summaryrefslogtreecommitdiff
path: root/app/bin/cbezier.c
blob: 92855c1b7ac9b7bffd3ed9e8e69d2832e89073e5 (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
/** \file cbezier.c
 * Bezier Command. Draw or modify a Bezier (Track or Line).
 */
 /*  XTrkCad - Model Railroad CAD
 *
 * Cubic Bezier curves have a definitional representation as an a set of four points.
 * The first and fourth are the end points, while the middle two are control points.
 * The control points positions define the angle at the ends and by their relative positions the overall
 * curvature. This representation is a familiar approach for those who know drawing programs such as Adobe
 * Illustrator or CorelDraw.
 *
 * In XTrackCAD, the Bezier form is also represented and drawn as a set of
 * joined circular arcs that approximate the Bezier form within a small tolerance. This is because
 * many of the operations we need to do are either computationally difficult or
 * impossible using the Bezier equations. For example, creating a parallel Bezier
 * which is necessary to draw a track with two lines or sleepers has no easy, stable solution.
 * But the program is already able to do these tasks for straight lines and curves.
 *
 * Note that every time we change the Bezier points we have to recalculate the arc approximation,
 * but that means that the majority of the time we are using the simpler approximation.
 *
 * We do not allow Bezier curves that have loops or cusps as they make no sense for tracks and
 * can easily be approximated for lines with multiple unaligned Bezier curves.
 *
 * This program borrows from particular ideas about converting Bezier curves that Pomax placed into
 * open source. The originals in Javascript can be found at github.com/Pomax.
 * The web pages that explain many other techniques are located at https://pomax.github.io/bezierinfo
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */


#include "track.h"
#include "draw.h"
#include "ccurve.h"
#include "cbezier.h"
#include "tbezier.h"
#include "cstraigh.h"
#include "drawgeom.h"
#include "cjoin.h"
#include "i18n.h"
#include "common.h"
#include "wcolors.h"
#include "math.h"
#include "utility.h"
#include "param.h"
#include "fileio.h"
#include "layout.h"
#include "cundo.h"

extern drawCmd_t tempD;


/*
 * STATE INFO
 */
enum Bezier_States { NONE,
	POS_1,
	CONTROL_ARM_1,
	POS_2,
	CONTROL_ARM_2,
	PICK_POINT,
	POINT_PICKED,
	TRACK_SELECTED };

typedef struct {
		curveData_t curveData;
		double start;
		double end;
		coOrd pos0;
		coOrd pos1;
		} bCurveData_t;

static struct {
		enum Bezier_States state;
		coOrd pos[4];
        int selectPoint;
        wDrawColor color;
        DIST_T width;
		track_p trk[2];
		EPINX_T ep[2];
		dynArr_t crvSegs_da;
		int crvSegs_da_cnt;
		trkSeg_t cp1Segs_da[4];
		int cp1Segs_da_cnt;
		trkSeg_t cp2Segs_da[4];
		int cp2Segs_da_cnt;
		BOOL_T unlocked;
		track_p selectTrack;
		BOOL_T track;
		DIST_T minRadius;
		} Da;



/**
 * Draw a ControlArm.
 * A control arm has two filled or unfilled circles for endpoints and a straight line between them.
 * If the end or control point is not selectable we don't mark it with a circle.
 * If a selectable end or control point is unlocked place a filled circle on it, otherwise an empty circle.
 * A red color indicates that this arm, end or control point is "active" as it was selected.
 */
int createControlArm(
                     trkSeg_t sp[],   //seg pointer for up to 3 trkSegs (ends and line)
                     coOrd pos0,     //end on curve
                     coOrd pos1,     // control point at other end of line
				     BOOL_T track,   // isTrack()? (otherwise Line)
				     BOOL_T selectable, 	// can this arm be selected?
                     BOOL_T cp_direction_locked, //isFixed to track
				     int point_selected, //number of point 0, 1 or -1
					 wDrawColor color   //drawColorBlack or drawColorWhite
                      )
{
    DIST_T d, w;
    d = tempD.scale*0.25;
    w = tempD.scale/tempD.dpi; /*double width*/
    sp[0].u.l.pos[0] = pos0;
    sp[0].u.l.pos[1] = pos1;
    sp[0].type = SEG_STRLIN;
    sp[0].width = w;
    sp[0].color = (point_selected>=0)?drawColorRed:drawColorBlack;
    int n = 0;
    if (selectable) {
    	for (int j=0;j<2;j++) {
    		if (j==0 && cp_direction_locked) continue;   //Don't show select circle if end locked
    		n++;
    		sp[n].u.c.center = j==0?pos0:pos1;
    		sp[n].u.c.radius = d/4;
    		sp[n].width = w;
    		sp[n].color = (j==point_selected)?drawColorRed:drawColorBlack;
    		if (j==point_selected && cp_direction_locked) {
    			sp[n].type = SEG_FILCRCL;
    		} else {
    			sp[n].type = SEG_CRVLIN;
    			sp[n].u.c.a0 = 0.0;
    			sp[n].u.c.a1 = 360.0;
    		}
    	}
    }
    return n+1;
}

coOrd getPoint(coOrd pos[4], double s) {
	double mt = 1-s;
	double a = mt*mt*mt;
	double b = mt*mt*s*3;
	double c = mt*s*s*3;
	double d = s*s*s;
	coOrd ret;
	ret.x = a*pos[0].x + b*pos[1].x + c*pos[2].x + d*pos[3].x;
	ret.y = a*pos[0].y + b*pos[1].y + c*pos[2].y + d*pos[3].y;
	return ret;
}
/*
 * Get Error between a Bezier and an arc centered at pc that goes from start to end
 *
 * Because the curve is defined to pass through the start and the end and the middle, the test is
 * to see how much of an error there is between those points. If the sum of the errors is off by more \
 * than 0.5 pixels - that will mean it is not a good fit.
 *
 */
double BezError(coOrd pos[4], coOrd center, coOrd start_point, double start, double end) {
	double quarter = (end - start) / 4;  // take point at 1/4 and 3/4 and check
	coOrd c1 = getPoint(pos, start + quarter);
	coOrd c2 = getPoint(pos, end - quarter);
	double ref = FindDistance(center, start_point); //radius
	double d1  = FindDistance(center, c1);          // distance to quarter
	double d2  = FindDistance(center, c2);          // distance to three quarters
	return fabs(d1-ref) + fabs(d2-ref);               //total error at quarter points
};

