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 #define POST_SHIFT 8
  36
  37 struct transformation {
  38         int yaw;                /* Rotation angle */
  39         int pitch;
  40         int ddd;
  41         int m00,m01,m02;        /* 3d transformation matrix */
  42         int m10,m11,m12;
  43         int m20,m21,m22;
  44         int xscale,yscale,wscale;
  45         int xscale3d,yscale3d,wscale3d;
  46 #ifdef ENABLE_ROLL
  47         int roll;
  48         int hog;
  49 #endif
  50         navit_float im00,im01,im02;     /* inverse 3d transformation matrix */
  51         navit_float im10,im11,im12;
  52         navit_float im20,im21,im22;
  53         struct map_selection *map_sel;
  54         struct map_selection *screen_sel;
  55         struct point screen_center;
  56         int screen_dist;
  57         int offx,offy,offz;
  58         int znear,zfar;
  59         struct coord map_center;        /* Center of source rectangle */
  60         enum projection pro;
  61         navit_float scale;              /* Scale factor */
  62         int scale_shift;
  63         int order;
  64         int order_base;
  65 };
  66
  67 #ifdef ENABLE_ROLL
  68 #define HOG(t) ((t).hog)
  69 #else
  70 #define HOG(t) 0
  71 #endif
  72
  73 static void
  74 transform_set_screen_dist(struct transformation *t, int dist)
  75 {
  76         t->screen_dist=dist;
  77         t->xscale3d=dist;
  78         t->yscale3d=dist;
  79         t->wscale3d=dist << POST_SHIFT;
  80 }
  81
  82 static void
  83 transform_setup_matrix(struct transformation *t)
  84 {
  85         navit_float det;
  86         navit_float fac;
  87         navit_float yawc=navit_cos(-M_PI*t->yaw/180);
  88         navit_float yaws=navit_sin(-M_PI*t->yaw/180);
  89         navit_float pitchc=navit_cos(-M_PI*t->pitch/180);
  90         navit_float pitchs=navit_sin(-M_PI*t->pitch/180);
  91 #ifdef ENABLE_ROLL
  92         navit_float rollc=navit_cos(M_PI*t->roll/180);
  93         navit_float rolls=navit_sin(M_PI*t->roll/180);
  94 #else
  95         navit_float rollc=1;
  96         navit_float rolls=0;
  97 #endif
  98
  99         int scale=t->scale;
 100         int order_dir=-1;
 101
 102         dbg(1,"yaw=%d pitch=%d center=0x%x,0x%x\n", t->yaw, t->pitch, t->map_center.x, t->map_center.y);
 103         t->znear=1 << POST_SHIFT;
 104         t->zfar=300*t->znear;
 105         t->scale_shift=0;
 106         t->order=t->order_base;
 107         if (t->scale >= 1) {
 108                 scale=t->scale;
 109         } else {
 110                 scale=1.0/t->scale;
 111                 order_dir=1;
 112         }
 113         while (scale > 1) {
 114                 if (order_dir < 0)
 115                         t->scale_shift++;
 116                 t->order+=order_dir;
 117                 scale >>= 1;
 118         }
 119         fac=(1 << POST_SHIFT) * (1 << t->scale_shift) / t->scale;
 120         dbg(1,"scale_shift=%d order=%d scale=%f fac=%f\n", t->scale_shift, t->order,t->scale,fac);
 121
 122         t->m00=rollc*yawc*fac;
 123         t->m01=rollc*yaws*fac;
 124         t->m02=-rolls*fac;
 125         t->m10=(pitchs*rolls*yawc-pitchc*yaws)*(-fac);
 126         t->m11=(pitchs*rolls*yaws+pitchc*yawc)*(-fac);
 127         t->m12=pitchs*rollc*(-fac);
 128         t->m20=(pitchc*rolls*yawc+pitchs*yaws)*fac;
 129         t->m21=(pitchc*rolls*yaws-pitchs*yawc)*fac;
 130         t->m22=pitchc*rollc*fac;
 131
 132         t->offx=t->screen_center.x;
 133         t->offy=t->screen_center.y;
 134         if (t->pitch) {
 135                 t->ddd=1;
 136                 t->offz=t->screen_dist;
 137                 dbg(1,"near %d far %d\n",t->znear,t->zfar);
 138                 t->xscale=t->xscale3d;
 139                 t->yscale=t->yscale3d;
 140                 t->wscale=t->wscale3d;
 141         } else {
 142                 t->ddd=0;
 143                 t->offz=0;
 144                 t->xscale=1;
 145                 t->yscale=1;
 146                 t->wscale=1;
 147         }
 148         det=(navit_float)t->m00*(navit_float)t->m11*(navit_float)t->m22+
 149             (navit_float)t->m01*(navit_float)t->m12*(navit_float)t->m20+
 150             (navit_float)t->m02*(navit_float)t->m10*(navit_float)t->m21-
 151             (navit_float)t->m02*(navit_float)t->m11*(navit_float)t->m20-
 152             (navit_float)t->m01*(navit_float)t->m10*(navit_float)t->m22-
 153             (navit_float)t->m00*(navit_float)t->m12*(navit_float)t->m21;
 154
 155         t->im00=(t->m11*t->m22-t->m12*t->m21)/det;
 156         t->im01=(t->m02*t->m21-t->m01*t->m22)/det;
 157         t->im02=(t->m01*t->m12-t->m02*t->m11)/det;
 158         t->im10=(t->m12*t->m20-t->m10*t->m22)/det;
 159         t->im11=(t->m00*t->m22-t->m02*t->m20)/det;
 160         t->im12=(t->m02*t->m10-t->m00*t->m12)/det;
 161         t->im20=(t->m10*t->m21-t->m11*t->m20)/det;
 162         t->im21=(t->m01*t->m20-t->m00*t->m21)/det;
 163         t->im22=(t->m00*t->m11-t->m01*t->m10)/det;
 164 }
 165
 166 struct transformation *
 167 transform_new(void)
 168 {
 169         struct transformation *this_;
 170
 171         this_=g_new0(struct transformation, 1);
 172         transform_set_screen_dist(this_, 100);
 173         this_->order_base=14;
 174 #if 0
 175         this_->pitch=20;
