summaryrefslogtreecommitdiff
path: root/Master/texmf-dist/tex/context/base/mkiv/trac-vis.lua
blob: 061cef8ba5c89bf04772ad929836ffcfc0d0a64e (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
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
if not modules then modules = { } end modules ['trac-vis'] = {
    version   = 1.001,
    comment   = "companion to trac-vis.mkiv",
    author    = "Hans Hagen, PRAGMA-ADE, Hasselt NL",
    copyright = "PRAGMA ADE / ConTeXt Development Team",
    license   = "see context related readme files"
}

local string, number, table = string, number, table
local node, nodes, attributes, fonts, tex = node, nodes, attributes, fonts, tex
local type = type
local format = string.format
local formatters = string.formatters

-- This module started out in the early days of mkiv and luatex with
-- visualizing kerns related to fonts. In the process of cleaning up the
-- visual debugger code it made sense to integrate some other code that
-- I had laying around and replace the old supp-vis debugging code. As
-- only a subset of the old visual debugger makes sense it has become a
-- different implementation. Soms of the m-visual functionality will also
-- be ported. The code is rather trivial. The caching is not really needed
-- but saves upto 50% of the time needed to add visualization. Of course
-- the overall runtime is larger because of color and layer processing in
-- the backend (can be times as much) so the runtime is somewhat larger
-- with full visualization enabled. In practice this will never happen
-- unless one is demoing.

-- We could use pdf literals and re stream codes but it's not worth the
-- trouble because we would end up in color etc mess. Maybe one day I'll
-- make a nodeinjection variant.

-- todo: global switch (so no attributes)
-- todo: maybe also xoffset, yoffset of glyph
-- todo: inline concat (more efficient)
-- todo: tags can also be numbers (just add to hash)

-- todo: dir and localpar nodes

local nodecodes           = nodes.nodecodes
local disc_code           = nodecodes.disc
local kern_code           = nodecodes.kern
local glyph_code          = nodecodes.glyph
local hlist_code          = nodecodes.hlist
local vlist_code          = nodecodes.vlist
local glue_code           = nodecodes.glue
local penalty_code        = nodecodes.penalty
local whatsit_code        = nodecodes.whatsit
local user_code           = nodecodes.user
local math_code           = nodecodes.math
local gluespec_code       = nodecodes.gluespec

local kerncodes           = nodes.kerncodes
local font_kern_code      = kerncodes.fontkern
local user_kern_code      = kerncodes.userkern

local gluecodes           = nodes.gluecodes
local cleaders_code       = gluecodes.cleaders
local userskip_code       = gluecodes.userskip
local space_code          = gluecodes.space
local xspace_code         = gluecodes.xspace
local leftskip_code       = gluecodes.leftskip
local rightskip_code      = gluecodes.rightskip

local whatsitcodes        = nodes.whatsitcodes
local mathcodes           = nodes.mathcodes

local nuts                = nodes.nuts
local tonut               = nuts.tonut
local tonode              = nuts.tonode

local setfield            = nuts.setfield
local setboth             = nuts.setboth
local setlink             = nuts.setlink
local setdisc             = nuts.setdisc
local setlist             = nuts.setlist
local setleader           = nuts.setleader
local setsubtype          = nuts.setsubtype
local setattr             = nuts.setattr

local getfield            = nuts.getfield
local getid               = nuts.getid
local getfont             = nuts.getfont
local getattr             = nuts.getattr
local getsubtype          = nuts.getsubtype
local getchar             = nuts.getchar
local getbox              = nuts.getbox
local getlist             = nuts.getlist
local getleader           = nuts.getleader
local getnext             = nuts.getnext
local getprev             = nuts.getprev
local getboth             = nuts.getboth
local getdisc             = nuts.getdisc

local hpack_nodes         = nuts.hpack
local vpack_nodes         = nuts.vpack
local copy_node           = nuts.copy
local copy_list           = nuts.copy_list
local free_node           = nuts.free
local free_node_list      = nuts.flush_list
local insert_node_before  = nuts.insert_before
local insert_node_after   = nuts.insert_after
local traverse_nodes      = nuts.traverse
local linked_nodes        = nuts.linked

local effectiveglue       = nuts.effective_glue

local hpack_string        = nuts.typesetters.tohpack

local texgetattribute     = tex.getattribute
local texsetattribute     = tex.setattribute

