forked from johnwhitington/camlpdf
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathpdftext.ml
1236 lines (1146 loc) · 44.5 KB
/
pdftext.ml
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
(* Reading and writing text *)
open Pdfutil
open Pdfio
(* Type 3 Specific Glyph Data *)
type type3_glpyhs =
{fontbbox : float * float * float * float;
fontmatrix : Pdftransform.transform_matrix;
charprocs : (string * Pdf.pdfobject) list;
type3_resources : Pdf.pdfobject}
(* A font is either one of the standard 14 fonts, a simple font, or.. *)
type simple_fonttype =
| Type1
| MMType1
| Type3 of type3_glpyhs
| Truetype
type fontmetrics = float array (*r widths of glyphs 0..255 *)
(* The fontfile is an indirect reference into the document, rather than a
PDFobject itself. This preserves polymorphic equality (a pdfobject can contain
functional values *)
type fontfile =
| FontFile of int
| FontFile2 of int
| FontFile3 of int
type fontdescriptor =
{ascent : float;
descent : float;
avgwidth : float;
maxwidth : float;
flags : int;
fontbbox: float * float * float * float;
italicangle : float;
capheight : float;
xheight : float;
stemv : float;
fontfile : fontfile option;
charset : string list option;
tounicode : (int, string) Hashtbl.t option} (* Hack. Hide tounicode in fontdescriptor, because no space at top level *)
type differences = (string * int) list
type encoding =
| ImplicitInFontFile
| StandardEncoding
| MacRomanEncoding
| WinAnsiEncoding
| MacExpertEncoding
| CustomEncoding of encoding * differences
| FillUndefinedWithStandard of encoding
type simple_font =
{fonttype : simple_fonttype;
basefont : string;
firstchar : int;
lastchar : int;
widths : int array;
fontdescriptor : fontdescriptor option;
fontmetrics : fontmetrics option;
encoding : encoding}
type standard_font =
| TimesRoman
| TimesBold
| TimesItalic
| TimesBoldItalic
| Helvetica
| HelveticaBold
| HelveticaOblique
| HelveticaBoldOblique
| Courier
| CourierBold
| CourierOblique
| CourierBoldOblique
| Symbol
| ZapfDingbats
let string_of_standard_font = function
| TimesRoman -> "Times-Roman"
| TimesBold -> "Times-Bold"
| TimesItalic -> "Times-Italic"
| TimesBoldItalic -> "Times-BoldItalic"
| Helvetica -> "Helvetica"
| HelveticaBold -> "Helvetica-Bold"
| HelveticaOblique -> "Helvetica-Oblique"
| HelveticaBoldOblique -> "Helvetica-BoldOblique"
| Courier -> "Courier"
| CourierBold -> "Courier-Bold"
| CourierOblique -> "Courier-Oblique"
| CourierBoldOblique -> "Courier-BoldOblique"
| Symbol -> "Symbol"
| ZapfDingbats -> "ZapfDingbats"
type cid_system_info =
{registry : string;
ordering : string;
supplement : int}
type composite_CIDfont =
{cid_system_info : cid_system_info;
cid_basefont : string;
cid_fontdescriptor : fontdescriptor;
cid_widths : (int * float) list;
cid_default_width : int}
type cmap_encoding =
| Predefined of string
| CMap of int (* indirect reference to CMap stream *)
type font =
| StandardFont of standard_font * encoding
| SimpleFont of simple_font
| CIDKeyedFont of string * composite_CIDfont * cmap_encoding (* string is top-level basefont *)
(* For Debug *)
let string_of_fonttype = function
| Type1 -> "Type 1"
| MMType1 -> "MM Type 1"
| Type3 {charprocs = charprocs} ->
"Type 3: charprocs for" ^
fold_left ( ^ ) "" (map (function (s, _) -> s) charprocs)
| Truetype -> "Truetype"
let rec string_of_encoding = function
| ImplicitInFontFile -> "ImplicitInFontFile"
| StandardEncoding -> "StandardEncoding"
| MacRomanEncoding -> "MacRomanEncoding"
| WinAnsiEncoding -> "WinAnsiEncoding"
| MacExpertEncoding -> "MacExpertEncoding"
| CustomEncoding (enc, diff) ->
Printf.sprintf
"CustomEncoding with base %s and differences %s"
(string_of_encoding enc)
(fold_left ( ^ ) "" (map (function (name, code) -> Printf.sprintf "%i -> %s, " code name) diff))