/*
 * Get distance between a point and a line segment
 */

double DistanceToLineSegment(coOrd p, coOrd l1, coOrd l2) {
	double A = p.x - l1.x;
    double B = p.y - l1.y;
    double C = l2.x - l1.x;
    double D = l2.y - l1.y;

    double dot = A * C + B * D;
    double len_sq = C * C + D * D;
    double param = -1;
    if (len_sq != 0) //non 0 length line
    	param = dot / len_sq;

    double xx, yy;

    if (param < 0) {      // zero length line or beyond end use point 1
    	xx = l1.x;
    	yy = l1.y;
    }  else if (param > 1) {  // beyond point 2 end of line segment
    	xx = l2.x;
    	yy = l2.y;
    }  else {					// In the middle
    	xx = l1.x + param * C;
    	yy = l1.y + param * D;
    }

    double dx = p.x - xx;        //distance to perpendicular (or end point)
    double dy = p.y - yy;
    return sqrt(dx * dx + dy * dy);
}

/*
 * Get Error between a straight line segment and the Bezier curve.
 * Sum distance to straight line of quarter points.
 */

double BezErrorLine(coOrd pos[4], coOrd start_point, coOrd end_point, double start, double end) {
	double quarter = (end - start) / 4;  // take point at 1/4 and 3/4 and check
	coOrd c1 = getPoint(pos, start + quarter);
	coOrd c2 = getPoint(pos, end - quarter);
	double d1 = DistanceToLineSegment(c1, start_point, end_point);
	double d2 = DistanceToLineSegment(c2, start_point, end_point);
	return fabs(d1)+fabs(d2);
}

/*
 * Add element to DYNARR pointed to by caller from segment handed in
 */
void addSegBezier(dynArr_t * const array_p, trkSeg_p seg) {
	trkSeg_p s;


	DYNARR_APPEND(trkSeg_t, * array_p, 1);          //Adds 1 to cnt
	s = &DYNARR_N(trkSeg_t,* array_p,array_p->cnt-1);
	s->type = seg->type;
	s->color = seg->color;
	s->width = seg->width;
	s->bezSegs.cnt = 0;
	if (s->bezSegs.ptr) MyFree(s->bezSegs.ptr);
	s->bezSegs.ptr=NULL;
	s->bezSegs.max = 0;
	if ((s->type == SEG_BEZLIN || s->type == SEG_BEZTRK) && seg->bezSegs.cnt) {
		s->u.b.angle0 = seg->u.b.angle0;  //Copy all the rest
		s->u.b.angle3 = seg->u.b.angle3;
		s->u.b.length = seg->u.b.length;
		s->u.b.minRadius = seg->u.b.minRadius;
		for (int i=0;i<4;i++) s->u.b.pos[i] = seg->u.b.pos[i];
		s->u.b.radius0 = seg->u.b.radius3;
		s->bezSegs.cnt = 0;
		if (s->bezSegs.ptr) MyFree(s->bezSegs.ptr);
		s->bezSegs.max = 0;
		s->bezSegs.ptr = NULL; //Make sure new space as addr copied in earlier from seg
		for (int i = 0; i<seg->bezSegs.cnt; i++) {
			addSegBezier(&s->bezSegs,(((trkSeg_p)seg->bezSegs.ptr)+i)); //recurse for copying embedded Beziers as in Cornu joint
		}
	} else {
		s->u = seg->u;
	}
}

enum BezierType {PLAIN, LOOP, CUSP, INFLECTION, DOUBLEINFLECTION, LINE, ENDS, COINCIDENT } bType;

/*
 * Analyse Bezier.
 *
 * Using results from Maureen C. Stone of XeroxParc and Tony deRose of U of Washington
 * characterise the curve type and find out what features it has.
 * We will eliminate cusps and loops as not useful forms. Line, Plain, Inflection and DoubleInflection are ok.
 *
 */
EXPORT enum BezierType AnalyseCurve(coOrd inpos[4], double *Rfx, double *Rfy, double *cusp) {

	*Rfx = *Rfy = 0;
	if (Da.track && inpos[0].x == inpos[3].x && inpos[0].y == inpos[3].y ) {
		return ENDS;
	}

	DIST_T d01 = FindDistance(inpos[0],inpos[1]);
	DIST_T d12 = FindDistance(inpos[1],inpos[2]);
	DIST_T d02 = FindDistance(inpos[0],inpos[2]);
	if (d01+d12 == d02) {								//straight
		DIST_T d23 = FindDistance(inpos[2],inpos[3]);
		DIST_T d03 = FindDistance(inpos[0],inpos[3]);
		if (d02+d23 == d03) return LINE;
	}
	int common_points = 0;
	for (int i=0;i<3;i++) {
		if (inpos[i].x == inpos[i+1].x && inpos[i].y == inpos[i+1].y) common_points++;
	}
	for (int i=0;i<2;i++) {
		if (inpos[i].x == inpos[i+2].x && inpos[i].y == inpos[i+2].y) common_points++;
	}

	if (common_points>2) {
		return COINCIDENT;
	}

	coOrd pos[4];
	coOrd offset2, offset = inpos[0];

	for (int i=0;i<4;i++) {     				//move to zero origin
		pos[i].x = inpos[i].x-offset.x;
		pos[i].y = inpos[i].y-offset.y;
	}

	offset2.x = -offset.x + pos[3].x;
	offset2.y = -offset.y + pos[3].y;
	if (pos[1].y == 0.0) {   					//flip order of points
		for (int i=0;i<4;i++) {
			coOrd temp_pos = pos[i];
			pos[i].x = pos[3-i].x - offset2.x;
			pos[i].y = pos[3-i].y - offset2.y;
			pos[3-i] = temp_pos;
		}
		if (pos[1].y == 0.0) {					//Both ways round the second point has no y left after translation
			return PLAIN;
		}
	}
	double f21 = (pos[2].y)/(pos[1].y);
	double f31 = (pos[3].y)/(pos[1].y);
	if (fabs(pos[2].x-(pos[1].x*f21)) <0.0001) return PLAIN;   //defend against divide by zero
	double fx = (pos[3].x-(pos[1].x*f31))/(pos[2].x-(pos[1].x*f21));
	double fy = f31+(1-f21)*fx;
	*Rfx = fx;
	*Rfy = fy;
	*cusp = fabs(fy - (-(fx*fx)+2*fx+3)/4);

	if (fy > 1.0) return INFLECTION;
	if (fx >= 1.0) return PLAIN;
	if (fabs(fy - (-(fx*fx)+2*fx+3)/4) <0.100) return CUSP;
	if (fy < (-(fx*fx)+2*fx+3)/4) {
		if (fx <= 0.0 && fy >= (3*fx-(fx*fx))/3) return LOOP;
		if (fx > 0.0 && fy >= (sqrt(3*(4*fx-fx*fx))-fx)/2) return LOOP;
		return PLAIN;
	}

