git.maemo.org Git - navit-package/blob - navit/transform.c

   1 /**
   2  * Navit, a modular navigation system.
   3  * Copyright (C) 2005-2008 Navit Team
   4  *
   5  * This program is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU General Public License
   7  * version 2 as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the
  16  * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA  02110-1301, USA.
  18  */
  19
  20 #include <assert.h>
  21 #include <stdio.h>
  22 #include <math.h>
  23 #include <limits.h>
  24 #include <glib.h>
  25 #include <string.h>
  26 #include "config.h"
  27 #include "coord.h"
  28 #include "debug.h"
  29 #include "item.h"
  30 #include "map.h"
  31 #include "transform.h"
  32 #include "projection.h"
  33 #include "point.h"
  34
  35 struct transformation {
  36         int angle;              /* Rotation angle */
  37         double cos_val,sin_val; /* cos and sin of rotation angle */
  38         struct map_selection *map_sel;
  39         struct map_selection *screen_sel;
  40         struct point screen_center;
  41         struct coord map_center;        /* Center of source rectangle */
  42         enum projection pro;
  43         long scale;             /* Scale factor */
  44 };
  45
  46 struct transformation *
  47 transform_new(void)
  48 {
  49         struct transformation *this_;
  50
  51         this_=g_new0(struct transformation, 1);
  52
  53         return this_;
  54 }
  55
  56 static const double gar2geo_units = 360.0/(1<<24);
  57 static const double geo2gar_units = 1/(360.0/(1<<24));
  58
  59 void
  60 transform_to_geo(enum projection pro, struct coord *c, struct coord_geo *g)
  61 {
  62         switch (pro) {
  63         case projection_mg:
  64                 g->lng=c->x/6371000.0/M_PI*180;
  65                 g->lat=atan(exp(c->y/6371000.0))/M_PI*360-90;
  66                 break;
  67         case projection_garmin:
  68                 g->lng=c->x*gar2geo_units;
  69                 g->lat=c->y*gar2geo_units;
  70                 break;
  71         default:
  72                 break;
  73         }
  74 }
  75
  76 void
  77 transform_from_geo(enum projection pro, struct coord_geo *g, struct coord *c)
  78 {
  79         switch (pro) {
  80         case projection_mg:
  81                 c->x=g->lng*6371000.0*M_PI/180;
  82                 c->y=log(tan(M_PI_4+g->lat*M_PI/360))*6371000.0;
  83                 break;
  84         case projection_garmin:
  85                 c->x=g->lng*geo2gar_units;
  86                 c->y=g->lat*geo2gar_units;
  87                 break;
  88         default:
  89                 break;
  90         }
  91 }
  92
  93 void
  94 transform_from_to(struct coord *cfrom, enum projection from, struct coord *cto, enum projection to)
  95 {
  96         struct coord_geo g;
  97         transform_to_geo(from, cfrom, &g);
  98         transform_from_geo(to, &g, cto);
  99 }
 100
 101 void
 102 transform_geo_to_cart(struct coord_geo *geo, double a, double b, struct coord_geo_cart *cart)
 103 {
 104         double n,ee=1-b*b/(a*a);
 105         n = a/sqrt(1-ee*sin(geo->lat)*sin(geo->lat));
 106         cart->x=n*cos(geo->lat)*cos(geo->lng);
 107         cart->y=n*cos(geo->lat)*sin(geo->lng);
 108         cart->z=n*(1-ee)*sin(geo->lat);
 109 }
 110
 111 void
 112 transform_cart_to_geo(struct coord_geo_cart *cart, double a, double b, struct coord_geo *geo)
 113 {
 114         double lat,lati,n,ee=1-b*b/(a*a), lng = atan(cart->y/cart->x);
 115
 116         lat = atan(cart->z / sqrt((cart->x * cart->x) + (cart->y * cart->y)));
 117         do
 118         {
 119                 lati = lat;
 120
 121                 n = a / sqrt(1-ee*sin(lat)*sin(lat));
 122                 lat = atan((cart->z + ee * n * sin(lat)) / sqrt(cart->x * cart->x + cart->y * cart->y));
 123         }
 124         while (fabs(lat - lati) >= 0.000000000000001);
 125
 126         geo->lng=lng/M_PI*180;
 127         geo->lat=lat/M_PI*180;