local unsetvalue          = attributes.unsetvalue

local current_font        = font.current

local fonthashes          = fonts.hashes
local chardata            = fonthashes.characters
local exheights           = fonthashes.exheights
local emwidths            = fonthashes.emwidths
local pt_factor           = number.dimenfactors.pt

local nodepool            = nuts.pool
local new_rule            = nodepool.rule
local new_kern            = nodepool.kern
local new_glue            = nodepool.glue
local new_penalty         = nodepool.penalty
local new_hlist           = nodepool.hlist
local new_vlist           = nodepool.vlist

local tracers             = nodes.tracers
local visualizers         = nodes.visualizers

local setcolor            = tracers.colors.set
local setlistcolor        = tracers.colors.setlist
local settransparency     = tracers.transparencies.set
local setlisttransparency = tracers.transparencies.setlist

local starttiming         = statistics.starttiming
local stoptiming          = statistics.stoptiming

local a_visual            = attributes.private("visual")
local a_fontkern          = attributes.private("fontkern")
local a_layer             = attributes.private("viewerlayer")

local hasbit              = number.hasbit
local bit                 = number.bit
local setbit              = number.setbit
local clearbit            = number.clearbit

local trace_hbox
local trace_vbox
local trace_vtop
local trace_kern
local trace_glue
local trace_penalty
local trace_fontkern
local trace_strut
local trace_whatsit
local trace_user
local trace_math
local trace_italic

local report_visualize = logs.reporter("visualize")

local modes = {
    hbox       =     1,
    vbox       =     2,
    vtop       =     4,
    kern       =     8,
    glue       =    16,
    penalty    =    32,
    fontkern   =    64,
    strut      =   128,
    whatsit    =   256,
    glyph      =   512,
    simple     =  1024,
    simplehbox =  1024 + 1,
    simplevbox =  1024 + 2,
    simplevtop =  1024 + 4,
    user       =  2048,
    math       =  4096,
    italic     =  8192,
    origin     = 16384,
}

local usedfont, exheight, emwidth
local l_penalty, l_glue, l_kern, l_fontkern, l_hbox, l_vbox, l_vtop, l_strut, l_whatsit, l_glyph, l_user, l_math, l_italic, l_origin

local enabled = false
local layers  = { }

local preset_boxes  = modes.hbox + modes.vbox + modes.origin
local preset_makeup = preset_boxes
                    + modes.kern + modes.glue + modes.penalty
local preset_all    = preset_makeup
                    + modes.fontkern + modes.whatsit + modes.glyph + modes.user + modes.math

function visualizers.setfont(id)
    usedfont = id or current_font()
    exheight = exheights[usedfont]
    emwidth  = emwidths[usedfont]
end

-- we can preset a bunch of bits

local function enable()
    if not usedfont then
        -- we use a narrow monospaced font -- infofont ?
        visualizers.setfont(fonts.definers.define { name = "lmmonoltcond10regular", size = tex.sp("4pt") })
    end
    for mode, value in next, modes do
        local tag = formatters["v_%s"](mode)
        attributes.viewerlayers.define {
            tag       = tag,
            title     = formatters["visualizer %s"](mode),
            visible   = "start",
            editable  = "yes",
            printable = "yes"
        }
        layers[mode] = attributes.viewerlayers.register(tag,true)
    end
    l_hbox     = layers.hbox
    l_vbox     = layers.vbox
    l_vtop     = layers.vtop
    l_glue     = layers.glue
    l_kern     = layers.kern
    l_penalty  = layers.penalty
    l_fontkern = layers.fontkern
    l_strut    = layers.strut
    l_whatsit  = layers.whatsit
    l_glyph    = layers.glyph
    l_user     = layers.user
    l_math     = layers.math
    l_italic   = layers.italic
    l_origin   = layers.origin
    nodes.tasks.enableaction("shipouts","nodes.visualizers.handler")
    report_visualize("enabled")
    enabled = true
    tex.setcount("global","c_syst_visualizers_state",1) -- so that we can optimize at the tex end
end