	return DOUBLEINFLECTION;
}

/*
 * ConvertToArcs
 * Take a Bezier curve and turn it into a set of circular arcs, such that the error between the arc and the
 * Bezier is under 0.5 pixels at maxiumum zoom.
 *
 * This enables us to use normal methods (operating over the array of arcs)
 * to perform actions on the Bezier and also to export it to DXF.
 *
 */
EXPORT BOOL_T ConvertToArcs (coOrd pos[4], dynArr_t * segs, BOOL_T track, wDrawColor color, DIST_T width) {
	 double t_s = 0.0, t_e = 1.0;
	 double errorThreshold = 0.05;
	 bCurveData_t prev_arc;
	 prev_arc.end = 0.0;
	 bCurveData_t arc;
	 segs->cnt = 0; //wipe out
	 BOOL_T safety;
	 int col = 0;

	 double prev_e = 0.0;
	      // we do a binary search to find the "good `t` closest to no-longer-good"
	 do {
	     safety=FALSE;
	     // step 1: start with the maximum possible arc length
	      t_e = 1.0;
	     // points:
	     coOrd start_point, mid_point, end_point;
	     // booleans:
	     BOOL_T curr_good = FALSE, prev_good = FALSE, done = FALSE;
	      // numbers:
	      double t_m, step = 0;
	      // step 2: find the best possible arc
	      do {						// !done
	          prev_good = curr_good;   //remember last time
	          t_m = (t_s + t_e)/2;
	          step++;
	          start_point = getPoint(pos, t_s); //Start of arc
	          mid_point = getPoint(pos, t_m);  //Middle of trial arc
	          end_point = getPoint(pos, t_e);  //End of trial Arc

	          PlotCurve( crvCmdFromChord, start_point, end_point, mid_point,
	        		  	  &(arc.curveData), TRUE );  //Find Arc through three points

	          arc.start = t_s; 		//remember start
	          arc.end = t_e;			//remember end
	          arc.pos0 = start_point; //remember start point (used for Straight)
	          arc.pos1 = end_point;	// Remember end point (used for Straight)

	          if (arc.curveData.type == curveTypeStraight) {
	          	  double error = BezErrorLine(pos,start_point,end_point, t_s, t_e);
	          	  curr_good = (error <= errorThreshold/2);
	          	  arc.curveData.a0 = FindAngle(start_point,end_point);
	          	  arc.curveData.a1 = FindAngle(end_point,start_point);

	          } else if (arc.curveData.type == curveTypeNone) {
	        	  return FALSE;			//Something wrong
	          } else {
	        	  double error = BezError(pos, arc.curveData.curvePos, start_point, t_s, t_e);
	          	  curr_good = (error <= errorThreshold/2);
	          };

	          done = prev_good && !curr_good; //Was better than this last time?
	          if(!done) {
	          	  // this arc is fine: we can move 'e' up to see if we can find a wider arc
	          	  if(curr_good) {
	          		  prev_e = t_e;		  //remember good end only
	          		  prev_arc = arc;
	          		  // if e is already at max, then we're done for this arc.
	          		  if (t_e >= 1.0) {
	          			  // make sure we cap at t=1
	          			  arc.end = prev_e = 1.0;
	          			  // if we capped the arc segment to t=1 we also need to make sure that
	          			  // the arc's end angle is correct with respect to the bezier end point.
	          			  if (t_e > 1.0) {
	          				  if (arc.curveData.type != curveTypeStraight) {
	          					  coOrd d;
	          					  d.x = arc.curveData.curvePos.x + fabs(arc.curveData.curveRadius) * cos(D2R(arc.curveData.a1));
	          					  d.y = arc.curveData.curvePos.y + fabs(arc.curveData.curveRadius) * sin(D2R(arc.curveData.a1));

	          					  arc.curveData.a1 += FindAngle(d, getPoint(pos,1.0));
	          					  t_e = 1.0;
	          				  }
	          			  }
	          			  prev_arc = arc;
	          			  done = TRUE;
	          			  break;
	          		  }
	          		  // if not, move it up by half the iteration distance or to end
	          		  t_e = t_e + (t_e-t_s)/2;
	          		  if (t_e > 1.0) t_e = 1.0;
	          	  }
	          	  // this is a bad arc: we need to move 'e' down to find a good arc
	          	  else {
	          		  t_e = t_m;
	          	  }
	          }         // If !Done end
	        } while(!done && safety++<100);
	        if(safety>=100) {
	          return FALSE;				//Failed to make into arcs
	        }
	        prev_arc = prev_arc.end==0.0?arc:prev_arc;
	        trkSeg_t curveSeg;  			//Now set up tempSeg to copy into array
	        curveSeg.width = track?0:width;
	        if ( prev_arc.curveData.type == curveTypeCurve ) {
	        		if (track)
	        			curveSeg.color = (fabs(prev_arc.curveData.curveRadius)<(GetLayoutMinTrackRadius()-EPSILON))?wDrawColorRed:wDrawColorBlack;
	        		else
	        			curveSeg.color = color;
	        		curveSeg.type = track?SEG_CRVTRK:SEG_CRVLIN;
	        		curveSeg.u.c.a0 = prev_arc.curveData.a0;
	        		curveSeg.u.c.a1 = prev_arc.curveData.a1;
	        		curveSeg.u.c.center = prev_arc.curveData.curvePos;
	        		if (prev_arc.curveData.negative)
	        			curveSeg.u.c.radius = -prev_arc.curveData.curveRadius;
	        		else
	        			curveSeg.u.c.radius = prev_arc.curveData.curveRadius;
	        } else {											//Straight Line because all points co-linear
	        	curveSeg.type = track?SEG_STRTRK:SEG_STRLIN;
	        	if (track)
	        		curveSeg.color = wDrawColorBlack;
	        	else
	        		curveSeg.color = color;
	        	curveSeg.u.l.angle = prev_arc.curveData.a1;
	        	curveSeg.u.l.pos[0] = prev_arc.pos0;
	        	curveSeg.u.l.pos[1] = prev_arc.pos1;
	        	curveSeg.u.l.option = 0;
	        }
	        addSegBezier(segs, &curveSeg);		//Add to array of segs used
	        t_s = prev_e;
	        col++;
	      } while(prev_e < 1.0);

	      return TRUE;
};
/*
 * Draw Bezier while editing it. It consists of three elements - the curve and one or two control arms.
 *
 */

