summaryrefslogtreecommitdiff
path: root/Master/texmf-dist/tex/luatex/luaotfload/luaotfload-harf-var-cff2.lua
blob: 38fa6b57d941a0e3c04f7f792dad36514bf5820e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
-----------------------------------------------------------------------
--         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       = "3.20",       --TAGVERSION
     date          = "2022-02-27", --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)
  if #result ~= 1 then
    print(require'inspect'(result))
  end
  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
    elseif cmd == 12 then
      start = start+1
      cmd = buf:byte(start)
      lastresult[1] = -cmd-1
      lastresult = {false}
      result[#result+1] = lastresult
    elseif cmd == 19 or cmd == 20 then
      if #result == 1 then
        lastresult = {}
        result[#result+1] = lastresult
      end
      lastresult[1] = cmd
      local newi = start+(result.stemcount+7)//8
      lastresult[2] = buf:sub(start+1, newi)
      start = newi
    else
      if 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

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