local function setvisual(n,a,what) -- this will become more efficient when we have the bit lib linked in
    if not n or n == "reset" then
        return unsetvalue
    elseif n == "makeup" then
        if not a or a == 0 or a == unsetvalue then
            a = preset_makeup
        else
            a = setbit(a,preset_makeup)
        end
    elseif n == "boxes" then
        if not a or a == 0 or a == unsetvalue then
            a = preset_boxes
        else
            a = setbit(a,preset_boxes)
        end
    elseif n == "all" then
        if what == false then
            return unsetvalue
        elseif not a or a == 0 or a == unsetvalue then
            a = preset_all
        else
            a = setbit(a,preset_all)
        end
    else
        local m = modes[n]
        if not m then
            -- go on
        elseif a == unsetvalue then
            if what == false then
                return unsetvalue
            else
             -- a = setbit(0,m)
                a = m
            end
        elseif what == false then
            a = clearbit(a,m)
        elseif not a or a == 0 then
            a = m
        else
            a = setbit(a,m)
        end
    end
    if not a or a == 0 or a == unsetvalue then
        return unsetvalue
    elseif not enabled then -- must happen at runtime (as we don't store layers yet)
        enable()
    end
    return a
end

function nuts.setvisual(n,mode)
    setattr(n,a_visual,setvisual(mode,getattr(n,a_visual),true))
end

function nuts.copyvisual(n,m)
    setattr(n,a_visual,getattr(m,a_visual))
end

function visualizers.setvisual(n)
    texsetattribute(a_visual,setvisual(n,texgetattribute(a_visual)))
end

function visualizers.setlayer(n)
    texsetattribute(a_layer,layers[n] or unsetvalue)
end

local function set(mode,v)
    texsetattribute(a_visual,setvisual(mode,texgetattribute(a_visual),v))
end

for mode, value in next, modes do
    trackers.register(formatters["visualizers.%s"](mode), function(v) set(mode,v) end)
end

local raisepenalties = false

directives.register("visualizers.raisepenalties",function(v) raisepenalties = v end)

local fraction = 10

trackers  .register("visualizers.reset",    function(v) set("reset", v) end)
trackers  .register("visualizers.all",      function(v) set("all",   v) end)
trackers  .register("visualizers.makeup",   function(v) set("makeup",v) end)
trackers  .register("visualizers.boxes",    function(v) set("boxes", v) end)
directives.register("visualizers.fraction", function(v) fraction = (v and tonumber(v)) or (v == "more" and 5) or 10 end)

local c_positive   = "trace:b"
local c_negative   = "trace:r"
local c_zero       = "trace:g"
local c_text       = "trace:s"
local c_space      = "trace:y"
local c_skip_a     = "trace:c"
local c_skip_b     = "trace:m"
local c_glyph      = "trace:o"
local c_ligature   = "trace:s"
local c_white      = "trace:w"
local c_math       = "trace:r"
local c_origin     = "trace:o"

local c_positive_d = "trace:db"
local c_negative_d = "trace:dr"
local c_zero_d     = "trace:dg"
local c_text_d     = "trace:ds"
local c_space_d    = "trace:dy"
local c_skip_a_d   = "trace:dc"
local c_skip_b_d   = "trace:dm"
local c_glyph_d    = "trace:do"
local c_ligature_d = "trace:ds"
local c_white_d    = "trace:dw"
local c_math_d     = "trace:dr"
local c_origin_d   = "trace:do"

local function sometext(str,layer,color,textcolor,lap) -- we can just paste verbatim together .. no typesteting needed
    local text = hpack_string(str,usedfont)
    local size = getfield(text,"width")
    local rule = new_rule(size,2*exheight,exheight/2)
    local kern = new_kern(-size)
    if color then
        setcolor(rule,color)
    end
    if textcolor then
        setlistcolor(getlist(text),textcolor)
    end
    local info = linked_nodes(rule,kern,text)
    setlisttransparency(info,c_zero)
    info = new_hlist(info)
    local width = getfield(info,"width")
    if lap then
        info = new_hlist(linked_nodes(new_kern(-width),info))
    end
    if layer then
        setattr(info,a_layer,layer)
    end
    return info, width
end

local f_cache = { }

local function fontkern(head,current)
    local kern = getfield(current,"kern") + getfield(current,"expansion_factor")
    local info = f_cache[kern]
    if info then
        -- print("hit fontkern")
    else
        local text = hpack_string(formatters[" %0.3f"](kern*pt_factor),usedfont)
        local rule = new_rule(emwidth/fraction,6*exheight,2*exheight)
        local list = getlist(text)
        if kern > 0 then
            setlistcolor(list,c_positive_d)
        elseif kern < 0 then
            setlistcolor(list,c_negative_d)
        else
            setlistcolor(list,c_zero_d)
        end
        setlisttransparency(list,c_text_d)
        settransparency(rule,c_text_d)
        setfield(text,"shift",-5 * exheight)
        info = new_hlist(linked_nodes(rule,text))
        setattr(info,a_layer,l_fontkern)
        f_cache[kern] = info
    end
    head = insert_node_before(head,current,copy_list(info))
    return head, current
end

