vcs.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,m10,m11;    /* 2d transformation matrix */
  42         int xscale,yscale,wscale;
  43         int m20,m21;            /* additional 3d parameters */
  44 #ifdef ENABLE_ROLL
  45         int roll;
  46         int m02,m12,m22;
  47         int hog;
  48         navit_float im02,im12,im20,im21,im22;
  49 #endif
  50         navit_float im00,im01,im10,im11;        /* inverse 2d transformation matrix */
  51         struct map_selection *map_sel;
  52         struct map_selection *screen_sel;
  53         struct point screen_center;
  54         int screen_dist;
  55         int offx,offy,offz;
  56         int znear,zfar;
  57         struct coord map_center;        /* Center of source rectangle */
  58         enum projection pro;
  59         navit_float scale;              /* Scale factor */
  60         int scale_shift;
  61         int order;
  62         int order_base;
  63 };
  64
  65
  66
  67 static void
  68 transform_setup_matrix(struct transformation *t)
  69 {
  70         navit_float det;
  71         navit_float fac;
  72 #if 0 /* FIXME */
  73 #if 0
  74         t->roll=0;
  75         t->pitch=90;
  76         t->yaw=0;
  77 #endif
  78 #if 0
  79         t->scale=1;
  80 #endif
  81         t->hog=2;
  82         t->ddd=1;
  83 #endif
  84         navit_float yawc=navit_cos(-M_PI*t->yaw/180);
  85         navit_float yaws=navit_sin(-M_PI*t->yaw/180);
  86         navit_float pitchc=navit_cos(-M_PI*t->pitch/180);
  87         navit_float pitchs=navit_sin(-M_PI*t->pitch/180);
  88 #ifdef ENABLE_ROLL
  89         navit_float rollc=navit_cos(M_PI*t->roll/180);
  90         navit_float rolls=navit_sin(M_PI*t->roll/180);
  91 #endif
  92
  93         int scale=t->scale;
  94         int order_dir=-1;
  95
  96         dbg(1,"yaw=%d pitch=%d center=0x%x,0x%x\n", t->yaw, t->pitch, t->map_center.x, t->map_center.y);
  97         t->znear=1 << POST_SHIFT;
  98         t->zfar=1000*t->znear;
  99         t->scale_shift=0;
 100         t->order=t->order_base;
 101         if (t->scale >= 1) {
 102                 scale=t->scale;
 103         } else {
 104                 scale=1.0/t->scale;
 105                 order_dir=1;
 106         }
 107         while (scale > 1) {
 108                 if (order_dir < 0)
 109                         t->scale_shift++;
 110                 t->order+=order_dir;
 111                 scale >>= 1;
 112         }
 113         fac=(1 << POST_SHIFT) * (1 << t->scale_shift) / t->scale;
 114         dbg(1,"scale_shift=%d order=%d scale=%f fac=%f\n", t->scale_shift, t->order,t->scale,fac);
 115
 116 #ifdef ENABLE_ROLL
 117         t->m00=rollc*yawc*fac;
 118         t->m01=rollc*yaws*fac;
 119         t->m02=-rolls*fac;
 120         t->m10=(pitchs*rolls*yawc-pitchc*yaws)*(-fac);
 121         t->m11=(pitchs*rolls*yaws+pitchc*yawc)*(-fac);
 122         t->m12=pitchs*rollc*(-fac);
 123         t->m20=(pitchc*rolls*yawc+pitchs*yaws)*fac;
 124         t->m21=(pitchc*rolls*yaws-pitchs*yawc)*fac;
 125         t->m22=pitchc*rollc*fac;
 126 #else
 127         t->m00=yawc*fac;
 128         t->m01=yaws*fac;
 129         t->m10=(-pitchc*yaws)*(-fac);
 130         t->m11=pitchc*yawc*(-fac);
 131         t->m20=pitchs*yaws*fac;
 132         t->m21=(-pitchs*yawc)*fac;
 133 #endif
 134         t->offz=0;
 135         t->xscale=1;
 136         t->yscale=1;
 137         t->wscale=1;