| FillUndefinedWithStandard enc ->
Printf.sprintf "FillUndefinedWithStandard %s" (string_of_encoding enc)
let string_of_simple_font font =
"fonttype = " ^ string_of_fonttype font.fonttype ^ "\n" ^
"basefont " ^ font.basefont ^ "\n" ^
"encoding is " ^ string_of_encoding font.encoding ^ "\n"
let string_of_font = function
| StandardFont (s, _) -> "StandardFont " ^ string_of_standard_font s
| SimpleFont s -> "SimpleFont " ^ string_of_simple_font s
| CIDKeyedFont (s, _, _) -> "CIDKeyedFont " ^ s
let read_type3_data pdf font =
{fontbbox =
(let obj = Pdf.lookup_fail "No fontbbox" pdf "/FontBBox" font in
Pdf.parse_rectangle pdf obj);
fontmatrix =
Pdf.parse_matrix pdf "/FontMatrix" font;
charprocs =
(match Pdf.lookup_fail "Bad Charprocs" pdf "/CharProcs" font with
| Pdf.Dictionary l -> l
| _ -> raise (Pdf.PDFError "Bad charprocs"));
type3_resources =
(match Pdf.lookup_direct pdf "/Resources" font with
| None -> Pdf.Dictionary []
| Some d -> d)}
let simple_fonttype_of_string pdf font = function
| "/Type1" -> Some Type1
| "/MMType1" -> Some MMType1
| "/Type3" ->
Some (Type3 (read_type3_data pdf font))
| "/TrueType" -> Some Truetype
| _ -> None
let read_basefont pdf font =
match Pdf.lookup_direct pdf "/BaseFont" font with
| Some (Pdf.Name n) -> n
| _ -> ""
let parse_charset s =
let i = Pdfio.input_of_string s in
let gs = ref [] in
try
while true do
Pdfread.dropwhite i;
begin match Pdfread.lex_name i with
| Pdfgenlex.LexName s ->
if s = "/" then raise Exit else gs := s::!gs
| _ -> raise Exit
end
done;
[]
with
_ -> rev !gs
let read_fontdescriptor pdf font =
match Pdf.lookup_direct pdf "/FontDescriptor" font with
| None -> None
| Some fontdescriptor ->
let ascent =
match Pdf.lookup_direct pdf "/Ascent" fontdescriptor with
| Some x -> Pdf.getnum pdf x
| None -> 0.
in let descent =
match Pdf.lookup_direct pdf "/Descent" fontdescriptor with
| Some x -> Pdf.getnum pdf x
| None -> 0.
in let avgwidth =
match Pdf.lookup_direct pdf "/AvgWidth" fontdescriptor with
| Some x -> Pdf.getnum pdf x
| None -> 0.
in let maxwidth =
match Pdf.lookup_direct pdf "/MaxWidth" fontdescriptor with
| Some x -> Pdf.getnum pdf x
| None -> 0.
in let fontfile =
match Pdf.find_indirect "/FontFile" fontdescriptor with
| Some i -> Some (FontFile i)
| None ->
match Pdf.find_indirect "/FontFile2" fontdescriptor with
| Some i -> Some (FontFile2 i)
| None ->
match Pdf.find_indirect "/FontFile3" fontdescriptor with
| Some i -> Some (FontFile3 i)
| None -> None
in let charset =
match Pdf.lookup_direct pdf "/CharSet" fontdescriptor with
| Some (Pdf.String s) -> Some (parse_charset s)
| _ -> None
in
Some
{ascent = ascent;
descent = descent;
avgwidth = avgwidth;
maxwidth = maxwidth;
fontfile = fontfile;
charset = charset;
flags = 0;
fontbbox = (0., 0., 0., 0.);
italicangle = 0.;
capheight = 0.;
xheight = 0.;
stemv = 0.;
tounicode = None}
(* Read the widths from a font. Normally in the font descriptor, but in Type3
fonts at the top level. *)
let read_metrics pdf font =
let fontdescriptor =
match Pdf.lookup_direct pdf "/Subtype" font with
| Some (Pdf.Name "/Type3") -> Some font
| _ -> Pdf.lookup_direct pdf "/FontDescriptor" font
in
match fontdescriptor with
| None -> None
| Some fontdescriptor ->
let firstchar =
match Pdf.lookup_direct pdf "/FirstChar" font with
| Some (Pdf.Integer i) ->
if i <= 255 && i >= 0 then i else
raise (Pdf.PDFError "Bad /Firstchar")
| _ -> raise (Pdf.PDFError "No /FirstChar")
in let lastchar =
match Pdf.lookup_direct pdf "/LastChar" font with
| Some (Pdf.Integer i) ->
if i <= 255 && i >= 0 then i else
raise (Pdf.PDFError "Bad /Lastchar")
| _ -> raise (Pdf.PDFError "No /LastChar")
in let missingwidth =
match Pdf.lookup_direct pdf "/MissingWidth" fontdescriptor with
| Some (Pdf.Integer w) -> float w
| Some (Pdf.Real w) -> w
| _ -> 0.