local w_cache = { }
local tags    = {
    open             = "FIC",
    write            = "FIW",
    close            = "FIC",
    special          = "SPE",
    latelua          = "LUA",
    savepos          = "POS",
    userdefined      = "USR",
 -- backend stuff
    pdfliteral       = "PDF",
    pdfrefobj        = "PDF",
    pdfannot         = "PDF",
    pdfstartlink     = "PDF",
    pdfendlink       = "PDF",
    pdfdest          = "PDF",
    pdfthread        = "PDF",
    pdfstartthread   = "PDF",
    pdfendthread     = "PDF",
    pdfthreaddata    = "PDF",
    pdflinkdata      = "PDF",
    pdfcolorstack    = "PDF",
    pdfsetmatrix     = "PDF",
    pdfsave          = "PDF",
    pdfrestore       = "PDF",
}

local function whatsit(head,current)
    local what = getsubtype(current)
    local info = w_cache[what]
    if info then
        -- print("hit whatsit")
    else
        local tag = whatsitcodes[what]
        -- maybe different text colors per tag
        info = sometext(formatters["W:%s"](tag and tags[tag] or what),usedfont,nil,c_white)
        setattr(info,a_layer,l_whatsit)
        w_cache[what] = info
    end
    head, current = insert_node_after(head,current,copy_list(info))
    return head, current
end

local u_cache = { }

local function user(head,current)
    local what = getsubtype(current)
    local info = u_cache[what]
    if info then
        -- print("hit user")
    else
        info = sometext(formatters["U:%s"](what),usedfont)
        setattr(info,a_layer,l_user)
        u_cache[what] = info
    end
    head, current = insert_node_after(head,current,copy_list(info))
    return head, current
end

local m_cache = { }
local tags    = {
    beginmath = "B",
    endmath   = "E",
}

local function math(head,current)
    local what = getsubtype(current)
    local info = m_cache[what]
    if info then
        -- print("hit math")
    else
        local tag = mathcodes[what]
        info = sometext(formatters["M:%s"](tag and tags[tag] or what),usedfont,nil,c_math_d)
        setattr(info,a_layer,l_math)
        m_cache[what] = info
    end
    head, current = insert_node_after(head,current,copy_list(info))
    return head, current
end

local b_cache = { }

local o_cache = table.setmetatableindex(function(t,size)
    local rule = new_rule(2*size,size,size)
    origin = hpack_nodes(rule)
    setcolor(rule,c_origin_d)
    settransparency(rule,c_origin_d)
    setattr(rule,a_layer,l_origin)
    t[size] = origin
    return origin
end)

