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|
-----------------------------------------------------------------------
-- FILE: luaotfload-harf-var-cff2.lua
-- DESCRIPTION: part of luaotfload / HarfBuzz / Parse and convert CFF2 tables
-----------------------------------------------------------------------
do
assert(luaotfload_module, "This is a part of luaotfload and should not be loaded independently") {
name = "luaotfload-harf-var-cff2",
version = "3.28", --TAGVERSION
date = "2024-02-14", --TAGDATE
description = "luaotfload submodule / CFF2 table processing",
license = "GPL v2.0",
author = "Marcel Krüger",
copyright = "Luaotfload Development Team",
}
end
local hb = assert(luaotfload.harfbuzz)
local cff2 = hb.Tag.new'CFF2'
local serialize = require'luaotfload-harf-var-t2-writer'
local offsetfmt = ">I%i"
local function parse_index(buf, i)
local count, offsize
count, offsize, i = string.unpack(">I4B", buf, i)
if count == 0 then return {}, i-1 end
local fmt = offsetfmt:format(offsize)
local offsets = {}
local dataoffset = i + offsize*count - 1
for j=1,count+1 do
offsets[j], i = string.unpack(fmt, buf, i)
end
for j=1,count+1 do
offsets[j] = offsets[j] + i - 1
end
return offsets, offsets[#offsets]
end
local real_mapping = { [0] = '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
'.', 'E', 'E-', nil, '-', nil}
local function parse_real(cs, offset)
local c = cs:byte(offset)
if not c then return offset end
local c1, c2 = real_mapping[c>>4], real_mapping[c&0xF]
if not c1 or not c2 then
return c1 or offset, c1 and offset
else
return c1, c2, parse_real(cs, offset+1) --Warning: This is not a tail-call,
-- so we are affected by the stack limit. On the other hand, as long as
-- there are less than ~50 bytes we should be safe.
end
end
local function get_number(result)
assert(#result == 1)
local num = result[1]
result[1] = nil
return num
end
local function get_bool(result)
return get_number(result) == 1
end
local function get_array(result)
local arr = table.move(result, 1, #result, 1, {})
for i=1,#result do result[i] = nil end
return arr
end
local function get_delta(result)
local arr = get_array(result)
local last = 0
for i=1,#arr do
arr[i] = arr[i]+last
last = arr[i]
end
return arr
end
local function get_private(result)
local arr = get_array(result)
assert(#arr == 2)
return arr
end
local function do_blend(result, vstore)
if not vstore then
error'blend operator only allowed in Private disctionary of variable fonts'
end
local vsindex = (result.vsindex or 0) + 1
local factors = vstore[vsindex]
local n = result[#result]
local k = #factors
local before = #result - 1 - n*(k+1)
for i = 1, n do
local val = result[before + i]
for j = 1, k do
val = val + factors[j] * result[before + n + (i-1) * k + j]
end
result[before + i] = math.floor(val + .5)
end
for i = before + n + 1, #result do
result[i] = nil
end
return arr
end
local function apply_matrix(m, x, y)
return (m[1] * x + m[3] * y + m[5])*1000, (m[2] * x + m[4] * y + m[6])*1000
end
local operators = {
[6] = {'BlueValues', get_delta},
[7] = {'OtherBlues', get_delta},
[8] = {'FamilyBlues', get_delta},
[9] = {'FamilyOtherBlues', get_delta},
[10] = {'StdHW', get_number},
[11] = {'StdVW', get_number},
[17] = {'CharStrings', get_number},
[18] = {'Private', get_private},
[19] = {'Subrs', get_number},
[22] = {'vsindex', get_number},
[23] = {'blend', do_blend},
[24] = {'vstore', get_number},
[-8] = {'FontMatrix', get_array},
[-10] = {'BlueScale', get_number},
[-11] = {'BlueShift', get_number},
[-12] = {'BlueFuzz', get_number},
[-13] = {'StemSnapH', get_delta},
[-14] = {'StemSnapV', get_delta},
[-15] = {'ForceBold', get_bool}, -- ???
[-18] = {'LanguageGroup', get_number},
[-19] = {'ExpansionFactor', get_number},
[-20] = {'initialRandomSeed', get_number}, -- ???
