summaryrefslogtreecommitdiff
blob: eb4d6edb253aa6535d67f203cb4f5fbb83256718 (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
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
/* Copyright (C) 2001-2020 Artifex Software, Inc.
   All Rights Reserved.

   This software is provided AS-IS with no warranty, either express or
   implied.

   This software is distributed under license and may not be copied,
   modified or distributed except as expressly authorized under the terms
   of the license contained in the file LICENSE in this distribution.

   Refer to licensing information at http://www.artifex.com or contact
   Artifex Software, Inc.,  1305 Grant Avenue - Suite 200, Novato,
   CA 94945, U.S.A., +1(415)492-9861, for further information.
*/


/*$Id: gxhts_thresh.c  $ */
/* Halftone thresholding code */

#include <stdlib.h> /* abs() */
#include "memory_.h"
#include "gx.h"
#include "gxgstate.h"
#include "gsiparam.h"
#include "math_.h"
#include "gxfixed.h"  /* needed for gximage.h */
#include "gximage.h"
#include "gxdevice.h"
#include "gxdht.h"
#include "gxht_thresh.h"
#include "gzht.h"
#include "gxdevsop.h"

/* Enable the following define to perform a little extra work to stop
 * spurious valgrind errors. The code should perform perfectly even without
 * this enabled, but enabling it makes debugging much easier.
 */
/* #define PACIFY_VALGRIND */

#ifndef __WIN32__
#define __align16  __attribute__((aligned(16)))
#else
#define __align16 __declspec(align(16))
#endif
#define fastfloor(x) (((int)(x)) - (((x)<0) && ((x) != (float)(int)(x))))

#ifdef HAVE_SSE2

#include <emmintrin.h>

static const byte bitreverse[] =
{ 0x00, 0x80, 0x40, 0xC0, 0x20, 0xA0, 0x60, 0xE0, 0x10, 0x90, 0x50, 0xD0,
  0x30, 0xB0, 0x70, 0xF0, 0x08, 0x88, 0x48, 0xC8, 0x28, 0xA8, 0x68, 0xE8,
  0x18, 0x98, 0x58, 0xD8, 0x38, 0xB8, 0x78, 0xF8, 0x04, 0x84, 0x44, 0xC4,
  0x24, 0xA4, 0x64, 0xE4, 0x14, 0x94, 0x54, 0xD4, 0x34, 0xB4, 0x74, 0xF4,
  0x0C, 0x8C, 0x4C, 0xCC, 0x2C, 0xAC, 0x6C, 0xEC, 0x1C, 0x9C, 0x5C, 0xDC,
  0x3C, 0xBC, 0x7C, 0xFC, 0x02, 0x82, 0x42, 0xC2, 0x22, 0xA2, 0x62, 0xE2,
  0x12, 0x92, 0x52, 0xD2, 0x32, 0xB2, 0x72, 0xF2, 0x0A, 0x8A, 0x4A, 0xCA,
  0x2A, 0xAA, 0x6A, 0xEA, 0x1A, 0x9A, 0x5A, 0xDA, 0x3A, 0xBA, 0x7A, 0xFA,
  0x06, 0x86, 0x46, 0xC6, 0x26, 0xA6, 0x66, 0xE6, 0x16, 0x96, 0x56, 0xD6,
  0x36, 0xB6, 0x76, 0xF6, 0x0E, 0x8E, 0x4E, 0xCE, 0x2E, 0xAE, 0x6E, 0xEE,
  0x1E, 0x9E, 0x5E, 0xDE, 0x3E, 0xBE, 0x7E, 0xFE, 0x01, 0x81, 0x41, 0xC1,
  0x21, 0xA1, 0x61, 0xE1, 0x11, 0x91, 0x51, 0xD1, 0x31, 0xB1, 0x71, 0xF1,
  0x09, 0x89, 0x49, 0xC9, 0x29, 0xA9, 0x69, 0xE9, 0x19, 0x99, 0x59, 0xD9,
  0x39, 0xB9, 0x79, 0xF9, 0x05, 0x85, 0x45, 0xC5, 0x25, 0xA5, 0x65, 0xE5,
  0x15, 0x95, 0x55, 0xD5, 0x35, 0xB5, 0x75, 0xF5, 0x0D, 0x8D, 0x4D, 0xCD,
  0x2D, 0xAD, 0x6D, 0xED, 0x1D, 0x9D, 0x5D, 0xDD, 0x3D, 0xBD, 0x7D, 0xFD,
  0x03, 0x83, 0x43, 0xC3, 0x23, 0xA3, 0x63, 0xE3, 0x13, 0x93, 0x53, 0xD3,
  0x33, 0xB3, 0x73, 0xF3, 0x0B, 0x8B, 0x4B, 0xCB, 0x2B, 0xAB, 0x6B, 0xEB,
  0x1B, 0x9B, 0x5B, 0xDB, 0x3B, 0xBB, 0x7B, 0xFB, 0x07, 0x87, 0x47, 0xC7,
  0x27, 0xA7, 0x67, 0xE7, 0x17, 0x97, 0x57, 0xD7, 0x37, 0xB7, 0x77, 0xF7,
  0x0F, 0x8F, 0x4F, 0xCF, 0x2F, 0xAF, 0x6F, 0xEF, 0x1F, 0x9F, 0x5F, 0xDF,
  0x3F, 0xBF, 0x7F, 0xFF};
#endif

#if RAW_HT_DUMP
/* This is slow thresholding, byte output for debug only */
void
gx_ht_threshold_row_byte(byte *contone, byte *threshold_strip, int contone_stride,
                              byte *halftone, int dithered_stride, int width,
                              int num_rows)
{
    int k, j;
    byte *contone_ptr;
    byte *thresh_ptr;
    byte *halftone_ptr;

    /* For the moment just do a very slow compare until we get
       get this working */
    for (j = 0; j < num_rows; j++) {
        contone_ptr = contone;
        thresh_ptr = threshold_strip + contone_stride * j;
        halftone_ptr = halftone + dithered_stride * j;
        for (k = 0; k < width; k++) {
            if (contone_ptr[k] < thresh_ptr[k]) {
                halftone_ptr[k] = 0;
            } else {
                halftone_ptr[k] = 255;
            }
        }
    }
}
#endif

