.copy
local copy_nodelist = nuts.copy_list
local insert_node_before = nuts.insert_before
local insert_node_after = nuts.insert_after
local end_of_math = nuts.end_of_math
local getfield = nuts.getfield
local setfield = nuts.setfield
local getnext = nuts.getnext
local getprev = nuts.getprev
local getid = nuts.getid
local getattr = nuts.getattr
local setattr = nuts.setattr
local getfont = nuts.getfont
local getsubtype = nuts.getsubtype
local getchar = nuts.getchar
local texsetattribute = tex.setattribute
local unsetvalue = attributes.unsetvalue
local new_gluespec = nodepool.gluespec
local new_kern = nodepool.kern
local new_glue = nodepool.glue
local nodecodes = nodes.nodecodes
local kerncodes = nodes.kerncodes
local skipcodes = nodes.skipcodes
local disccodes = nodes.disccodes
local glyph_code = nodecodes.glyph
local kern_code = nodecodes.kern
local disc_code = nodecodes.disc
local glue_code = nodecodes.glue
local hlist_code = nodecodes.hlist
local vlist_code = nodecodes.vlist
local math_code = nodecodes.math
local discretionary_code = disccodes.discretionary
local kerning_code = kerncodes.kerning
local userkern_code = kerncodes.userkern
local userskip_code = skipcodes.userskip
local spaceskip_code = skipcodes.spaceskip
local xspaceskip_code = skipcodes.xspaceskip
local fonthashes = fonts.hashes
local fontdata = fonthashes.identifiers
local chardata = fonthashes.characters
local quaddata = fonthashes.quads
local markdata = fonthashes.marks
local fontproperties = fonthashes.properties
local fontdescriptions = fonthashes.descriptions
local fontfeatures = fonthashes.features
local tracers = nodes.tracers
local setcolor = tracers.colors.set
local resetcolor = tracers.colors.reset
local v_max = interfaces.variables.max
local v_auto = interfaces.variables.auto
typesetters = typesetters or { }
local typesetters = typesetters
typesetters.kerns = typesetters.kerns or { }
local kerns = typesetters.kerns
local report = logs.reporter("kerns")
local trace_ligatures = false trackers.register("typesetters.kerns.ligatures",function(v) trace_ligatures = v end)
kerns.mapping = kerns.mapping or { }
kerns.factors = kerns.factors or { }
local a_kerns = attributes.private("kern")
local a_fontkern = attributes.private('fontkern')
local contextsetups = fonts.specifiers.contextsetups
storage.register("typesetters/kerns/mapping", kerns.mapping, "typesetters.kerns.mapping")
storage.register("typesetters/kerns/factors", kerns.factors, "typesetters.kerns.factors")
local mapping = kerns.mapping
local factors = kerns.factors
-- one must use liga=no and mode=base and kern=yes
-- use more helpers
-- make sure it runs after all others
-- there will be a width adaptor field in nodes so this will change
-- todo: interchar kerns / disc nodes / can be made faster
-- todo: use insert_before etc
local gluefactor = 4 -- assumes quad = .5 enspace
kerns.keepligature = false -- just for fun (todo: control setting with key/value)
kerns.keeptogether = false -- just for fun (todo: control setting with key/value)
-- red : kept by dynamic feature
-- green : kept by static feature
-- blue : keep by goodie
function kerns.keepligature(n) -- might become default
local f = getfont(n)
local a = getattr(n,0) or 0
if trace_ligatures then
local c = getchar(n)
local d = fontdescriptions[f][c].name
if a > 0 and contextsetups[a].keepligatures == v_auto then
report("font %!font:name!, glyph %a, slot %X -> ligature %s, by %s feature %a",f,d,c,"kept","dynamic","keepligatures")
setcolor(n,"darkred")
return true
end
local k = fontfeatures[f].keepligatures
if k == v_auto then
report("font %!font:name!, glyph %a, slot %X -> ligature %s, by %s feature %a",f,d,c,"kept","static","keepligatures")
setcolor(n,"darkgreen")
return true
end
if not k then
report("font %!font:name!, glyph %a, slot %X -> ligature %s, by %s feature %a",f,d,c,"split","static","keepligatures")
