summaryrefslogtreecommitdiffstats
path: root/src/kernel/qpolygonscanner.cpp
blob: 7db531b7602e4041e44a87e8070266e542459533 (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
/****************************************************************************
**
** Implementation of TQPolygonScanner class
**
** Created : 000120
**
** Copyright (C) 1999-2008 Trolltech ASA.  All rights reserved.
**
** This file is part of the kernel module of the TQt GUI Toolkit.
**
** This file may be used under the terms of the GNU General
** Public License versions 2.0 or 3.0 as published by the Free
** Software Foundation and appearing in the files LICENSE.GPL2
** and LICENSE.GPL3 included in the packaging of this file.
** Alternatively you may (at your option) use any later version
** of the GNU General Public License if such license has been
** publicly approved by Trolltech ASA (or its successors, if any)
** and the KDE Free TQt Foundation.
**
** Please review the following information to ensure GNU General
** Public Licensing retquirements will be met:
** http://trolltech.com/products/qt/licenses/licensing/opensource/.
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://trolltech.com/products/qt/licenses/licensing/licensingoverview
** or contact the sales department at sales@trolltech.com.
**
** This file may be used under the terms of the Q Public License as
** defined by Trolltech ASA and appearing in the file LICENSE.TQPL
** included in the packaging of this file.  Licensees holding valid TQt
** Commercial licenses may use this file in accordance with the TQt
** Commercial License Agreement provided with the Software.
**
** This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
** INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE. Trolltech reserves all rights not granted
** herein.
**
**********************************************************************/

#include "qpolygonscanner.h"
#include "qpointarray.h"
#include <stdlib.h>


// Based on Xserver code miFillGeneralPoly...
/*
 *
 *     Written by Brian Kelleher;  Oct. 1985
 *
 *     Routine to fill a polygon.  Two fill rules are
 *     supported: frWINDING and frEVENODD.
 *
 *     See fillpoly.h for a complete description of the algorithm.
 */

/*
 *     These are the data structures needed to scan
 *     convert regions.  Two different scan conversion
 *     methods are available -- the even-odd method, and
 *     the winding number method.
 *     The even-odd rule states that a point is inside
 *     the polygon if a ray drawn from that point in any
 *     direction will pass through an odd number of
 *     path segments.
 *     By the winding number rule, a point is decided
 *     to be inside the polygon if a ray drawn from that
 *     point in any direction passes through a different
 *     number of clockwise and counterclockwise path
 *     segments.
 *
 *     These data structures are adapted somewhat from
 *     the algorithm in (Foley/Van Dam) for scan converting
 *     polygons.
 *     The basic algorithm is to start at the top (smallest y)
 *     of the polygon, stepping down to the bottom of
 *     the polygon by incrementing the y coordinate.  We
 *     keep a list of edges which the current scanline crosses,
 *     sorted by x.  This list is called the Active Edge Table (AET)
 *     As we change the y-coordinate, we update each entry in
 *     in the active edge table to reflect the edges new xcoord.
 *     This list must be sorted at each scanline in case
 *     two edges intersect.
 *     We also keep a data structure known as the Edge Table (ET),
 *     which keeps track of all the edges which the current
 *     scanline has not yet reached.  The ET is basically a
 *     list of ScanLineList structures containing a list of
 *     edges which are entered at a given scanline.  There is one
 *     ScanLineList per scanline at which an edge is entered.
 *     When we enter a new edge, we move it from the ET to the AET.
 *
 *     From the AET, we can implement the even-odd rule as in
 *     (Foley/Van Dam).
 *     The winding number rule is a little trickier.  We also
 *     keep the EdgeTableEntries in the AET linked by the
 *     nextWETE (winding EdgeTableEntry) link.  This allows
 *     the edges to be linked just as before for updating
 *     purposes, but only uses the edges linked by the nextWETE
 *     link as edges representing spans of the polygon to
 *     drawn (as with the even-odd rule).
 */

/* $XConsortium: miscanfill.h,v 1.5 94/04/17 20:27:50 dpw Exp $ */
/*

Copyright (c) 1987  X Consortium

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be included
in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR
OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of the X Consortium shall
not be used in advertising or otherwise to promote the sale, use or
other dealings in this Software without prior written authorization
from the X Consortium.