EXPORT void DrawBezCurve(trkSeg_p control_arm1,
					int cp1Segs_cnt,
					trkSeg_p control_arm2,
					int cp2Segs_cnt,
					trkSeg_p curveSegs,
					int crvSegs_cnt,
					wDrawColor color
					) {
	long oldDrawOptions = tempD.funcs->options;
	tempD.funcs->options = wDrawOptTemp;
	long oldOptions = tempD.options;
	tempD.options = DC_TICKS;
	tempD.orig = mainD.orig;
	tempD.angle = mainD.angle;
	if (crvSegs_cnt && curveSegs)
		DrawSegs( &tempD, zero, 0.0, curveSegs, crvSegs_cnt, trackGauge, color );
	if (cp1Segs_cnt && control_arm1)
		DrawSegs( &tempD, zero, 0.0, control_arm1, cp1Segs_cnt, trackGauge, drawColorBlack );
	if (cp2Segs_cnt && control_arm2)
		DrawSegs( &tempD, zero, 0.0, control_arm2, cp2Segs_cnt, trackGauge, drawColorBlack );
	tempD.funcs->options = oldDrawOptions;
	tempD.options = oldOptions;

}

/*
 * If Track, make it red if the radius is below minimum
 */
void DrawTempBezier(BOOL_T track) {
  if (track) DrawBezCurve(Da.cp1Segs_da,Da.cp1Segs_da_cnt,Da.cp2Segs_da,Da.cp2Segs_da_cnt, (trkSeg_t *)Da.crvSegs_da.ptr,Da.crvSegs_da_cnt,Da.minRadius<(GetLayoutMinTrackRadius()-EPSILON)?drawColorRed:drawColorBlack);
  else
	DrawBezCurve(Da.cp1Segs_da,Da.cp1Segs_da_cnt,Da.cp2Segs_da,Da.cp2Segs_da_cnt, (trkSeg_t *)Da.crvSegs_da.ptr,Da.crvSegs_da_cnt,drawColorBlack); //Add Second Arm
}

void CreateBothControlArms(int selectPoint, BOOL_T track) {
	if (selectPoint == -1) {
		Da.cp1Segs_da_cnt = createControlArm(Da.cp1Segs_da, Da.pos[0],
				Da.pos[1], track, TRUE, Da.trk[0]!=NULL, -1,
				drawColorBlack);
		Da.cp2Segs_da_cnt = createControlArm(Da.cp2Segs_da, Da.pos[3],
				Da.pos[2], track, TRUE, Da.trk[1]!=NULL, -1,
				drawColorBlack);
	} else if (selectPoint == 0 || selectPoint == 1) {
		Da.cp1Segs_da_cnt = createControlArm(Da.cp1Segs_da, Da.pos[0],
				Da.pos[1], track, TRUE, Da.trk[0]!=NULL, selectPoint,
				drawColorBlack);
		Da.cp2Segs_da_cnt = createControlArm(Da.cp2Segs_da, Da.pos[3],
				Da.pos[2], track, FALSE, Da.trk[1]!=NULL, -1,
				drawColorBlack);
	} else {
		Da.cp1Segs_da_cnt = createControlArm(Da.cp1Segs_da, Da.pos[0],
				Da.pos[1], track, FALSE, Da.trk[0]!=NULL, -1,
				drawColorBlack);
		Da.cp2Segs_da_cnt = createControlArm(Da.cp2Segs_da, Da.pos[3],
				Da.pos[2], track, TRUE, Da.trk[1]!=NULL,
				3-selectPoint, drawColorBlack);
	}
}

/*
 * AdjustBezCurve
 *
 * Called to adjust the curve either when creating it or modifying it
 * States are "PICK_POINT" and "POINT_PICKED" and "TRACK_SELECTED".
 *
 * In PICK_POINT, the user can select an end-point to drag and release in POINT_PICKED. They can also
 * hit Enter (which saves the changes) or ESC (which cancels them).
 *
 * Only those points which can be picked are shown with circles - locked end-points are not shown.
 *
 * SHIFT at release will lock , re-locking any end-points that are aligned with like items at the same position
 * (Track to unconnected Track, Line to any Line end).
 *
 */
EXPORT STATUS_T AdjustBezCurve(
		wAction_t action,
		coOrd pos,
		BOOL_T track,
		wDrawColor color,
		DIST_T width,
		bezMessageProc message )
{
	track_p t;
	DIST_T d;
	ANGLE_T angle1, angle2;
	static coOrd pos0, pos3, p;
	enum BezierType b;
	DIST_T dd;
	EPINX_T ep;
	double fx, fy, cusp;
	int controlArm = -1;


	if (Da.state != PICK_POINT && Da.state != POINT_PICKED && Da.state != TRACK_SELECTED) return C_CONTINUE;

	switch ( action & 0xFF) {

	case C_START:
			Da.selectPoint = -1;
			CreateBothControlArms(Da.selectPoint, track);
			if (ConvertToArcs(Da.pos,&Da.crvSegs_da,track,color,Da.width)) Da.crvSegs_da_cnt = Da.crvSegs_da.cnt;
			Da.minRadius = BezierMinRadius(Da.pos,Da.crvSegs_da);
			Da.unlocked = FALSE;
			if (track)
				InfoMessage( _("Select End-Point - Ctrl unlocks end-point") );
			else
				InfoMessage( _("Select End-Point") );
			DrawTempBezier(Da.track);
			return C_CONTINUE;

	case C_DOWN:
		if (Da.state != PICK_POINT) return C_CONTINUE;
		dd = 10000.0;
		Da.selectPoint = -1;
		DrawTempBezier(Da.track);   //wipe out
		for (int i=0;i<4;i++) {
			d = FindDistance(Da.pos[i],pos);
			if (d < dd) {
				if (i==0 && Da.trk[0]) continue;
				if (i==3 && Da.trk[1]) continue;   //ignore locked points
				dd = d;
				Da.selectPoint = i;
			}