 128 }
 129
 130
 131 void
 132 transform_datum(struct coord_geo *from, enum map_datum from_datum, struct coord_geo *to, enum map_datum to_datum)
 133 {
 134 }
 135
 136 int
 137 transform(struct transformation *t, enum projection pro, struct coord *c, struct point *p, int count, int unique)
 138 {
 139         struct coord c1;
 140         int xcn, ycn;
 141         struct coord_geo g;
 142 #ifdef AVOID_FLOAT
 143         int xc,yc;
 144 #else
 145         double xc,yc;
 146 #endif
 147         int i,j = 0;
 148         for (i=0; i < count; i++) {
 149                 if (pro == t->pro) {
 150                         xc=c[i].x;
 151                         yc=c[i].y;
 152                 } else {
 153                         transform_to_geo(pro, &c[i], &g);
 154                         transform_from_geo(t->pro, &g, &c1);
 155                         xc=c1.x;
 156                         yc=c1.y;
 157                 }
 158 //              dbg(2,"0x%x, 0x%x - 0x%x,0x%x contains 0x%x,0x%x\n", t->r.lu.x, t->r.lu.y, t->r.rl.x, t->r.rl.y, c->x, c->y);
 159 //              ret=coord_rect_contains(&t->r, c);
 160                 xc-=t->map_center.x;
 161                 yc-=t->map_center.y;
 162                 yc=-yc;
 163                 if (t->angle) {
 164                         xcn=xc*t->cos_val+yc*t->sin_val;
 165                         ycn=-xc*t->sin_val+yc*t->cos_val;
 166                         xc=xcn;
 167                         yc=ycn;
 168                 }
 169                 xc=xc*16;
 170                 yc=yc*16;
 171 #ifndef AVOID_FLOAT
 172                 if (t->scale!=1) {
 173                         xc=xc/(double)(t->scale);
 174                         yc=yc/(double)(t->scale);
 175                 }
 176 #else
 177                 if (t->scale!=1) {
 178                         xc=xc/t->scale;
 179                         yc=yc/t->scale;
 180                 }
 181 #endif
 182                 xc+=t->screen_center.x;
 183                 yc+=t->screen_center.y;
 184                 if (xc < -0x8000)
 185                         xc=-0x8000;
 186                 if (xc > 0x7fff) {
 187                         xc=0x7fff;
 188                 }
 189                 if (yc < -0x8000)
 190                         yc=-0x8000;
 191                 if (yc > 0x7fff)
 192                         yc=0x7fff;
 193                 if (j == 0 || !unique || p[j-1].x != xc || p[j-1].y != yc) {
 194                         p[j].x=xc;
 195                         p[j].y=yc;
 196                         j++;
 197                 }
 198         }
 199         return j;
 200 }
 201
 202 void
 203 transform_reverse(struct transformation *t, struct point *p, struct coord *c)
 204 {
 205         int xc,yc;
 206         xc=p->x;
 207         yc=p->y;
 208         xc-=t->screen_center.x;
 209         yc-=t->screen_center.y;
 210         xc=xc*t->scale/16;
 211         yc=-yc*t->scale/16;
 212         if (t->angle) {
 213                 int xcn, ycn;
 214                 xcn=xc*t->cos_val+yc*t->sin_val;
 215                 ycn=-xc*t->sin_val+yc*t->cos_val;
 216                 xc=xcn;
 217                 yc=ycn;
 218         }
 219         c->x=t->map_center.x+xc;
 220         c->y=t->map_center.y+yc;
 221 }
 222
 223 enum projection
 224 transform_get_projection(struct transformation *this_)
 225 {
 226         return this_->pro;
 227 }
 228
 229 void
 230 transform_set_projection(struct transformation *this_, enum projection pro)
 231 {
 232         this_->pro=pro;
 233 }
 234
 235 static int
 236 min4(int v1,int v2, int v3, int v4)
 237 {
 238         int res=v1;
 239         if (v2 < res)
 240                 res=v2;
 241         if (v3 < res)
 242                 res=v3;
 243         if (v4 < res)
 244                 res=v4;
 245         return res;
 246 }
 247
 248 static int
 249 max4(int v1,int v2, int v3, int v4)
 250 {
 251         int res=v1;
 252         if (v2 > res)