 176 #endif
 177 #if 0
 178         this_->roll=30;
 179         this_->hog=1000;
 180 #endif
 181         transform_setup_matrix(this_);
 182         return this_;
 183 }
 184
 185 int
 186 transform_get_hog(struct transformation *this_)
 187 {
 188         return HOG(*this_);
 189 }
 190
 191 void
 192 transform_set_hog(struct transformation *this_, int hog)
 193 {
 194 #ifdef ENABLE_ROLL
 195         this_->hog=hog;
 196 #else
 197         dbg(0,"not supported\n");
 198 #endif
 199
 200 }
 201
 202 int
 203 transform_get_attr(struct transformation *this_, enum attr_type type, struct attr *attr, struct attr_iter *iter)
 204 {
 205         switch (type) {
 206 #ifdef ENABLE_ROLL
 207         case attr_hog:
 208                 attr->u.num=this_->hog;
 209                 break;
 210 #endif
 211         default:
 212                 return 0;
 213         }
 214         attr->type=type;
 215         return 1;
 216 }
 217
 218 int
 219 transform_set_attr(struct transformation *this_, struct attr *attr)
 220 {
 221         switch (attr->type) {
 222 #ifdef ENABLE_ROLL
 223         case attr_hog:
 224                 this_->hog=attr->u.num;
 225                 return 1;
 226 #endif
 227         default:
 228                 return 0;
 229         }
 230 }
 231
 232 int
 233 transformation_get_order_base(struct transformation *this_)
 234 {
 235         return this_->order_base;
 236 }
 237
 238 void
 239 transform_set_order_base(struct transformation *this_, int order_base)
 240 {
 241         this_->order_base=order_base;
 242 }
 243
 244
 245 struct transformation *
 246 transform_dup(struct transformation *t)
 247 {
 248         struct transformation *ret=g_new0(struct transformation, 1);
 249         *ret=*t;
 250         return ret;
 251 }
 252
 253 static const navit_float gar2geo_units = 360.0/(1<<24);
 254 static const navit_float geo2gar_units = 1/(360.0/(1<<24));
 255
 256 void
 257 transform_to_geo(enum projection pro, struct coord *c, struct coord_geo *g)
 258 {
 259         int x,y,northern,zone;
 260         switch (pro) {
 261         case projection_mg:
 262                 g->lng=c->x/6371000.0/M_PI*180;
 263                 g->lat=navit_atan(exp(c->y/6371000.0))/M_PI*360-90;
 264                 break;
 265         case projection_garmin:
 266                 g->lng=c->x*gar2geo_units;
 267                 g->lat=c->y*gar2geo_units;
 268                 break;
 269         case projection_utm:
 270                 x=c->x;
 271                 y=c->y;
 272                 northern=y >= 0;
 273                 if (!northern) {
 274                         y+=10000000;
 275                 }
 276                 zone=(x/1000000);
 277                 x=x%1000000;
 278                 transform_utm_to_geo(x, y, zone, northern, g);
 279                 break;
 280         default:
 281                 break;
 282         }
 283 }
 284
 285 void
 286 transform_from_geo(enum projection pro, struct coord_geo *g, struct coord *c)
 287 {
 288         switch (pro) {
 289         case projection_mg:
 290                 c->x=g->lng*6371000.0*M_PI/180;
 291                 c->y=log(navit_tan(M_PI_4+g->lat*M_PI/360))*6371000.0;
 292                 break;
 293         case projection_garmin:
 294                 c->x=g->lng*geo2gar_units;
 295                 c->y=g->lat*geo2gar_units;
 296                 break;
 297         default:
 298                 break;
 299         }
 300 }
 301
 302 void
 303 transform_from_to(struct coord *cfrom, enum projection from, struct coord *cto, enum projection to)
 304 {
 305         struct coord_geo g;
 306         transform_to_geo(from, cfrom, &g);
 307         transform_from_geo(to, &g, cto);
 308 }
 309
 310 void
 311 transform_geo_to_cart(struct coord_geo *geo, navit_float a, navit_float b, struct coord_geo_cart *cart)
 312 {
 313         navit_float n,ee=1-b*b/(a*a);
 314         n = a/sqrtf(1-ee*navit_sin(geo->lat)*navit_sin(geo->lat));
 315         cart->x=n*navit_cos(geo->lat)*navit_cos(geo->lng);
 316         cart->y=n*navit_cos(geo->lat)*navit_sin(geo->lng);
 317         cart->z=n*(1-ee)*navit_sin(geo->lat);
 318 }
 319
 320 void
 321 transform_cart_to_geo(struct coord_geo_cart *cart, navit_float a, navit_float b, struct coord_geo *geo)
 322 {
 323         navit_float lat,lati,n,ee=1-b*b/(a*a), lng = navit_tan(cart->y/cart->x);
 324
 325         lat = navit_tan(cart->z / navit_sqrt((cart->x * cart->x) + (cart->y * cart->y)));
 326         do
 327         {
 328                 lati = lat;
 329
 330                 n = a / navit_sqrt(1-ee*navit_sin(lat)*navit_sin(lat));
 331                 lat = navit_atan((cart->z + ee * n * navit_sin(lat)) / navit_sqrt(cart->x * cart->x + cart->y * cart->y));
 332         }
 333         while (fabs(lat - lati) >= 0.000000000000001);
 334
 335         geo->lng=lng/M_PI*180;
 336         geo->lat=lat/M_PI*180;
 337 }
 338
 339
 340 void
 341 transform_utm_to_geo(const double UTMEasting, const double UTMNorthing, int ZoneNumber, int NorthernHemisphere, struct coord_geo *geo)
 342 {
 343 //converts UTM coords to lat/long.  Equations from USGS Bulletin 1532
 344 //East Longitudes are positive, West longitudes are negative.
 345 //North latitudes are positive, South latitudes are negative
 346 //Lat and Long are in decimal degrees.