#ifndef HAVE_SSE2
/* A simple case for use in the landscape mode. Could probably be coded up
   faster */
static void
threshold_16_bit(byte *contone_ptr, byte *thresh_ptr, byte *ht_data)
{
    int j;

    for (j = 2; j > 0; j--) {
        byte h = 0;
        byte bit_init = 0x80;
        do {
            if (*contone_ptr++ < *thresh_ptr++) {
                h |=  bit_init;
            }
            bit_init >>= 1;
        } while (bit_init != 0);
        *ht_data++ = h;
    }
}
#else
/* Note this function has strict data alignment needs */
static void
threshold_16_SSE(byte *contone_ptr, byte *thresh_ptr, byte *ht_data)
{
    __m128i input1;
    __m128i input2;
    register int result_int;
    const unsigned int mask1 = 0x80808080;
    __m128i sign_fix = _mm_set_epi32(mask1, mask1, mask1, mask1);

    /* Load */
    input1 = _mm_load_si128((const __m128i *)contone_ptr);
    input2 = _mm_load_si128((const __m128i *) thresh_ptr);
    /* Unsigned subtraction does Unsigned saturation so we
       have to use the signed operation */
    input1 = _mm_xor_si128(input1, sign_fix);
    input2 = _mm_xor_si128(input2, sign_fix);
    /* Subtract the two */
    input2 = _mm_subs_epi8(input1, input2);
    /* Grab the sign mask */
    result_int = _mm_movemask_epi8(input2);
    /* bit wise reversal on 16 bit word */
    ht_data[0] = bitreverse[(result_int & 0xff)];
    ht_data[1] = bitreverse[((result_int >> 8) & 0xff)];
}

/* Not so fussy on its alignment */
static void
threshold_16_SSE_unaligned(byte *contone_ptr, byte *thresh_ptr, byte *ht_data)
{
    __m128i input1;
    __m128i input2;
    int result_int;
    byte *sse_data;
    const unsigned int mask1 = 0x80808080;
    __m128i sign_fix = _mm_set_epi32(mask1, mask1, mask1, mask1);

    sse_data = (byte*) &(result_int);
    /* Load */
    input1 = _mm_loadu_si128((const __m128i *)contone_ptr);
    input2 = _mm_loadu_si128((const __m128i *) thresh_ptr);
    /* Unsigned subtraction does Unsigned saturation so we
       have to use the signed operation */
    input1 = _mm_xor_si128(input1, sign_fix);
    input2 = _mm_xor_si128(input2, sign_fix);
    /* Subtract the two */
    input2 = _mm_subs_epi8(input1, input2);
    /* Grab the sign mask */
    result_int = _mm_movemask_epi8(input2);
    /* bit wise reversal on 16 bit word */
    ht_data[0] = bitreverse[sse_data[0]];
    ht_data[1] = bitreverse[sse_data[1]];
}
#endif

/* SSE2 and non-SSE2 implememntation of thresholding a row. Subtractive case
   There is some code replication between the two of these (additive and subtractive)
   that I need to go back and determine how we can combine them without
   any performance loss. */
void
gx_ht_threshold_row_bit_sub(byte *contone,  byte *threshold_strip,  int contone_stride,
                  byte *halftone, int dithered_stride, int width,
                  int num_rows, int offset_bits)
{
#ifndef HAVE_SSE2
    int k, j;
    byte *contone_ptr;
    byte *thresh_ptr;
    byte *halftone_ptr;
    byte bit_init;

    /* For the moment just do a very slow compare until we get
       get this working.  This could use some serious optimization */
    width -= offset_bits;
    for (j = 0; j < num_rows; j++) {
        byte h;
        contone_ptr = contone;
        thresh_ptr = threshold_strip + contone_stride * j;
        halftone_ptr = halftone + dithered_stride * j;
        /* First get the left remainder portion.  Put into MSBs of first byte */
        bit_init = 0x80;
        h = 0;
        k = offset_bits;
        if (k > 0) {
            do {
                if (*contone_ptr++ > *thresh_ptr++) {
                    h |=  bit_init;
                }
                bit_init >>= 1;
                if (bit_init == 0) {
                    bit_init = 0x80;
                    *halftone_ptr++ = h;
                    h = 0;
                }
                k--;
            } while (k > 0);
            bit_init = 0x80;
            *halftone_ptr++ = h;
            h = 0;
            if (offset_bits < 8)
                *halftone_ptr++ = 0;
        }
        /* Now get the rest, which will be 16 bit aligned. */
        k = width;
        if (k > 0) {
            do {
                if (*contone_ptr++ > *thresh_ptr++) {
                    h |=  bit_init;
                }
                bit_init >>= 1;
                if (bit_init == 0) {
                    bit_init = 0x80;
                    *halftone_ptr++ = h;
                    h = 0;
                }
                k--;
            } while (k > 0);
            if (bit_init != 0x80) {
                *halftone_ptr++ = h;
            }
            if ((width & 15) < 8)
                *halftone_ptr++ = 0;
        }
    }
#else
    byte *contone_ptr;
    byte *thresh_ptr;
    byte *halftone_ptr;
    int num_tiles = (width - offset_bits + 15)>>4;
    int k, j;

    for (j = 0; j < num_rows; j++) {
        /* contone and thresh_ptr are 128 bit aligned.  We do need to do this in
           two steps to ensure that we pack the bits in an aligned fashion
           into halftone_ptr.  */
        contone_ptr = contone;
        thresh_ptr = threshold_strip + contone_stride * j;
        halftone_ptr = halftone + dithered_stride * j;
        if (offset_bits > 0) {
            /* Since we allowed for 16 bits in our left remainder
               we can go directly in to the destination.  threshold_16_SSE
               requires 128 bit alignment.  contone_ptr and thresh_ptr
               are set up so that after we move in by offset_bits elements
               then we are 128 bit aligned.  */
            threshold_16_SSE_unaligned(thresh_ptr, contone_ptr,
                                       halftone_ptr);
            halftone_ptr += 2;
            thresh_ptr += offset_bits;
            contone_ptr += offset_bits;
        }
        /* Now we should have 128 bit aligned with our input data. Iterate
           over sets of 16 going directly into our HT buffer.  Sources and
           halftone_ptr buffers should be padded to allow 15 bit overrun */
        for (k = 0; k < num_tiles; k++) {
            threshold_16_SSE(thresh_ptr, contone_ptr, halftone_ptr);
            thresh_ptr += 16;
            contone_ptr += 16;
            halftone_ptr += 2;
        }
    }
#endif
}