local function ruledbox(head,current,vertical,layer,what,simple,previous,trace_origin,parent)
    local wd = getfield(current,"width")
    if wd ~= 0 then
        local ht = getfield(current,"height")
        local dp = getfield(current,"depth")
        local shift = getfield(current,"shift")
        local next = getnext(current)
        local prev = previous
     -- local prev = getprev(current) -- prev can be wrong in math mode < 0.78.3
        setboth(current)
        local linewidth = emwidth/fraction
        local size      = 2*linewidth
        local baseline, baseskip
        if dp ~= 0 and ht ~= 0 then
            if wd > 20*linewidth then
                baseline = b_cache.baseline
                if not baseline then
                    -- due to an optimized leader color/transparency we need to set the glue node in order
                    -- to trigger this mechanism
                    local leader = linked_nodes(new_glue(size),new_rule(3*size,linewidth,0),new_glue(size))
                    leader = hpack_nodes(leader)
                    baseline = new_glue(0)
                    setleader(baseline,leader)
                    setsubtype(baseline,cleaders_code)
                    setfield(baseline,"stretch",65536)
                    setfield(baseline,"stretch_order",2)
                    setlisttransparency(baseline,c_text)
                    b_cache.baseline = baseline
                end
                baseline = copy_list(baseline)
                baseline = hpack_nodes(baseline,wd-size)
                -- or new_hlist, set head and also:
                -- baseline.width = wd
                -- baseline.glue_set = wd/65536
                -- baseline.glue_order = 2
                -- baseline.glue_sign = 1
                baseskip = new_kern(-wd+linewidth)
            else
                baseline = new_rule(wd-size,linewidth,0)
                baseskip = new_kern(-wd+size)
            end
        end
        local this
        if not simple then
            this = b_cache[what]
            if not this then
                local text = hpack_string(what,usedfont)
                this = linked_nodes(new_kern(-getfield(text,"width")),text)
                setlisttransparency(this,c_text)
                this = new_hlist(this)
                b_cache[what] = this
            end
        end
        -- we need to trigger the right mode (else sometimes no whatits)
        local info = linked_nodes(
            this and copy_list(this) or nil,
            new_rule(linewidth,ht,dp),
            new_rule(wd-size,-dp+linewidth,dp),
            new_rule(linewidth,ht,dp),
            new_kern(-wd+linewidth),
            new_rule(wd-size,ht,-ht+linewidth)
        )
        if baseskip then
            info = linked_nodes(info,baseskip,baseline) -- could be in previous linked
        end
        setlisttransparency(info,c_text)
        info = new_hlist(info)
        --
        setattr(info,a_layer,layer)
        if vertical then
            if shift == 0 then
                info = linked_nodes(current,info)
            elseif trace_origin then
                local size   = 2*size
                local origin = o_cache[size]
                origin = copy_list(origin)
                if getid(parent) == vlist_code then
                    setfield(origin,"shift",-shift)
                    info = linked_nodes(current,new_kern(-size),origin,new_kern(-size),info)
                else
                    -- todo .. i need an example
                    info = linked_nodes(current,info)
                end
                setfield(current,"shift",0)
            else
                info = linked_nodes(current,info)
                setfield(current,"shift",0)
            end
            info = new_vlist(info,wd,ht,dp,shift)
        else
            if shift == 0 then
                info = linked_nodes(current,new_kern(-wd),info)
            elseif trace_origin then
                local size   = 2*size
                local origin = o_cache[size]
                origin = copy_list(origin)
                if getid(parent) == vlist_code then
                    info = linked_nodes(current,new_kern(-wd-size-shift),origin,new_kern(-size+shift),info)
                else
                    setfield(origin,"shift",-shift)
                    info = linked_nodes(current,new_kern(-wd-size),origin,new_kern(-size),info)
                end
                setfield(current,"shift",0)
            else
                info = linked_nodes(current,new_kern(-wd),info)
                setfield(current,"shift",0)
            end
            info = new_hlist(info,wd,ht,dp,shift)
        end

-- how about dir, so maybe just copy the node
--
-- local l = getlist(current)
-- setlist(current,nil)
-- local c = copy_node(current)
-- setlist(current,l)
-- setlist(c,info)
-- info = c

        if next then
            setlink(info,next)
        end
        if prev then
            if getid(prev) == gluespec_code then
                report_visualize("ignoring invalid prev")
                -- weird, how can this happen, an inline glue-spec, probably math
            else
                setlink(prev,info)
            end
        end
        if head == current then
            return info, info
        else
            return head, info
        end
    else
        return head, current
    end
end

local bpfactor =  number.dimenfactors.bp

-- callback.register("process_rule",function(n,h,v)
--     local p = string.formatters["0 0 %0.6F %0.6F re f"](h*bpfactor,v*bpfactor)
--     pdf.print("direct",p)
-- end)

local function ruledglyph(head,current,previous)
    local wd = getfield(current,"width")
 -- local wd = chardata[getfont(current)][getchar(current)].width
    if wd ~= 0 then
        local ht = getfield(current,"height")
        local dp = getfield(current,"depth")
        local next = getnext(current)
        local prev = previous
        setboth(current)
        local linewidth = emwidth/(2*fraction)
        local baseline
     -- if dp ~= 0 and ht ~= 0 then
        if (dp >= 0 and ht >= 0) or (dp <= 0 and ht <= 0) then
            baseline = new_rule(wd-2*linewidth,linewidth,0)
        end
        local doublelinewidth = 2*linewidth
        -- could be a pdf rule (or a user rule now)
        local info = linked_nodes(
            new_rule(linewidth,ht,dp),
            new_rule(wd-doublelinewidth,-dp+linewidth,dp),
            new_rule(linewidth,ht,dp),
            new_kern(-wd+linewidth),
            new_rule(wd-doublelinewidth,ht,-ht+linewidth),
            new_kern(-wd+doublelinewidth),
            baseline
        )
        local char = chardata[getfont(current)][getchar(current)]
        if char and type(char.unicode) == "table" then -- hackery test
            setlistcolor(info,c_ligature)
            setlisttransparency(info,c_ligature_d)
        else
            setlistcolor(info,c_glyph)
            setlisttransparency(info,c_glyph_d)
        end
        info = new_hlist(info)
        setattr(info,a_layer,l_glyph)
        local info = linked_nodes(current,new_kern(-wd),info)
        info = hpack_nodes(info)
        setfield(info,"width",wd)
        if next then
            setlink(info,next)
        end
        if prev then
            setlink(prev,info)
        end
        if head == current then
            return info, info
        else
            return head, info
        end
    else
        return head, current
    end
end