 138         t->ddd=0;
 139         t->offx=t->screen_center.x;
 140         t->offy=t->screen_center.y;
 141         if (t->pitch) {
 142                 t->ddd=1;
 143                 t->offz=t->screen_dist;
 144                 t->xscale=t->offz;
 145                 t->yscale=t->offz;
 146                 t->wscale=t->offz << POST_SHIFT;
 147         }
 148 #if 0 /* FIXME */
 149         t->offz=0;
 150         t->xscale=750;
 151         t->yscale=620;
 152         t->wscale=32 << POST_SHIFT;
 153 #endif
 154 #ifdef ENABLE_ROLL
 155         det=(navit_float)t->m00*(navit_float)t->m11*(navit_float)t->m22+
 156             (navit_float)t->m01*(navit_float)t->m12*(navit_float)t->m20+
 157             (navit_float)t->m02*(navit_float)t->m10*(navit_float)t->m21-
 158             (navit_float)t->m02*(navit_float)t->m11*(navit_float)t->m20-
 159             (navit_float)t->m01*(navit_float)t->m10*(navit_float)t->m22-
 160             (navit_float)t->m00*(navit_float)t->m12*(navit_float)t->m21;
 161
 162         t->im00=(t->m11*t->m22-t->m12*t->m21)/det;
 163         t->im01=(t->m02*t->m21-t->m01*t->m22)/det;
 164         t->im02=(t->m01*t->m12-t->m02*t->m11)/det;
 165         t->im10=(t->m12*t->m20-t->m10*t->m22)/det;
 166         t->im11=(t->m00*t->m22-t->m02*t->m20)/det;
 167         t->im12=(t->m02*t->m10-t->m00*t->m12)/det;
 168         t->im20=(t->m10*t->m21-t->m11*t->m20)/det;
 169         t->im21=(t->m01*t->m20-t->m00*t->m21)/det;
 170         t->im22=(t->m00*t->m11-t->m01*t->m10)/det;
 171 #else
 172         det=((navit_float)t->m00*(navit_float)t->m11-(navit_float)t->m01*(navit_float)t->m10);
 173         t->im00=t->m11/det;
 174         t->im01=-t->m01/det;
 175         t->im10=-t->m10/det;
 176         t->im11=t->m00/det;
 177 #endif
 178 }
 179
 180 struct transformation *
 181 transform_new(void)
 182 {
 183         struct transformation *this_;
 184
 185         this_=g_new0(struct transformation, 1);
 186         this_->screen_dist=100;
 187         this_->order_base=14;
 188 #if 0
 189         this_->pitch=20;
 190 #endif
 191 #if 0
 192         this_->roll=30;
 193         this_->hog=1000;
 194 #endif
 195         transform_setup_matrix(this_);
 196         return this_;
 197 }
 198
 199 #ifdef ENABLE_ROLL
 200
 201 int
 202 transform_get_hog(struct transformation *this_)
 203 {
 204         return this_->hog;
 205 }
 206
 207 void
 208 transform_set_hog(struct transformation *this_, int hog)
 209 {
 210         this_->hog=hog;
 211 }
 212
 213 #else
 214
 215 int
 216 transform_get_hog(struct transformation *this_)
 217 {
 218         return 0;
 219 }
 220
 221 void
 222 transform_set_hog(struct transformation *this_, int hog)
 223 {
 224         dbg(0,"not supported\n");
 225 }
 226
 227 #endif
 228
 229 int
 230 transformation_get_order_base(struct transformation *this_)
 231 {
 232         return this_->order_base;
 233 }
 234
 235 void
 236 transform_set_order_base(struct transformation *this_, int order_base)
 237 {
 238         this_->order_base=order_base;
 239 }
 240
 241
 242 struct transformation *
 243 transform_dup(struct transformation *t)
 244 {
 245         struct transformation *ret=g_new0(struct transformation, 1);
 246         *ret=*t;
 247         return ret;
 248 }
 249
 250 static const navit_float gar2geo_units = 360.0/(1<<24);
 251 static const navit_float geo2gar_units = 1/(360.0/(1<<24));