/* SSE2 and non-SSE2 implememntation of thresholding a row. additive case  */
void
gx_ht_threshold_row_bit(byte *contone,  byte *threshold_strip,  int contone_stride,
                  byte *halftone, int dithered_stride, int width,
                  int num_rows, int offset_bits)
{
#ifndef HAVE_SSE2
    int k, j;
    byte *contone_ptr;
    byte *thresh_ptr;
    byte *halftone_ptr;
    byte bit_init;

    /* For the moment just do a very slow compare until we get
       get this working.  This could use some serious optimization */
    width -= offset_bits;
    for (j = 0; j < num_rows; j++) {
        byte h;
        contone_ptr = contone;
        thresh_ptr = threshold_strip + contone_stride * j;
        halftone_ptr = halftone + dithered_stride * j;
        /* First get the left remainder portion.  Put into MSBs of first byte */
        bit_init = 0x80;
        h = 0;
        k = offset_bits;
        if (k > 0) {
            do {
                if (*contone_ptr++ < *thresh_ptr++) {
                    h |=  bit_init;
                }
                bit_init >>= 1;
                if (bit_init == 0) {
                    bit_init = 0x80;
                    *halftone_ptr++ = h;
                    h = 0;
                }
                k--;
            } while (k > 0);
            bit_init = 0x80;
            *halftone_ptr++ = h;
            h = 0;
            if (offset_bits < 8)
                *halftone_ptr++ = 0;
        }
        /* Now get the rest, which will be 16 bit aligned. */
        k = width;
        if (k > 0) {
            do {
                if (*contone_ptr++ < *thresh_ptr++) {
                    h |=  bit_init;
                }
                bit_init >>= 1;
                if (bit_init == 0) {
                    bit_init = 0x80;
                    *halftone_ptr++ = h;
                    h = 0;
                }
                k--;
            } while (k > 0);
            if (bit_init != 0x80) {
                *halftone_ptr++ = h;
            }
            if ((width & 15) < 8)
                *halftone_ptr++ = 0;
        }
    }
#else
    byte *contone_ptr;
    byte *thresh_ptr;
    byte *halftone_ptr;
    int num_tiles = (width - offset_bits + 15)>>4;
    int k, j;

    for (j = 0; j < num_rows; j++) {
        /* contone and thresh_ptr are 128 bit aligned.  We do need to do this in
           two steps to ensure that we pack the bits in an aligned fashion
           into halftone_ptr.  */
        contone_ptr = contone;
        thresh_ptr = threshold_strip + contone_stride * j;
        halftone_ptr = halftone + dithered_stride * j;
        if (offset_bits > 0) {
            /* Since we allowed for 16 bits in our left remainder
               we can go directly in to the destination.  threshold_16_SSE
               requires 128 bit alignment.  contone_ptr and thresh_ptr
               are set up so that after we move in by offset_bits elements
               then we are 128 bit aligned.  */
            threshold_16_SSE_unaligned(contone_ptr, thresh_ptr,
                                       halftone_ptr);
            halftone_ptr += 2;
            thresh_ptr += offset_bits;
            contone_ptr += offset_bits;
        }
        /* Now we should have 128 bit aligned with our input data. Iterate
           over sets of 16 going directly into our HT buffer.  Sources and
           halftone_ptr buffers should be padded to allow 15 bit overrun */
        for (k = 0; k < num_tiles; k++) {
            threshold_16_SSE(contone_ptr, thresh_ptr, halftone_ptr);
            thresh_ptr += 16;
            contone_ptr += 16;
            halftone_ptr += 2;
        }
    }
#endif
}

/* This thresholds a buffer that is LAND_BITS wide by data_length tall.
   Subtractive case */
void
gx_ht_threshold_landscape_sub(byte *contone_align, byte *thresh_align,
                    ht_landscape_info_t *ht_landscape, byte *halftone,
                    int data_length)
{
    __align16 byte contone[LAND_BITS];
    int position_start, position, curr_position;
    int *widths = &(ht_landscape->widths[0]);
    int local_widths[LAND_BITS];
    int num_contone = ht_landscape->num_contones;
    int k, j, w, contone_out_posit;
    byte *contone_ptr, *thresh_ptr, *halftone_ptr;
#ifdef PACIFY_VALGRIND
    int extra = 0;
#endif

