summaryrefslogtreecommitdiff
path: root/luaotfload-extralibs.lua
blob: 3769e06741b7efcda2d63165b1a54b9fbdb6fbf5 (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
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
if not modules then modules = { } end modules ["extralibs"] = {
    version   = "2.3a",
    comment   = "companion to luaotfload.lua",
    author    = "Hans Hagen, Philipp Gesang",
    copyright = "PRAGMA ADE / ConTeXt Development Team",
    license   = "GPL v.2.0",
}

-- extralibs: set up an emulation layer to load additional Context
--            libraries

--===================================================================--
---                             PREPARE
--===================================================================--

local getmetatable    = getmetatable
local require         = require
local select          = select
local setmetatable    = setmetatable
local tonumber        = tonumber

local texattribute    = tex.attribute

local new_node        = node.new
local copy_node       = node.copy
local otffeatures     = fonts.constructors.newfeatures "otf"

-----------------------------------------------------------------------
--- namespace
-----------------------------------------------------------------------

--- The “typesetters” namespace isn’t bad at all; there is no need
--- to remove it after loading.

typesetters              = typesetters or { }
local typesetters        = typesetters
typesetters.kerns        = typesetters.kerns or { }
local kerns              = typesetters.kerns
kerns.mapping            = kerns.mapping or { }
kerns.factors            = kerns.factors or { }

local kern_callback      = "typesetters.kerncharacters"

typesetters.kernfont     = typesetters.kernfont or { }
local kernfont           = typesetters.kernfont

-----------------------------------------------------------------------
--- node-ini
-----------------------------------------------------------------------

nodes              = nodes or { } --- should be present with luaotfload
local bothways     = function (t) return table.swapped (t, t) end

local kerncodes = bothways({
  [0] = "fontkern",
  [1] = "userkern",
  [2] = "accentkern",
})

kerncodes.kerning = kerncodes.fontkern --- idiosyncrasy

nodes.kerncodes = kerncodes

nodes.skipcodes = bothways({
  [  0] = "userskip",
  [  1] = "lineskip",
  [  2] = "baselineskip",
  [  3] = "parskip",
  [  4] = "abovedisplayskip",
  [  5] = "belowdisplayskip",
  [  6] = "abovedisplayshortskip",
  [  7] = "belowdisplayshortskip",
  [  8] = "leftskip",
  [  9] = "rightskip",
  [ 10] = "topskip",
  [ 11] = "splittopskip",
  [ 12] = "tabskip",
  [ 13] = "spaceskip",
  [ 14] = "xspaceskip",
  [ 15] = "parfillskip",
  [ 16] = "thinmuskip",
  [ 17] = "medmuskip",
  [ 18] = "thickmuskip",
  [100] = "leaders",
  [101] = "cleaders",
  [102] = "xleaders",
  [103] = "gleaders",
})

-----------------------------------------------------------------------
--- node-res
-----------------------------------------------------------------------

nodes.pool        = nodes.pool or { }
local pool        = nodes.pool

local kern        = new_node("kern", nodes.kerncodes.userkern)
local glue_spec   = new_node "glue_spec"

pool.kern = function (k)
  local n = copy_node(kern)
  n.kern = k
  return n
end

pool.gluespec = function (width, stretch, shrink, 
                          stretch_order, shrink_order)
  local s = copy_node(glue_spec)
  if width         then s.width         = width         end
  if stretch       then s.stretch       = stretch       end
  if shrink        then s.shrink        = shrink        end
  if stretch_order then s.stretch_order = stretch_order end
  if shrink_order  then s.shrink_order  = shrink_order  end
  return s
end

pool.glue = function (width, stretch, shrink,
                      stretch_order, shrink_order)
  local n = new_node"glue"
  if not width then
    -- no spec
  elseif width == false or tonumber(width) then
    local s = copy_node(glue_spec)
    if width         then s.width         = width         end
    if stretch       then s.stretch       = stretch       end
    if shrink        then s.shrink        = shrink        end
    if stretch_order then s.stretch_order = stretch_order end
    if shrink_order  then s.shrink_order  = shrink_order  end
    n.spec = s
  else
    -- shared
    n.spec = copy_node(width)
  end
  return n
end

-----------------------------------------------------------------------
--- font-hsh
-----------------------------------------------------------------------
--- some initialization resembling font-hsh
local fonthashes         = fonts.hashes
local identifiers        = fonthashes.identifiers --- was: fontdata
local chardata           = fonthashes.characters
local quaddata           = fonthashes.quads
local markdata           = fonthashes.marks
local parameters         = fonthashes.parameters