 252
 253 void
 254 transform_to_geo(enum projection pro, struct coord *c, struct coord_geo *g)
 255 {
 256         int x,y,northern,zone;
 257         switch (pro) {
 258         case projection_mg:
 259                 g->lng=c->x/6371000.0/M_PI*180;
 260                 g->lat=navit_atan(exp(c->y/6371000.0))/M_PI*360-90;
 261                 break;
 262         case projection_garmin:
 263                 g->lng=c->x*gar2geo_units;
 264                 g->lat=c->y*gar2geo_units;
 265                 break;
 266         case projection_utm:
 267                 x=c->x;
 268                 y=c->y;
 269                 northern=y >= 0;
 270                 if (!northern) {
 271                         y+=10000000;
 272                 }
 273                 zone=(x/1000000);
 274                 x=x%1000000;
 275                 transform_utm_to_geo(x, y, zone, northern, g);
 276                 break;
 277         default:
 278                 break;
 279         }
 280 }
 281
 282 void
 283 transform_from_geo(enum projection pro, struct coord_geo *g, struct coord *c)
 284 {
 285         switch (pro) {
 286         case projection_mg:
 287                 c->x=g->lng*6371000.0*M_PI/180;
 288                 c->y=log(navit_tan(M_PI_4+g->lat*M_PI/360))*6371000.0;
 289                 break;
 290         case projection_garmin:
 291                 c->x=g->lng*geo2gar_units;
 292                 c->y=g->lat*geo2gar_units;
 293                 break;
 294         default:
 295                 break;
 296         }
 297 }
 298
 299 void
 300 transform_from_to(struct coord *cfrom, enum projection from, struct coord *cto, enum projection to)
 301 {
 302         struct coord_geo g;
 303         transform_to_geo(from, cfrom, &g);
 304         transform_from_geo(to, &g, cto);
 305 }
 306
 307 void
 308 transform_geo_to_cart(struct coord_geo *geo, navit_float a, navit_float b, struct coord_geo_cart *cart)
 309 {
 310         navit_float n,ee=1-b*b/(a*a);
 311         n = a/sqrtf(1-ee*navit_sin(geo->lat)*navit_sin(geo->lat));
 312         cart->x=n*navit_cos(geo->lat)*navit_cos(geo->lng);
 313         cart->y=n*navit_cos(geo->lat)*navit_sin(geo->lng);
 314         cart->z=n*(1-ee)*navit_sin(geo->lat);
 315 }
 316
 317 void
 318 transform_cart_to_geo(struct coord_geo_cart *cart, navit_float a, navit_float b, struct coord_geo *geo)
 319 {
 320         navit_float lat,lati,n,ee=1-b*b/(a*a), lng = navit_tan(cart->y/cart->x);
 321
 322         lat = navit_tan(cart->z / navit_sqrt((cart->x * cart->x) + (cart->y * cart->y)));
 323         do
 324         {
 325                 lati = lat;
 326
 327                 n = a / navit_sqrt(1-ee*navit_sin(lat)*navit_sin(lat));
 328                 lat = navit_atan((cart->z + ee * n * navit_sin(lat)) / navit_sqrt(cart->x * cart->x + cart->y * cart->y));
 329         }
 330         while (fabs(lat - lati) >= 0.000000000000001);
 331
 332         geo->lng=lng/M_PI*180;
 333         geo->lat=lat/M_PI*180;
 334 }
 335
 336
 337 void
 338 transform_utm_to_geo(const double UTMEasting, const double UTMNorthing, int ZoneNumber, int NorthernHemisphere, struct coord_geo *geo)
 339 {
 340 //converts UTM coords to lat/long.  Equations from USGS Bulletin 1532
 341 //East Longitudes are positive, West longitudes are negative.
 342 //North latitudes are positive, South latitudes are negative
 343 //Lat and Long are in decimal degrees.