    /* Work through chunks of 16.  */
    /* Data may have come in left to right or right to left. */
    if (ht_landscape->index > 0) {
        position = position_start = 0;
    } else {
        position = position_start = ht_landscape->curr_pos + 1;
    }
    thresh_ptr = thresh_align;
    halftone_ptr = halftone;
    /* Copy the widths to a local array, and truncate the last one (which may
     * be the first one!) if required. */
    k = 0;
    for (j = 0; j < num_contone; j++)
        k += (local_widths[j] = widths[position_start+j]);
    if (k > LAND_BITS) {
        if (ht_landscape->index > 0) {
            local_widths[num_contone-1] -= k-LAND_BITS;
        } else {
            local_widths[0] -= k-LAND_BITS;
        }
    }
#ifdef PACIFY_VALGRIND
    if (k < LAND_BITS) {
        extra = LAND_BITS - k;
    }
#endif
    for (k = data_length; k > 0; k--) { /* Loop on rows */
        contone_ptr = &(contone_align[position]); /* Point us to our row start */
        curr_position = 0; /* We use this in keeping track of widths */
        contone_out_posit = 0; /* Our index out */
        for (j = num_contone; j > 0; j--) {
            byte c = *contone_ptr;
            /* The microsoft compiler, cleverly spots that the following loop
             * can be replaced by a memset. Unfortunately, it can't spot that
             * the typical length values of the memset are so small that we'd
             * be better off doing it the slow way. We therefore introduce a
             * sneaky 'volatile' cast below that stops this optimisation. */
            w = local_widths[curr_position];
            do {
                ((volatile byte *)contone)[contone_out_posit] = c;
                contone_out_posit++;
            } while (--w);
#ifdef PACIFY_VALGRIND
            if (extra)
                memset(contone+contone_out_posit, 0, extra);
#endif
            curr_position++; /* Move us to the next position in our width array */
            contone_ptr++;   /* Move us to a new location in our contone buffer */
        }
        /* Now we have our left justified and expanded contone data for
           LAND_BITS/16 sets of 16 bits. Go ahead and threshold these. */
        contone_ptr = &contone[0];
#if LAND_BITS > 16
        j = LAND_BITS;
        do {
#endif
#ifdef HAVE_SSE2
            threshold_16_SSE(thresh_ptr, contone_ptr, halftone_ptr);
#else
            threshold_16_bit(thresh_ptr, contone_ptr, halftone_ptr);
#endif
            thresh_ptr += 16;
            position += 16;
            halftone_ptr += 2;
            contone_ptr += 16;
#if LAND_BITS > 16
            j -= 16;
        } while (j > 0);
#endif
    }
}

/* This thresholds a buffer that is LAND_BITS wide by data_length tall.
   Additive case.  Note I could likely do some code reduction between
   the additive and subtractive cases */
void
gx_ht_threshold_landscape(byte *contone_align, byte *thresh_align,
                    ht_landscape_info_t *ht_landscape, byte *halftone,
                    int data_length)
{
    __align16 byte contone[LAND_BITS];
    int position_start, position, curr_position;
    int *widths = &(ht_landscape->widths[0]);
    int local_widths[LAND_BITS];
    int num_contone = ht_landscape->num_contones;
    int k, j, w, contone_out_posit;
    byte *contone_ptr, *thresh_ptr, *halftone_ptr;
#ifdef PACIFY_VALGRIND
    int extra = 0;
#endif

    /* Work through chunks of 16.  */
    /* Data may have come in left to right or right to left. */
    if (ht_landscape->index > 0) {
        position = position_start = 0;
    } else {
        position = position_start = ht_landscape->curr_pos + 1;
    }
    thresh_ptr = thresh_align;
    halftone_ptr = halftone;
    /* Copy the widths to a local array, and truncate the last one (which may
     * be the first one!) if required. */
    k = 0;
    for (j = 0; j < num_contone; j++)
        k += (local_widths[j] = widths[position_start+j]);
    if (k > LAND_BITS) {
        if (ht_landscape->index > 0) {
            local_widths[num_contone-1] -= k-LAND_BITS;
        } else {
            local_widths[0] -= k-LAND_BITS;
        }
    }
#ifdef PACIFY_VALGRIND
    if (k < LAND_BITS) {
        extra = LAND_BITS - k;
    }
#endif
    for (k = data_length; k > 0; k--) { /* Loop on rows */
        contone_ptr = &(contone_align[position]); /* Point us to our row start */
        curr_position = 0; /* We use this in keeping track of widths */
        contone_out_posit = 0; /* Our index out */
        for (j = num_contone; j > 0; j--) {
            byte c = *contone_ptr;
            /* The microsoft compiler, cleverly spots that the following loop
             * can be replaced by a memset. Unfortunately, it can't spot that
             * the typical length values of the memset are so small that we'd
             * be better off doing it the slow way. We therefore introduce a
             * sneaky 'volatile' cast below that stops this optimisation. */
            w = local_widths[curr_position];
            do {
                ((volatile byte *)contone)[contone_out_posit] = c;
                contone_out_posit++;
            } while (--w);
#ifdef PACIFY_VALGRIND
            if (extra)
                memset(contone+contone_out_posit, 0, extra);
#endif
            curr_position++; /* Move us to the next position in our width array */
            contone_ptr++;   /* Move us to a new location in our contone buffer */
        }
        /* Now we have our left justified and expanded contone data for
           LAND_BITS/16 sets of 16 bits. Go ahead and threshold these. */
        contone_ptr = &contone[0];
#if LAND_BITS > 16
        j = LAND_BITS;
        do {
#endif
#ifdef HAVE_SSE2
            threshold_16_SSE(contone_ptr, thresh_ptr, halftone_ptr);
#else
            threshold_16_bit(contone_ptr, thresh_ptr, halftone_ptr);
#endif
            thresh_ptr += 16;
            position += 16;
            halftone_ptr += 2;
            contone_ptr += 16;
#if LAND_BITS > 16
            j -= 16;
        } while (j > 0);
#endif
    }
}

int
gxht_thresh_image_init(gx_image_enum *penum)
{
    int code = 0;
    fixed ox;
    int temp;
    int dev_width, max_height;
    int spp_out;
    int k;
    gx_ht_order *d_order;
    gx_dda_fixed dda_ht;

    if (gx_device_must_halftone(penum->dev)) {
        if (penum->pgs != NULL && penum->pgs->dev_ht != NULL) {
            for (k = 0; k < penum->pgs->dev_ht->num_comp; k++) {
                d_order = &(penum->pgs->dev_ht->components[k].corder);
                code = gx_ht_construct_threshold(d_order, penum->dev,
                                                 penum->pgs, k);
                if (code < 0 ) {
                    return gs_rethrow(code, "threshold creation failed");
                }
            }
        } else {
            return -1;
        }
    }
    spp_out = penum->dev->color_info.num_components;
    /* Precompute values needed for rasterizing. */
    penum->dxx = float2fixed(penum->matrix.xx + fixed2float(fixed_epsilon) / 2);
    /* If the image is landscaped then we want to maintain a buffer
       that is sufficiently large so that we can hold a byte
       of halftoned data along the column.  This way we avoid doing
       multiple writes into the same position over and over.
       The size of the buffer we need depends upon the bitdepth of
       the output device, the number of device coloranants and the
       number of  colorants in the source space.  Note we will
       need to eventually  consider  multi-level halftone case
       here too.  For now, to make use of the SSE2 stuff, we would
       like to have a multiple of 16 bytes of data to process at a time.
       So we will collect the columns of data in a buffer that is LAND_BITS
       wide.  We will also keep track of the widths of each column.  When
       the total width count reaches LAND_BITS, we will create our
       threshold array and apply it.  We may have one column that is
       buffered between calls in this case.  Also if a call is made
       with h=0 we will flush the buffer as we are at the end of the
       data.  */
    if (penum->posture == image_landscape) {
        int col_length = fixed2int_var_rounded(any_abs(penum->x_extent.y));
        dda_ht = penum->dda.pixel0.y;
        if (penum->dxx > 0)
            dda_translate(dda_ht, -fixed_epsilon);      /* to match rounding in non-fast code */