		}
		if (!IsClose(dd) )	Da.selectPoint = -1;
		if (Da.selectPoint == -1) {
			InfoMessage( _("Not close enough to any valid, selectable point, reselect") );
			DrawTempBezier(Da.track);
			return C_CONTINUE;
		} else {
			pos = Da.pos[Da.selectPoint];
			Da.state = POINT_PICKED;
			InfoMessage( _("Drag point %d to new location and release it"),Da.selectPoint+1 );
		}
		CreateBothControlArms(Da.selectPoint, track);
		if (ConvertToArcs(Da.pos, &Da.crvSegs_da, track, color,Da.width)) Da.crvSegs_da_cnt = Da.crvSegs_da.cnt;
		Da.minRadius = BezierMinRadius(Da.pos, Da.crvSegs_da);
		DrawTempBezier(Da.track);
		return C_CONTINUE;

	case C_MOVE:
		if (Da.state != POINT_PICKED) {
			InfoMessage(_("Pick any circle to adjust it - Enter to confirm, ESC to abort"));
			return C_CONTINUE;
		}
		//If locked, reset pos to be on line from other track
		DrawTempBezier(Da.track);   //wipe out
		if (Da.selectPoint == 1 || Da.selectPoint == 2) {  //CPs
			int controlArm = Da.selectPoint-1;			//Snap to direction of track
			if (Da.trk[controlArm]) {
				angle1 = NormalizeAngle(GetTrkEndAngle(Da.trk[controlArm], Da.ep[controlArm]));
				angle2 = NormalizeAngle(FindAngle(pos, Da.pos[Da.selectPoint==1?0:3])-angle1);
				if (angle2 > 90.0 && angle2 < 270.0)
					Translate( &pos, Da.pos[Da.selectPoint==1?0:3], angle1, -FindDistance( Da.pos[Da.selectPoint==1?0:3], pos )*cos(D2R(angle2)) );
				else pos = Da.pos[Da.selectPoint==1?0:3];
			} // Dont Snap control points
		} else SnapPos(&pos);
		Da.pos[Da.selectPoint] = pos;
		CreateBothControlArms(Da.selectPoint, track);
		if (ConvertToArcs(Da.pos,&Da.crvSegs_da,track, color, Da.width)) Da.crvSegs_da_cnt = Da.crvSegs_da.cnt;
		Da.minRadius = BezierMinRadius(Da.pos,Da.crvSegs_da);
		if (Da.track) {
			b = AnalyseCurve(Da.pos,&fx,&fy,&cusp);
			if (b==ENDS) {
				wBeep();
				InfoMessage(_("Bezier Curve Invalid has identical end points Change End Point"),b==CUSP?"Cusp":"Loop");
			} else if ( b == CUSP || b == LOOP) {
				wBeep();
				InfoMessage(_("Bezier Curve Invalid has %s Change End Point"),b==CUSP?"Cusp":"Loop");
			} else if ( b == COINCIDENT ) {
				wBeep();
				InfoMessage(_("Bezier Curve Invalid has three co-incident points"),b==CUSP?"Cusp":"Loop");
			} else if ( b == LINE ) {
				InfoMessage(_("Bezier is Straight Line"));
			} else
				InfoMessage( _("Bezier %s : Min Radius=%s Length=%s fx=%0.3f fy=%0.3f cusp=%0.3f"),track?"Track":"Line",
													FormatDistance(Da.minRadius>=100000?0:Da.minRadius),
													FormatDistance(BezierLength(Da.pos,Da.crvSegs_da)),fx,fy,cusp);
		} else
				InfoMessage( _("Bezier %s : Min Radius=%s Length=%s"),track?"Track":"Line",
									FormatDistance(Da.minRadius>=100000?0:Da.minRadius),
									FormatDistance(BezierLength(Da.pos,Da.crvSegs_da)));
		DrawTempBezier(Da.track);
		return C_CONTINUE;

	case C_UP:
		if (Da.state != POINT_PICKED) return C_CONTINUE;
		//Take last pos and decide if it should be snapped to a track because SHIFT is held (pos0 and pos3)
		ep = 0;
		BOOL_T found = FALSE;

		DrawTempBezier(Da.track);  //wipe out

		p = pos;

		if (track && (Da.selectPoint == 0 || Da.selectPoint == 3)) {  //EPs
			if ((MyGetKeyState() & WKEY_SHIFT) != 0) {   //Snap Track
				if ((t = OnTrackIgnore(&p, FALSE, TRUE, Da.selectTrack)) != NULL) { //Snap to endPoint
					ep = PickUnconnectedEndPointSilent(p, t);
					if (ep != -1) {
						Da.trk[Da.selectPoint/3] = t;
						Da.ep[Da.selectPoint/3] = ep;
						pos0 = Da.pos[(Da.selectPoint == 0)?1:2];
						pos = GetTrkEndPos(t, ep);
						found = TRUE;
					}
				} else {
					wBeep();
					InfoMessage(_("No unconnected End Point to lock to"));
				}
			}
		}
		if (found) {
			angle1 = NormalizeAngle(GetTrkEndAngle(Da.trk[Da.selectPoint/3], Da.ep[Da.selectPoint/3]));
			angle2 = NormalizeAngle(FindAngle(pos, pos0)-angle1);
			Translate(&Da.pos[Da.selectPoint==0?1:2], Da.pos[Da.selectPoint==0?0:3], angle1, FindDistance(Da.pos[Da.selectPoint==0?1:2],pos)*cos(D2R(angle2)));
		}
		Da.selectPoint = -1;
		CreateBothControlArms(Da.selectPoint,track);
		if (ConvertToArcs(Da.pos,&Da.crvSegs_da,track,color,Da.width)) Da.crvSegs_da_cnt = Da.crvSegs_da.cnt;
		Da.minRadius = BezierMinRadius(Da.pos,Da.crvSegs_da);
		if (Da.track) {
			b = AnalyseCurve(Da.pos,&fx,&fy,&cusp);
			if (b==ENDS) {
				wBeep();
				InfoMessage(_("Bezier curve invalid has identical end points Change End Point"),b==CUSP?"Cusp":"Loop");
			} else if ( b == CUSP || b == LOOP) {
				wBeep();
				InfoMessage(_("Bezier curve invalid has %s Change End Point"),b==CUSP?"Cusp":"Loop");
			} else if ( b == COINCIDENT ) {
				wBeep();
				InfoMessage(_("Bezier curve invalid has three co-incident points"),b==CUSP?"Cusp":"Loop");
			} else if ( b == LINE) {
				InfoMessage(_("Bezier curve is straight line"));
			}
				InfoMessage(_("Pick any circle to adjust it - Enter to confirm, ESC to abort"));
		} else
			InfoMessage(_("Pick any circle to adjust it - Enter to confirm, ESC to abort"));
		DrawTempBezier(Da.track);
		Da.state = PICK_POINT;

		return C_CONTINUE;