--- ('a, 'a) hash -> (('a, 'a) hash -> 'a -> 'a) -> ('a, 'a) hash
local setmetatableindex = function (t, f)
  local mt = getmetatable(t)
  if mt then
    mt.__index = f
  else
    setmetatable(t, { __index = f })
  end
  return t
end

if not parameters then
  parameters = { }
  setmetatableindex(parameters, function(t, k)
    if k == true then
      return parameters[currentfont()]
    else
      local parameters = identifiers[k].parameters
      t[k] = parameters
      return parameters
    end
  end)
  fonthashes.parameters = parameters
end

if not chardata then
  chardata = { }
  setmetatableindex(chardata, function(t, k)
    if k == true then
      return chardata[currentfont()]
    else
      local tfmdata = identifiers[k]
      if not tfmdata then --- unsafe
        tfmdata = font.fonts[k]
      end
      if tfmdata then
        local characters = tfmdata.characters
        t[k] = characters
        return characters
      end
    end
  end)
  fonthashes.characters = chardata
end

if not quaddata then
  quaddata = { }
  setmetatableindex(quaddata, function(t, k)
    if k == true then
      return quads[currentfont()]
    else
      local parameters = parameters[k]
      local quad = parameters and parameters.quad or 0
      t[k] = quad
      return quad
    end
  end)
  fonthashes.quads = quaddata
end

if not markdata then
  markdata = { }
  setmetatableindex(markdata, function(t, k)
    if k == true then
      return marks[currentfont()]
    else
      local resources = identifiers[k].resources or { }
      local marks = resources.marks or { }
      t[k] = marks
      return marks
    end
  end)
  fonthashes.marks = markdata
end

--- next stems from the multilingual interface
interfaces                = interfaces or { }
interfaces.variables      = interfaces.variables or { }
interfaces.variables.max  = "max"

-----------------------------------------------------------------------
--- attr-ini
-----------------------------------------------------------------------

attributes = attributes or { } --- to be removed with cleanup

local hidden = {
  a_kerns     = luatexbase.new_attribute("typo-krn:a_kerns",    true),
  a_fontkern  = luatexbase.new_attribute("typo-krn:a_fontkern", true),
}

attributes.private = attributes.private or function (attr_name)
  local res = hidden[attr_name]
  if not res then
    res = luatexbase.new_attribute(attr_name)
  end
  return res
end

if luatexbase.get_unset_value then
  attributes.unsetvalue = luatexbase.get_unset_value()
else -- old luatexbase
  attributes.unsetvalue = (luatexbase.luatexversion < 37) and -1
                       or -2147483647
end

-----------------------------------------------------------------------
--- luat-sto
-----------------------------------------------------------------------

--- Storage is so ridiculously well designed in Context it’s a pity
--- we can’t just force every package author to use it.

storage           = storage or { }
storage.register  = storage.register or function (...)
  local t = { ... }
  --- sorry
  return t
end

-----------------------------------------------------------------------
--- node-fin
-----------------------------------------------------------------------

local plugin_store = { }

local installattributehandler = function (plugin)
  --- Context has some load() magic here.
  plugin_store[plugin.name] = plugin.processor
end

nodes.installattributehandler = installattributehandler

-----------------------------------------------------------------------
--- node-tsk
-----------------------------------------------------------------------

nodes.tasks               = nodes.tasks or { }
nodes.tasks.enableaction  = function () end

-----------------------------------------------------------------------
--- core-ctx
-----------------------------------------------------------------------

commands = commands or { }

--===================================================================--
---                              LOAD
--===================================================================--

--- we should be ready at this moment to insert the libraries

require "luaotfload-typo-krn"    --- typesetters.kerns
require "luaotfload-letterspace" --- typesetters.kernfont

--===================================================================--
---                              CLEAN
--===================================================================--
--- interface
-----------------------------------------------------------------------

local factors           = kerns.factors
local mapping           = kerns.mapping
local unsetvalue        = attributes.unset_value
local process_kerns     = plugin_store.kern

--- kern_callback     : normal
--- · callback:     process_kerns
--- · enabler:      enablecharacterkerning
--- · disabler:     disablecharacterkerning
--- · interface:    kerns.set

--- kernfont_callback : fontwise
--- · callback:     kernfont.handler
--- · enabler:      enablefontkerning
--- · disabler:     disablefontkerning