resetcolor(n)
return false
end
local k = fontproperties[f].keptligatures
if not k then
report("font %!font:name!, glyph %a, slot %X -> ligature %s, %s goodie specification",f,d,c,"split","no")
resetcolor(n)
return false
end
if k and k[c] then
report("font %!font:name!, glyph %a, slot %X -> ligature %s, %s goodie specification",f,d,c,"kept","by")
setcolor(n,"darkblue")
return true
else
report("font %!font:name!, glyph %a, slot %X -> ligature %s, %s goodie specification",f,d,c,"split","by")
resetcolor(n)
return false
end
else
if a > 0 and contextsetups[a].keepligatures == v_auto then
return true
end
local k = fontfeatures[f].keepligatures
if k == v_auto then
return true
end
if not k then
return false
end
local k = fontproperties[f].keptligatures
if not k then
return false
end
if k and k[c] then
return true
end
end
end
-- can be optimized .. the prev thing .. but hardly worth the effort
local function kern_injector(fillup,kern)
if fillup then
local g = new_glue(kern)
local s = getfield(g,"spec")
setfield(s,"stretch",kern)
setfield(s,"stretch_order",1)
return g
else
return new_kern(kern)
end
end
local function spec_injector(fillup,width,stretch,shrink)
if fillup then
local s = new_gluespec(width,2*stretch,2*shrink)
setfield(s,"stretch_order",1)
return s
else
return new_gluespec(width,stretch,shrink)
end
end
-- needs checking ... base mode / node mode -- also use insert_before/after etc
local function do_process(head,force) -- todo: glue so that we can fully stretch
local start, done, lastfont = head, false, nil
local keepligature = kerns.keepligature
local keeptogether = kerns.keeptogether
local fillup = false
while start do
-- faster to test for attr first
local attr = force or getattr(start,a_kerns)
if attr and attr > 0 then
setattr(start,a_kerns,unsetvalue)
local krn = mapping[attr]
if krn == v_max then
krn = .25
fillup = true
else
fillup = false
end
if krn and krn ~= 0 then
local id = getid(start)
if id == glyph_code then -- we could use the subtype ligature
lastfont = getfont(start)
local c = getfield(start,"components")
if not c then
-- fine
elseif keepligature and keepligature(start) then
-- keep 'm
else
c = do_process(c,attr)
local s = start
local p, n = getprev(s), getnext(s)
local tail = find_node_tail(c)
if p then
setfield(p,"next",c)
setfield(c,"prev",p)
else
head = c
end
if n then
setfield(n,"prev",tail)
end
setfield(tail,"next",n)
start = c
setfield(s,"components",nil)
-- we now leak nodes !
-- free_node(s)
done = true
end
local prev = getprev(start)
if not prev then
-- skip
elseif markdata[lastfont][getchar(start)] then
-- skip
else
local pid = getid(prev)
if not pid then
-- nothing
elseif pid == kern_code then
if getsubtype(prev) == kerning_code or getattr(prev,a_fontkern) then
if keeptogether and getid(getprev(prev)) == glyph_code and keeptogether(getprev(prev),start) then -- we could also pass start
-- keep 'm
else
-- not yet ok, as injected kerns can be overlays (from node-inj.lua)
setfield(prev,"subtype",userkern_code)
setfield(prev,"kern",getfield(prev,"kern") + quaddata[lastfont]*krn) -- here
done = true
end
end
elseif pid == glyph_code then
if getfont(prev) == lastfont then
local prevchar, lastchar = getchar(prev), getchar(start)
if keeptogether and keeptogether(prev,start) then
-- keep 'm
else
local kerns = chardata[lastfont][prevchar].kerns
local kern = kerns and kerns[lastchar] or 0
krn = kern + quaddata[lastfont]*krn -- here
insert_node_before(head,start,kern_injector(fillup,krn))
done = true
end
else
krn = quaddata[lastfont]*krn -- here
insert_node_before(head,start,kern_injector(fillup,krn))
done = true
end
elseif pid == disc_code then
-- a bit too complicated, we can best not copy and just calculate
-- but we could have multiple glyphs involved so ...