in
let elts =
match Pdf.lookup_direct pdf "/Widths" font with
| Some (Pdf.Array elts) -> elts
| _ -> raise (Pdf.PDFError "No /Widths")
in
if length elts <> lastchar - firstchar + 1
then raise (Pdf.PDFError "Bad /Widths")
else
let before =
many missingwidth firstchar
in let given =
map
(fun elt ->
match Pdf.direct pdf elt with
| Pdf.Integer i -> float i
| Pdf.Real f -> f
| _ -> raise (Pdf.PDFError "Bad /Width entry"))
elts
in let after =
many missingwidth (255 - lastchar)
in
Some (Array.of_list (before @ given @ after))
(* Parse a /Differences entry to get a list of (name, number) pairs *)
let pairs_of_differences pdf differences =
let rec groups_of_differences prev elts =
match elts with
| [] -> prev
| Pdf.Integer n::rest ->
let stripname = function Pdf.Name n -> n | _ -> assert false in
let names, more =
cleavewhile (function Pdf.Name _ -> true | _ -> false) rest
in
groups_of_differences ((n, map stripname names)::prev) more
| _ -> raise (Pdf.PDFError "Malformed /Differences")
and mappings_of_group (x, es) =
let additions = ilist 0 (length es - 1) in
map2 (fun e a -> (x + a, e)) es additions
in
match differences with
| Pdf.Array elts ->
let direct_elements = map (Pdf.direct pdf) elts in
let groups = groups_of_differences [] direct_elements in
map
(fun (k, v) -> (v, k))
(flatten (map mappings_of_group groups))
| _ -> raise (Pdf.PDFError "Bad /Differences")
let standard_font_of_name = function
| "/Times-Roman" | "/TimesNewRoman" -> Some TimesRoman
| "/Times-Bold" | "/TimesNewRoman,Bold" -> Some TimesBold
| "/Times-Italic" | "/TimesNewRoman,Italic" -> Some TimesItalic
| "/Times-BoldItalic" | "/TimesNewRoman,BoldItalic" -> Some TimesBoldItalic
| "/Helvetica" | "/Arial" -> Some Helvetica
| "/Helvetica-Bold" | "/Arial,Bold" -> Some HelveticaBold
| "/Helvetica-Oblique" | "/Arial,Italic" -> Some HelveticaOblique
| "/Helvetica-BoldOblique" | "/Arial,BoldItalic" -> Some HelveticaBoldOblique
| "/Courier" | "/CourierNew" -> Some Courier
| "/Courier-Bold" | "/CourierNew,Bold" -> Some CourierBold
| "/Courier-Oblique" | "/CourierNew,Italic" -> Some CourierOblique
| "/Courier-BoldOblique" | "/CourierNew,BoldItalic" -> Some CourierBoldOblique
| "/Symbol" -> Some Symbol
| "/ZapfDingbats" -> Some ZapfDingbats
| _ -> None
(* Predicate: is it a standard 14 font? If it's been overriden (contains widths
etc, we treat it as a simple font. *)
let is_standard14font pdf font =
match Pdf.lookup_direct pdf "/Subtype" font with
| Some (Pdf.Name "/Type1") ->
begin match Pdf.lookup_direct pdf "/BaseFont" font with
| Some (Pdf.Name name) ->
begin match standard_font_of_name name with
| None -> false
| Some _ ->
(* Check to see if it's been overriden *)
match Pdf.lookup_direct pdf "/Widths" font with
| None -> true
| _ -> false
end
| _ -> false
end
| _ -> false
(* Is a font embedded in the document? *)
let is_embedded pdf font =
match Pdf.lookup_direct pdf "/FontDescriptor" font with
| None -> false
| Some fontdescriptor ->
match
Pdf.lookup_direct_orelse pdf "/FontFile" "/FontFile2" fontdescriptor
with
| Some _ -> true
| None ->
match Pdf.lookup_direct pdf "/FontFile3" fontdescriptor with
| Some _ -> true
| None -> false
(* Is a font symbolic? (Doesn't deal with standard 14 Zapf and Symbol) *)
let is_symbolic pdf font =
match Pdf.lookup_direct pdf "/FontDescriptor" font with
| None -> false
| Some fontdescriptor ->
match Pdf.lookup_direct pdf "/Flags" fontdescriptor with
| Some (Pdf.Integer flags) -> flags land (1 lsl 3) > 0
| _ -> raise (Pdf.PDFError "No /Flags in font descriptor")
(* For now, not for truetype fonts: add pg 399-401 later. Need to clarify what
happens if a standard-14 font is overriden. *)
let read_encoding pdf font =