	case C_OK:                            //C_OK is not called by Modify.
		if ( Da.state == PICK_POINT ) {
			char c = (unsigned char)(action >> 8);
			if (Da.track && Da.pos[0].x == Da.pos[3].x && Da.pos[0].y == Da.pos[3].y ) {
				wBeep();
				ErrorMessage(_("Invalid Bezier Track - end points are identical"));
				return C_CONTINUE;
			}
			if (Da.track) {
				b = AnalyseCurve(Da.pos,&fx,&fy,&cusp);
				if ( b == CUSP || b == LOOP ) {
					wBeep();
					ErrorMessage(_("Invalid Bezier Curve has a %s - Adjust"),b==CUSP?"Cusp":"Loop");
					return C_CONTINUE;
				} else if (b==COINCIDENT) {
					wBeep();
					ErrorMessage(_("Invalid Bezier Curve has three coincident points - Adjust"));
					return C_CONTINUE;
				} else if(b==ENDS) {
					ErrorMessage(_("Invalid Bezier Track - end points are identical"));
					return C_CONTINUE;
				}
			}
			Da.minRadius = BezierMinRadius(Da.pos,Da.crvSegs_da);
			DrawTempBezier(Da.track);
			UndoStart( _("Create Bezier"), "newBezier - CR" );
			if (Da.track) {
				t = NewBezierTrack( Da.pos, (trkSeg_p)Da.crvSegs_da.ptr, Da.crvSegs_da.cnt);
				for (int i=0;i<2;i++)
							if (Da.trk[i] != NULL) ConnectAbuttingTracks(t,i,Da.trk[i],Da.ep[i]);
			}
			else t = NewBezierLine(Da.pos, (trkSeg_p)Da.crvSegs_da.ptr, Da.crvSegs_da.cnt,color,width);
			UndoEnd();
			if (Da.crvSegs_da.ptr) MyFree(Da.crvSegs_da.ptr);
			Da.crvSegs_da.ptr = NULL;
			Da.crvSegs_da.cnt = 0;
			Da.crvSegs_da.max = 0;
			DrawNewTrack(t);
			Da.state = NONE;
			MainRedraw();
			MapRedraw();
			return C_TERMINATE;

		}
		return C_CONTINUE;

	case C_REDRAW:
		DrawTempBezier(Da.track);
		return C_CONTINUE;

	default:
		return C_CONTINUE;
	}


}

struct extraData {
				BezierData_t bezierData;
		};

/*
 * CmdBezModify
 *
 * Called from Modify Command - this function deals with the real (old) track and calls AdjustBezCurve to tune up the new one
 * Sequence is this -
 * - The C_START is called from CmdModify C_DOWN action if a track has being selected. The old track is hidden, the editable one is shown.
 * - C_MOVES will be ignored until a C_UP ends the track selection and moves the state to PICK_POINT,
 * - C_DOWN then hides the track and shows the Bezier handles version. Selects a point (if close enough and available) and the state moves to POINT_PICKED
 * - C_MOVE drags the point around modifying the curve
 * - C_UP puts the state back to PICK_POINT (pick another)
 * - C_OK (Enter/Space) creates the new track, deletes the old and shows the changed track.
 * - C_CANCEL (Esc) sets the state to NONE and reshows the original track unchanged.
 *
 * Note: Available points are shown - if a Bezier track is attached to its neighbor, only the control point on that side is selectable.
 * Any free end-point can be locked to a unconnected end point using SHIFT during drag.
 */
STATUS_T CmdBezModify (track_p trk, wAction_t action, coOrd pos) {
	BOOL_T track = TRUE;
	track_p t;
	double width = 1.0;
	long mode = 0;
	long cmd;

	struct extraData *xx = GetTrkExtraData(trk);
	cmd = (long)commandContext;


	switch (action&0xFF) {
	case C_START:
		Da.state = NONE;
		DYNARR_RESET(trkSeg_t,Da.crvSegs_da);
		Da.cp1Segs_da_cnt = 0;
		Da.cp2Segs_da_cnt = 0;
		Da.selectPoint = -1;
		Da.selectTrack = NULL;

		if (IsTrack(trk)) Da.track = TRUE;
		else Da.track = FALSE;

		Da.selectTrack = trk;
	    Da.trk[0] = GetTrkEndTrk( trk, 0 );
		if (Da.trk[0]) Da.ep[0] = GetEndPtConnectedToMe(Da.trk[0],trk);
		Da.trk[1] = GetTrkEndTrk( trk, 1 );
		if (Da.trk[1]) Da.ep[1] = GetEndPtConnectedToMe(Da.trk[1],trk);

	    for (int i=0;i<4;i++) Da.pos[i] = xx->bezierData.pos[i];              //Copy parms from old trk
		InfoMessage(_("%s picked - now select a Point"),track?"Track":"Line");
		Da.state = TRACK_SELECTED;
		DrawTrack(Da.selectTrack,&mainD,wDrawColorWhite);                    //Wipe out real track, draw replacement
		return AdjustBezCurve(C_START, pos, Da.track, xx->bezierData.segsColor, xx->bezierData.segsWidth, InfoMessage);

	case C_DOWN:
		if (Da.state == TRACK_SELECTED) return C_CONTINUE;                   //Ignore until first up
		return AdjustBezCurve(C_DOWN, pos, Da.track, xx->bezierData.segsColor, xx->bezierData.segsWidth, InfoMessage);


	case C_MOVE:
		if (Da.state == TRACK_SELECTED) return C_CONTINUE;                   //Ignore until first up and down
		return AdjustBezCurve(C_MOVE, pos, Da.track, xx->bezierData.segsColor, xx->bezierData.segsWidth, InfoMessage);

	case C_UP:
		if (Da.state == TRACK_SELECTED) {
			Da.state = PICK_POINT;                                           //First time up, next time pick a point
		}
		return AdjustBezCurve(C_UP, pos, Da.track, xx->bezierData.segsColor, xx->bezierData.segsWidth,  InfoMessage);					//Run Adjust

	case C_TEXT:
		if ((action>>8) != 32)
			return C_CONTINUE;
		/* no break */
	case C_OK:
		if (Da.state != PICK_POINT) {										//Too early - abandon
			InfoMessage(_("No changes made"));
			Da.state = NONE;
			return C_CANCEL;
		}
		UndoStart( _("Modify Bezier"), "newBezier - CR" );
		if (Da.track) t = NewBezierTrack( Da.pos, (trkSeg_p)Da.crvSegs_da.ptr, Da.crvSegs_da.cnt);
		else t = NewBezierLine(Da.pos, (trkSeg_p)Da.crvSegs_da.ptr, Da.crvSegs_da.cnt,xx->bezierData.segsColor,xx->bezierData.segsWidth);