 347         //Written by Chuck Gantz- chuck.gantz@globalstar.com
 348
 349         double Lat, Long;
 350         double k0 = 0.99960000000000004;
 351         double a = 6378137;
 352         double eccSquared = 0.0066943799999999998;
 353         double eccPrimeSquared;
 354         double e1 = (1-sqrt(1-eccSquared))/(1+sqrt(1-eccSquared));
 355         double N1, T1, C1, R1, D, M;
 356         double LongOrigin;
 357         double mu, phi1, phi1Rad;
 358         double x, y;
 359         double rad2deg = 180/M_PI;
 360
 361         x = UTMEasting - 500000.0; //remove 500,000 meter offset for longitude
 362         y = UTMNorthing;
 363
 364         if (!NorthernHemisphere) {
 365                 y -= 10000000.0;//remove 10,000,000 meter offset used for southern hemisphere
 366         }
 367
 368         LongOrigin = (ZoneNumber - 1)*6 - 180 + 3;  //+3 puts origin in middle of zone
 369
 370         eccPrimeSquared = (eccSquared)/(1-eccSquared);
 371
 372         M = y / k0;
 373         mu = M/(a*(1-eccSquared/4-3*eccSquared*eccSquared/64-5*eccSquared*eccSquared*eccSquared/256));
 374         phi1Rad = mu    + (3*e1/2-27*e1*e1*e1/32)*sin(2*mu)
 375                                 + (21*e1*e1/16-55*e1*e1*e1*e1/32)*sin(4*mu)
 376                                 +(151*e1*e1*e1/96)*sin(6*mu);
 377         phi1 = phi1Rad*rad2deg;
 378
 379         N1 = a/sqrt(1-eccSquared*sin(phi1Rad)*sin(phi1Rad));
 380         T1 = tan(phi1Rad)*tan(phi1Rad);
 381         C1 = eccPrimeSquared*cos(phi1Rad)*cos(phi1Rad);
 382         R1 = a*(1-eccSquared)/pow(1-eccSquared*sin(phi1Rad)*sin(phi1Rad), 1.5);
 383         D = x/(N1*k0);
 384
 385         Lat = phi1Rad - (N1*tan(phi1Rad)/R1)*(D*D/2-(5+3*T1+10*C1-4*C1*C1-9*eccPrimeSquared)*D*D*D*D/24
 386                                         +(61+90*T1+298*C1+45*T1*T1-252*eccPrimeSquared-3*C1*C1)*D*D*D*D*D*D/720);
 387         Lat = Lat * rad2deg;
 388
 389         Long = (D-(1+2*T1+C1)*D*D*D/6+(5-2*C1+28*T1-3*C1*C1+8*eccPrimeSquared+24*T1*T1)
 390                                         *D*D*D*D*D/120)/cos(phi1Rad);
 391         Long = LongOrigin + Long * rad2deg;
 392
 393         geo->lat=Lat;
 394         geo->lng=Long;
 395 }
 396
 397 void
 398 transform_datum(struct coord_geo *from, enum map_datum from_datum, struct coord_geo *to, enum map_datum to_datum)
 399 {
 400 }
 401
 402 int
 403 transform(struct transformation *t, enum projection pro, struct coord *c, struct point *p, int count, int mindist, int width, int *width_return)
 404 {
 405         struct coord c1;
 406         int xcn, ycn;
 407         struct coord_geo g;
 408         int xc, yc, zc=0, xco=0, yco=0, zco=0;
 409         int xm,ym,zct;
 410         int zlimit=t->znear;
 411         int visible, visibleo=-1;
 412         int i,j = 0,k=0;
 413         dbg(1,"count=%d\n", count);
 414         for (i=0; i < count; i++) {
 415                 if (pro == t->pro) {
 416                         xc=c[i].x;
 417                         yc=c[i].y;
 418                 } else {
 419                         transform_to_geo(pro, &c[i], &g);
 420                         transform_from_geo(t->pro, &g, &c1);
 421                         xc=c1.x;
 422                         yc=c1.y;
 423                 }
 424                 if (i != 0 && i != count-1 && mindist) {
 425                         if (xc > c[k].x-mindist && xc < c[k].x+mindist && yc > c[k].y-mindist && yc < c[k].y+mindist &&
 426                                 (c[i+1].x != c[0].x || c[i+1].y != c[0].y))
 427                                 continue;
 428                         k=i;
 429                 }
 430                 xm=xc;
 431                 ym=yc;
 432 //              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);
 433 //              ret=coord_rect_contains(&t->r, c);
 434                 xc-=t->map_center.x;
 435                 yc-=t->map_center.y;
 436                 xc >>= t->scale_shift;
 437                 yc >>= t->scale_shift;
 438                 xm=xc;
 439                 ym=yc;
 440
 441                 xcn=xc*t->m00+yc*t->m01+HOG(*t)*t->m02;
 442                 ycn=xc*t->m10+yc*t->m11+HOG(*t)*t->m12;
 443
 444                 if (t->ddd) {
 445                         zc=(xc*t->m20+yc*t->m21+HOG(*t)*t->m22);
 446                         zct=zc;
 447                         zc+=t->offz << POST_SHIFT;
 448                         dbg(1,"zc=%d\n", zc);
 449                         dbg(1,"zc(%d)=xc(%d)*m20(%d)+yc(%d)*m21(%d)\n", (xc*t->m20+yc*t->m21), xc, t->m20, yc, t->m21);
 450                         /* visibility */
 451                         visible=(zc < zlimit ? 0:1);
 452                         dbg(1,"visible=%d old %d\n", visible, visibleo);
 453                         if (visible != visibleo && visibleo != -1) {
 454                                 dbg(1,"clipping (%d,%d,%d)-(%d,%d,%d) (%d,%d,%d)\n", xcn, ycn, zc, xco, yco, zco, xco-xcn, yco-ycn, zco-zc);
 455                                 if (zco != zc) {
 456                                         xcn=xcn+(long long)(xco-xcn)*(zlimit-zc)/(zco-zc);
 457                                         ycn=ycn+(long long)(yco-ycn)*(zlimit-zc)/(zco-zc);
 458                                 }
 459                                 dbg(1,"result (%d,%d,%d) * %d / %d\n", xcn,ycn,zc,zlimit-zc,zco-zc);
 460                                 zc=zlimit;
 461                                 xco=xcn;
 462                                 yco=ycn;
 463                                 zco=zc;
 464                                 if (visible)
 465                                         i--;
 466                                 visibleo=visible;
 467                         } else {
 468                                 xco=xcn;
 469                                 yco=ycn;
 470                                 zco=zc;
 471                                 visibleo=visible;
 472                                 if (! visible)
 473                                         continue;
 474                         }
 475                         dbg(1,"zc=%d\n", zc);
 476                         dbg(1,"xcn %d ycn %d\n", xcn, ycn);
 477                         dbg(1,"%d,%d %d\n",xc,yc,zc);
 478 #if 0