match Pdf.lookup_direct pdf "/Encoding" font with
| Some (Pdf.Name "/MacRomanEncoding") -> MacRomanEncoding
| Some (Pdf.Name "/MacExpertEncoding") -> MacExpertEncoding
| Some (Pdf.Name "/WinAnsiEncoding") -> WinAnsiEncoding
| Some (Pdf.Dictionary _ as encdict) ->
begin match Pdf.lookup_direct pdf "/Subtype" font with
| Some
(Pdf.Name (("/Type1" | "/MMType1" | "/Type3" | "/TrueType") as fonttype))
->
let encoding =
let base_encoding =
match Pdf.lookup_direct pdf "/BaseEncoding" encdict with
| Some (Pdf.Name "/MacRomanEncoding") -> MacRomanEncoding
| Some (Pdf.Name "/MacExpertEncoding") -> MacExpertEncoding
| Some (Pdf.Name "/WinAnsiEncoding") -> WinAnsiEncoding
| None ->
if is_embedded pdf font
then ImplicitInFontFile
else if is_symbolic pdf font
then ImplicitInFontFile
else StandardEncoding
| _ -> raise (Pdf.PDFError "unknown /BaseEncoding")
in
begin match Pdf.lookup_direct pdf "/Differences" encdict with
| Some differences ->
CustomEncoding
(base_encoding, pairs_of_differences pdf differences)
| _ -> base_encoding
end
in
if fonttype = "/Truetype"
then FillUndefinedWithStandard encoding
else encoding
| _ -> raise (Pdf.PDFError "Bad font /Subtype")
end
| _ -> ImplicitInFontFile
let read_simple_font pdf font =
match Pdf.lookup_direct pdf "/Subtype" font with
| Some (Pdf.Name n) ->
begin match simple_fonttype_of_string pdf font n with
| Some fonttype ->
let fontdescriptor = read_fontdescriptor pdf font in
let fontmetrics = read_metrics pdf font in
SimpleFont
{fonttype = fonttype;
basefont = read_basefont pdf font;
fontmetrics;
firstchar = 0;
lastchar = 0;
widths = [||];
fontdescriptor = fontdescriptor;
encoding = read_encoding pdf font}
| None -> raise (Pdf.PDFError "Not a simple font")
end
| _ -> raise (Pdf.PDFError "No font /Subtype")
(* Read a base 14 font *)
let read_standard14font pdf font =
match Pdf.lookup_direct pdf "/BaseFont" font with
| Some (Pdf.Name name) ->
begin match standard_font_of_name name with
| None -> raise (Pdf.PDFError "Not a base 14 font")
| Some f -> StandardFont (f, read_encoding pdf font)
end
| _ -> raise (Pdf.PDFError "Bad base 14 font")
(* Predicate: is it a simple font, assuming it's not a standard 14 font. *)
let is_simple_font pdf font =
match Pdf.lookup_direct pdf "/Subtype" font with
| Some (Pdf.Name ("/Type1" | "/MMType1" | "/Type3" | "/TrueType")) -> true
| _ -> false
(* Predicate: is it a CIDKeyed font? *)
let is_cidkeyed_font pdf font =
match Pdf.lookup_direct pdf "/Subtype" font with
| Some (Pdf.Name "/Type0") -> true
| _ -> false
(* Read a CID system info dictionary *)
let read_cid_system_info pdf dict =
{registry =
begin match Pdf.lookup_direct pdf "/Registry" dict with
| Some (Pdf.String s) -> s
| _ -> raise (Pdf.PDFError "No /Registry")
end;
ordering =
begin match Pdf.lookup_direct pdf "/Ordering" dict with
| Some (Pdf.String s) -> s
| _ -> raise (Pdf.PDFError "No /Ordering")
end;
supplement =
begin match Pdf.lookup_direct pdf "/Supplement" dict with
| Some (Pdf.Integer i) -> i
| _ -> raise (Pdf.PDFError "No /Supplement")
end}
(* This returns the explicit pairs, which need to be combined
with the default value to look a width up. *)
let rec read_cid_widths = function
| Pdf.Integer c::Pdf.Array ws::more ->
let nums =
map
(function
| Pdf.Integer i -> float i
| Pdf.Real r -> r
| _ -> raise (Pdf.PDFError "Bad /W array"))
ws
in
combine (indxn c nums) nums @ read_cid_widths more
| Pdf.Integer c_first::Pdf.Integer c_last::w::more ->
let w =
match w with
| Pdf.Integer i -> float i
| Pdf.Real r -> r
| _ -> raise (Pdf.PDFError "Bad /W array")
in
if c_last < c_first
then raise (Pdf.PDFError "Bad /W array")
else
let pairs =
combine
(ilist c_first c_last)
