From 00ac320063ff016aea9f997948aa104d31bc95ff Mon Sep 17 00:00:00 2001 From: Khaled Hosny Date: Fri, 2 Apr 2010 17:14:01 +0200 Subject: Support 'opbd' (OpenType protrusion) feature Code scrapped from ConTeXt, AFAIK, no font implements OpenType optical bounds (on of Linux Libertine font has traces of it), but I plan to use it in my fonts. The committed feature file is prepared for Pagella, we can later have font specific feature files like this. --- otfl-font-dum.lua | 121 +++++++++++++++++++++++++++++++++++++++++++++++++----- 1 file changed, 110 insertions(+), 11 deletions(-) (limited to 'otfl-font-dum.lua') diff --git a/otfl-font-dum.lua b/otfl-font-dum.lua index 8e13b5b..1d79ab1 100644 --- a/otfl-font-dum.lua +++ b/otfl-font-dum.lua @@ -155,20 +155,119 @@ fonts.protrusions.setups = fonts.protrusions.setups or { } local setups = fonts.protrusions.setups +-- As this is experimental code, users should not depend on it. The +-- implications are still discussed on the ConTeXt Dev List and we're +-- not sure yet what exactly the spec is (the next code is tested with +-- a gyre font patched by / fea file made by Khaled Hosny). The double +-- trick should not be needed it proper hanging punctuation is used in +-- which case values < 1 can be used. +-- +-- preferred (in context, usine vectors): +-- +-- \definefontfeature[whatever][default][mode=node,protrusion=quality] +-- +-- using lfbd and rtbd, with possibibility to enable only one side : +-- +-- \definefontfeature[whocares][default][mode=node,protrusion=yes, opbd=yes,script=latn] +-- \definefontfeature[whocares][default][mode=node,protrusion=right,opbd=yes,script=latn] +-- +-- idem, using multiplier +-- +-- \definefontfeature[whocares][default][mode=node,protrusion=2,opbd=yes,script=latn] +-- \definefontfeature[whocares][default][mode=node,protrusion=double,opbd=yes,script=latn] +-- +-- idem, using named feature file (less frozen): +-- +-- \definefontfeature[whocares][default][mode=node,protrusion=2,opbd=yes,script=latn,featurefile=texgyrepagella-regularxx.fea] + +local function map_opbd_onto_protrusion(tfmdata,value,opbd) + local characters, descriptions = tfmdata.characters, tfmdata.descriptions + local otfdata = tfmdata.shared.otfdata + local singles = otfdata.shared.featuredata.gpos_single + local script, language = tfmdata.script, tfmdata.language + local done, factor, left, right = false, 1, 1, 1 + local setup = setups[value] + if setup then + factor = setup.factor or 1 + left = setup.left or 1 + right = setup.right or 1 + else + factor = tonumber(value) or 1 + end + if opbd ~= "right" then + local validlookups, lookuplist = fonts.otf.collect_lookups(otfdata,"lfbd",script,language) + if validlookups then + for i=1,#lookuplist do + local lookup = lookuplist[i] + local data = singles[lookup] + if data then + if trace_protrusion then + logs.report("fonts","set left protrusion using lfbd lookup '%s'",lookup) + end + for k, v in next, data do + -- local p = - v[3] / descriptions[k].width-- or 1 ~= 0 too but the same + local p = - (v[1] / 1000) * factor * left + characters[k].left_protruding = p + if trace_protrusion then + logs.report("opbd","lfbd -> %s -> 0x%05X (%s) -> %0.03f (%s)",lookup,k,utfchar(k),p,concat(v," ")) + end + end + done = true + end + end + end + end + if opbd ~= "left" then + local validlookups, lookuplist = fonts.otf.collect_lookups(otfdata,"rtbd",script,language) + if validlookups then + for i=1,#lookuplist do + local lookup = lookuplist[i] + local data = singles[lookup] + if data then + if trace_protrusion then + logs.report("fonts","set right protrusion using rtbd lookup '%s'",lookup) + end + for k, v in next, data do + -- local p = v[3] / descriptions[k].width -- or 3 + local p = (v[1] / 1000) * factor * right + characters[k].right_protruding = p + if trace_protrusion then + logs.report("opbd","rtbd -> %s -> 0x%05X (%s) -> %0.03f (%s)",lookup,k,utfchar(k),p,concat(v," ")) + end + end + end + done = true + end + end + end + tfmdata.auto_protrude = done +end + +-- The opbd test is just there because it was discussed on the +-- context development list. However, the mentioned fxlbi.otf font +-- only has some kerns for digits. So, consider this feature not +-- supported till we have a proper test font. + function fonts.initializers.common.protrusion(tfmdata,value) if value then - local setup = setups[value] - if setup then - local factor, left, right = setup.factor or 1, setup.left or 1, setup.right or 1 - local emwidth = tfmdata.parameters.quad - tfmdata.auto_protrude = true - for i, chr in next, tfmdata.characters do - local v, pl, pr = setup[i], nil, nil - if v then - pl, pr = v[1], v[2] + local opbd = tfmdata.shared.features.opbd + if opbd then + -- possible values: left right both yes no (experimental) + map_opbd_onto_protrusion(tfmdata,value,opbd) + elseif value then + local setup = setups[value] + if setup then + local factor, left, right = setup.factor or 1, setup.left or 1, setup.right or 1 + local emwidth = tfmdata.parameters.quad + tfmdata.auto_protrude = true + for i, chr in next, tfmdata.characters do + local v, pl, pr = setup[i], nil, nil + if v then + pl, pr = v[1], v[2] + end + if pl and pl ~= 0 then chr.left_protruding = left *pl*factor end + if pr and pr ~= 0 then chr.right_protruding = right*pr*factor end end - if pl and pl ~= 0 then chr.left_protruding = left *pl*factor end - if pr and pr ~= 0 then chr.right_protruding = right*pr*factor end end end end -- cgit v1.2.3