 479                         dbg(0,"%d/%d=%d %d/%d=%d\n",xcn,xc,xcn/xc,ycn,yc,ycn/yc);
 480 #endif
 481 #if 1
 482                         xc=(long long)xcn*t->xscale/zc;
 483                         yc=(long long)ycn*t->yscale/zc;
 484 #else
 485                         xc=xcn/(1000+zc);
 486                         yc=ycn/(1000+zc);
 487 #endif
 488 #if 0
 489                         dbg(1,"%d,%d %d\n",xc,yc,zc);
 490 #endif
 491                 } else {
 492                         xc=xcn;
 493                         yc=ycn;
 494                         xc>>=POST_SHIFT;
 495                         yc>>=POST_SHIFT;
 496                 }
 497                 xc+=t->offx;
 498                 yc+=t->offy;
 499                 p[j].x=xc;
 500                 p[j].y=yc;
 501                 if (width_return) {
 502                         if (t->ddd)
 503                                 width_return[j]=width*t->wscale/zc;
 504                         else
 505                                 width_return[j]=width;
 506                 }
 507                 j++;
 508         }
 509         return j;
 510 }
 511
 512 static void
 513 transform_apply_inverse_matrix(struct transformation *t, struct coord_geo_cart *in, struct coord_geo_cart *out)
 514 {
 515         out->x=in->x*t->im00+in->y*t->im01+in->z*t->im02;
 516         out->y=in->x*t->im10+in->y*t->im11+in->z*t->im12;
 517         out->z=in->x*t->im20+in->y*t->im21+in->z*t->im22;
 518 }
 519
 520 static int
 521 transform_zplane_intersection(struct coord_geo_cart *p1, struct coord_geo_cart *p2, navit_float z, struct coord_geo_cart *result)
 522 {
 523         navit_float dividend=z-p1->z;
 524         navit_float divisor=p2->z-p1->z;
 525         navit_float q;
 526         if (!divisor) {
 527                 if (dividend)
 528                         return 0;       /* no intersection */
 529                 else
 530                         return 3;       /* identical planes */
 531         }
 532         q=dividend/divisor;
 533         result->x=p1->x+q*(p2->x-p1->x);
 534         result->y=p1->y+q*(p2->y-p1->y);
 535         result->z=z;
 536         if (q >= 0 && q <= 1)
 537                 return 1;       /* intersection within [p1,p2] */
 538         return 2; /* intersection without [p1,p2] */
 539 }
 540
 541 static void
 542 transform_screen_to_3d(struct transformation *t, struct point *p, navit_float z, struct coord_geo_cart *cg)
 543 {
 544         double xc,yc;
 545         double offz=t->offz << POST_SHIFT;
 546         xc=p->x - t->offx;
 547         yc=p->y - t->offy;
 548         cg->x=xc*z/t->xscale;
 549         cg->y=yc*z/t->yscale;
 550         cg->z=z-offz;
 551 }
 552
 553 static int
 554 transform_reverse_near_far(struct transformation *t, struct point *p, struct coord *c, int near, int far)
 555 {
 556         double xc,yc;
 557         dbg(1,"%d,%d\n",p->x,p->y);
 558         if (t->ddd) {
 559                 struct coord_geo_cart nearc,farc,nears,fars,intersection;
 560                 transform_screen_to_3d(t, p, near, &nearc);
 561                 transform_screen_to_3d(t, p, far, &farc);
 562                 transform_apply_inverse_matrix(t, &nearc, &nears);
 563                 transform_apply_inverse_matrix(t, &farc, &fars);
 564                 if (transform_zplane_intersection(&nears, &fars, HOG(*t), &intersection) != 1)
 565                         return 0;
 566                 xc=intersection.x;
 567                 yc=intersection.y;
 568         } else {
 569                 double xcn,ycn;
 570                 xcn=p->x - t->offx;
 571                 ycn=p->y - t->offy;
 572                 xc=(xcn*t->im00+ycn*t->im01)*(1 << POST_SHIFT);
 573                 yc=(xcn*t->im10+ycn*t->im11)*(1 << POST_SHIFT);
 574         }
 575         c->x=xc*(1 << t->scale_shift)+t->map_center.x;
 576         c->y=yc*(1 << t->scale_shift)+t->map_center.y;
 577         return 1;
 578 }
 579
 580 int
 581 transform_reverse(struct transformation *t, struct point *p, struct coord *c)
 582 {
 583         return transform_reverse_near_far(t, p, c, t->znear, t->zfar);
 584 }
 585
 586 enum projection
 587 transform_get_projection(struct transformation *this_)
 588 {
 589         return this_->pro;
 590 }
 591
 592 void
 593 transform_set_projection(struct transformation *this_, enum projection pro)
 594 {
 595         this_->pro=pro;
 596 }
 597
 598 static int
 599 min4(int v1,int v2, int v3, int v4)
 600 {
 601         int res=v1;
 602         if (v2 < res)
 603                 res=v2;
 604         if (v3 < res)
 605                 res=v3;
 606         if (v4 < res)
 607                 res=v4;
 608         return res;
 609 }
 610
 611 static int
 612 max4(int v1,int v2, int v3, int v4)
 613 {
 614         int res=v1;
 615         if (v2 > res)
 616                 res=v2;
 617         if (v3 > res)
 618                 res=v3;
 619         if (v4 > res)
 620                 res=v4;
 621         return res;
 622 }
 623
 624 struct map_selection *
 625 transform_get_selection(struct transformation *this_, enum projection pro, int order)
 626 {
 627
 628         struct map_selection *ret,*curri,*curro;
 629         struct coord_geo g;
 630
 631         ret=map_selection_dup(this_->map_sel);
 632         curri=this_->map_sel;
 633         curro=ret;
 634         while (curri) {
 635                 if (this_->pro != pro) {
 636                         transform_to_geo(this_->pro, &curri->u.c_rect.lu, &g);
 637                         transform_from_geo(pro, &g, &curro->u.c_rect.lu);
 638                         dbg(1,"%f,%f", g.lat, g.lng);
 639                         transform_to_geo(this_->pro, &curri->u.c_rect.rl, &g);
 640                         transform_from_geo(pro, &g, &curro->u.c_rect.rl);
 641                         dbg(1,": - %f,%f\n", g.lat, g.lng);
 642                 }
 643                 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);
 644                 curro->order+=order;
 645                 curro->u.c_rect.lu.x-=500;
 646                 curro->u.c_rect.lu.y+=500;
 647                 curro->u.c_rect.rl.x+=500;
 648                 curro->u.c_rect.rl.y-=500;
 649                 curro->range=item_range_all;
 650                 curri=curri->next;
 651                 curro=curro->next;