local g_cache_v = { }
local g_cache_h = { }

local tags = {
 -- userskip              = "US",
    lineskip              = "LS",
    baselineskip          = "BS",
    parskip               = "PS",
    abovedisplayskip      = "DA",
    belowdisplayskip      = "DB",
    abovedisplayshortskip = "SA",
    belowdisplayshortskip = "SB",
    leftskip              = "LS",
    rightskip             = "RS",
    topskip               = "TS",
    splittopskip          = "ST",
    tabskip               = "AS",
    spaceskip             = "SS",
    xspaceskip            = "XS",
    parfillskip           = "PF",
    thinmuskip            = "MS",
    medmuskip             = "MM",
    thickmuskip           = "ML",
    leaders               = "NL",
    cleaders              = "CL",
    xleaders              = "XL",
    gleaders              = "GL",
 -- true                  = "VS",
 -- false                 = "HS",
}

-- we sometimes pass previous as we can have issues in math (not watertight for all)

local function ruledglue(head,current,vertical,parent)
    local subtype = getsubtype(current)
    local width   = effectiveglue(current,parent)
    local amount  = formatters["%s:%0.3f"](tags[subtype] or (vertical and "VS") or "HS",width*pt_factor)
    local info    = (vertical and g_cache_v or g_cache_h)[amount]
    if info then
        -- print("glue hit")
    else
        if subtype == space_code or subtype == xspace_code then -- not yet all space
            info = sometext(amount,l_glue,c_space)
        elseif subtype == leftskip_code or subtype == rightskip_code then
            info = sometext(amount,l_glue,c_skip_a)
        elseif subtype == userskip_code then
            if width > 0 then
                info = sometext(amount,l_glue,c_positive)
            elseif width < 0 then
                info = sometext(amount,l_glue,c_negative)
            else
                info = sometext(amount,l_glue,c_zero)
            end
        else
            info = sometext(amount,l_glue,c_skip_b)
        end
        (vertical and g_cache_v or g_cache_h)[amount] = info
    end
    info = copy_list(info)
    if vertical then
        info = vpack_nodes(info)
    end
    head, current = insert_node_before(head,current,info)
    return head, getnext(current)
end

local k_cache_v = { }
local k_cache_h = { }

local function ruledkern(head,current,vertical)
    local kern = getfield(current,"kern")
    local info = (vertical and k_cache_v or k_cache_h)[kern]
    if info then
        -- print("kern hit")
    else
        local amount = formatters["%s:%0.3f"](vertical and "VK" or "HK",kern*pt_factor)
        if kern > 0 then
            info = sometext(amount,l_kern,c_positive)
        elseif kern < 0 then
            info = sometext(amount,l_kern,c_negative)
        else
            info = sometext(amount,l_kern,c_zero)
        end
        (vertical and k_cache_v or k_cache_h)[kern] = info
    end
    info = copy_list(info)
    if vertical then
        info = vpack_nodes(info)
    end
    head, current = insert_node_before(head,current,info)
    return head, getnext(current)
end

local i_cache = { }

local function ruleditalic(head,current)
    local kern = getfield(current,"kern")
    local info = i_cache[kern]
    if info then
        -- print("kern hit")
    else
        local amount = formatters["%s:%0.3f"]("IC",kern*pt_factor)
        if kern > 0 then
            info = sometext(amount,l_kern,c_positive)
        elseif kern < 0 then
            info = sometext(amount,l_kern,c_negative)
        else
            info = sometext(amount,l_kern,c_zero)
        end
        i_cache[kern] = info
    end
    info = copy_list(info)
    head, current = insert_node_before(head,current,info)
    return head, getnext(current)
end