(many w (c_last - c_first + 1))
in
pairs @ read_cid_widths more
| [] -> []
| _ -> raise (Pdf.PDFError "Malformed /W in CIDfont")
(* Read a composite CID font *)
(* FIXME: Doesn't support vertical modes (DW2 / W2) *)
let read_descendant pdf dict =
let cid_system_info =
match Pdf.lookup_direct pdf "/CIDSystemInfo" dict with
| Some cid_dict -> read_cid_system_info pdf cid_dict
| None -> raise (Pdf.PDFError "No CIDSystemInfo")
in let cid_basefont =
match Pdf.lookup_direct pdf "/BaseFont" dict with
| Some (Pdf.Name n) -> n
| _ -> raise (Pdf.PDFError "No /BaseFont")
in let cid_fontdescriptor =
match read_fontdescriptor pdf dict with
| Some f -> f
| None -> raise (Pdf.PDFError "No FontDescriptor in CIDkeyed font")
in let cid_widths =
match Pdf.lookup_direct pdf "/W" dict with
| Some (Pdf.Array ws) -> read_cid_widths ws
| _ -> []
in let default_width =
match Pdf.lookup_direct pdf "/DW" dict with
| Some (Pdf.Integer d) -> d
| _ -> 1000
in
{cid_system_info = cid_system_info;
cid_basefont = cid_basefont;
cid_fontdescriptor = cid_fontdescriptor;
cid_widths = cid_widths;
cid_default_width = default_width}
(* Read a CIDKeyed (Type 0) font *)
let read_cidkeyed_font pdf font =
let basefont =
match Pdf.lookup_direct pdf "/BaseFont" font with
| Some (Pdf.Name b) -> b
| _ -> raise (Pdf.PDFError "Bad /BaseFont")
in let composite_CIDfont =
match Pdf.lookup_direct pdf "/DescendantFonts" font with
| Some (Pdf.Array [e]) ->
read_descendant pdf (Pdf.direct pdf e)
| _ -> raise (Pdf.PDFError "Bad descendant font")
in let encoding =
match Pdf.lookup_direct pdf "/Encoding" font with
| Some (Pdf.Name e) -> Predefined e
| Some (Pdf.Stream _) ->
begin match Pdf.find_indirect "/Encoding" font with
| Some n -> CMap n
| None -> raise (Pdf.PDFError "malformed /Encoding")
end
| _ -> raise (Pdf.PDFError "malformed or missing /Encoding")
in
CIDKeyedFont (basefont, composite_CIDfont, encoding)
(* Parse a /ToUnicode CMap to extract font mapping. *)
type section =
| BfChar of char list
| BfRange of char list
let rec getuntilend prev = function
| [] -> rev prev, []
| 'e'::'n'::'d'::'b'::'f'::'c'::'h'::'a'::'r'::more -> rev prev, more
| h::t -> getuntilend (h::prev) t
let rec getuntilend_range prev = function
| [] -> rev prev, []
| 'e'::'n'::'d'::'b'::'f'::'r'::'a'::'n'::'g'::'e'::more -> rev prev, more
| h::t -> getuntilend_range (h::prev) t
let rec get_section = function
| [] -> None
| 'b'::'e'::'g'::'i'::'n'::'b'::'f'::'c'::'h'::'a'::'r'::more ->
let numbers, rest = getuntilend [] more in
Some (BfChar numbers, rest)
| 'b'::'e'::'g'::'i'::'n'::'b'::'f'::'r'::'a'::'n'::'g'::'e'::more ->
let numbers, rest = getuntilend_range [] more in
Some (BfRange numbers, rest)
| _::t -> get_section t
(* Read a character code. *)
let rec read_number = function
| x::more when Pdf.is_whitespace x -> read_number more
| '<'::a::'>'::more ->
int_of_string (implode ['0'; 'x'; a]), more
| '<'::a::b::'>'::more ->
int_of_string (implode ['0'; 'x'; a; b]), more
| '<'::a::b::c::'>'::more ->
int_of_string (implode ['0'; 'x'; a; b; c]), more
| '<'::a::b::c::d::'>'::more ->
int_of_string (implode ['0'; 'x'; a; b; c; d]), more
| [] -> raise Not_found
| _ -> raise (Pdf.PDFError "Unknown number in /ToUnicode")
(* Read the bytes of the UTF-16BE unicode sequence as a string. *)
let fail () =
raise (Pdf.PDFError "Bad unicode value")
let rec read_unicode = function
| x::rest when Pdf.is_whitespace x -> read_unicode rest
| '<'::rest ->
let chars, rest = cleavewhile (neq '>') rest in
let is_hex_digit = function
| x when (x >= '0' && x <= '9') || (x >= 'a' && x <= 'f') || (x >= 'A' && x <= 'F') -> true
| _ -> false
in
iter
(fun x -> if not (is_hex_digit x) then fail ())
chars;