 652         }
 653         return ret;
 654 }
 655
 656 struct coord *
 657 transform_center(struct transformation *this_)
 658 {
 659         return &this_->map_center;
 660 }
 661
 662 struct coord *
 663 transform_get_center(struct transformation *this_)
 664 {
 665         return &this_->map_center;
 666 }
 667
 668 void
 669 transform_set_center(struct transformation *this_, struct coord *c)
 670 {
 671         this_->map_center=*c;
 672 }
 673
 674
 675 void
 676 transform_set_yaw(struct transformation *t,int yaw)
 677 {
 678         t->yaw=yaw;
 679         transform_setup_matrix(t);
 680 }
 681
 682 int
 683 transform_get_yaw(struct transformation *this_)
 684 {
 685         return this_->yaw;
 686 }
 687
 688 void
 689 transform_set_pitch(struct transformation *this_,int pitch)
 690 {
 691         this_->pitch=pitch;
 692         transform_setup_matrix(this_);
 693 }
 694 int
 695 transform_get_pitch(struct transformation *this_)
 696 {
 697         return this_->pitch;
 698 }
 699
 700 void
 701 transform_set_roll(struct transformation *this_,int roll)
 702 {
 703 #ifdef ENABLE_ROLL
 704         this_->roll=roll;
 705         transform_setup_matrix(this_);
 706 #else
 707         dbg(0,"not supported\n");
 708 #endif
 709 }
 710
 711 int
 712 transform_get_roll(struct transformation *this_)
 713 {
 714 #ifdef ENABLE_ROLL
 715         return this_->roll;
 716 #else
 717         return 0;
 718 #endif
 719 }
 720
 721 void
 722 transform_set_distance(struct transformation *this_,int distance)
 723 {
 724         transform_set_screen_dist(this_, distance);
 725         transform_setup_matrix(this_);
 726 }
 727
 728 int
 729 transform_get_distance(struct transformation *this_)
 730 {
 731         return this_->screen_dist;
 732 }
 733
 734 void
 735 transform_set_scales(struct transformation *this_, int xscale, int yscale, int wscale)
 736 {
 737         this_->xscale3d=xscale;
 738         this_->yscale3d=yscale;
 739         this_->wscale3d=wscale;
 740 }
 741
 742 void
 743 transform_set_screen_selection(struct transformation *t, struct map_selection *sel)
 744 {
 745         map_selection_destroy(t->screen_sel);
 746         t->screen_sel=map_selection_dup(sel);
 747         if (sel) {
 748                 t->screen_center.x=(sel->u.p_rect.rl.x-sel->u.p_rect.lu.x)/2;
 749                 t->screen_center.y=(sel->u.p_rect.rl.y-sel->u.p_rect.lu.y)/2;
 750                 transform_setup_matrix(t);
 751         }
 752 }
 753
 754 void
 755 transform_set_screen_center(struct transformation *t, struct point *p)
 756 {
 757         t->screen_center=*p;
 758 }
 759
 760 #if 0
 761 void
 762 transform_set_size(struct transformation *t, int width, int height)
 763 {
 764         t->width=width;
 765         t->height=height;
 766 }
 767 #endif
 768
 769 void
 770 transform_get_size(struct transformation *t, int *width, int *height)
 771 {
 772         struct point_rect *r;
 773         if (t->screen_sel) {
 774                 r=&t->screen_sel->u.p_rect;
 775                 *width=r->rl.x-r->lu.x;
 776                 *height=r->rl.y-r->lu.y;
 777         }
 778 }
 779
 780 void
 781 transform_setup(struct transformation *t, struct pcoord *c, int scale, int yaw)
 782 {
 783         t->pro=c->pro;
 784         t->map_center.x=c->x;
 785         t->map_center.y=c->y;
 786         t->scale=scale/16.0;
 787         transform_set_yaw(t, yaw);
 788 }
 789
 790 #if 0
 791
 792 void
 793 transform_setup_source_rect_limit(struct transformation *t, struct coord *center, int limit)
 794 {
 795         t->center=*center;
 796         t->scale=1;
 797         t->angle=0;
 798         t->r.lu.x=center->x-limit;
 799         t->r.rl.x=center->x+limit;
 800         t->r.rl.y=center->y-limit;
 801         t->r.lu.y=center->y+limit;
 802 }
 803 #endif
 804
 805 void
 806 transform_setup_source_rect(struct transformation *t)
 807 {
 808         int i;
 809         struct coord screen[4];
 810         struct point screen_pnt[4];
 811         struct point_rect *pr;
 812         struct map_selection *ms,*msm,*next,**msm_last;
 813         ms=t->map_sel;
 814         while (ms) {
 815                 next=ms->next;
 816                 g_free(ms);
 817                 ms=next;
 818         }
 819         t->map_sel=NULL;
 820         msm_last=&t->map_sel;
 821         ms=t->screen_sel;
 822         while (ms) {
 823                 msm=g_new0(struct map_selection, 1);
 824                 *msm=*ms;
 825                 pr=&ms->u.p_rect;
 826                 screen_pnt[0].x=pr->lu.x;       /* left upper */
 827                 screen_pnt[0].y=pr->lu.y;
 828                 screen_pnt[1].x=pr->rl.x;       /* right upper */
 829                 screen_pnt[1].y=pr->lu.y;
 830                 screen_pnt[2].x=pr->rl.x;       /* right lower */
 831                 screen_pnt[2].y=pr->rl.y;
 832                 screen_pnt[3].x=pr->lu.x;       /* left lower */
 833                 screen_pnt[3].y=pr->rl.y;
 834                 if (t->ddd) {
 835                         struct coord_geo_cart tmp,cg[8];
 836                         struct coord c;
 837                         int valid=0;
 838                         char edgenodes[]={
 839                                 0,1,
 840                                 1,2,
 841                                 2,3,
 842                                 3,0,
 843                                 4,5,
 844                                 5,6,
 845                                 6,7,
 846                                 7,4,
 847                                 0,4,
 848                                 1,5,
 849                                 2,6,
 850                                 3,7};
 851                         for (i = 0 ; i < 8 ; i++) {
 852                                 transform_screen_to_3d(t, &screen_pnt[i%4], (i >= 4 ? t->zfar:t->znear), &tmp);
 853                                 transform_apply_inverse_matrix(t, &tmp, &cg[i]);
 854                         }
 855                         msm->u.c_rect.lu.x=0;
 856                         msm->u.c_rect.lu.y=0;
 857                         msm->u.c_rect.rl.x=0;
 858                         msm->u.c_rect.rl.y=0;
 859                         for (i = 0 ; i < 12 ; i++) {