 253                 res=v2;
 254         if (v3 > res)
 255                 res=v3;
 256         if (v4 > res)
 257                 res=v4;
 258         return res;
 259 }
 260
 261 struct map_selection *
 262 transform_get_selection(struct transformation *this_, enum projection pro, int order)
 263 {
 264
 265         struct map_selection *ret,*curri,*curro;
 266         struct coord_geo g;
 267
 268         ret=map_selection_dup(this_->map_sel);
 269         curri=this_->map_sel;
 270         curro=ret;
 271         while (curri) {
 272                 if (this_->pro != pro) {
 273                         transform_to_geo(this_->pro, &curri->u.c_rect.lu, &g);
 274                         transform_from_geo(pro, &g, &curro->u.c_rect.lu);
 275                         dbg(1,"%f,%f", g.lat, g.lng);
 276                         transform_to_geo(this_->pro, &curri->u.c_rect.rl, &g);
 277                         transform_from_geo(pro, &g, &curro->u.c_rect.rl);
 278                         dbg(1,": - %f,%f\n", g.lat, g.lng);
 279                 }
 280                 dbg(1,"transform rect for %d is %d,%d - %d,%d\n", pro, curro->u.c_rect.lu.x, curro->u.c_rect.lu.y, curro->u.c_rect.rl.x, curro->u.c_rect.rl.y);
 281                 curro->order+=order;
 282                 curro->range=item_range_all;
 283                 curri=curri->next;
 284                 curro=curro->next;
 285         }
 286         return ret;
 287 }
 288
 289 struct coord *
 290 transform_center(struct transformation *this_)
 291 {
 292         return &this_->map_center;
 293 }
 294
 295 void
 296 transform_set_angle(struct transformation *t,int angle)
 297 {
 298         t->angle=angle;
 299         t->cos_val=cos(M_PI*t->angle/180);
 300         t->sin_val=sin(M_PI*t->angle/180);
 301 }
 302
 303 int
 304 transform_get_angle(struct transformation *this_,int angle)
 305 {
 306         return this_->angle;
 307 }
 308
 309 void
 310 transform_set_screen_selection(struct transformation *t, struct map_selection *sel)
 311 {
 312         map_selection_destroy(t->screen_sel);
 313         t->screen_sel=map_selection_dup(sel);
 314         if (sel) {
 315                 t->screen_center.x=(sel->u.p_rect.rl.x-sel->u.p_rect.lu.x)/2;
 316                 t->screen_center.y=(sel->u.p_rect.rl.y-sel->u.p_rect.lu.y)/2;
 317         }
 318 }
 319
 320 void
 321 transform_set_screen_center(struct transformation *t, struct point *p)
 322 {
 323         t->screen_center=*p;
 324 }
 325
 326 #if 0
 327 void
 328 transform_set_size(struct transformation *t, int width, int height)
 329 {
 330         t->width=width;
 331         t->height=height;
 332 }
 333 #endif
 334
 335 void
 336 transform_get_size(struct transformation *t, int *width, int *height)
 337 {
 338         struct point_rect *r;
 339         if (t->screen_sel) {
 340                 r=&t->screen_sel->u.p_rect;
 341                 *width=r->rl.x-r->lu.x;
 342                 *height=r->rl.y-r->lu.y;
 343         }
 344 }
 345
 346 void
 347 transform_setup(struct transformation *t, struct pcoord *c, int scale, int angle)
 348 {
 349         t->pro=c->pro;
 350         t->map_center.x=c->x;
 351         t->map_center.y=c->y;
 352         t->scale=scale;
 353         transform_set_angle(t, angle);
 354 }
 355
 356 #if 0
 357
 358 void
 359 transform_setup_source_rect_limit(struct transformation *t, struct coord *center, int limit)
 360 {
 361         t->center=*center;
 362         t->scale=1;
 363         t->angle=0;
 364         t->r.lu.x=center->x-limit;
 365         t->r.rl.x=center->x+limit;
 366         t->r.rl.y=center->y-limit;
 367         t->r.lu.y=center->y+limit;
 368 }
 369 #endif
 370
 371 void
 372 transform_setup_source_rect(struct transformation *t)
 373 {
 374         int i;
 375         struct coord screen[4];
 376         struct point screen_pnt[4];
 377         struct point_rect *pr;
 378         struct map_selection *ms,*msm,*next,**msm_last;
 379         ms=t->map_sel;