[-37] = {'FDArray', get_number},
[-38] = {'FDSelect', get_number},
}
local function parse_dict(buf, i, j, vstore)
result = {}
while i<=j do
local cmd = buf:byte(i)
if cmd == 29 then
result[#result+1] = string.unpack(">i4", buf:sub(i+1, i+4))
i = i+4
elseif cmd == 28 then
result[#result+1] = string.unpack(">i2", buf:sub(i+1, i+2))
i = i+2
elseif cmd >= 251 then -- Actually "and cmd ~= 255", but 255 is reserved
result[#result+1] = -((cmd-251)*256)-string.byte(buf, i+1)-108
i = i+1
elseif cmd >= 247 then
result[#result+1] = (cmd-247)*256+string.byte(buf, i+1)+108
i = i+1
elseif cmd >= 32 then
result[#result+1] = cmd-139
elseif cmd == 30 then -- 31 is reserved again
local real = {parse_real(buf, i+1)}
i = real[#real]
real[#real] = nil
result[#result+1] = tonumber(table.concat(real))
else
if cmd == 12 then
i = i+1
cmd = -buf:byte(i)-1
end
local op = operators[cmd]
if not op then error[[Unknown CFF operator]] end
result[op[1]] = op[2](result, vstore)
end
i = i+1
end
return result
end
local function parse_charstring(buf, start, after, globalsubrs, subrs, result)
local lastresult = result[#result]
while start ~= after do
local cmd = buf:byte(start)
if cmd == 28 then
lastresult[#lastresult+1] = string.unpack(">i2", buf:sub(start+1, start+2))
start = start+2
elseif cmd == 255 then
lastresult[#lastresult+1] = string.unpack(">i4", buf:sub(start+1, start+4))/0x10000
start = start+4
elseif cmd >= 251 then
lastresult[#lastresult+1] = -((cmd-251)*256)-string.byte(buf, start+1)-108
start = start+1
elseif cmd >= 247 then
lastresult[#lastresult+1] = (cmd-247)*256+string.byte(buf, start+1)+108
start = start+1
elseif cmd >= 32 then
lastresult[#lastresult+1] = cmd-139
elseif cmd == 10 then
local idx = lastresult[#lastresult]+subrs.bias
local sub_start = subrs[idx]
local sub_stop = subrs[idx+1]
lastresult[#lastresult] = nil
parse_charstring(buf, sub_start, sub_stop, globalsubrs, subrs, result)
lastresult = result[#result]
elseif cmd == 29 then
local idx = lastresult[#lastresult]+globalsubrs.bias
local sub_start = globalsubrs[idx]
local sub_stop = globalsubrs[idx+1]
lastresult[#lastresult] = nil
parse_charstring(buf, sub_start, sub_stop, globalsubrs, subrs, result)
lastresult = result[#result]
elseif cmd == 11 then
break -- We do not keep subroutines, so drop returns and continue with the outer commands
elseif cmd == 15 then -- vsindex
assert(#lastresult == 2)
result.factors = result.vstore[lastresult[2] + 1]
lastresult[2] = nil
elseif cmd == 16 then -- blend
local factors = result.factors
if not factors then
error'blend operator outside of variable font or with invalid vsindex'
end
local n = lastresult[#lastresult]
local k = #factors
local before = #lastresult - 1 - n*(k+1)
for i = 1, n do
local val = lastresult[before + i]
for j = 1, k do
val = val + factors[j] * lastresult[before + n + (i-1) * k + j]
end
lastresult[before + i] = math.floor(val + .5)
end
for i = before + n + 1, #lastresult do
lastresult[i] = nil
end
else
if cmd == 12 then
start = start+1
cmd = -buf:byte(start)-1
elseif cmd == 19 or cmd == 20 then
if #result == 1 then
lastresult = {}
result[#result+1] = lastresult
end
local newi = start+(result.stemcount+7)//8
lastresult[2] = buf:sub(start+1, newi)
start = newi
elseif cmd == 21 and #result == 1 then
table.insert(result, 1, {false})
if #lastresult == 4 then
result[1][2] = lastresult[2]
table.remove(lastresult, 2)
end
elseif (cmd == 4 or cmd == 22) and #result == 1 then
table.insert(result, 1, {false})
if #lastresult == 3 then
result[1][2] = lastresult[2]
table.remove(lastresult, 2)
end
elseif cmd == 14 and #result == 1 then
table.insert(result, 1, {false})
if #lastresult == 2 or #lastresult == 6 then
result[1][2] = lastresult[2]
table.remove(lastresult, 2)
end
elseif cmd == 1 or cmd == 3 or cmd == 18 or cmd == 23 then
if #result == 1 then
table.insert(result, 1, {false})
if #lastresult % 2 == 0 then
result[1][2] = lastresult[2]
table.remove(lastresult, 2)
end
end
result.stemcount = result.stemcount + #lastresult//2
end
lastresult[1] = cmd
lastresult = {false}
result[#result+1] = lastresult
end
start = start+1
end
return result
end
local function parse_fdselect(buf, offset, CharStrings)
local format
format, offset = string.unpack(">B", buf, offset)
if format == 0 then
for i=0,#CharStrings-1 do
local code
code, offset = string.unpack(">B", buf, offset)
CharStrings[i][3] = code + 1
end -- Reimplement with string.byte