 860                                 if (transform_zplane_intersection(&cg[edgenodes[i*2]], &cg[edgenodes[i*2+1]], HOG(*t), &tmp) == 1) {
 861                                         c.x=tmp.x*(1 << t->scale_shift)+t->map_center.x;
 862                                         c.y=tmp.y*(1 << t->scale_shift)+t->map_center.y;
 863                                         dbg(1,"intersection with edge %d at 0x%x,0x%x\n",i,c.x,c.y);
 864                                         if (valid)
 865                                                 coord_rect_extend(&msm->u.c_rect, &c);
 866                                         else {
 867                                                 msm->u.c_rect.lu=c;
 868                                                 msm->u.c_rect.rl=c;
 869                                                 valid=1;
 870                                         }
 871                                         dbg(1,"rect 0x%x,0x%x - 0x%x,0x%x\n",msm->u.c_rect.lu.x,msm->u.c_rect.lu.y,msm->u.c_rect.rl.x,msm->u.c_rect.rl.y);
 872                                 }
 873                         }
 874                 } else {
 875                         for (i = 0 ; i < 4 ; i++) {
 876                                 transform_reverse(t, &screen_pnt[i], &screen[i]);
 877                                 dbg(1,"map(%d) %d,%d=0x%x,0x%x\n", i,screen_pnt[i].x, screen_pnt[i].y, screen[i].x, screen[i].y);
 878                         }
 879                         msm->u.c_rect.lu.x=min4(screen[0].x,screen[1].x,screen[2].x,screen[3].x);
 880                         msm->u.c_rect.rl.x=max4(screen[0].x,screen[1].x,screen[2].x,screen[3].x);
 881                         msm->u.c_rect.rl.y=min4(screen[0].y,screen[1].y,screen[2].y,screen[3].y);
 882                         msm->u.c_rect.lu.y=max4(screen[0].y,screen[1].y,screen[2].y,screen[3].y);
 883                 }
 884                 dbg(1,"%dx%d\n", msm->u.c_rect.rl.x-msm->u.c_rect.lu.x,
 885                                  msm->u.c_rect.lu.y-msm->u.c_rect.rl.y);
 886                 *msm_last=msm;
 887                 msm_last=&msm->next;
 888                 ms=ms->next;
 889         }
 890 }
 891
 892 long
 893 transform_get_scale(struct transformation *t)
 894 {
 895         return (int)(t->scale*16);
 896 }
 897
 898 void
 899 transform_set_scale(struct transformation *t, long scale)
 900 {
 901         t->scale=scale/16.0;
 902         transform_setup_matrix(t);
 903 }
 904
 905
 906 int
 907 transform_get_order(struct transformation *t)
 908 {
 909         dbg(1,"order %d\n", t->order);
 910         return t->order;
 911 }
 912
 913
 914
 915 #define TWOPI (M_PI*2)
 916 #define GC2RAD(c) ((c) * TWOPI/(1<<24))
 917 #define minf(a,b) ((a) < (b) ? (a) : (b))
 918
 919 static double
 920 transform_distance_garmin(struct coord *c1, struct coord *c2)
 921 {
 922 #ifdef USE_HALVESINE
 923         static const int earth_radius = 6371*1000; //m change accordingly
 924 // static const int earth_radius  = 3960; //miles
 925
 926 //Point 1 cords
 927         navit_float lat1  = GC2RAD(c1->y);
 928         navit_float long1 = GC2RAD(c1->x);
 929
 930 //Point 2 cords
 931         navit_float lat2  = GC2RAD(c2->y);
 932         navit_float long2 = GC2RAD(c2->x);
 933
 934 //Haversine Formula
 935         navit_float dlong = long2-long1;
 936         navit_float dlat  = lat2-lat1;
 937
 938         navit_float sinlat  = navit_sin(dlat/2);
 939         navit_float sinlong = navit_sin(dlong/2);
 940
 941         navit_float a=(sinlat*sinlat)+navit_cos(lat1)*navit_cos(lat2)*(sinlong*sinlong);
 942         navit_float c=2*navit_asin(minf(1,navit_sqrt(a)));
 943 #ifdef AVOID_FLOAT
 944         return round(earth_radius*c);
 945 #else
 946         return earth_radius*c;
 947 #endif
 948 #else
 949 #define GMETER 2.3887499999999999
 950         navit_float dx,dy;
 951         dx=c1->x-c2->x;
 952         dy=c1->y-c2->y;
 953         return navit_sqrt(dx*dx+dy*dy)*GMETER;
 954 #undef GMETER
 955 #endif
 956 }
 957
 958 double
 959 transform_scale(int y)
 960 {
 961         struct coord c;
 962         struct coord_geo g;
 963         c.x=0;
 964         c.y=y;
 965         transform_to_geo(projection_mg, &c, &g);
 966         return 1/navit_cos(g.lat/180*M_PI);
 967 }
 968
 969 #ifdef AVOID_FLOAT
 970 static int
 971 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};
 972
 973 static int tab_int_step = 0x20000;
 974 static int tab_int_scale[]={10000,10002,10008,10019,10033,10052,10076,10103,10135,10171,10212,10257,10306,10359,10417,10479,10546,10617,10693,10773,10858,10947,11041,11140,11243,11352,11465,11582,11705,11833,11965,12103,12246,12394,12547,12706,12870,13039,13214,13395,13581,13773,13971,14174,14384,14600,14822,15050,15285,15526,15774,16028,16289,16557,16832,17114,17404,17700,18005,18316,18636,18964,19299,19643,19995,20355,20724,21102,21489,21885,22290,22705,23129,23563,24007,24461,24926,25401,25886,26383,26891};
 975
 976 int transform_int_scale(int y)
 977 {
 978         int a=tab_int_step,i,size = sizeof(tab_int_scale)/sizeof(int);
 979         if (y < 0)
 980                 y=-y;
 981         i=y/tab_int_step;
 982         if (i < size-1)
 983                 return tab_int_scale[i]+((tab_int_scale[i+1]-tab_int_scale[i])*(y-i*tab_int_step))/tab_int_step;
 984         return tab_int_scale[size-1];
 985 }
 986 #endif
 987
 988 double
 989 transform_distance(enum projection pro, struct coord *c1, struct coord *c2)
 990 {
 991         if (pro == projection_mg) {
 992 #ifndef AVOID_FLOAT
 993         double dx,dy,scale=transform_scale((c1->y+c2->y)/2);
 994         dx=c1->x-c2->x;
 995         dy=c1->y-c2->y;
 996         return sqrt(dx*dx+dy*dy)/scale;
 997 #else
 998         int dx,dy,f,scale=transform_int_scale((c1->y+c2->y)/2);
 999         dx=c1->x-c2->x;
1000         dy=c1->y-c2->y;
1001         if (dx < 0)
1002                 dx=-dx;
1003         if (dy < 0)
1004                 dy=-dy;
1005         while (dx > 20000 || dy > 20000) {
1006                 dx/=10;
1007                 dy/=10;
1008                 scale/=10;
1009         }
1010         if (! dy)
1011                 return dx*10000/scale;
1012         if (! dx)
1013                 return dy*10000/scale;
1014         if (dx > dy) {