 380         while (ms) {
 381                 next=ms->next;
 382                 g_free(ms);
 383                 ms=next;
 384         }
 385         t->map_sel=NULL;
 386         msm_last=&t->map_sel;
 387         ms=t->screen_sel;
 388         while (ms) {
 389                 msm=g_new0(struct map_selection, 1);
 390                 *msm=*ms;
 391                 pr=&ms->u.p_rect;
 392                 screen_pnt[0].x=pr->lu.x;
 393                 screen_pnt[0].y=pr->lu.y;
 394                 screen_pnt[1].x=pr->rl.x;
 395                 screen_pnt[1].y=pr->lu.y;
 396                 screen_pnt[2].x=pr->lu.x;
 397                 screen_pnt[2].y=pr->rl.y;
 398                 screen_pnt[3].x=pr->rl.x;
 399                 screen_pnt[3].y=pr->rl.y;
 400                 for (i = 0 ; i < 4 ; i++) {
 401                         transform_reverse(t, &screen_pnt[i], &screen[i]);
 402                 }
 403                 msm->u.c_rect.lu.x=min4(screen[0].x,screen[1].x,screen[2].x,screen[3].x);
 404                 msm->u.c_rect.rl.x=max4(screen[0].x,screen[1].x,screen[2].x,screen[3].x);
 405                 msm->u.c_rect.rl.y=min4(screen[0].y,screen[1].y,screen[2].y,screen[3].y);
 406                 msm->u.c_rect.lu.y=max4(screen[0].y,screen[1].y,screen[2].y,screen[3].y);
 407                 *msm_last=msm;
 408                 msm_last=&msm->next;
 409                 ms=ms->next;
 410         }
 411 }
 412
 413 long
 414 transform_get_scale(struct transformation *t)
 415 {
 416         return t->scale;
 417 }
 418
 419 void
 420 transform_set_scale(struct transformation *t, long scale)
 421 {
 422         t->scale=scale;
 423 }
 424
 425
 426 int
 427 transform_get_order(struct transformation *t)
 428 {
 429         int scale=t->scale;
 430         int order=0;
 431         while (scale > 1) {
 432                 order++;
 433                 scale>>=1;
 434         }
 435         order=18-order;
 436         if (order < 0)
 437                 order=0;
 438         return order;
 439 }
 440
 441
 442
 443 #define TWOPI (M_PI*2)
 444 #define GC2RAD(c) ((c) * TWOPI/(1<<24))
 445 #define minf(a,b) ((a) < (b) ? (a) : (b))
 446
 447 static double
 448 transform_distance_garmin(struct coord *c1, struct coord *c2)
 449 {
 450 #ifdef USE_HALVESINE
 451         static const int earth_radius = 6371*1000; //m change accordingly
 452 // static const int earth_radius  = 3960; //miles
 453
 454 //Point 1 cords
 455         float lat1  = GC2RAD(c1->y);
 456         float long1 = GC2RAD(c1->x);
 457
 458 //Point 2 cords
 459         float lat2  = GC2RAD(c2->y);
 460         float long2 = GC2RAD(c2->x);
 461
 462 //Haversine Formula
 463         float dlong = long2-long1;
 464         float dlat  = lat2-lat1;
 465
 466         float sinlat  = sinf(dlat/2);
 467         float sinlong = sinf(dlong/2);
 468
 469         float a=(sinlat*sinlat)+cosf(lat1)*cosf(lat2)*(sinlong*sinlong);
 470         float c=2*asinf(minf(1,sqrt(a)));
 471 #ifdef AVOID_FLOAT
 472         return round(earth_radius*c);
 473 #else
 474         return earth_radius*c;
 475 #endif
 476 #else
 477 #define GMETER 2.3887499999999999
 478         double dx,dy;
 479         dx=c1->x-c2->x;
 480         dy=c1->y-c2->y;
 481         return sqrt(dx*dx+dy*dy)*GMETER;
 482 #undef GMETER
 483 #endif
 484 }
 485
 486 double
 487 transform_scale(int y)
 488 {
 489         struct coord c;
 490         struct coord_geo g;
 491         c.x=0;
 492         c.y=y;
 493         transform_to_geo(projection_mg, &c, &g);
 494         return 1/cos(g.lat/180*M_PI);
 495 }
 496
 497 #ifdef AVOID_FLOAT
 498 static int
 499 tab_sqrt[]={14142,13379,12806,12364,12018,11741,11517,11333,11180,11051,10943,10850,10770,10701,10640,10587,10540,10499,10462,10429,10400,10373,10349,10327,10307,10289,10273,10257,10243,10231,10219,10208};
 500 #endif
 501
 502 double
 503 transform_distance(enum projection pro, struct coord *c1, struct coord *c2)
 504 {