*/


/*
 *     scanfill.h
 *
 *     Written by Brian Kelleher; Jan 1985
 *
 *     This file contains a few macros to help track
 *     the edge of a filled object.  The object is assumed
 *     to be filled in scanline order, and thus the
 *     algorithm used is an extension of Bresenham's line
 *     drawing algorithm which assumes that y is always the
 *     major axis.
 *     Since these pieces of code are the same for any filled shape,
 *     it is more convenient to gather the library in one
 *     place, but since these pieces of code are also in
 *     the inner loops of output primitives, procedure call
 *     overhead is out of the question.
 *     See the author for a derivation if needed.
 */

/*
 *  In scan converting polygons, we want to choose those pixels
 *  which are inside the polygon.  Thus, we add .5 to the starting
 *  x coordinate for both left and right edges.  Now we choose the
 *  first pixel which is inside the pgon for the left edge and the
 *  first pixel which is outside the pgon for the right edge.
 *  Draw the left pixel, but not the right.
 *
 *  How to add .5 to the starting x coordinate:
 *      If the edge is moving to the right, then subtract dy from the
 *  error term from the general form of the algorithm.
 *      If the edge is moving to the left, then add dy to the error term.
 *
 *  The reason for the difference between edges moving to the left
 *  and edges moving to the right is simple:  If an edge is moving
 *  to the right, then we want the algorithm to flip immediately.
 *  If it is moving to the left, then we don't want it to flip until
 *  we traverse an entire pixel.
 */
#define BRESINITPGON(dy, x1, x2, xStart, d, m, m1, incr1, incr2) { \
    int dx;      /* local storage */ \
\
    /* \
     *  if the edge is horizontal, then it is ignored \
     *  and assumed not to be processed.  Otherwise, do this stuff. \
     */ \
    if ((dy) != 0) { \
        xStart = (x1); \
        dx = (x2) - xStart; \
        if (dx < 0) { \
            m = dx / (dy); \
            m1 = m - 1; \
            incr1 = -2 * dx + 2 * (dy) * m1; \
            incr2 = -2 * dx + 2 * (dy) * m; \
            d = 2 * m * (dy) - 2 * dx - 2 * (dy); \
        } else { \
            m = dx / (dy); \
            m1 = m + 1; \
            incr1 = 2 * dx - 2 * (dy) * m1; \
            incr2 = 2 * dx - 2 * (dy) * m; \
            d = -2 * m * (dy) + 2 * dx; \
        } \
    } \
}

#define BRESINCRPGON(d, minval, m, m1, incr1, incr2) { \
    if (m1 > 0) { \
        if (d > 0) { \
            minval += m1; \
            d += incr1; \
        } \
        else { \
            minval += m; \
            d += incr2; \
        } \
    } else {\
        if (d >= 0) { \
            minval += m1; \
            d += incr1; \
        } \
        else { \
            minval += m; \
            d += incr2; \
        } \
    } \
}


/*
 *     This structure contains all of the information needed
 *     to run the bresenham algorithm.
 *     The variables may be hardcoded into the declarations
 *     instead of using this structure to make use of
 *     register declarations.
 */
typedef struct {
    int minor;         /* minor axis        */
    int d;           /* decision variable */
    int m, m1;       /* slope and slope+1 */
    int incr1, incr2; /* error increments */
} BRESINFO;


#define BRESINITPGONSTRUCT(dmaj, min1, min2, bres) \
	BRESINITPGON(dmaj, min1, min2, bres.minor, bres.d, \
                     bres.m, bres.m1, bres.incr1, bres.incr2)