		DeleteTrack(trk, TRUE);

		if (Da.track) {
			for (int i=0;i<2;i++) {										//Attach new track
				if (Da.trk[i] != NULL && Da.ep[i] != -1) {								//Like the old track
					ConnectAbuttingTracks(t,i,Da.trk[i],Da.ep[i]);
				}
			}
		}
		UndoEnd();
		InfoMessage(_("Modify Bezier Complete - select another"));
		Da.state = NONE;
		return C_TERMINATE;

	case C_CANCEL:
		InfoMessage(_("Modify Bezier Cancelled"));
		Da.state = NONE;
		MainRedraw();
		MapRedraw();
		return C_TERMINATE;

	case C_REDRAW:
		return AdjustBezCurve(C_REDRAW, pos, Da.track, xx->bezierData.segsColor, xx->bezierData.segsWidth, InfoMessage);
	}

	return C_CONTINUE;

}

/*
 * Find length by adding up the underlying segments. The segments can be straights, curves or bezier.
 */
DIST_T BezierLength(coOrd pos[4],dynArr_t segs) {

	DIST_T dd = 0.0;
	if (segs.cnt == 0 ) return dd;
	for (int i = 0;i<segs.cnt;i++) {
		trkSeg_t t = DYNARR_N(trkSeg_t, segs, i);
		if (t.type == SEG_CRVTRK || t.type == SEG_CRVLIN) {
			dd += fabs(t.u.c.radius*D2R(t.u.c.a1));
		} else if (t.type == SEG_BEZLIN || t.type == SEG_BEZTRK) {
			dd +=BezierLength(t.u.b.pos,t.bezSegs);
		} else if (t.type == SEG_STRLIN || t.type == SEG_STRTRK ) {
			dd += FindDistance(t.u.l.pos[0],t.u.l.pos[1]);
		}
	}
	return dd;
}

DIST_T BezierMinRadius(coOrd pos[4],dynArr_t segs) {
	DIST_T r = 100000.0, rr;
	if (segs.cnt == 0 ) return r;
	for (int i = 0;i<segs.cnt;i++) {
		trkSeg_t t = DYNARR_N(trkSeg_t, segs, i);
		if (t.type == SEG_CRVTRK || t.type == SEG_CRVLIN) {
			rr = fabs(t.u.c.radius);
		} else if (t.type == SEG_BEZLIN || t.type == SEG_BEZTRK) {
			rr = BezierMinRadius(t.u.b.pos, t.bezSegs);
		} else rr = 100000.00;
		if (rr<r) r = rr;
	}
	return r;
}

/*
 * Create a Bezier Curve (Track or Line)
 * Sequence is
 * 1. Place 1st End (snapping if needed)
 * 2.Drag out 1st Control Arm (in one direction if snapped)
 * 3.Place 2nd End (again snapping)
 * 4.Drag out 2nd Control Arm (constrained if snapped)
 * 5 to n. Select and drag around points until done
 * n+1. Confirm with enter or Cancel with Esc
 */
STATUS_T CmdBezCurve( wAction_t action, coOrd pos )
{
	track_p t;
	static int segCnt;
	STATUS_T rc = C_CONTINUE;
	long curveMode = 0;
	long cmd;
	if (action>>8) {
		cmd = action>>8;
	} else cmd = (long)commandContext;

	Da.color = lineColor;
	Da.width = (double)lineWidth/mainD.dpi;

	switch (action&0xFF) {

	case C_START:

		Da.track = (cmd == bezCmdModifyTrack || cmd == bezCmdCreateTrack)?TRUE:FALSE;

		Da.state = POS_1;
		Da. selectPoint = -1;
		for (int i=0;i<4;i++) {
			Da.pos[i] = zero;
		}
		Da.trk[0] = Da.trk[1] = NULL;
		//tempD.orig = mainD.orig;

		DYNARR_RESET(trkSeg_t,Da.crvSegs_da);
		Da.cp1Segs_da_cnt = 0;
		Da.cp2Segs_da_cnt = 0;
		InfoMessage( _("Place 1st end point of Bezier + Shift -> snap to %s end"), Da.track?"Unconnected Track":"Line" );
		return C_CONTINUE;


	case C_DOWN:
		if ( Da.state == POS_1 || Da.state == POS_2) {   //Set the first or third point
			coOrd p = pos;
			BOOL_T found = FALSE;
			int end = Da.state==POS_1?0:1;
			EPINX_T ep;
			if (Da.track) {
				if ((MyGetKeyState() & WKEY_SHIFT) != 0) {   //Snap Track
					if ((t = OnTrack(&p, FALSE, TRUE)) != NULL) {
						ep = PickUnconnectedEndPointSilent(p, t);
						if (ep != -1) {
							Da.trk[end] = t;
							Da.ep[end] = ep;
							pos = GetTrkEndPos(t, ep);
							found = TRUE;
						}
					}
					if (!found) {
						wBeep();
						InfoMessage(_("Shift used, but no Unconnected Track End there"));
						return C_CONTINUE;
					}
				}
			} else {													//Snap Bez Line to Lines
				if ((MyGetKeyState() & WKEY_SHIFT) != 0) {
					if ((t = OnTrack(&p,FALSE, FALSE)) != NULL) {
						if (GetClosestEndPt(t,&p)) {
							pos = p;
							found = TRUE;
						}
					} else {
						wBeep();
						InfoMessage(_("Shift used, but no Line End there"));
						return C_CONTINUE;
					}
				}
			}
			if (!found) SnapPos( &pos );
			if (Da.state == POS_1) {
				Da.pos[0] = pos;
				Da.pos[1] = pos;
				Da.state = CONTROL_ARM_1;  //Draw the first control arm
				Da.selectPoint = 1;
				InfoMessage( _("Drag end of first Control Arm") );
				Da.cp1Segs_da_cnt = createControlArm(Da.cp1Segs_da, Da.pos[0], Da.pos[1], Da.track,TRUE,Da.trk[1]!=NULL,1,wDrawColorBlack);
				DrawBezCurve(Da.cp1Segs_da,Da.cp1Segs_da_cnt,NULL,0,NULL,0,drawColorBlack);
			} else {
				Da.pos[3] = pos;  //2nd End Point
				Da.pos[2] = pos;  //2nd Ctl Point
				Da.state = POINT_PICKED; // Drag out the second control arm
				Da.selectPoint = 2;
				InfoMessage( _("Drag end of second Control Arm") );
				DrawBezCurve(Da.cp1Segs_da,Da.cp1Segs_da_cnt,NULL,0,NULL,0,drawColorBlack); //Wipe out initial Arm
				Da.cp1Segs_da_cnt = createControlArm(Da.cp1Segs_da, Da.pos[0], Da.pos[1], Da.track,FALSE,Da.trk[0]!=NULL,-1,wDrawColorBlack);
				Da.cp2Segs_da_cnt = createControlArm(Da.cp2Segs_da, Da.pos[3], Da.pos[2], Da.track,TRUE,Da.trk[1]!=NULL,1,wDrawColorBlack);
				if (ConvertToArcs(Da.pos,&Da.crvSegs_da,Da.track,Da.color,Da.width)) Da.crvSegs_da_cnt = Da.crvSegs_da.cnt;
				DrawTempBezier(Da.track);
			}
			return C_CONTINUE;
		} else  {
			return AdjustBezCurve( action&0xFF, pos, Da.track, Da.color, Da.width, InfoMessage );
		}
		return C_CONTINUE;
			