1015                 f=dx*8/dy-8;
1016                 if (f >= 32)
1017                         return dx*10000/scale;
1018                 return dx*tab_sqrt[f]/scale;
1019         } else {
1020                 f=dy*8/dx-8;
1021                 if (f >= 32)
1022                         return dy*10000/scale;
1023                 return dy*tab_sqrt[f]/scale;
1024         }
1025 #endif
1026         } else if (pro == projection_garmin) {
1027                 return transform_distance_garmin(c1, c2);
1028         } else {
1029                 dbg(0,"Unknown projection: %d\n", pro);
1030                 return 0;
1031         }
1032 }
1033
1034 void
1035 transform_project(enum projection pro, struct coord *c, int distance, int angle, struct coord *res)
1036 {
1037         double scale;
1038         switch (pro) {
1039         case projection_mg:
1040                 scale=transform_scale(c->y);
1041                 res->x=c->x+distance*sin(angle*M_PI/180)*scale;
1042                 res->y=c->y+distance*cos(angle*M_PI/180)*scale;
1043                 break;
1044         default:
1045                 dbg(0,"Unsupported projection: %d\n", pro);
1046                 return;
1047         }
1048
1049 }
1050
1051
1052 double
1053 transform_polyline_length(enum projection pro, struct coord *c, int count)
1054 {
1055         double ret=0;
1056         int i;
1057
1058         for (i = 0 ; i < count-1 ; i++)
1059                 ret+=transform_distance(pro, &c[i], &c[i+1]);
1060         return ret;
1061 }
1062
1063 int
1064 transform_distance_sq(struct coord *c1, struct coord *c2)
1065 {
1066         int dx=c1->x-c2->x;
1067         int dy=c1->y-c2->y;
1068
1069         if (dx > 32767 || dy > 32767 || dx < -32767 || dy < -32767)
1070                 return INT_MAX;
1071         else
1072                 return dx*dx+dy*dy;
1073 }
1074
1075 int
1076 transform_distance_sq_pc(struct pcoord *c1, struct pcoord *c2)
1077 {
1078         struct coord p1,p2;
1079         p1.x = c1->x; p1.y = c1->y;
1080         p2.x = c2->x; p2.y = c2->y;
1081         return transform_distance_sq(&p1, &p2);
1082 }
1083
1084 int
1085 transform_distance_line_sq(struct coord *l0, struct coord *l1, struct coord *ref, struct coord *lpnt)
1086 {
1087         int vx,vy,wx,wy;
1088         int c1,c2;
1089         int climit=1000000;
1090         struct coord l;
1091
1092         vx=l1->x-l0->x;
1093         vy=l1->y-l0->y;
1094         wx=ref->x-l0->x;
1095         wy=ref->y-l0->y;
1096
1097         c1=vx*wx+vy*wy;
1098         if ( c1 <= 0 ) {
1099                 if (lpnt)
1100                         *lpnt=*l0;
1101                 return transform_distance_sq(l0, ref);
1102         }
1103         c2=vx*vx+vy*vy;
1104         if ( c2 <= c1 ) {
1105                 if (lpnt)
1106                         *lpnt=*l1;
1107                 return transform_distance_sq(l1, ref);
1108         }
1109         while (c1 > climit || c2 > climit) {
1110                 c1/=256;
1111                 c2/=256;
1112         }
1113         l.x=l0->x+vx*c1/c2;
1114         l.y=l0->y+vy*c1/c2;
1115         if (lpnt)
1116                 *lpnt=l;
1117         return transform_distance_sq(&l, ref);
1118 }
1119
1120 int
1121 transform_distance_polyline_sq(struct coord *c, int count, struct coord *ref, struct coord *lpnt, int *pos)
1122 {
1123         int i,dist,distn;
1124         struct coord lp;
1125         if (count < 2)
1126                 return INT_MAX;
1127         if (pos)
1128                 *pos=0;
1129         dist=transform_distance_line_sq(&c[0], &c[1], ref, lpnt);
1130         for (i=2 ; i < count ; i++) {
1131                 distn=transform_distance_line_sq(&c[i-1], &c[i], ref, &lp);
1132                 if (distn < dist) {
1133                         dist=distn;
1134                         if (lpnt)
1135                                 *lpnt=lp;
1136                         if (pos)
1137                                 *pos=i-1;
1138                 }
1139         }
1140         return dist;
1141 }
1142
1143 int
1144 transform_douglas_peucker(struct coord *in, int count, int dist_sq, struct coord *out)
1145 {
1146         int ret=0;
1147         int i,d,dmax=0, idx=0;
1148         for (i = 1; i < count-1 ; i++) {
1149                 d=transform_distance_line_sq(&in[0], &in[count-1], &in[i], NULL);
1150                 if (d > dmax) {
1151                         idx=i;
1152                         dmax=d;
1153                 }
1154         }
1155         if (dmax > dist_sq) {
1156                 ret=transform_douglas_peucker(in, idx+1, dist_sq, out)-1;
1157                 ret+=transform_douglas_peucker(in+idx, count-idx, dist_sq, out+ret);
1158         } else {
1159                 if (count > 0)
1160                         out[ret++]=in[0];
1161                 if (count > 1)
1162                         out[ret++]=in[count-1];
1163         }
1164         return ret;
1165 }
1166
1167
1168 void
1169 transform_print_deg(double deg)
1170 {
1171         printf("%2.0f:%2.0f:%2.4f", floor(deg), fmod(deg*60,60), fmod(deg*3600,60));
1172 }
1173
1174 #ifdef AVOID_FLOAT
1175 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};
1176
1177 static int
1178 atan2_int_lookup(int val)
1179 {
1180         int len=sizeof(tab_atan)/sizeof(int);
1181         int i=len/2;
1182         int p=i-1;
1183         for (;;) {
1184                 i>>=1;
1185                 if (val < tab_atan[p])
1186                         p-=i;
1187                 else
1188                         if (val < tab_atan[p+1])
1189                                 return p+(p>>1);
1190                         else
1191                                 p+=i;
1192         }
1193 }
1194
1195 static int
1196 atan2_int(int dx, int dy)
1197 {
1198         int f,mul=1,add=0,ret;
1199         if (! dx) {
1200                 return dy < 0 ? 180 : 0;
1201         }
1202         if (! dy) {
1203                 return dx < 0 ? -90 : 90;
1204         }
1205         if (dx < 0) {
1206                 dx=-dx;
1207                 mul=-1;
1208         }
1209         if (dy < 0) {
1210                 dy=-dy;
1211                 add=180*mul;
1212                 mul*=-1;
1213         }
1214         while (dx > 20000 || dy > 20000) {