#define BRESINCRPGONSTRUCT(bres) \
        BRESINCRPGON(bres.d, bres.minor, bres.m, bres.m1, bres.incr1, bres.incr2)


typedef struct _EdgeTableEntry {
     int ymax;             /* ycoord at which we exit this edge. */
     BRESINFO bres;        /* Bresenham info to run the edge     */
     struct _EdgeTableEntry *next;       /* next in the list     */
     struct _EdgeTableEntry *back;       /* for insertion sort   */
     struct _EdgeTableEntry *nextWETE;   /* for winding num rule */
     int ClockWise;        /* flag for winding number rule       */
} EdgeTableEntry;


typedef struct _ScanLineList{
     int scanline;              /* the scanline represented */
     EdgeTableEntry *edgelist;  /* header node              */
     struct _ScanLineList *next;  /* next in the list       */
} ScanLineList;


typedef struct {
     int ymax;                 /* ymax for the polygon     */
     int ymin;                 /* ymin for the polygon     */
     ScanLineList scanlines;   /* header node              */
} EdgeTable;


/*
 * Here is a struct to help with storage allocation
 * so we can allocate a big chunk at a time, and then take
 * pieces from this heap when we need to.
 */
#define SLLSPERBLOCK 25

typedef struct _ScanLineListBlock {
     ScanLineList SLLs[SLLSPERBLOCK];
     struct _ScanLineListBlock *next;
} ScanLineListBlock;

/*
 * number of points to buffer before sending them off
 * to scanlines() :  Must be an even number
 */
#define NUMPTSTOBUFFER 200

/*
 *
 *     a few macros for the inner loops of the fill code where
 *     performance considerations don't allow a procedure call.
 *
 *     Evaluate the given edge at the given scanline.
 *     If the edge has expired, then we leave it and fix up
 *     the active edge table; otherwise, we increment the
 *     x value to be ready for the next scanline.
 *     The winding number rule is in effect, so we must notify
 *     the caller when the edge has been removed so he
 *     can reorder the Winding Active Edge Table.
 */
#define EVALUATEEDGEWINDING(pAET, pPrevAET, y, fixWAET) { \
   if (pAET->ymax == y) {          /* leaving this edge */ \
      pPrevAET->next = pAET->next; \
      pAET = pPrevAET->next; \
      fixWAET = 1; \
      if (pAET) \
         pAET->back = pPrevAET; \
   } \
   else { \
      BRESINCRPGONSTRUCT(pAET->bres); \
      pPrevAET = pAET; \
      pAET = pAET->next; \
   } \
}


/*
 *     Evaluate the given edge at the given scanline.
 *     If the edge has expired, then we leave it and fix up
 *     the active edge table; otherwise, we increment the
 *     x value to be ready for the next scanline.
 *     The even-odd rule is in effect.
 */
#define EVALUATEEDGEEVENODD(pAET, pPrevAET, y) { \
   if (pAET->ymax == y) {          /* leaving this edge */ \
      pPrevAET->next = pAET->next; \
      pAET = pPrevAET->next; \
      if (pAET) \
         pAET->back = pPrevAET; \
   } \
   else { \
      BRESINCRPGONSTRUCT(pAET->bres) \
      pPrevAET = pAET; \
      pAET = pAET->next; \
   } \
}

/***********************************************************

Copyright (c) 1987  X Consortium

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL THE
X CONSORTIUM BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

Except as contained in this notice, the name of the X Consortium shall not be
used in advertising or otherwise to promote the sale, use or other dealings
in this Software without prior written authorization from the X Consortium.


Copyright 1987 by Digital Etquipment Corporation, Maynard, Massachusetts.

                        All Rights Reserved

Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the name of Digital not be
used in advertising or publicity pertaining to distribution of the
software without specific, written prior permission.

DIGITAL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING
ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL
DIGITAL BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSETQUENTIAL DAMAGES OR
ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS
SOFTWARE.