	case C_MOVE:
		if (Da.state == POS_1) {
			InfoMessage( _("Place 1st end point of Bezier + Shift -> snap to %s end"), Da.track?"Unconnected Track":"Line" );
			return C_CONTINUE;
		}
		if (Da.state == POS_2) {
			InfoMessage( _("Select other end of Bezier, +Shift -> snap to %s end"), Da.track?"Unconnected Track":"Line" );
		}
		if (Da.state == CONTROL_ARM_1 ) {
			DrawBezCurve(Da.cp1Segs_da,Da.cp1Segs_da_cnt,NULL,0,NULL,0,drawColorBlack);
			if (Da.trk[0]) {
				EPINX_T ep = 0;
				ANGLE_T angle1,angle2;
				angle1 = NormalizeAngle(GetTrkEndAngle(Da.trk[0],Da.ep[0]));
				angle2 = NormalizeAngle(FindAngle(pos, Da.pos[0])-angle1);
				if (angle2 > 90.0 && angle2 < 270.0)
					Translate( &pos, Da.pos[0], angle1, -FindDistance( Da.pos[0], pos )*cos(D2R(angle2)));
				else pos = Da.pos[0];
			} // Don't Snap control points
			Da.pos[1] = pos;
			Da.cp1Segs_da_cnt = createControlArm(Da.cp1Segs_da, Da.pos[0], Da.pos[1], Da.track, TRUE, Da.trk[0]!=NULL, 1, wDrawColorBlack);
			DrawBezCurve(Da.cp1Segs_da,Da.cp1Segs_da_cnt,NULL,0,NULL,0,drawColorBlack);
		} else {
			return AdjustBezCurve( action&0xFF, pos, Da.track, Da.color, Da.width, InfoMessage );
		}
		return C_CONTINUE;

	case C_UP:
		if (Da.state == CONTROL_ARM_1) {
			DrawBezCurve(Da.cp1Segs_da,Da.cp1Segs_da_cnt,NULL,0,NULL,0,drawColorBlack);
			if (Da.trk[0]) {
				EPINX_T ep = Da.ep[0];
				ANGLE_T angle1,angle2;
				angle1 = NormalizeAngle(GetTrkEndAngle(Da.trk[0],Da.ep[0]));
				angle2 = NormalizeAngle(FindAngle(pos, Da.pos[0])-angle1);
				if (angle2 > 90.0 && angle2 < 270.0)
					Translate( &pos, Da.pos[0], angle1, -FindDistance( Da.pos[0], pos )*cos(D2R(angle2)));
				else pos = Da.pos[0];
			} // Don't Snap control points
			Da.pos[1] = pos;
			if (FindDistance(Da.pos[0],Da.pos[1]) <=minLength) {
				InfoMessage( _("Control Arm 1 is too short, try again") );
				Da.state = POS_1;
				return C_CONTINUE;
			}
			Da.state = POS_2;
			InfoMessage( _("Select other end of Bezier, +Shift -> snap to %s end"), Da.track?"Unconnected Track":"Line" );
			Da.cp1Segs_da_cnt = createControlArm(Da.cp1Segs_da, Da.pos[0], Da.pos[1], Da.track, FALSE, Da.trk[0]!=NULL, -1, wDrawColorBlack);
			DrawBezCurve(Da.cp1Segs_da,Da.cp1Segs_da_cnt,NULL,0,NULL,0,drawColorBlack);
			return C_CONTINUE;
		} else {
			return AdjustBezCurve( action&0xFF, pos, Da.track, Da.color, Da.width, InfoMessage );
		}
	case C_TEXT:
			if (Da.state != PICK_POINT || (action>>8) != ' ')  //Space is same as Enter.
				return C_CONTINUE;
			/* no break */
    case C_OK:
    	if (Da.state != PICK_POINT) return C_CONTINUE;
        return AdjustBezCurve( C_OK, pos, Da.track, Da.color, Da.width, InfoMessage);

	case C_REDRAW:
		if ( Da.state != NONE ) {

			DrawBezCurve(Da.cp1Segs_da,Da.cp1Segs_da_cnt,Da.cp2Segs_da,Da.cp2Segs_da_cnt,(trkSeg_t *)Da.crvSegs_da.ptr,Da.crvSegs_da.cnt, Da.color);
		}
		return C_CONTINUE;

	case C_CANCEL:
		if (Da.state != NONE) {
			DrawBezCurve(Da.cp1Segs_da,Da.cp1Segs_da_cnt,Da.cp2Segs_da,Da.cp2Segs_da_cnt,(trkSeg_t *)Da.crvSegs_da.ptr,Da.crvSegs_da.cnt, Da.color);
			Da.cp1Segs_da_cnt = 0;
			Da.cp2Segs_da_cnt = 0;
			Da.crvSegs_da_cnt = 0;
			for (int i=0;i<2;i++) {
				Da.trk[i] = NULL;
				Da.ep[i] = -1;
			}
			if (Da.crvSegs_da.ptr) MyFree(Da.crvSegs_da.ptr);
			Da.crvSegs_da.ptr = NULL;
			Da.crvSegs_da.cnt = 0;
			Da.crvSegs_da.max = 0;
		}
		Da.state = NONE;
		return C_CONTINUE;
		
	default:

	return C_CONTINUE;
	}

}

void UpdateParms(wDrawColor color,long width) {
	DrawTempBezier(Da.track);
	Da.color = lineColor;
	Da.width = (double)lineWidth/mainD.dpi;
	if (Da.crvSegs_da.cnt) {
		ConvertToArcs(Da.pos,&Da.crvSegs_da,Da.track,Da.color,Da.width);
	}
	DrawTempBezier(Da.track);
}


#include "bitmaps/bezier.xpm"
#include "bitmaps/dbezier.xpm"

EXPORT void InitCmdBezier( wMenu_p menu )
{	

}