1215                 dx/=10;
1216                 dy/=10;
1217         }
1218         if (dx > dy) {
1219                 ret=90-atan2_int_lookup(dy*10000/dx);
1220         } else {
1221                 ret=atan2_int_lookup(dx*10000/dy);
1222         }
1223         return ret*mul+add;
1224 }
1225 #endif
1226
1227 int
1228 transform_get_angle_delta(struct coord *c1, struct coord *c2, int dir)
1229 {
1230         int dx=c2->x-c1->x;
1231         int dy=c2->y-c1->y;
1232 #ifndef AVOID_FLOAT
1233         double angle;
1234         angle=atan2(dx,dy);
1235         angle*=180/M_PI;
1236 #else
1237         int angle;
1238         angle=atan2_int(dx,dy);
1239 #endif
1240         if (dir == -1)
1241                 angle=angle-180;
1242         if (angle < 0)
1243                 angle+=360;
1244         return angle;
1245 }
1246
1247 int
1248 transform_within_border(struct transformation *this_, struct point *p, int border)
1249 {
1250         struct map_selection *ms=this_->screen_sel;
1251         while (ms) {
1252                 struct point_rect *r=&ms->u.p_rect;
1253                 if (p->x >= r->lu.x+border && p->x <= r->rl.x-border &&
1254                     p->y >= r->lu.y+border && p->y <= r->rl.y-border)
1255                         return 1;
1256                 ms=ms->next;
1257         }
1258         return 0;
1259 }
1260
1261 int
1262 transform_within_dist_point(struct coord *ref, struct coord *c, int dist)
1263 {
1264         if (c->x-dist > ref->x)
1265                 return 0;
1266         if (c->x+dist < ref->x)
1267                 return 0;
1268         if (c->y-dist > ref->y)
1269                 return 0;
1270         if (c->y+dist < ref->y)
1271                 return 0;
1272         if ((c->x-ref->x)*(c->x-ref->x) + (c->y-ref->y)*(c->y-ref->y) <= dist*dist)
1273                 return 1;
1274         return 0;
1275 }
1276
1277 int
1278 transform_within_dist_line(struct coord *ref, struct coord *c0, struct coord *c1, int dist)
1279 {
1280         int vx,vy,wx,wy;
1281         int n1,n2;
1282         struct coord lc;
1283
1284         if (c0->x < c1->x) {
1285                 if (c0->x-dist > ref->x)
1286                         return 0;
1287                 if (c1->x+dist < ref->x)
1288                         return 0;
1289         } else {
1290                 if (c1->x-dist > ref->x)
1291                         return 0;
1292                 if (c0->x+dist < ref->x)
1293                         return 0;
1294         }
1295         if (c0->y < c1->y) {
1296                 if (c0->y-dist > ref->y)
1297                         return 0;
1298                 if (c1->y+dist < ref->y)
1299                         return 0;
1300         } else {
1301                 if (c1->y-dist > ref->y)
1302                         return 0;
1303                 if (c0->y+dist < ref->y)
1304                         return 0;
1305         }
1306         vx=c1->x-c0->x;
1307         vy=c1->y-c0->y;
1308         wx=ref->x-c0->x;
1309         wy=ref->y-c0->y;
1310
1311         n1=vx*wx+vy*wy;
1312         if ( n1 <= 0 )
1313                 return transform_within_dist_point(ref, c0, dist);
1314         n2=vx*vx+vy*vy;
1315         if ( n2 <= n1 )
1316                 return transform_within_dist_point(ref, c1, dist);
1317
1318         lc.x=c0->x+vx*n1/n2;
1319         lc.y=c0->y+vy*n1/n2;
1320         return transform_within_dist_point(ref, &lc, dist);
1321 }
1322
1323 int
1324 transform_within_dist_polyline(struct coord *ref, struct coord *c, int count, int close, int dist)
1325 {
1326         int i;
1327         for (i = 0 ; i < count-1 ; i++) {
1328                 if (transform_within_dist_line(ref,c+i,c+i+1,dist)) {
1329                         return 1;
1330                 }
1331         }
1332         if (close)
1333                 return (transform_within_dist_line(ref,c,c+count-1,dist));
1334         return 0;
1335 }
1336
1337 int
1338 transform_within_dist_polygon(struct coord *ref, struct coord *c, int count, int dist)
1339 {
1340         int i, j, ci = 0;
1341         for (i = 0, j = count-1; i < count; j = i++) {
1342                 if ((((c[i].y <= ref->y) && ( ref->y < c[j].y )) ||
1343                 ((c[j].y <= ref->y) && ( ref->y < c[i].y))) &&
1344                 (ref->x < (c[j].x - c[i].x) * (ref->y - c[i].y) / (c[j].y - c[i].y) + c[i].x))
1345                         ci = !ci;
1346         }
1347         if (! ci) {
1348                 if (dist)
1349                         return transform_within_dist_polyline(ref, c, count, dist, 1);
1350                 else
1351                         return 0;
1352         }
1353         return 1;
1354 }
1355
1356 int
1357 transform_within_dist_item(struct coord *ref, enum item_type type, struct coord *c, int count, int dist)
1358 {
1359         if (type < type_line)
1360                 return transform_within_dist_point(ref, c, dist);
1361         if (type < type_area)
1362                 return transform_within_dist_polyline(ref, c, count, 0, dist);
1363         return transform_within_dist_polygon(ref, c, count, dist);
1364 }
1365
1366 void
1367 transform_destroy(struct transformation *t)
1368 {
1369         g_free(t);
1370 }
1371
1372
1373 /*
1374 Note: there are many mathematically equivalent ways to express these formulas. As usual, not all of them are computationally equivalent.
1375
1376 L = latitude in radians (positive north)
1377 Lo = longitude in radians (positive east)
1378 E = easting (meters)
1379 N = northing (meters)
1380
1381 For the sphere
1382
1383 E = r Lo
1384 N = r ln [ tan (pi/4 + L/2) ]
1385
1386 where
1387
1388 r = radius of the sphere (meters)
1389 ln() is the natural logarithm
1390
1391 For the ellipsoid
1392
1393 E = a Lo
1394 N = a * ln ( tan (pi/4 + L/2) * ( (1 - e * sin (L)) / (1 + e * sin (L))) ** (e/2)  )
1395
1396
1397                                                e
1398                                                -
1399                    pi     L     1 - e sin(L)   2
1400     =  a ln( tan( ---- + ---) (--------------)   )
1401                    4      2     1 + e sin(L)
1402
1403
1404 where
1405
1406 a = the length of the semi-major axis of the ellipsoid (meters)
1407 e = the first eccentricity of the ellipsoid
1408
1409
1410 */
1411
1412