******************************************************************/

#define MAXINT 0x7fffffff
#define MININT -MAXINT

/*
 *     fillUtils.c
 *
 *     Written by Brian Kelleher;  Oct. 1985
 *
 *     This module contains all of the utility functions
 *     needed to scan convert a polygon.
 *
 */
/*
 *     InsertEdgeInET
 *
 *     Insert the given edge into the edge table.
 *     First we must find the correct bucket in the
 *     Edge table, then find the right slot in the
 *     bucket.  Finally, we can insert it.
 *
 */
static bool
miInsertEdgeInET(EdgeTable *ET, EdgeTableEntry *ETE,
	int scanline, ScanLineListBlock **SLLBlock, int *iSLLBlock)
{
    register EdgeTableEntry *start, *prev;
    register ScanLineList *pSLL, *pPrevSLL;
    ScanLineListBlock *tmpSLLBlock;

    /*
     * find the right bucket to put the edge into
     */
    pPrevSLL = &ET->scanlines;
    pSLL = pPrevSLL->next;
    while (pSLL && (pSLL->scanline < scanline))
    {
        pPrevSLL = pSLL;
        pSLL = pSLL->next;
    }

    /*
     * reassign pSLL (pointer to ScanLineList) if necessary
     */
    if ((!pSLL) || (pSLL->scanline > scanline))
    {
        if (*iSLLBlock > SLLSPERBLOCK-1)
        {
            tmpSLLBlock =
		  (ScanLineListBlock *)malloc(sizeof(ScanLineListBlock));
	    if (!tmpSLLBlock)
		return FALSE;
            (*SLLBlock)->next = tmpSLLBlock;
            tmpSLLBlock->next = 0;
            *SLLBlock = tmpSLLBlock;
            *iSLLBlock = 0;
        }
        pSLL = &((*SLLBlock)->SLLs[(*iSLLBlock)++]);

        pSLL->next = pPrevSLL->next;
        pSLL->edgelist = 0;
        pPrevSLL->next = pSLL;
    }
    pSLL->scanline = scanline;

    /*
     * now insert the edge in the right bucket
     */
    prev = 0;
    start = pSLL->edgelist;
    while (start && (start->bres.minor < ETE->bres.minor))
    {
        prev = start;
        start = start->next;
    }
    ETE->next = start;

    if (prev)
        prev->next = ETE;
    else
        pSLL->edgelist = ETE;
    return TRUE;
}

/*
 *     CreateEdgeTable
 *
 *     This routine creates the edge table for
 *     scan converting polygons.
 *     The Edge Table (ET) looks like:
 *
 *    EdgeTable
 *     --------
 *    |  ymax  |        ScanLineLists
 *    |scanline|-->------------>-------------->...
 *     --------   |scanline|   |scanline|
 *                |edgelist|   |edgelist|
 *                ---------    ---------
 *                    |             |
 *                    |             |
 *                    V             V
 *              list of ETEs   list of ETEs
 *
 *     where ETE is an EdgeTableEntry data structure,
 *     and there is one ScanLineList per scanline at
 *     which an edge is initially entered.
 *
 */

typedef struct {
#if defined(Q_OS_MAC)
    int y, x;
#else
    int x, y;
#endif

} DDXPointRec, *DDXPointPtr;

/*
 *     Clean up our act.
 */
static void
miFreeStorage(ScanLineListBlock   *pSLLBlock)
{
    register ScanLineListBlock   *tmpSLLBlock;

    while (pSLLBlock)
    {
        tmpSLLBlock = pSLLBlock->next;
        free(pSLLBlock);
        pSLLBlock = tmpSLLBlock;
    }
}

static bool
miCreateETandAET(int count, DDXPointPtr pts, EdgeTable *ET,
	EdgeTableEntry *AET, EdgeTableEntry *pETEs, ScanLineListBlock *pSLLBlock)
{
    register DDXPointPtr top, bottom;
    register DDXPointPtr PrevPt, CurrPt;
    int iSLLBlock = 0;

    int dy;

    if (count < 2)  return TRUE;