local disc = prev -- disc
local prv, nxt = getprev(disc), getnext(disc)
if getsubtype(disc) == discretionary_code then
-- maybe we should forget about this variant as there is no glue
-- possible
local pre, post, replace = getfield(disc,"pre"), getfield(disc,"post"), getfield(disc,"replace")
if pre and prv then -- must pair with getprev(start)
local before = copy_node(prv)
setfield(pre,"prev",before)
setfield(before,"next",pre)
setfield(before,"prev",nil)
pre = do_process(before,attr)
pre = getnext(pre)
setfield(pre,"prev",nil)
setfield(disc,"pre",pre)
free_node(before)
end
if post and nxt then -- must pair with start
local after = copy_node(nxt)
local tail = find_node_tail(post)
setfield(tail,"next",after)
setfield(after,"prev",tail)
setfield(after,"next",nil)
post = do_process(post,attr)
setfield(tail,"next",nil)
setfield(disc,"post",post)
free_node(after)
end
if replace and prv and nxt then -- must pair with start and start.prev
local before = copy_node(prv)
local after = copy_node(nxt)
local tail = find_node_tail(replace)
setfield(replace,"prev",before)
setfield(before,"next",replace)
setfield(before,"prev",nil)
setfield(tail,"next",after)
setfield(after,"prev",tail)
setfield(after,"next",nil)
replace = do_process(before,attr)
replace = getnext(replace)
setfield(replace,"prev",nil)
setfield(getfield(after,"prev"),"next",nil)
setfield(disc,"replace",replace)
free_node(after)
free_node(before)
elseif prv and getid(prv) == glyph_code and getfont(prv) == lastfont then
local prevchar, lastchar = getchar(prv), getchar(start)
local kerns = chardata[lastfont][prevchar].kerns
local kern = kerns and kerns[lastchar] or 0
krn = kern + quaddata[lastfont]*krn -- here
setfield(disc,"replace",kern_injector(false,krn)) -- only kerns permitted, no glue
else
krn = quaddata[lastfont]*krn -- here
setfield(disc,"replace",kern_injector(false,krn)) -- only kerns permitted, no glue
end
else
-- this one happens in most cases: automatic (-), explicit (\-), regular (patterns)
if prv and getid(prv) == glyph_code and getfont(prv) == lastfont then
-- the normal case
local prevchar, lastchar = getchar(prv), getchar(start)
local kerns = chardata[lastfont][prevchar].kerns
local kern = kerns and kerns[lastchar] or 0
krn = kern + quaddata[lastfont]*krn
else
krn = quaddata[lastfont]*krn
end
insert_node_before(head,start,kern_injector(fillup,krn))
end
end
end
elseif id == glue_code then
local subtype = getsubtype(start)
if subtype == userskip_code or subtype == xspaceskip_code or subtype == spaceskip_code then
local s = getfield(start,"spec")
local w = getfield(s,"width")
if w > 0 then
local width, stretch, shrink = w+gluefactor*w*krn, getfield(s,"stretch"), getfield(s,"shrink")
setfield(start,"spec",spec_injector(fillup,width,stretch*width/w,shrink*width/w))
done = true
end
end
elseif id == kern_code then
-- if getsubtype(start) == kerning_code then -- handle with glyphs
-- local sk = getfield(start,"kern")
-- if sk > 0 then
-- setfield(start,"kern",sk*krn)
-- done = true
-- end
-- end
elseif lastfont and (id == hlist_code or id == vlist_code) then -- todo: lookahead
local p = getprev(start)
if p and getid(p) ~= glue_code then
insert_node_before(head,start,kern_injector(fillup,quaddata[lastfont]*krn))
done = true
end
local n = getnext(start)
if n and getid(n) ~= glue_code then
insert_node_after(head,start,kern_injector(fillup,quaddata[lastfont]*krn))
done = true
end
elseif id == math_code then
start = end_of_math(start)
end
end
end
if start then
start = getnext(start)
end
end
return head, done
end
local enabled = false
function kerns.set(factor)
if factor ~= v_max then
factor = tonumber(factor) or 0
end
if factor == v_max or factor ~= 0 then
if not enabled then
tasks.enableaction("processors","typesetters.kerns.handler")
enabled = true
end
local a = factors[factor]
if not a then
a = #mapping + 1
factors[factors], mapping[a] = a, factor
end
factor = a
else
factor = unsetvalue
end
texsetattribute(a_kerns,factor)
return factor
end
function kerns.handler(head)
local head, done = do_process(tonut(head)) -- no direct map, because else fourth argument is tail == true
return tonode(head), done
end
-- interface
commands.setcharacterkerning = kerns.set
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