 344         //Written by Chuck Gantz- chuck.gantz@globalstar.com
 345
 346         double Lat, Long;
 347         double k0 = 0.99960000000000004;
 348         double a = 6378137;
 349         double eccSquared = 0.0066943799999999998;
 350         double eccPrimeSquared;
 351         double e1 = (1-sqrt(1-eccSquared))/(1+sqrt(1-eccSquared));
 352         double N1, T1, C1, R1, D, M;
 353         double LongOrigin;
 354         double mu, phi1, phi1Rad;
 355         double x, y;
 356         double rad2deg = 180/M_PI;
 357
 358         x = UTMEasting - 500000.0; //remove 500,000 meter offset for longitude
 359         y = UTMNorthing;
 360
 361         if (!NorthernHemisphere) {
 362                 y -= 10000000.0;//remove 10,000,000 meter offset used for southern hemisphere
 363         }
 364
 365         LongOrigin = (ZoneNumber - 1)*6 - 180 + 3;  //+3 puts origin in middle of zone
 366
 367         eccPrimeSquared = (eccSquared)/(1-eccSquared);
 368
 369         M = y / k0;
 370         mu = M/(a*(1-eccSquared/4-3*eccSquared*eccSquared/64-5*eccSquared*eccSquared*eccSquared/256));
 371         phi1Rad = mu    + (3*e1/2-27*e1*e1*e1/32)*sin(2*mu)
 372                                 + (21*e1*e1/16-55*e1*e1*e1*e1/32)*sin(4*mu)
 373                                 +(151*e1*e1*e1/96)*sin(6*mu);
 374         phi1 = phi1Rad*rad2deg;
 375
 376         N1 = a/sqrt(1-eccSquared*sin(phi1Rad)*sin(phi1Rad));
 377         T1 = tan(phi1Rad)*tan(phi1Rad);
 378         C1 = eccPrimeSquared*cos(phi1Rad)*cos(phi1Rad);
 379         R1 = a*(1-eccSquared)/pow(1-eccSquared*sin(phi1Rad)*sin(phi1Rad), 1.5);
 380         D = x/(N1*k0);
 381
 382         Lat = phi1Rad - (N1*tan(phi1Rad)/R1)*(D*D/2-(5+3*T1+10*C1-4*C1*C1-9*eccPrimeSquared)*D*D*D*D/24
 383                                         +(61+90*T1+298*C1+45*T1*T1-252*eccPrimeSquared-3*C1*C1)*D*D*D*D*D*D/720);
 384         Lat = Lat * rad2deg;
 385
 386         Long = (D-(1+2*T1+C1)*D*D*D/6+(5-2*C1+28*T1-3*C1*C1+8*eccPrimeSquared+24*T1*T1)
 387                                         *D*D*D*D*D/120)/cos(phi1Rad);
 388         Long = LongOrigin + Long * rad2deg;
 389
 390         geo->lat=Lat;
 391         geo->lng=Long;
 392 }
 393
 394 void
 395 transform_datum(struct coord_geo *from, enum map_datum from_datum, struct coord_geo *to, enum map_datum to_datum)
 396 {
 397 }
 398
 399 int
 400 transform(struct transformation *t, enum projection pro, struct coord *c, struct point *p, int count, int mindist, int width, int *width_return)
 401 {
 402         struct coord c1;
 403         int xcn, ycn;
 404         struct coord_geo g;
 405         int xc, yc, zc=0, xco=0, yco=0, zco=0;
 406         int xm,ym,zct;
 407         int zlimit=t->znear;
 408         int visible, visibleo=-1;
 409         int i,j = 0,k=0;
 410         dbg(1,"count=%d\n", count);
 411         for (i=0; i < count; i++) {
 412                 if (pro == t->pro) {
 413                         xc=c[i].x;
 414                         yc=c[i].y;
 415                 } else {
 416                         transform_to_geo(pro, &c[i], &g);
 417                         transform_from_geo(t->pro, &g, &c1);
 418                         xc=c1.x;
 419                         yc=c1.y;
 420                 }
 421                 if (i != 0 && i != count-1 && mindist) {
 422                         if (xc > c[k].x-mindist && xc < c[k].x+mindist && yc > c[k].y-mindist && yc < c[k].y+mindist)
 423                                 continue;
 424                         k=i;
 425                 }
 426                 xm=xc;
 427                 ym=yc;
 428 //              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);
 429 //              ret=coord_rect_contains(&t->r, c);
 430                 xc-=t->map_center.x;
 431                 yc-=t->map_center.y;