    /*
     *  initialize the Active Edge Table
     */
    AET->next = 0;
    AET->back = 0;
    AET->nextWETE = 0;
    AET->bres.minor = MININT;

    /*
     *  initialize the Edge Table.
     */
    ET->scanlines.next = 0;
    ET->ymax = MININT;
    ET->ymin = MAXINT;
    pSLLBlock->next = 0;

    PrevPt = &pts[count-1];

    /*
     *  for each vertex in the array of points.
     *  In this loop we are dealing with two vertices at
     *  a time -- these make up one edge of the polygon.
     */
    while (count--)
    {
        CurrPt = pts++;

        /*
         *  find out which point is above and which is below.
         */
        if (PrevPt->y > CurrPt->y)
        {
            bottom = PrevPt, top = CurrPt;
            pETEs->ClockWise = 0;
        }
        else
        {
            bottom = CurrPt, top = PrevPt;
            pETEs->ClockWise = 1;
        }

        /*
         * don't add horizontal edges to the Edge table.
         */
        if (bottom->y != top->y)
        {
            pETEs->ymax = bottom->y-1;  /* -1 so we don't get last scanline */

            /*
             *  initialize integer edge algorithm
             */
            dy = bottom->y - top->y;
            BRESINITPGONSTRUCT(dy, top->x, bottom->x, pETEs->bres)

            if (!miInsertEdgeInET(ET, pETEs, top->y, &pSLLBlock, &iSLLBlock))
	    {
		miFreeStorage(pSLLBlock->next);
		return FALSE;
	    }

            ET->ymax = TQMAX(ET->ymax, PrevPt->y);
            ET->ymin = TQMIN(ET->ymin, PrevPt->y);
            pETEs++;
        }

        PrevPt = CurrPt;
    }
    return TRUE;
}

/*
 *     loadAET
 *
 *     This routine moves EdgeTableEntries from the
 *     EdgeTable into the Active Edge Table,
 *     leaving them sorted by smaller x coordinate.
 *
 */

static void
miloadAET(EdgeTableEntry *AET, EdgeTableEntry *ETEs)
{
    register EdgeTableEntry *pPrevAET;
    register EdgeTableEntry *tmp;

    pPrevAET = AET;
    AET = AET->next;
    while (ETEs)
    {
        while (AET && (AET->bres.minor < ETEs->bres.minor))
        {
            pPrevAET = AET;
            AET = AET->next;
        }
        tmp = ETEs->next;
        ETEs->next = AET;
        if (AET)
            AET->back = ETEs;
        ETEs->back = pPrevAET;
        pPrevAET->next = ETEs;
        pPrevAET = ETEs;

        ETEs = tmp;
    }
}

/*
 *     computeWAET
 *
 *     This routine links the AET by the
 *     nextWETE (winding EdgeTableEntry) link for
 *     use by the winding number rule.  The final
 *     Active Edge Table (AET) might look something
 *     like:
 *
 *     AET
 *     ----------  ---------   ---------
 *     |ymax    |  |ymax    |  |ymax    |
 *     | ...    |  |...     |  |...     |
 *     |next    |->|next    |->|next    |->...
 *     |nextWETE|  |nextWETE|  |nextWETE|
 *     ---------   ---------   ^--------
 *         |                   |       |
 *         V------------------->       V---> ...
 *
 */
static void
micomputeWAET(EdgeTableEntry *AET)
{
    register EdgeTableEntry *pWETE;
    register int inside = 1;
    register int isInside = 0;

    AET->nextWETE = 0;
    pWETE = AET;
    AET = AET->next;
    while (AET)
    {
        if (AET->ClockWise)
            isInside++;
        else
            isInside--;

        if ((!inside && !isInside) ||
            ( inside &&  isInside))
        {
            pWETE->nextWETE = AET;
            pWETE = AET;
            inside = !inside;
        }
        AET = AET->next;
    }
    pWETE->nextWETE = 0;
}