if length chars > 0 && even (length chars) then
let bytes =
map
(function
| [x; y] -> char_of_int (int_of_string (implode ['0'; 'x'; x; y]))
| _ -> assert false)
(splitinto 2 chars)
in
let rest' =
match rest with
| [] -> []
| _ -> tl rest
in
implode bytes, rest'
else
fail ()
| _ -> fail ()
let rec get_sections chars =
match get_section chars with
| None -> []
| Some (sec, restchars) ->
sec::get_sections restchars
let pairs_of_section = function
| BfChar numbers ->
let results = ref []
in let numbers = ref numbers in
begin try
while true do
let number, rest = read_number !numbers in
let str, rest = read_unicode rest in
numbers := rest;
results =| (number, str)
done;
[]
with
Not_found -> rev !results
end
| BfRange numbers ->
let results = ref []
in let numbers = ref numbers in
begin try
while true do
let src1, rest = read_number !numbers in
let src2, rest = read_number rest in
if src1 > src2 then raise (Pdf.PDFError "Bad /ToUnicode") else
match rest with
| '<'::_ ->
(* It's a single unicode string *)
let increment_final code d =
match code with
| "" -> ""
| s ->
let chars = rev (explode s) in
implode ((rev (tl chars)) @
[char_of_int (int_of_char (hd chars) + d)])
in
let code, rest = read_unicode rest in
results =@
rev
(combine
(ilist src1 src2)
(map (increment_final code) (ilist 0 (src2 - src1))));
numbers := rest
| '['::rest ->
(* It's several. *)
let rest = ref rest in
results =@
combine
(ilist src1 src2)
(map
(fun _ ->
let num, rest' = read_unicode !rest in
rest := rest';
num)
(ilist 0 (src2 - src1)));
rest := (match !rest with [] -> [] | x -> tl x);
numbers := !rest
| _ -> raise (Pdf.PDFError "Bad BfRange")
done;
[]
with
Not_found -> rev !results
end
let rec parse_tounicode pdf tounicode =
match tounicode with
| Pdf.Stream {contents = (dict, Pdf.Got data)} ->
Pdfcodec.decode_pdfstream pdf tounicode;
begin match tounicode with
| Pdf.Stream {contents = (dict, Pdf.Got data)} ->
begin try
flatten
(map pairs_of_section
(get_sections
(lose Pdf.is_whitespace (charlist_of_bytes data))))
with
e ->
Pdfe.log (Printf.sprintf "/ToUnicode Parse Error : %s\n" (Printexc.to_string e));
raise e
end
| _ -> assert false
end
| Pdf.Stream {contents = (_, Pdf.ToGet _)} ->
Pdf.getstream tounicode;
parse_tounicode pdf tounicode
| e -> raise (Pdf.PDFError (Printf.sprintf "Bad /ToUnicode %s" (Pdfwrite.string_of_pdf e)))
(* We didn't originally parse the /ToUnicode when reading the font, but we
should have. The hack now is to hide the parsed /ToUnicode hash table in the
fontdescriptor. To avoid complicated code, we read the font as normal, then
read the /ToUnicode, and insert it into the Font descriptor. *)
let add_tounicode pdf font fontdict =
let tounicode =
match Pdf.lookup_direct pdf "/ToUnicode" fontdict with
| Some tounicode ->
begin try
Some (hashtable_of_dictionary <| parse_tounicode pdf tounicode)
with
e -> Pdfe.log (Printf.sprintf "bad tounicode (%s)\n" (Printexc.to_string e)); None
end
| None -> None
in
match font with
| SimpleFont ({fontdescriptor = Some fd} as r) ->
SimpleFont {r with fontdescriptor = Some {fd with tounicode}}
| SimpleFont ({fontdescriptor = None} as r) ->
SimpleFont {r with fontdescriptor = (* fabricate one. ok? fix somehow in future... *)
Some {ascent = 0.;
descent = 0.;
avgwidth = 0.;
maxwidth = 0.;
fontfile = None;
charset = None;
flags = 0;
fontbbox = (0., 0., 0., 0.);
italicangle = 0. ;
capheight = 0.;
xheight = 0.;
stemv = 0.;
tounicode}}
| CIDKeyedFont (a, ({cid_fontdescriptor} as r), c) ->
CIDKeyedFont (a, {r with cid_fontdescriptor = {r.cid_fontdescriptor with tounicode}}, c)
| x -> x
let find_tounicode = function
| SimpleFont {fontdescriptor = Some {tounicode}}