local p_cache_v = { }
local p_cache_h = { }

local function ruledpenalty(head,current,vertical)
    local penalty = getfield(current,"penalty")
    local info = (vertical and p_cache_v or p_cache_h)[penalty]
    if info then
        -- print("penalty hit")
    else
        local amount = formatters["%s:%s"](vertical and "VP" or "HP",penalty)
        if penalty > 0 then
            info = sometext(amount,l_penalty,c_positive)
        elseif penalty < 0 then
            info = sometext(amount,l_penalty,c_negative)
        else
            info = sometext(amount,l_penalty,c_zero)
        end
        (vertical and p_cache_v or p_cache_h)[penalty] = info
    end
    info = copy_list(info)
    if vertical then
        info = vpack_nodes(info)
    elseif raisepenalties then
        setfield(info,"shift",-65536*4)
    end
    head, current = insert_node_before(head,current,info)
    return head, getnext(current)
end

local function visualize(head,vertical,forced,parent)
    local trace_hbox     = false
    local trace_vbox     = false
    local trace_vtop     = false
    local trace_kern     = false
    local trace_glue     = false
    local trace_penalty  = false
    local trace_fontkern = false
    local trace_strut    = false
    local trace_whatsit  = false
    local trace_glyph    = false
    local trace_simple   = false
    local trace_user     = false
    local trace_math     = false
    local trace_italic   = false
    local trace_origin   = false
    local current        = head
    local previous       = nil
    local attr           = unsetvalue
    local prev_trace_fontkern = nil
    while current do
        local id = getid(current)
        local a = forced or getattr(current,a_visual) or unsetvalue
        if a ~= attr then
            prev_trace_fontkern = trace_fontkern
            if a == unsetvalue then
                trace_hbox     = false
                trace_vbox     = false
                trace_vtop     = false
                trace_kern     = false
                trace_glue     = false
                trace_penalty  = false
                trace_fontkern = false
                trace_strut    = false
                trace_whatsit  = false
                trace_glyph    = false
                trace_simple   = false
                trace_user     = false
                trace_math     = false
                trace_italic   = false
                trace_origin   = false
            else -- dead slow:
                trace_hbox     = hasbit(a,    1)
                trace_vbox     = hasbit(a,    2)
                trace_vtop     = hasbit(a,    4)
                trace_kern     = hasbit(a,    8)
                trace_glue     = hasbit(a,   16)
                trace_penalty  = hasbit(a,   32)
                trace_fontkern = hasbit(a,   64)
                trace_strut    = hasbit(a,  128)
                trace_whatsit  = hasbit(a,  256)
                trace_glyph    = hasbit(a,  512)
                trace_simple   = hasbit(a, 1024)
                trace_user     = hasbit(a, 2048)
                trace_math     = hasbit(a, 4096)
                trace_italic   = hasbit(a, 8192)
                trace_origin   = hasbit(a,16384)
            end
            attr = a
        end
        if trace_strut then
            setattr(current,a_layer,l_strut)
        elseif id == glyph_code then
            if trace_glyph then
                head, current = ruledglyph(head,current,previous)
            end
        elseif id == disc_code then
            local pre, post, replace = getdisc(current)
            if pre then
                pre = visualize(pre,false,a,parent)
            end
            if post then
                post = visualize(post,false,a,parent)
            end
            if replace then
                replace = visualize(replace,false,a,parent)
            end
            setdisc(current,pre,post,replace)
        elseif id == kern_code then
            local subtype = getsubtype(current)
            -- tricky ... we don't copy the trace attribute in node-inj (yet)
            if subtype == font_kern_code or getattr(current,a_fontkern) then
                if trace_fontkern or prev_trace_fontkern then
                    head, current = fontkern(head,current)
                end
            else -- if subtype == user_kern_code then
                if trace_italic then
                    head, current = ruleditalic(head,current)
                elseif trace_kern then
                    head, current = ruledkern(head,current,vertical)
                end
            end
        elseif id == glue_code then
            local content = getleader(current)
            if content then
                setleader(current,visualize(content,false,nil,parent))
            elseif trace_glue then
                head, current = ruledglue(head,current,vertical,parent)
            end
        elseif id == penalty_code then
            if trace_penalty then
                head, current = ruledpenalty(head,current,vertical)
            end
        elseif id == hlist_code then
            local content = getlist(current)
            if content then
                setlist(current,visualize(content,false,nil,current))
            end
            if trace_hbox then
                head, current = ruledbox(head,current,false,l_hbox,"H__",trace_simple,previous,trace_origin,parent)
            end
        elseif id == vlist_code then
            local content = getlist(current)
            if content then
                setlist(current,visualize(content,true,nil,current))
            end
            if trace_vtop then
                head, current = ruledbox(head,current,true,l_vtop,"_T_",trace_simple,previous,trace_origin,parent)
            elseif trace_vbox then
                head, current = ruledbox(head,current,true,l_vbox,"__V",trace_simple,previous,trace_origin,parent)
            end
        elseif id == whatsit_code then
            if trace_whatsit then
                head, current = whatsit(head,current)
            end
        elseif id == user_code then
            if trace_user then
                head, current = user(head,current)
            end
        elseif id == math_code then
            if trace_math then
                head, current = math(head,current)
            end
        end
        previous = current
        current  = getnext(current)
    end
    return head
end