        ox = dda_current(penum->dda.pixel0.x);
        temp = gxht_dda_length(&dda_ht, penum->rect.w);
        if (col_length < temp)
            col_length = temp;          /* choose max to make sure line_size is large enough */
        temp = (col_length + LAND_BITS)/LAND_BITS;      /* round up to allow for offset bits */
        /* bitmap_raster() expects the width in bits, hence "* 8" */
        penum->line_size = bitmap_raster((temp * LAND_BITS) * 8);  /* The stride */
        /* Now we need at most LAND_BITS of these */
        penum->line = gs_alloc_bytes(penum->memory,
                                     LAND_BITS * penum->line_size * spp_out + 16,
                                     "gxht_thresh");
        /* Same with this.  However, we only need one plane here */
        penum->thresh_buffer = gs_alloc_bytes(penum->memory,
                                           penum->line_size * LAND_BITS + 16,
                                           "gxht_thresh");
        /* That maps into (LAND_BITS/8) bytes of Halftone data */
        penum->ht_buffer =
                        gs_alloc_bytes(penum->memory,
                           penum->line_size * (LAND_BITS>>3) * spp_out,
                           "gxht_thresh");
        penum->ht_plane_height = penum->line_size;
        penum->ht_stride = penum->line_size;
        if (penum->line == NULL || penum->thresh_buffer == NULL
                    || penum->ht_buffer == NULL)
            return -1;
        penum->ht_landscape.count = 0;
        penum->ht_landscape.num_contones = 0;
        if (penum->y_extent.x < 0) {
            /* Going right to left */
            penum->ht_landscape.curr_pos = LAND_BITS-1;
            penum->ht_landscape.index = -1;
        } else {
            /* Going left to right */
            penum->ht_landscape.curr_pos = 0;
            penum->ht_landscape.index = 1;
        }
        if (penum->x_extent.y < 0) {
            penum->ht_landscape.flipy = true;
            penum->ht_landscape.y_pos =
                fixed2int_pixround_perfect(dda_current(penum->dda.pixel0.y) + penum->x_extent.y);
        } else {
            penum->ht_landscape.flipy = false;
            penum->ht_landscape.y_pos =
                fixed2int_pixround_perfect(dda_current(penum->dda.pixel0.y));
        }
        memset(&(penum->ht_landscape.widths[0]), 0, sizeof(int)*LAND_BITS);
        penum->ht_landscape.offset_set = false;
        penum->ht_offset_bits = 0; /* Will get set in call to render */
        if (code >= 0) {
#if defined(DEBUG) || defined(PACIFY_VALGRIND)
            memset(penum->line, 0, LAND_BITS * penum->line_size * spp_out + 16);
            memset(penum->ht_buffer, 0, penum->line_size * (LAND_BITS>>3) * spp_out);
            memset(penum->thresh_buffer, 0, LAND_BITS * penum->line_size + 16);
#endif
        }
    } else {
        /* In the portrait case we allocate a single line buffer
           in device width, a threshold buffer of the same size
           and possibly wider and the buffer for the halftoned
           bits. We have to do a bit of work to enable 16 byte
           boundary after an offset to ensure that we can make use
           of  the SSE2 operations for thresholding.  We do the
           allocations now to avoid doing them with every line */
        dda_ht = penum->dda.pixel0.x;
        if (penum->dxx > 0)
            dda_translate(dda_ht, -fixed_epsilon);      /* to match rounding in non-fast code */
        /* Initialize the ht_landscape stuff to zero */
        memset(&(penum->ht_landscape), 0, sizeof(ht_landscape_info_t));
        ox = dda_current(dda_ht);
        dev_width = gxht_dda_length(&dda_ht, penum->rect.w);
        /* Get the bit position so that we can do a copy_mono for
           the left remainder and then 16 bit aligned copies for the
           rest.  The right remainder will be OK as it will land in
           the MSBit positions. Note the #define chunk bits16 in
           gdevm1.c.  Allow also for a 15 sample over run.
        */
        penum->ht_offset_bits = (-fixed2int_var_rounded(ox)) & (bitmap_raster(1) - 1);
        if (penum->ht_offset_bits > 0) {
            penum->ht_stride = bitmap_raster((7 + (dev_width + 4)) + (ARCH_SIZEOF_LONG * 8));
        } else {
            penum->ht_stride = bitmap_raster((7 + (dev_width + 2)) + (ARCH_SIZEOF_LONG * 8));
        }
        /* We want to figure out the maximum height that we may
           have in taking a single source row and going to device
           space */
        max_height = (int) ceil(fixed2float(any_abs(penum->dst_height)) /
                                            (float) penum->Height);
        if (max_height <= 0)
            return -1;		/* shouldn't happen, but check so we don't div by zero */
        if (penum->ht_stride * spp_out > max_int / max_height)
            return -1;         /* overflow */

