luametalatex/luametalatex-pdf-font-ttf.lua

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2019-07-17 21:14:34 +02:00
local sfnt = require'libSfnt'
local stdnames = require'ttfstaticstrings'
local function round(x)
local i, f = math.modf(x)
if f < 0 then
return i - (f<=-0.5 and 1 or 0)
else
return i + (f>=-0.5 and 1 or 0)
end
end
local function addglyph(glyph, usedcids, cidtogid)
-- FIXME: Pseudocode
if string.unpack(">i2", glyph) < 0 then -- We have a composite glyph.
-- This is an untested mess. Disaster will follow.
local offset = 11
while offset do
local flags, component = string.unpack(">I2I2", glyph, offset)
local gid = cidtogid[component]
if not gid then
gid = #usedcids+1
usedcids[gid] = {component}
cidtogid[component] = gid
end
glyph = glyph:sub(1, offset-1) .. string.pack(">I2", gid).. glyph:sub(offset+2)
offset = flags&32==32 and offset + 4 + (flags&1==1 and 4 or 2) + (flags&8==8 and 2 or (flags&64==64 and 4 or (flags&128==128 and 8 or 0)))
end
end
return glyph
end
local function readpostnames(buf, i, usedcids, encoding)
local usednames = {}
local numglyphs
numglyphs, i = string.unpack(">I2", buf, i)
local stroffset = 2*numglyphs + i
local names = setmetatable({}, {__index = function(t, i)
for j=#t+1,i do
t[j], stroffset = string.unpack("s1", buf, stroffset)
end
return t[i]
end})
local newusedcids = {}
for j=1,#usedcids do
local name = encoding[usedcids[j][1]]
if name then
local new = {}
usednames[name], newusedcids[j] = new, new
else
newusedcids[j] = {j} -- FIXME: Someone used a character which does not exists in the encoding.
-- This should probably at least trigger a warning.
end
end
for j=1,numglyphs do
local name
name, i = string.unpack(">I2", buf, i)
if name < 258 then
name = stdnames[name]
else
name = names[name-257]
end
if usednames[name] then
usednames[name][1] = j-1
usednames[name] = nil
end
end
if next(usednames) then
error[[Missing character]]
end
return newusedcids
end
return function(filename, fontid, reencode)
local file = io.open(filename)
local buf = file:read'a'
file:close()
local magic, tables = sfnt.parse(buf, 1, fontid)
if magic ~= "\0\1\0\0" then error[[Invalid TTF font]] end
-- TODO: Parse post table and add reencoding support
-- if tables.post and string.unpack(">I4", buf, tables.post[1]) == 0x00020000 and reencode then
-- local encoding = require'parseEnc'(reencode)
-- if encoding then
-- local names = {}
-- local off = tables.post[1] + 4
-- for i = 1,string.unpack(">I2", buf, tables.maxp[1] + 4) do
return function(fontdir, usedcids)
if reencode and string.unpack(">I4", buf, tables.post[1]) == 0x00020000 then
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usedcids = readpostnames(buf, tables.post[1] + 32, usedcids, require'luametalatex-font-enc'(reencode))
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else
usedcids = table.move(usedcids, 1, #usedcids, 1, {})
end
table.insert(usedcids, 1, {0})
local newtables = {}
newtables.head = buf:sub(tables.head[1], tables.head[1]+tables.head[2]-1)
local bbox1, bbox2, bbox3, bbox4, scale, _
scale, _, _, bbox1, bbox2, bbox3, bbox4 = string.unpack(">I2I8I8i2i2i2i2", buf, tables.head[1]+18)
scale = 1000/scale
fontdir.bbox = {math.floor(bbox1*scale), math.floor(bbox2*scale), math.ceil(bbox3*scale), math.ceil(bbox4*scale)}
local cidtogid = {}
for i=1,#usedcids do
cidtogid[usedcids[i][1]] = i
end
local loca, glyf, locaOff, glyfOff = {}, {}, tables.loca[1], tables.glyf[1]
hmtx = nil
if string.unpack(">i2", buf, tables.head[1]+50) == 0 then -- short offsets
local s, i = 0, 1
while i <= #usedcids do
local from, til = string.unpack(">I2I2", buf, locaOff+2*usedcids[i][1])
loca[i] = string.pack(">I2", s)
s = s+til-from
glyf[i] = from ~= til and addglyph(buf:sub(glyfOff+from*2, glyfOff+til*2-1), usedcids, cidtogid) or ""
i = i+1
end
loca[#usedcids+1] = string.pack(">I2", s)
else -- long offsets
local s, i = 0, 1
while i <= #usedcids do
local from, til = string.unpack(">I4I4", buf, locaOff+4*usedcids[i][1])
loca[i] = string.pack(">I4", s)
s = s+til-from
glyf[i] = til == from and "" or addglyph(buf:sub(glyfOff+from, glyfOff+til-1), usedcids, cidtogid)
i = i+1
end
loca[#usedcids+1] = string.pack(">I4", s)
end
newtables.loca = table.concat(loca)
loca = nil
newtables.glyf = table.concat(glyf)
local hmtx = glyf
glyf = nil
for i = 1,#hmtx do hmtx[i] = nil end
assert(tables.hhea[2] == 36)
local numhmetrics = string.unpack(">I2", buf, tables.hhea[1]+34)
newtables.hhea = buf:sub(tables.hhea[1], tables.hhea[1]+33) .. string.pack(">I2", #usedcids)
local off = tables.hmtx[1]
local finaladv, off2 = buf:sub(off+(numhmetrics-1)*4, off+numhmetrics*4-3), off+2*numhmetrics
for i=1,#usedcids do
if usedcids[i][1] < numhmetrics then
hmtx[i] = buf:sub(off+usedcids[i][1]*4, off+usedcids[i][1]*4+3)
else
hmtx[i] = finaladv .. buf:sub(off2+usedcids[i][1]*2, off2+usedcids[i][1]*2+1)
end
end
newtables.hmtx = table.concat(hmtx)
newtables.maxp = buf:sub(tables.maxp[1], tables.maxp[1]+3) .. string.pack(">I2", #usedcids) .. buf:sub(tables.maxp[1]+6, tables.maxp[1]+tables.maxp[2]-1)
if tables.fpgm then
newtables.fpgm = buf:sub(tables.fpgm[1], tables.fpgm[1]+tables.fpgm[2]-1)
end
if tables.prep then
newtables.prep = buf:sub(tables.prep[1], tables.prep[1]+tables.prep[2]-1)
end
if tables['cvt '] then
newtables['cvt '] = buf:sub(tables['cvt '][1], tables['cvt '][1]+tables['cvt '][2]-1)
end
return sfnt.write(magic, newtables)
end
end