 505         if (pro == projection_mg) {
 506 #ifndef AVOID_FLOAT
 507         double dx,dy,scale=transform_scale((c1->y+c2->y)/2);
 508         dx=c1->x-c2->x;
 509         dy=c1->y-c2->y;
 510         return sqrt(dx*dx+dy*dy)/scale;
 511 #else
 512         int dx,dy,f,scale=15539;
 513         dx=c1->x-c2->x;
 514         dy=c1->y-c2->y;
 515         if (dx < 0)
 516                 dx=-dx;
 517         if (dy < 0)
 518                 dy=-dy;
 519         while (dx > 20000 || dy > 20000) {
 520                 dx/=10;
 521                 dy/=10;
 522                 scale/=10;
 523         }
 524         if (! dy)
 525                 return dx*10000/scale;
 526         if (! dx)
 527                 return dy*10000/scale;
 528         if (dx > dy) {
 529                 f=dx*8/dy-8;
 530                 if (f >= 32)
 531                         return dx*10000/scale;
 532                 return dx*tab_sqrt[f]/scale;
 533         } else {
 534                 f=dy*8/dx-8;
 535                 if (f >= 32)
 536                         return dy*10000/scale;
 537                 return dy*tab_sqrt[f]/scale;
 538         }
 539 #endif
 540         } else if (pro == projection_garmin) {
 541                 return transform_distance_garmin(c1, c2);
 542         } else {
 543                 dbg(0,"Unknown projection: %d\n", pro);
 544                 return 0;
 545         }
 546 }
 547
 548 double
 549 transform_polyline_length(enum projection pro, struct coord *c, int count)
 550 {
 551         double ret=0;
 552         int i;
 553
 554         for (i = 0 ; i < count-1 ; i++)
 555                 ret+=transform_distance(pro, &c[i], &c[i+1]);
 556         return ret;
 557 }
 558
 559 int
 560 transform_distance_sq(struct coord *c1, struct coord *c2)
 561 {
 562         int dx=c1->x-c2->x;
 563         int dy=c1->y-c2->y;
 564
 565         if (dx > 32767 || dy > 32767 || dx < -32767 || dy < -32767)
 566                 return INT_MAX;
 567         else
 568                 return dx*dx+dy*dy;
 569 }
 570
 571 int
 572 transform_distance_sq_pc(struct pcoord *c1, struct pcoord *c2)
 573 {
 574         struct coord p1,p2;
 575         p1.x = c1->x; p1.y = c1->y;
 576         p2.x = c2->x; p2.y = c2->y;
 577         return transform_distance_sq(&p1, &p2);
 578 }
 579
 580 int
 581 transform_distance_line_sq(struct coord *l0, struct coord *l1, struct coord *ref, struct coord *lpnt)
 582 {
 583         int vx,vy,wx,wy;
 584         int c1,c2;
 585         int climit=1000000;
 586         struct coord l;
 587
 588         vx=l1->x-l0->x;
 589         vy=l1->y-l0->y;
 590         wx=ref->x-l0->x;
 591         wy=ref->y-l0->y;
 592
 593         c1=vx*wx+vy*wy;
 594         if ( c1 <= 0 ) {
 595                 if (lpnt)
 596                         *lpnt=*l0;
 597                 return transform_distance_sq(l0, ref);
 598         }
 599         c2=vx*vx+vy*vy;
 600         if ( c2 <= c1 ) {
 601                 if (lpnt)
 602                         *lpnt=*l1;
 603                 return transform_distance_sq(l1, ref);
 604         }
 605         while (c1 > climit || c2 > climit) {
 606                 c1/=256;
 607                 c2/=256;
 608         }
 609         l.x=l0->x+vx*c1/c2;
 610         l.y=l0->y+vy*c1/c2;
 611         if (lpnt)
 612                 *lpnt=l;
 613         return transform_distance_sq(&l, ref);
 614 }
 615
 616 int
 617 transform_distance_polyline_sq(struct coord *c, int count, struct coord *ref, struct coord *lpnt, int *pos)
 618 {
 619         int i,dist,distn;
 620         struct coord lp;
 621         if (count < 2)
 622                 return INT_MAX;
 623         if (pos)
 624                 *pos=0;
 625         dist=transform_distance_line_sq(&c[0], &c[1], ref, lpnt);
 626         for (i=2 ; i < count ; i++) {
 627                 distn=transform_distance_line_sq(&c[i-1], &c[i], ref, &lp);
 628                 if (distn < dist) {
 629                         dist=distn;