        penum->ht_buffer =
                        gs_alloc_bytes(penum->memory,
                           (size_t)penum->ht_stride * max_height * spp_out,
                           "gxht_thresh");
        penum->ht_plane_height = penum->ht_stride * max_height;
        /* We want to have 128 bit alignement for our contone and
           threshold strips so that we can use SSE operations
           in the threshold operation.  Add in a minor buffer and offset
           to ensure this.  If gs_alloc_bytes provides at least 16
           bit alignment so we may need to move 14 bytes.  However, the
           HT process is split in two operations.  One that involves
           the HT of a left remainder and the rest which ensures that
           we pack in the HT data in the bits with no skew for a fast
           copy into the gdevm1 device (16 bit copies).  So, we
           need to account for those pixels which occur first and which
           are NOT aligned for the contone buffer.  After we offset
           by this remainder portion we should be 128 bit aligned.
           Also allow a 15 sample over run during the execution.  */
        temp = (int) ceil((float) ((dev_width + 15.0) + 15.0)/16.0);
        penum->line_size = bitmap_raster(temp * 16 * 8);  /* The stride */
        if (penum->line_size > max_int / max_height) {
            gs_free_object(penum->memory, penum->ht_buffer, "gxht_thresh");
            penum->ht_buffer = NULL;
            return -1;         /* thresh_buffer size overflow */
        }
        penum->line = gs_alloc_bytes(penum->memory, penum->line_size * spp_out,
                                     "gxht_thresh");
        penum->thresh_buffer = gs_alloc_bytes(penum->memory,
                                              (size_t)penum->line_size * max_height,
                                              "gxht_thresh");
        if (penum->line == NULL || penum->thresh_buffer == NULL ||
            penum->ht_buffer == NULL) {
            return -1;
        } else {
#if defined(DEBUG) || defined(PACIFY_VALGRIND)
            memset(penum->line, 0, penum->line_size * spp_out);
            memset(penum->ht_buffer, 0, penum->ht_stride * max_height * spp_out);
            memset(penum->thresh_buffer, 0, penum->line_size * max_height);
#endif
        }
    }
    return code;
}

static void
fill_threshold_buffer(byte *dest_strip, byte *src_strip, int src_width,
                       int left_offset, int left_width, int num_tiles,
                       int right_width)
{
    byte *ptr_out_temp = dest_strip;
    int ii;

    /* Left part */
    memcpy(dest_strip, src_strip + left_offset, left_width);
    ptr_out_temp += left_width;
    /* Now the full parts */
    for (ii = 0; ii < num_tiles; ii++){
        memcpy(ptr_out_temp, src_strip, src_width);
        ptr_out_temp += src_width;
    }
    /* Now the remainder */
    memcpy(ptr_out_temp, src_strip, right_width);
#ifdef PACIFY_VALGRIND
    ptr_out_temp += right_width;
    ii = (dest_strip-ptr_out_temp) % (LAND_BITS-1);
    if (ii > 0)
        memset(ptr_out_temp, 0, ii);
#endif
}
/* This only moves the data but does not do a reset of the variables.  Used
   for case where we have multiple bands of data (e.g. CMYK output) */
static void
move_landscape_buffer(ht_landscape_info_t *ht_landscape, byte *contone_align,
                       int data_length)
{
    int k;
    int position_curr, position_new;

    if (ht_landscape->index < 0) {
        /* Moving right to left, move column to far right */
        position_curr = ht_landscape->curr_pos + 1;
        position_new = LAND_BITS-1;
    } else {
        /* Moving left to right, move column to far left */
        position_curr = ht_landscape->curr_pos - 1;
        position_new = 0;
    }
    if (position_curr != position_new) {
        for (k = 0; k < data_length; k++) {
                contone_align[position_new] = contone_align[position_curr];
                position_curr += LAND_BITS;
                position_new += LAND_BITS;
        }
    }
}


/* If we are in here, we had data left over.  Move it to the proper position
   and get ht_landscape_info_t set properly */
static void
reset_landscape_buffer(ht_landscape_info_t *ht_landscape, byte *contone_align,
                       int data_length, int num_used)
{
    int delta;
    int curr_x_pos = ht_landscape->xstart;

    if (ht_landscape->index < 0) {
        /* Moving right to left, move column to far right */
        delta = ht_landscape->count - num_used;
        memset(&(ht_landscape->widths[0]), 0, sizeof(int)*LAND_BITS);
        ht_landscape->widths[LAND_BITS-1] = delta;
        ht_landscape->curr_pos = LAND_BITS-2;
        ht_landscape->xstart = curr_x_pos - num_used;
    } else {
        /* Moving left to right, move column to far left */
        delta = ht_landscape->count - num_used;
        memset(&(ht_landscape->widths[0]), 0, sizeof(int)*LAND_BITS);
        ht_landscape->widths[0] = delta;
        ht_landscape->curr_pos = 1;
        ht_landscape->xstart = curr_x_pos + num_used;
    }
    ht_landscape->count = delta;
    ht_landscape->num_contones = 1;
}

/* This performs a thresholding operation on multiple planes of data and
   stores the bits into a planar buffer which can then be used for
   copy_planes */
int
gxht_thresh_planes(gx_image_enum *penum, fixed xrun,
                   int dest_width, int dest_height,
                   byte *thresh_align, gx_device * dev, int offset_contone[],
                   int contone_stride)
{
    int thresh_width, thresh_height, dx;
    int left_rem_end, left_width, vdi;
    int num_full_tiles, right_tile_width;
    int k, jj, dy, j;
    byte *thresh_tile;
    int position;
    bool replicate_tile;
    image_posture posture = penum->posture;
    const int y_pos = penum->yci;
    int width = 0; /* Init to silence compiler warnings */
    byte *ptr_out, *row_ptr, *ptr_out_temp;
    byte *threshold;
    int init_tile, in_row_offset, ii, num_tiles, tile_remainder;
    int offset_bits = penum->ht_offset_bits;
    byte *halftone;
    int dithered_stride = penum->ht_stride;
    bool is_planar_dev = dev->is_planar;
    gx_color_index dev_white = gx_device_white(dev);
    gx_color_index dev_black = gx_device_black(dev);
    int spp_out = dev->color_info.num_components;
    byte *contone_align = NULL; /* Init to silence compiler warnings */

    /* Go ahead and fill the threshold line buffer with tiled threshold values.
       First just grab the row or column that we are going to tile with and
       then do memcpy into the buffer */