| CIDKeyedFont (_, {cid_fontdescriptor = {tounicode}}, _) -> tounicode
| _ -> None
(* Reads a font *)
let read_font pdf fontdict =
let without_tounicode =
if is_standard14font pdf fontdict
then read_standard14font pdf fontdict
else if is_simple_font pdf fontdict
then read_simple_font pdf fontdict
else if is_cidkeyed_font pdf fontdict
then read_cidkeyed_font pdf fontdict
else raise (Pdf.PDFError "Unknown font type")
in
add_tounicode pdf without_tounicode fontdict
let make_font fontname encoding =
Pdf.Dictionary
[("/Type", Pdf.Name "/Font");
("/Subtype", Pdf.Name "/Type1");
("/Encoding", Pdf.Name ("/" ^ string_of_encoding encoding));
("/BaseFont", Pdf.Name ("/" ^ fontname))]
let write_encoding pdf = function
| CustomEncoding (ImplicitInFontFile, diffs) ->
let diffarray =
Pdf.Array
(flatten (map (function (name, number) -> [Pdf.Integer number; Pdf.Name name]) diffs))
in
let encodingdict =
Pdf.Dictionary
[("/Type", Pdf.Name "/Encoding");
("/Differences", diffarray)]
in
Pdf.addobj pdf encodingdict
| _ -> raise (Pdf.PDFError "write_encoding: not supported")
let tounicode_preamble =
"/CIDInit /ProcSet findresource begin\n\
12 dict begin\n\
begincmap\n\
/CIDSystemInfo <<\n\
/Registry (Adobe)\n\
/Ordering (UCS)\n\
/Supplement 0\n\
>> def\n\
/CMapName /Adobe-Identity-UCS def\n\
/CMapType 2 def\n\
1 begincodespacerange\n\
<00><FF>\n\
endcodespacerange\n"
let tounicode_postamble =
"endbfrange\n\
endcmap\n\
CMapName currentdict /CMap defineresource pop\n\
end\n\
end\n"
let hex u =
let b = Buffer.create 32 in
String.iter (fun x -> Buffer.add_string b (Printf.sprintf "%02X" (int_of_char x))) u;
Buffer.contents b
let tounicode_map s us =
let b = Buffer.create 1024 in
let s = ref s in
Buffer.add_string b tounicode_preamble;
Buffer.add_string b (Printf.sprintf "%i beginbfrange\n" (length us));
iter
(fun u -> Buffer.add_string b (Printf.sprintf "<%02x><%02x><%s>\n" !s !s (hex u));
s := !s + 1)
us;
Buffer.add_string b tounicode_postamble;
bytes_of_string (Buffer.contents b)
(* Just for the kind produced by the font subsetter for now. *)
let write_tounicode pdf u =
let bytes = tounicode_map 33 (map (fun (_, s) -> s) (sort compare ((list_of_hashtbl u)))) in
Pdf.addobj pdf (Pdf.Stream {contents = (Pdf.Dictionary [("/Length", Pdf.Integer (bytes_size bytes))], Pdf.Got bytes)})
let write_font ?objnum pdf = function
| SimpleFont
{fonttype = Type3
{fontbbox = fontbbox;
fontmatrix = fontmatrix;
charprocs = charprocs};
encoding = encoding;
fontdescriptor = Some fontdescriptor} ->
let encoding_entry =
match encoding with
| ImplicitInFontFile -> []
| _ -> [("/Encoding", Pdf.Indirect (write_encoding pdf encoding))]
in
let dict =
Pdf.Dictionary
([("/Type", Pdf.Name "/Font");
("/Subtype", Pdf.Name "/Type3");
("/FontBBox", Pdf.Array [Pdf.Real 0.; Pdf.Real 0.; Pdf.Real 0.; Pdf.Real 0.]);
("/FontMatrix", Pdf.Array [Pdf.Real 0.; Pdf.Real 0.; Pdf.Real 0.; Pdf.Real 0.; Pdf.Real 0.; Pdf.Real 0.]);
("/CharProcs", Pdf.Dictionary (map (fun (s, _) -> (s, Pdf.Null)) charprocs));
("/FirstChar", Pdf.Integer 0);
("/LastChar", Pdf.Integer 0);
("/Widths", Pdf.Array [Pdf.Real 0.])] @ encoding_entry)
in
Pdf.addobj pdf dict
| SimpleFont (* This case is for TrueType fonts embedded by cpdf *)
{fonttype = Truetype;
basefont;
firstchar;
lastchar;
widths;
fontdescriptor =
Some {ascent; descent; avgwidth; maxwidth; flags;
fontbbox = (minx, miny, maxx, maxy);
italicangle; capheight; xheight; stemv; fontfile = Some (FontFile2 ttf);
tounicode};
encoding} ->
let fontdescriptor =
Pdf.Dictionary
[("/Type", Pdf.Name "/FontDescriptor");
("/FontName", Pdf.Name basefont);
("/Flags", Pdf.Integer flags);
("/FontBBox",
Pdf.Array
[Pdf.Integer (int_of_float minx); Pdf.Integer (int_of_float miny);
