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|
-----------------------------------------------------------------------
-- FILE: luaotfload-fallback.lua
-- DESCRIPTION: part of luaotfload / fallback
-----------------------------------------------------------------------
assert(luaotfload_module, "This is a part of luaotfload and should not be loaded independently") {
name = "luaotfload-fallback",
version = "3.23", --TAGVERSION
date = "2022-10-03", --TAGDATE
description = "luaotfload submodule / fallback",
license = "GPL v2.0",
author = "Marcel Krüger"
}
local nodenew = node.direct.new
local getfont = font.getfont
local setfont = node.direct.setfont
local getwhd = node.direct.getwhd
local insert_after = node.direct.insert_after
local traverse_char = node.direct.traverse_char
local protect_glyph = node.direct.protect_glyph
local otffeatures = fonts.constructors.newfeatures "otf"
-- local normalize = fonts.handlers.otf.features.normalize
local definers = fonts.definers
local define_font -- = luaotfload.define_font % This is set when the first font is loaded.
local fallback_table_fontnames = {}
local fallback_table = setmetatable({}, {
__index = function(t, name)
local names = fallback_table_fontnames[name]
if not names then
t[name] = false
return false
end
local res = setmetatable({}, {
__index = function(tt, size)
local lookup = {}
for i=#names,1,-1 do
local f = define_font(names[i] .. ';-fallback', size)
local fid
if type(f) == 'table' then
fid = font.define(f)
definers.register(f, fid)
elseif f then
fid = f
f = font.getfont(fid)
end
lookup[-i] = f -- Needed for multiscript interactions
for uni, _ in next, f.characters do
rawset(lookup, uni, fid)
end
end
tt[size] = lookup
return lookup
end,
})
t[name] = res
return res
end,
})
local fallback_lookups = setmetatable({}, {
__index = function(t, fid)
local f = font.getfont(fid)
-- table.tofile('myfont2', f)
local res = f and f.fallback_lookup or false
if res then
res = table.merged(res)
for uni in next, f.characters do
rawset(res, uni, nil)
end
end
t[fid] = res
return res
end,
})
local function makefallbackfont(tfmdata, _, fallback)
local t = fallback_table[fallback]
if not t then error(string.format("Unknown fallback table %s", fallback)) end
fallback = t[tfmdata.size]
local fallback_lookup = {}
tfmdata.fallback_lookup = fallback
end
local glyph_id = node.id'glyph'
-- TODO: inherited fonts (combining accents etc.)
local function dofallback(head, _, _, _, direction)
head = node.direct.todirect(head)
local last_fid, last_fallbacks
for cur, cid, fid in traverse_char(head) do
if fid ~= last_fid then
last_fid, last_fallbacks = fid, fallback_lookups[fid]
end
if last_fallbacks then
local new_fid = last_fallbacks[cid]
if new_fid then
setfont(cur, new_fid)
end
end
end
end
function luaotfload.add_fallback(name, fonts)
define_font = define_font or luaotfload.define_font -- Lazy loading because this file get's loaded before define_font is defined
if fonts == nil then
fonts = name
name = #fallback_table_fontnames + 1
else
name = name:lower()
end
fallback_table_fontnames[name] = fonts
fallback_table[name] = nil
return name
end
otffeatures.register {
name = "fallback",
description = "Fill in missing glyphs from other fonts",
manipulators = {
node = makefallbackfont,
plug = makefallbackfont,
},
-- processors = { -- processors would be nice, but they are applied
-- -- too late for our purposes
-- node = donotdef,
-- }
}
return {
process = dofallback,
}
--- vim:sw=2:ts=2:expandtab:tw=71
|