 630                         if (lpnt)
 631                                 *lpnt=lp;
 632                         if (pos)
 633                                 *pos=i-1;
 634                 }
 635         }
 636         return dist;
 637 }
 638
 639
 640 void
 641 transform_print_deg(double deg)
 642 {
 643         printf("%2.0f:%2.0f:%2.4f", floor(deg), fmod(deg*60,60), fmod(deg*3600,60));
 644 }
 645
 646 #ifdef AVOID_FLOAT
 647 static int tab_atan[]={0,262,524,787,1051,1317,1584,1853,2126,2401,2679,2962,3249,3541,3839,4142,4452,4770,5095,5430,5774,6128,6494,6873,7265,7673,8098,8541,9004,9490,10000,10538};
 648
 649 static int
 650 atan2_int_lookup(int val)
 651 {
 652         int len=sizeof(tab_atan)/sizeof(int);
 653         int i=len/2;
 654         int p=i-1;
 655         for (;;) {
 656                 i>>=1;
 657                 if (val < tab_atan[p])
 658                         p-=i;
 659                 else
 660                         if (val < tab_atan[p+1])
 661                                 return p+(p>>1);
 662                         else
 663                                 p+=i;
 664         }
 665 }
 666
 667 static int
 668 atan2_int(int dx, int dy)
 669 {
 670         int f,mul=1,add=0,ret;
 671         if (! dx) {
 672                 return dy < 0 ? 180 : 0;
 673         }
 674         if (! dy) {
 675                 return dx < 0 ? -90 : 90;
 676         }
 677         if (dx < 0) {
 678                 dx=-dx;
 679                 mul=-1;
 680         }
 681         if (dy < 0) {
 682                 dy=-dy;
 683                 add=180*mul;
 684                 mul*=-1;
 685         }
 686         while (dx > 20000 || dy > 20000) {
 687                 dx/=10;
 688                 dy/=10;
 689         }
 690         if (dx > dy) {
 691                 ret=90-atan2_int_lookup(dy*10000/dx);
 692         } else {
 693                 ret=atan2_int_lookup(dx*10000/dy);
 694         }
 695         return ret*mul+add;
 696 }
 697 #endif
 698
 699 int
 700 transform_get_angle_delta(struct coord *c1, struct coord *c2, int dir)
 701 {
 702         int dx=c2->x-c1->x;
 703         int dy=c2->y-c1->y;
 704 #ifndef AVOID_FLOAT
 705         double angle;
 706         angle=atan2(dx,dy);
 707         angle*=180/M_PI;
 708 #else
 709         int angle;
 710         angle=atan2_int(dx,dy);
 711 #endif
 712         if (dir == -1)
 713                 angle=angle-180;
 714         if (angle < 0)
 715                 angle+=360;
 716         return angle;
 717 }
 718
 719 int
 720 transform_within_border(struct transformation *this_, struct point *p, int border)
 721 {
 722         struct map_selection *ms=this_->screen_sel;
 723         while (ms) {
 724                 struct point_rect *r=&ms->u.p_rect;
 725                 if (p->x >= r->lu.x+border && p->x <= r->rl.x-border &&
 726                     p->y >= r->lu.y+border && p->y <= r->rl.y-border)
 727                         return 1;
 728                 ms=ms->next;
 729         }
 730         return 0;
 731 }
 732
 733 int
 734 transform_within_dist_point(struct coord *ref, struct coord *c, int dist)
 735 {
 736         if (c->x-dist > ref->x)
 737                 return 0;
 738         if (c->x+dist < ref->x)
 739                 return 0;
 740         if (c->y-dist > ref->y)
 741                 return 0;
 742         if (c->y+dist < ref->y)
 743                 return 0;
 744         if ((c->x-ref->x)*(c->x-ref->x) + (c->y-ref->y)*(c->y-ref->y) <= dist*dist)
 745                 return 1;
 746         return 0;
 747 }
 748
 749 int
 750 transform_within_dist_line(struct coord *ref, struct coord *c0, struct coord *c1, int dist)
 751 {
 752         int vx,vy,wx,wy;
 753         int n1,n2;
 754         struct coord lc;
 755
 756         if (c0->x < c1->x) {
 757                 if (c0->x-dist > ref->x)
 758                         return 0;
 759                 if (c1->x+dist < ref->x)
 760                         return 0;
 761         } else {