/*
 *     InsertionSort
 *
 *     Just a simple insertion sort using
 *     pointers and back pointers to sort the Active
 *     Edge Table.
 *
 */

static int
miInsertionSort(EdgeTableEntry *AET)
{
    register EdgeTableEntry *pETEchase;
    register EdgeTableEntry *pETEinsert;
    register EdgeTableEntry *pETEchaseBackTMP;
    register int changed = 0;

    AET = AET->next;
    while (AET)
    {
        pETEinsert = AET;
        pETEchase = AET;
        while (pETEchase->back->bres.minor > AET->bres.minor)
            pETEchase = pETEchase->back;

        AET = AET->next;
        if (pETEchase != pETEinsert)
        {
            pETEchaseBackTMP = pETEchase->back;
            pETEinsert->back->next = AET;
            if (AET)
                AET->back = pETEinsert->back;
            pETEinsert->next = pETEchase;
            pETEchase->back->next = pETEinsert;
            pETEchase->back = pETEinsert;
            pETEinsert->back = pETEchaseBackTMP;
            changed = 1;
        }
    }
    return(changed);
}

/*!
    \overload
*/
void TQPolygonScanner::scan(const TQPointArray& pa, bool winding, int index, int npoints)
{
    scan( pa, winding, index, npoints, TRUE );
}

/*!
    \overload

    If \a stitchable is FALSE, the right and bottom edges of the
    polygon are included. This causes adjacent polygons to overlap.
*/
void TQPolygonScanner::scan(const TQPointArray& pa, bool winding, int index, int npoints, bool stitchable)
{
    scan( pa, winding, index, npoints,
	stitchable ? Edge(Left+Top) : Edge(Left+Right+Top+Bottom) );
}

/*!
    Calls processSpans() for all scanlines of the polygon defined by
    \a npoints starting at \a index in \a pa.

    If \a winding is TRUE, the Winding algorithm rather than the
    Odd-Even rule is used.

    The \a edges is any bitwise combination of:
    \list
    \i \c TQPolygonScanner::Left
    \i \c TQPolygonScanner::Right
    \i \c TQPolygonScanner::Top
    \i \c TQPolygonScanner::Bottom
    \endlist
    \a edges determines which edges are included.

    \warning The edges feature does not work properly.

*/
void TQPolygonScanner::scan( const TQPointArray& pa, bool winding, int index, int npoints, Edge edges )
{


    DDXPointPtr ptsIn = (DDXPointPtr)pa.data();
    ptsIn += index;
    register EdgeTableEntry *pAET;  /* the Active Edge Table   */
    register int y;                 /* the current scanline    */
    register int nPts = 0;          /* number of pts in buffer */
    register EdgeTableEntry *pWETE; /* Winding Edge Table      */
    register ScanLineList *pSLL;    /* Current ScanLineList    */
    register DDXPointPtr ptsOut;      /* ptr to output buffers   */
    int *width;
    DDXPointRec FirstPoint[NUMPTSTOBUFFER]; /* the output buffers */
    int FirstWidth[NUMPTSTOBUFFER];
    EdgeTableEntry *pPrevAET;       /* previous AET entry      */
    EdgeTable ET;                   /* Edge Table header node  */
    EdgeTableEntry AET;             /* Active ET header node   */
    EdgeTableEntry *pETEs;          /* Edge Table Entries buff */
    ScanLineListBlock SLLBlock;     /* header for ScanLineList */
    int fixWAET = 0;
    int edge_l = (edges & Left) ? 1 : 0;
    int edge_r = (edges & Right) ? 1 : 0;
    int edge_t = 1; //#### (edges & Top) ? 1 : 0;
    int edge_b = (edges & Bottom) ? 1 : 0;

    if (npoints == -1)
	npoints = pa.size();

    if (npoints < 3)
	return;