Pdf.Integer (int_of_float maxx); Pdf.Integer (int_of_float maxy)]);
("/ItalicAngle", Pdf.Integer (int_of_float italicangle));
("/Ascent", Pdf.Integer (int_of_float ascent));
("/Descent", Pdf.Integer (int_of_float descent));
("/CapHeight", Pdf.Integer (int_of_float capheight));
("/StemV", Pdf.Integer (int_of_float stemv));
("/XHeight", Pdf.Integer (int_of_float xheight));
("/AvgWidth", Pdf.Integer (int_of_float avgwidth));
("/MaxWidth", Pdf.Integer (int_of_float maxwidth));
("/FontFile2", Pdf.Indirect ttf)]
in
let fontdesc_num = Pdf.addobj pdf fontdescriptor in
let font =
Pdf.Dictionary
([("/Type", Pdf.Name "/Font");
("/Subtype", Pdf.Name "/TrueType");
("/BaseFont", Pdf.Name basefont);
("/FontDescriptor", Pdf.Indirect fontdesc_num);
("/FirstChar", Pdf.Integer firstchar);
("/LastChar", Pdf.Integer lastchar);
("/Widths", Pdf.Array (map (fun i -> Pdf.Integer i) (Array.to_list widths)))]
@ (match tounicode with
| None -> [("/Encoding", Pdf.Name ("/" ^ string_of_encoding encoding))]
| Some u -> [("/ToUnicode", Pdf.Indirect (write_tounicode pdf u))]))
in
begin match objnum with
| None -> Pdf.addobj pdf font
| Some o -> Pdf.addobj_given_num pdf (o, font); o
end
| StandardFont (standard_font, encoding) ->
Pdf.addobj pdf (make_font (string_of_standard_font standard_font) encoding)
| _ -> raise (Pdf.PDFError "Pdftext.write_font does not support this font")
(* Extracting of Text *)
(* A text extractor takes a character and returns a decoded PDF codepoint, a
glyphname, and a list of unicode codepoints. This may have to be extended
when we deal with composite fonts. *)
type text_extractor =
{convert: int -> string * int list; (* Glyph name, List of unicode codepoints *)
font: font}
(* Encode utf16be *)
let utf16be_of_codepoint u =
if u < 0 || u > 0x10FFFF then
raise (Invalid_argument "utf16be_of_codepoints")
else
(* Two bytes, bottom one first *)
let bytes_of_double x = [x lsr 8; x land 255] in
if u < 0x10000 then bytes_of_double u else
let u' = u - 0x10000
in let w1 = 0xD800
in let w2 = 0xDC00 in
let w1 = w1 lor (u' lsr 10)
in let w2 = w2 lor (u' land 0b1111111111) in
bytes_of_double w1 @ bytes_of_double w2
let utf16be_of_codepoints l =
implode (['\254'; '\255'] @ map char_of_int (flatten (map utf16be_of_codepoint l)))
(* Return a list of codepoints from a UTF-16BE string. See RFC2871 *)
let fail2 () =
raise (Invalid_argument "codepoints_of_utf16be")
let rec codepoints_of_utf16be_inner prev = function
| [] -> rev prev
| [w1] -> fail2 ()
| [w1a; w1b] ->
let w1 = (w1a lsl 8) lor w1b in
if w1 < 0xD800 || w1 > 0xDFFF then
codepoints_of_utf16be_inner (w1::prev) []
else
fail2 ()
| [_; _; _] -> fail2 ()
| w1a::w1b::w2a::w2b::more ->
let w1 = (w1a lsl 8) lor w1b in
if w1 < 0xD800 || w1 > 0xDFFF then
codepoints_of_utf16be_inner (w1::prev) (w2a::w2b::more)
else
if w1 >= 0xD800 && w1 <= 0xDBFF then
let w2 = (w2a lsl 8) lor w2b in
if w2 >= 0xDC00 && w2 <= 0xDFFF then
let ho = w1 land 0b1111111111
in let lo = w2 lsr 6 in
codepoints_of_utf16be_inner
((((ho lsl 10) lor lo) + 0x10000)::prev) more
else
fail2 ()
else
fail2 ()
let codepoints_of_utf16be str =
codepoints_of_utf16be_inner [] (map int_of_char (explode str))
(* Build a hashtable for lookups based on an encoding *)
let rec add_encoding addvals = function
| ImplicitInFontFile -> ()
| StandardEncoding -> addvals Pdfglyphlist.name_to_standard
| MacRomanEncoding -> addvals Pdfglyphlist.name_to_macroman
| WinAnsiEncoding -> addvals Pdfglyphlist.name_to_win
| MacExpertEncoding -> addvals Pdfglyphlist.name_to_macexpert
| CustomEncoding (e, ds) ->
add_encoding addvals e;
addvals ds
| FillUndefinedWithStandard e ->
addvals Pdfglyphlist.name_to_standard;
add_encoding addvals e