--- callback wrappers

--- (node_t -> node_t) -> string -> string list -> bool
local registered_as = { } --- procname -> callbacks
local add_processor = function (processor, name, ...)
  local callbacks = { ... }
  for i=1, #callbacks do
    luatexbase.add_to_callback(callbacks[i], processor, name)
  end
  registered_as[name] = callbacks --- for removal
  return true
end

--- string -> bool
local remove_processor = function (name)
  local callbacks = registered_as[name]
  if callbacks then
    for i=1, #callbacks do
      luatexbase.remove_from_callback(callbacks[i], name)
    end
    return true
  end
  return false --> unregistered
end

--- we use the same callbacks as a node processor in Context
--- unit -> bool
local enablecharacterkerning = function ( )
  return add_processor(function (head)
      return process_kerns("kerns", hidden.a_kerns, head)
    end,
    "typesetters.kerncharacters",
    "pre_linebreak_filter", "hpack_filter"
  )
end

--- unit -> bool
local disablecharacterkerning = function ( )
  return remove_processor "typesetters.kerncharacters"
end

kerns.enablecharacterkerning     = enablecharacterkerning
kerns.disablecharacterkerning    = disablecharacterkerning

--- now for the simplistic variant
--- unit -> bool
local enablefontkerning = function ( )
  return add_processor(
    kernfont.handler,
    "typesetters.kernfont",
    "pre_linebreak_filter", "hpack_filter"
  )
end

--- unit -> bool
local disablefontkerning = function ( )
  return remove_processor "typesetters.kernfont"
end

--- fontwise kerning uses a font property for passing along the
--- letterspacing factor

local fontkerning_enabled = false --- callback state

--- fontobj -> float -> unit
local initializefontkerning = function (tfmdata, factor)
  if factor ~= "max" then
    factor = tonumber(factor) or 0
  end
  if factor == "max" or factor ~= 0 then
    local fontproperties = tfmdata.properties
    if fontproperties then
      --- hopefully this field stays unused otherwise
      fontproperties.kerncharacters = factor
    end
    if not fontkerning_enabled then
      fontkerning_enabled = enablefontkerning()
    end
  end
end

--- like the font colorization, fontwise kerning is hooked into the
--- feature mechanism

otffeatures.register {
  name        = "letterspace", --"kerncharacters",
  description = "letterspace", --"kerncharacters",
  initializers = {
    base = initializefontkerning,
    node = initializefontkerning,
  }
}

kerns.set = nil

local characterkerning_enabled = false

kerns.set = function (factor)
    if factor ~= "max" then
        factor = tonumber(factor) or 0
    end
    if factor == "max" or factor ~= 0 then
        if not characterkerning_enabled then
            enablecharacterkerning()
            characterkerning_enabled = true
        end
        local a = factors[factor]
        if not a then
            a = #mapping + 1
            factors[factors], mapping[a] = a, factor
        end
        factor = a
    else
        factor = unsetvalue
    end
    texattribute[hidden.a_kerns] = factor
    return factor
end



-----------------------------------------------------------------------
--- options
-----------------------------------------------------------------------

kerns   .keepligature     = false --- supposed to be of type function
kerns   .keeptogether     = false --- supposed to be of type function
kernfont.keepligature     = false --- supposed to be of type function
kernfont.keeptogether     = false --- supposed to be of type function

-----------------------------------------------------------------------
--- erase fake Context layer
-----------------------------------------------------------------------

attributes     = nil
--commands       = nil  --- used in lualibs
storage        = nil    --- not to confuse with utilities.storage
nodes.tasks    = nil

collectgarbage"collect"

--[[example--

\input luaotfload.sty
\def\setcharacterkerning#1{% #1 factor : float
  \directlua{typesetters.kerns.set(0.618)}%
}
%directlua{typesetters.kerns.enablecharacterkerning()}

\font\iwona       = "name:Iwona:mode=node"                at 42pt
\font\lmregular   = "name:Latin Modern Roman:mode=node"   at 42pt

{\iwona
 foo
 {\setcharacterkerning{0.618}%
  bar}
 baz}

{\lmregular
 foo {\setcharacterkerning{0.125}ff fi ffi fl Th} baz}

{\lmregular
 \directlua{ %% I’m not exactly sure how those work
    typesetters.kerns.keepligature = function (start)
      print("[liga]", start)
      return true
    end
    typesetters.kerns.keeptogether = function (start)
      print("[keeptogether]", start)
      return true
    end}%
 foo {\setcharacterkerning{0.125}ff fi ffi fl Th} baz}

\bye
--example]]--

-- vim:ts=2:sw=2:expandtab