    /* Figure out the tile steps.  Left offset, Number of tiles, Right offset. */
    switch (posture) {
        case image_portrait:
            vdi = penum->hci;
            /*  Iterate over the vdi and fill up our threshold buffer.  We
                 also need to loop across the planes of data */
            for (j = 0; j < spp_out; j++) {
                bool threshold_inverted = penum->pgs->dev_ht->components[j].corder.threshold_inverted;

                thresh_width = penum->pgs->dev_ht->components[j].corder.width;
                thresh_height = penum->pgs->dev_ht->components[j].corder.full_height;
                halftone = penum->ht_buffer + j * vdi * dithered_stride;
                /* Compute the tiling positions with dest_width */
                dx = (fixed2int_var_rounded(xrun) + penum->pgs->screen_phase[0].x) % thresh_width;
                /* Left remainder part */
                left_rem_end = min(dx + dest_width, thresh_width);
                /* The left width of our tile part */
                left_width = left_rem_end - dx;
                /* Now the middle part */
                num_full_tiles =
                    (int)fastfloor((dest_width - left_width)/ (float) thresh_width);
                /* Now the right part */
                right_tile_width = dest_width -  num_full_tiles * thresh_width -
                                   left_width;
                /* Get the proper threshold for the colorant count */
                threshold = penum->pgs->dev_ht->components[j].corder.threshold;
                /* Point to the proper contone data */
                contone_align = penum->line + contone_stride * j +
                                offset_contone[j];
                for (k = 0; k < vdi; k++) {
                    /* Get a pointer to our tile row */
                    dy = (penum->yci + k -
                          penum->pgs->screen_phase[0].y) % thresh_height;
                    if (dy < 0)
                        dy += thresh_height;
                    thresh_tile = threshold + thresh_width * dy;
                    /* Fill the buffer, can be multiple rows.  Make sure
                       to update with stride */
                    position = contone_stride * k;
                    /* Tile into the 128 bit aligned threshold strip */
                    fill_threshold_buffer(&(thresh_align[position]),
                                           thresh_tile, thresh_width, dx, left_width,
                                           num_full_tiles, right_tile_width);
                }
                /* Apply the threshold operation */
                if (offset_bits > dest_width)
                    offset_bits = dest_width;

                if (threshold_inverted ||
                    (dev->color_info.polarity == GX_CINFO_POLARITY_SUBTRACTIVE && is_planar_dev)) {
                    gx_ht_threshold_row_bit_sub(contone_align, thresh_align, contone_stride,
                                      halftone, dithered_stride, dest_width, vdi,
                                      offset_bits);
                } else {
                    gx_ht_threshold_row_bit(contone_align, thresh_align, contone_stride,
                          halftone, dithered_stride, dest_width, vdi,
                          offset_bits);
                }
            }
            /* FIXME: An improvement here would be to generate the initial
             * offset_bits at the correct offset within the byte so that they
             * align with the remainder of the line. This would mean not
             * always packing them into the first offset_bits (in MSB order)
             * of our 16 bit word, but rather into the last offset_bits
             * (in MSB order) (except when the entire run is small!).
             *
             * This would enable us to do just one aligned copy_mono call for
             * the entire scanline. */
            /* Now do the copy mono or copy plane operation */
            /* First the left remainder bits */
            if (offset_bits > 0) {
                int x_pos = fixed2int_var_rounded(xrun);
                if (!is_planar_dev) {
                    (*dev_proc(dev, copy_mono)) (dev, penum->ht_buffer, 0, dithered_stride,
                                                 gx_no_bitmap_id, x_pos, y_pos,
                                                 offset_bits, vdi, dev_white,
                                                 dev_black);
                } else {
                    (*dev_proc(dev, copy_planes)) (dev, penum->ht_buffer, 0, dithered_stride,
                                                 gx_no_bitmap_id, x_pos, y_pos,
                                                 offset_bits, vdi, vdi);
                }
            }
            if ((dest_width - offset_bits) > 0 ) {
                /* Now the primary aligned bytes */
                int curr_width = dest_width - offset_bits;
                int x_pos = fixed2int_var_rounded(xrun) + offset_bits;
                /* FIXME: This assumes the allowed offset_bits will always be <= 16 */
                int xoffs = offset_bits > 0 ? 16 : 0;

                if (!is_planar_dev) {
                    (*dev_proc(dev, copy_mono)) (dev, penum->ht_buffer, xoffs, dithered_stride,
                                                 gx_no_bitmap_id, x_pos, y_pos,
                                                 curr_width, vdi, dev_white,
                                                 dev_black);
                } else {
                    (*dev_proc(dev, copy_planes)) (dev, penum->ht_buffer, xoffs, dithered_stride,
                                                 gx_no_bitmap_id, x_pos, y_pos,
                                                 curr_width, vdi, vdi);
                }
            }