    if(!(pETEs = (EdgeTableEntry *)
        malloc(sizeof(EdgeTableEntry) * npoints)))
	return;
    ptsOut = FirstPoint;
    width = FirstWidth;
    if (!miCreateETandAET(npoints, ptsIn, &ET, &AET, pETEs, &SLLBlock))
    {
	free(pETEs);
	return;
    }
    pSLL = ET.scanlines.next;

    if (!winding)
    {
        /*
         *  for each scanline
         */
        for (y = ET.ymin+1-edge_t; y < ET.ymax+edge_b; y++)
        {
            /*
             *  Add a new edge to the active edge table when we
             *  get to the next edge.
             */
            if (pSLL && y == pSLL->scanline)
            {
                miloadAET(&AET, pSLL->edgelist);
                pSLL = pSLL->next;
            }
            pPrevAET = &AET;
            pAET = AET.next;

            /*
             *  for each active edge
             */
            while (pAET)
            {
                ptsOut->x = pAET->bres.minor + 1 - edge_l;
		ptsOut++->y = y;
                *width++ = pAET->next->bres.minor - pAET->bres.minor
		    - 1 + edge_l + edge_r;
                nPts++;

                /*
                 *  send out the buffer when its full
                 */
                if (nPts == NUMPTSTOBUFFER)
		{
		    processSpans( nPts, (TQPoint*)FirstPoint, FirstWidth );
                    ptsOut = FirstPoint;
                    width = FirstWidth;
                    nPts = 0;
                }
                EVALUATEEDGEEVENODD(pAET, pPrevAET, y)
                EVALUATEEDGEEVENODD(pAET, pPrevAET, y)
            }
            miInsertionSort(&AET);
        }
    }
    else      /* default to WindingNumber */
    {
        /*
         *  for each scanline
         */
        for (y = ET.ymin+1-edge_t; y < ET.ymax+edge_b; y++)
        {
            /*
             *  Add a new edge to the active edge table when we
             *  get to the next edge.
             */
            if (pSLL && y == pSLL->scanline)
            {
                miloadAET(&AET, pSLL->edgelist);
                micomputeWAET(&AET);
                pSLL = pSLL->next;
            }
            pPrevAET = &AET;
            pAET = AET.next;
            pWETE = pAET;

            /*
             *  for each active edge
             */
            while (pAET)
            {
                /*
                 *  if the next edge in the active edge table is
                 *  also the next edge in the winding active edge
                 *  table.
                 */
                if (pWETE == pAET)
                {
                    ptsOut->x = pAET->bres.minor + 1 - edge_l;
		    ptsOut++->y = y;
                    *width++ = pAET->nextWETE->bres.minor - pAET->bres.minor - 1 + edge_l + edge_r;
                    nPts++;

                    /*
                     *  send out the buffer
                     */
                    if (nPts == NUMPTSTOBUFFER)
                    {
			processSpans( nPts, (TQPoint*)FirstPoint, FirstWidth );
                        ptsOut = FirstPoint;
                        width  = FirstWidth;
                        nPts = 0;
                    }

                    pWETE = pWETE->nextWETE;
                    while (pWETE != pAET) {
                        EVALUATEEDGEWINDING(pAET, pPrevAET, y, fixWAET)
		    }
                    pWETE = pWETE->nextWETE;
                }
                EVALUATEEDGEWINDING(pAET, pPrevAET, y, fixWAET)
            }

            /*
             *  reevaluate the Winding active edge table if we
             *  just had to resort it or if we just exited an edge.
             */
            if (miInsertionSort(&AET) || fixWAET)
            {
                micomputeWAET(&AET);
                fixWAET = 0;
            }
        }
    }

    /*
     *     Get any spans that we missed by buffering
     */


    processSpans( nPts, (TQPoint*)FirstPoint, FirstWidth );
    free(pETEs);
    miFreeStorage(SLLBlock.next);
}
/***** END OF X11-based CODE *****/