elseif format == 3 then
local count, last
count, offset = string.unpack(">I2", buf, offset)
for i=1,count do
local first, code, after = string.unpack(">I2BI2", buf, offset)
for j=first, after-1 do
CharStrings[j][3] = code + 1
end
offset = offset + 3
end
elseif format == 4 then
local count, last
count, offset = string.unpack(">I4", buf, offset)
for i=1,count do
local first, code, after = string.unpack(">I4I2I4", buf, offset)
for j=first, after-1 do
CharStrings[j][3] = code + 1
end
offset = offset + 6
end
else
error[[Invalid FDSelect format]]
end
end
local function parse_vstore(buf, offset, variation)
local size, format, region_list_off, item_variation_count, off = string.unpack(">I2I2I4I2", buf, offset)
if format ~= 1 then
error'Unsupported vstore format'
end
offset = offset + 2 -- Skip the size
region_list_off = offset + region_list_off
local axis_count, region_count
axis_count, region_count, region_list_off = string.unpack(">I2I2", buf, region_list_off)
local variation_regions = {}
for i = 1, region_count do
local factor = 1
for j = 1, axis_count do
local start, peak, stop
start, peak, stop, region_list_off = string.unpack(">i2i2i2", buf, region_list_off)
local coord = variation[j]
if peak == 0 then -- Skip
elseif peak == coord then
-- factor = factor * 1
elseif coord <= start or coord >= stop then
factor = 0
break
elseif coord < peak then
factor = factor * ((coord-start) / (peak-start))
else--if coord > peak then
factor = factor * ((stop-coord) / (stop-peak))
end
end
variation_regions[i] = factor
end
local variation_data = {}
for i = 1, item_variation_count do
local item_off
item_off, off = string.unpack(">I4", buf, off)
local i_count, short_count, region_count
i_count, short_count, region_count, item_off = string.unpack(">I2I2I2", buf, item_off + offset)
if i_count ~= 0 or short_count ~= 0 then
error'Unexpected variation items in CFF2 table'
end
local factors = {}
for j = 1, region_count do
local region
region, item_off = string.unpack(">I2", buf, item_off)
factors[j] = variation_regions[region+1]
end
variation_data[i] = factors
end
return variation_data
end
local function parse_cff2(buf, i0, coords)
local fontid = 1
local major, minor, hdrSize, topSize = string.unpack(">BBBH", buf, i0)
if major ~= 2 then error[[Unsupported CFF version]] end
local i = i0 + hdrSize
local top = parse_dict(buf, i, i + topSize - 1)
i = i + topSize
local globalsubrs
globalsubrs, i = parse_index(buf, i)
globalsubrs.bias = #globalsubrs-1 < 1240 and 108 or #globalsubrs-1 < 33900 and 1132 or 32769
top.GlobalSubrs = globalsubrs
local CharStrings = parse_index(buf, i0+top.CharStrings)
for i=1,#CharStrings-1 do
CharStrings[i-1] = {CharStrings[i], CharStrings[i+1]-1}
end
CharStrings[#CharStrings] = nil
CharStrings[#CharStrings] = nil
local fonts = parse_index(buf, i0+top.FDArray)
top.FDArray = nil
top.vstore = parse_vstore(buf, i0 + top.vstore, coords)
local privates = {}
top.Privates = privates
for i=1,#fonts-1 do
local font = fonts[i]
local fontdir = parse_dict(buf, fonts[i], fonts[i+1]-1)
privates[i] = parse_dict(buf, i0+fontdir.Private[2], i0+fontdir.Private[2]+fontdir.Private[1]-1, top.vstore)
local subrs = privates[i].Subrs
if subrs then
subrs = parse_index(buf, i0+fontdir.Private[2]+subrs)
subrs.bias = #subrs-1 < 1240 and 108 or #subrs-1 < 33900 and 1132 or 32769
privates[i].Subrs = subrs
end
end
if top.FDSelect then
parse_fdselect(buf, i0+top.FDSelect, CharStrings)
else
for i=0,#CharStrings-1 do
CharStrings[i][3] = 1
end
end
top.CharStrings = CharStrings
local bbox
if top.FontMatrix then
local x0, y0 = apply_matrix(top.FontMatrix, top.FontBBox[1], top.FontBBox[2])
local x1, y1 = apply_matrix(top.FontMatrix, top.FontBBox[3], top.FontBBox[4])
bbox = {x0, y0, x1, y1}
else
bbox = top.FontBBox
end
return top, bbox
end
local function parse_glyph(buffer, top, gid)
local cs = top.CharStrings[gid]
local Private = top.Privates[cs[3]]
return parse_charstring(buffer, cs[1], cs[2] + 1,
top.GlobalSubrs, Private.Subrs,
{{false}, stemcount = 0, vstore = top.vstore, factors = top.vstore and top.vstore[(Private.vsindex or 0) + 1]})
end
return function(face, font)
local data = face:get_table(cff2):get_data()
local content = parse_cff2(data, 1, {font:get_var_coords_normalized()})
return function(gid)
local glyph = parse_glyph(data, content, gid)
glyph[1][2] = font:get_glyph_h_advance(gid)
return serialize(glyph)
end
end
|