            break;
        case image_landscape:
            /* Go ahead and paint the chunk if we have LAND_BITS values or a
             * partial to get us in sync with the 1 bit devices 16 bit
             * positions. */
            vdi = penum->wci;
                /* Now do the haftoning into our buffer.  We basically check
                   first if we have enough data or are all done */
            while ( (penum->ht_landscape.count >= LAND_BITS ||
                   ((penum->ht_landscape.count >= offset_bits) &&
                    penum->ht_landscape.offset_set))) {
                /* Go ahead and 2D tile in the threshold buffer at this time */
                /* Always work the tiling from the upper left corner of our
                   LAND_BITS columns */
                for (j = 0; j < spp_out; j++) {
                    halftone = penum->ht_buffer +
                                   j * penum->ht_plane_height * (LAND_BITS>>3);
                    thresh_width = penum->pgs->dev_ht->components[j].corder.width;
                    thresh_height =
                          penum->pgs->dev_ht->components[j].corder.full_height;
                    /* Get the proper threshold for the colorant count */
                    threshold = penum->pgs->dev_ht->components[j].corder.threshold;
                    /* Point to the proper contone data */
                    contone_align = penum->line + offset_contone[j] +
                                      LAND_BITS * j * contone_stride;
                    if (penum->ht_landscape.offset_set) {
                        width = offset_bits;
                    } else {
                        width = LAND_BITS;
                    }
                    if (penum->y_extent.x < 0) {
                        dx = penum->ht_landscape.xstart - width + 1;
                    } else {
                        dx = penum->ht_landscape.xstart;
                    }
                    dx = (dx + penum->pgs->screen_phase[0].x) % thresh_width;
                    dy = (penum->ht_landscape.y_pos -
                              penum->pgs->screen_phase[0].y) % thresh_height;
                    if (dy < 0)
                        dy += thresh_height;
                    /* Left remainder part */
                    left_rem_end = min(dx + LAND_BITS, thresh_width);
                    left_width = left_rem_end - dx;
                    /* Now the middle part */
                    num_full_tiles = (LAND_BITS - left_width) / thresh_width;
                    /* Now the right part */
                    right_tile_width =
                        LAND_BITS - num_full_tiles * thresh_width - left_width;
                    /* Now loop over the y stuff */
                    ptr_out = thresh_align;
                    /* Do this in three parts.  We do a top part, followed by
                       larger mem copies followed by a bottom partial. After
                       a slower initial fill we are able to do larger faster
                       expansions */
                    if (dest_height <= 2 * thresh_height) {
                        init_tile = dest_height;
                        replicate_tile = false;
                    } else {
                        init_tile = thresh_height;
                        replicate_tile = true;
                    }
                    for (jj = 0; jj < init_tile; jj++) {
                        in_row_offset = (jj + dy) % thresh_height;
                        row_ptr = threshold + in_row_offset * thresh_width;
                        ptr_out_temp = ptr_out;
                        /* Left part */
                        memcpy(ptr_out_temp, row_ptr + dx, left_width);
                        ptr_out_temp += left_width;
                        /* Now the full tiles */
                        for (ii = 0; ii < num_full_tiles; ii++) {
                            memcpy(ptr_out_temp, row_ptr, thresh_width);
                            ptr_out_temp += thresh_width;
                        }
                        /* Now the remainder */
                        memcpy(ptr_out_temp, row_ptr, right_tile_width);
                        ptr_out += LAND_BITS;
                    }
                    if (replicate_tile) {
                        /* Find out how many we need to copy */
                        num_tiles =
                            (int)fastfloor((float) (dest_height - thresh_height)/ (float) thresh_height);
                        tile_remainder = dest_height - (num_tiles + 1) * thresh_height;
                        for (jj = 0; jj < num_tiles; jj ++) {
                            memcpy(ptr_out, thresh_align, LAND_BITS * thresh_height);
                            ptr_out += LAND_BITS * thresh_height;
                        }
                        /* Now fill in the remainder */
                        memcpy(ptr_out, thresh_align, LAND_BITS * tile_remainder);
                    }
                    /* Apply the threshold operation */
                    if (dev->color_info.polarity == GX_CINFO_POLARITY_SUBTRACTIVE
                        && is_planar_dev) {
                        gx_ht_threshold_landscape_sub(contone_align, thresh_align,
                                            &(penum->ht_landscape), halftone, dest_height);
                    } else {
                        gx_ht_threshold_landscape(contone_align, thresh_align,
                                            &(penum->ht_landscape), halftone, dest_height);
                    }
                    /* We may have a line left over that has to be maintained
                       due to line replication in the resolution conversion. */
                    if (width != penum->ht_landscape.count) {
                        /* move the line do not reset the stuff */
                        move_landscape_buffer(&(penum->ht_landscape),
                                              contone_align, dest_height);
                    }
                }
                /* Perform the copy mono */
                if (penum->ht_landscape.index < 0) {
                    if (!is_planar_dev) {
                        (*dev_proc(dev, copy_mono))
                                       (dev, penum->ht_buffer, 0, LAND_BITS>>3,
                                        gx_no_bitmap_id,
                                        penum->ht_landscape.xstart - width + 1,
                                        penum->ht_landscape.y_pos,
                                        width, dest_height,
                                        dev_white, dev_black);
                    } else {
                        (*dev_proc(dev, copy_planes))
                                       (dev, penum->ht_buffer, 0, LAND_BITS>>3,
                                        gx_no_bitmap_id,
                                        penum->ht_landscape.xstart - width + 1,
                                        penum->ht_landscape.y_pos,
                                        width, dest_height,
                                        penum->ht_plane_height);
                    }
                } else {
                    if (!is_planar_dev) {
                        (*dev_proc(dev, copy_mono)) (dev, penum->ht_buffer, 0, LAND_BITS>>3,
                                                     gx_no_bitmap_id,
                                                     penum->ht_landscape.xstart,
                                                     penum->ht_landscape.y_pos,
                                                     width, dest_height,
                                                     dev_white, dev_black);
                    } else {
                        (*dev_proc(dev, copy_planes)) (dev, penum->ht_buffer, 0, LAND_BITS>>3,
                                                     gx_no_bitmap_id,
                                                     penum->ht_landscape.xstart,
                                                     penum->ht_landscape.y_pos,
                                                     width, dest_height,
                                                     penum->ht_plane_height);
                    }
                }
                penum->ht_landscape.offset_set = false;
                if (width != penum->ht_landscape.count) {
                    reset_landscape_buffer(&(penum->ht_landscape),
                                           contone_align, dest_height,
                                           width);
                } else {
                    /* Reset the whole buffer */
                    penum->ht_landscape.count = 0;
                    if (penum->ht_landscape.index < 0) {
                        /* Going right to left */
                        penum->ht_landscape.curr_pos = LAND_BITS-1;
                    } else {
                        /* Going left to right */
                        penum->ht_landscape.curr_pos = 0;
                    }
                    penum->ht_landscape.num_contones = 0;
                    memset(&(penum->ht_landscape.widths[0]), 0, sizeof(int)*LAND_BITS);
                }
            }
            break;
        default:
            return gs_rethrow(-1, "Invalid orientation for thresholding");
    }
    return 0;
}

int gxht_dda_length(gx_dda_fixed *dda, int src_size)
{
    gx_dda_fixed d = (*dda);
    dda_advance(d, src_size);
    return abs(fixed2int_var_rounded(dda_current(d)) - fixed2int_var_rounded(dda_current(*dda)));
}