 762                 if (c1->x-dist > ref->x)
 763                         return 0;
 764                 if (c0->x+dist < ref->x)
 765                         return 0;
 766         }
 767         if (c0->y < c1->y) {
 768                 if (c0->y-dist > ref->y)
 769                         return 0;
 770                 if (c1->y+dist < ref->y)
 771                         return 0;
 772         } else {
 773                 if (c1->y-dist > ref->y)
 774                         return 0;
 775                 if (c0->y+dist < ref->y)
 776                         return 0;
 777         }
 778         vx=c1->x-c0->x;
 779         vy=c1->y-c0->y;
 780         wx=ref->x-c0->x;
 781         wy=ref->y-c0->y;
 782
 783         n1=vx*wx+vy*wy;
 784         if ( n1 <= 0 )
 785                 return transform_within_dist_point(ref, c0, dist);
 786         n2=vx*vx+vy*vy;
 787         if ( n2 <= n1 )
 788                 return transform_within_dist_point(ref, c1, dist);
 789
 790         lc.x=c0->x+vx*n1/n2;
 791         lc.y=c0->y+vy*n1/n2;
 792         return transform_within_dist_point(ref, &lc, dist);
 793 }
 794
 795 int
 796 transform_within_dist_polyline(struct coord *ref, struct coord *c, int count, int close, int dist)
 797 {
 798         int i;
 799         for (i = 0 ; i < count-1 ; i++) {
 800                 if (transform_within_dist_line(ref,c+i,c+i+1,dist)) {
 801                         return 1;
 802                 }
 803         }
 804         if (close)
 805                 return (transform_within_dist_line(ref,c,c+count-1,dist));
 806         return 0;
 807 }
 808
 809 int
 810 transform_within_dist_polygon(struct coord *ref, struct coord *c, int count, int dist)
 811 {
 812         int i, j, ci = 0;
 813         for (i = 0, j = count-1; i < count; j = i++) {
 814                 if ((((c[i].y <= ref->y) && ( ref->y < c[j].y )) ||
 815                 ((c[j].y <= ref->y) && ( ref->y < c[i].y))) &&
 816                 (ref->x < (c[j].x - c[i].x) * (ref->y - c[i].y) / (c[j].y - c[i].y) + c[i].x))
 817                         ci = !ci;
 818         }
 819         if (! ci) {
 820                 if (dist)
 821                         return transform_within_dist_polyline(ref, c, count, dist, 1);
 822                 else
 823                         return 0;
 824         }
 825         return 1;
 826 }
 827
 828 int
 829 transform_within_dist_item(struct coord *ref, enum item_type type, struct coord *c, int count, int dist)
 830 {
 831         if (type < type_line)
 832                 return transform_within_dist_point(ref, c, dist);
 833         if (type < type_area)
 834                 return transform_within_dist_polyline(ref, c, count, 0, dist);
 835         return transform_within_dist_polygon(ref, c, count, dist);
 836 }
 837
 838 void
 839 transform_destroy(struct transformation *t)
 840 {
 841         g_free(t);
 842 }
 843
 844
 845 /*
 846 Note: there are many mathematically equivalent ways to express these formulas. As usual, not all of them are computationally equivalent.
 847
 848 L = latitude in radians (positive north)
 849 Lo = longitude in radians (positive east)
 850 E = easting (meters)
 851 N = northing (meters)
 852
 853 For the sphere
 854
 855 E = r Lo
 856 N = r ln [ tan (pi/4 + L/2) ]
 857
 858 where
 859
 860 r = radius of the sphere (meters)
 861 ln() is the natural logarithm
 862
 863 For the ellipsoid
 864
 865 E = a Lo
 866 N = a * ln ( tan (pi/4 + L/2) * ( (1 - e * sin (L)) / (1 + e * sin (L))) ** (e/2)  )
 867
 868
 869                                                e
 870                                                -
 871                    pi     L     1 - e sin(L)   2
 872     =  a ln( tan( ---- + ---) (--------------)   )
 873                    4      2     1 + e sin(L)
 874
 875
 876 where
 877
 878 a = the length of the semi-major axis of the ellipsoid (meters)
 879 e = the first eccentricity of the ellipsoid
 880
 881
 882 */
 883
 884