do

    local function freed(cache)
        local n = 0
        for k, v in next, cache do
            free_node_list(v)
            n = n + 1
        end
        if n == 0 then
            return 0, cache
        else
            return n, { }
        end
    end

    local function cleanup()
        local hf, nw, nb, ng_v, ng_h, np_v, np_h, nk_v, nk_h
        nf,   f_cache   = freed(f_cache)
        nw,   w_cache   = freed(w_cache)
        nb,   b_cache   = freed(b_cache)
        no,   o_cache   = freed(o_cache)
        ng_v, g_cache_v = freed(g_cache_v)
        ng_h, g_cache_h = freed(g_cache_h)
        np_v, p_cache_v = freed(p_cache_v)
        np_h, p_cache_h = freed(p_cache_h)
        nk_v, k_cache_v = freed(k_cache_v)
        nk_h, k_cache_h = freed(k_cache_h)
     -- report_visualize("cache cleanup: %s fontkerns, %s skips, %s penalties, %s kerns, %s whatsits, %s boxes, %s origins",
     --     nf,ng_v+ng_h,np_v+np_h,nk_v+nk_h,nw,nb,no)
    end

    local function handler(head)
        if usedfont then
            starttiming(visualizers)
         -- local l = texgetattribute(a_layer)
         -- local v = texgetattribute(a_visual)
         -- texsetattribute(a_layer,unsetvalue)
         -- texsetattribute(a_visual,unsetvalue)
            head = visualize(tonut(head),true)
         -- texsetattribute(a_layer,l)
         -- texsetattribute(a_visual,v)
         -- -- cleanup()
            stoptiming(visualizers)
            return tonode(head), true
        else
            return head, false
        end
    end

    visualizers.handler = handler

    luatex.registerstopactions(cleanup)

end

function visualizers.box(n)
    if usedfont then
        starttiming(visualizers)
        local box = getbox(n)
        if box then
            setlist(box,visualize(getlist(box),getid(box) == vlist_code))
        end
        stoptiming(visualizers)
        return head, true
    else
        return head, false
    end
end

do

    local last = nil
    local used = nil

    local mark = {
        "trace:1", "trace:2", "trace:3",
        "trace:4", "trace:5", "trace:6",
        "trace:7",
    }

    local function markfonts(list)
        for n in traverse_nodes(list) do
            local id = getid(n)
            if id == glyph_code then
                local font = getfont(n)
                local okay = used[font]
                if not okay then
                    last = last + 1
                    okay = mark[last]
                    used[font] = okay
                end
                setcolor(n,okay)
            elseif id == hlist_code or id == vlist_code then
                markfonts(getlist(n))
            end
        end
    end

    function visualizers.markfonts(list)
        last, used = 0, { }
        markfonts(type(n) == "number" and getlist(getbox(n)) or n)
    end

end

statistics.register("visualization time",function()
    if enabled then
     -- cleanup() -- in case we don't don't do it each time
        return format("%s seconds",statistics.elapsedtime(visualizers))
    end
end)

-- interface

local implement = interfaces.implement

implement { name = "setvisual",       arguments = "string",  actions = visualizers.setvisual }
implement { name = "getvisual",       arguments = "string",  actions = { setvisual, context } }
implement { name = "setvisuallayer",  arguments = "string",  actions = visualizers.setlayer }
implement { name = "markvisualfonts", arguments = "integer", actions = visualizers.markfonts }
implement { name = "setvisualfont",   arguments = "integer", actions = visualizers.setfont }