 432                 xc >>= t->scale_shift;
 433                 yc >>= t->scale_shift;
 434                 xm=xc;
 435                 ym=yc;
 436 #ifdef ENABLE_ROLL
 437                 xcn=xc*t->m00+yc*t->m01+t->hog*t->m02;
 438                 ycn=xc*t->m10+yc*t->m11+t->hog*t->m12;
 439 #else
 440                 xcn=xc*t->m00+yc*t->m01;
 441                 ycn=xc*t->m10+yc*t->m11;
 442 #endif
 443
 444                 if (t->ddd) {
 445 #ifdef ENABLE_ROLL
 446                         zc=(xc*t->m20+yc*t->m21+t->hog*t->m22);
 447 #else
 448                         zc=(xc*t->m20+yc*t->m21);
 449 #endif
 450                         zct=zc;
 451                         zc+=t->offz << POST_SHIFT;
 452                         dbg(1,"zc=%d\n", zc);
 453                         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);
 454                         /* visibility */
 455                         visible=(zc < zlimit ? 0:1);
 456                         dbg(1,"visible=%d old %d\n", visible, visibleo);
 457                         if (visible != visibleo && visibleo != -1) {
 458                                 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);
 459                                 if (zco != zc) {
 460                                         xcn=xcn+(long long)(xco-xcn)*(zlimit-zc)/(zco-zc);
 461                                         ycn=ycn+(long long)(yco-ycn)*(zlimit-zc)/(zco-zc);
 462                                 }
 463                                 dbg(1,"result (%d,%d,%d) * %d / %d\n", xcn,ycn,zc,zlimit-zc,zco-zc);
 464                                 zc=zlimit;
 465                                 xco=xcn;
 466                                 yco=ycn;
 467                                 zco=zc;
 468                                 if (visible)
 469                                         i--;
 470                                 visibleo=visible;
 471                         } else {
 472                                 xco=xcn;
 473                                 yco=ycn;
 474                                 zco=zc;
 475                                 visibleo=visible;
 476                                 if (! visible)
 477                                         continue;
 478                         }
 479                         dbg(1,"zc=%d\n", zc);
 480                         dbg(1,"xcn %d ycn %d\n", xcn, ycn);
 481                         dbg(1,"%d,%d %d\n",xc,yc,zc);
 482 #if 0
 483                         dbg(0,"%d/%d=%d %d/%d=%d\n",xcn,xc,xcn/xc,ycn,yc,ycn/yc);
 484 #endif
 485 #if 1
 486                         xc=(long long)xcn*t->xscale/zc;
 487                         yc=(long long)ycn*t->yscale/zc;
 488 #else
 489                         xc=xcn/(1000+zc);
 490                         yc=ycn/(1000+zc);
 491 #endif
 492 #if 0
 493                         dbg(1,"%d,%d %d\n",xc,yc,zc);
 494 #endif
 495                 } else {
 496                         xc=xcn;
 497                         yc=ycn;
 498                         xc>>=POST_SHIFT;
 499                         yc>>=POST_SHIFT;
 500                 }
 501                 xc+=t->offx;
 502                 yc+=t->offy;
 503                 p[j].x=xc;
 504                 p[j].y=yc;
 505                 if (width_return) {
 506                         if (t->ddd)
 507                                 width_return[j]=width*t->wscale/zc;
 508                         else
 509                                 width_return[j]=width;
 510                 }
 511                 j++;
 512         }
 513         return j;
 514 }
 515
 516 static void
 517 transform_apply_inverse_matrix(struct transformation *t, struct coord_geo_cart *in, struct coord_geo_cart *out)
 518 {
 519         out->x=in->x*t->im00+in->y*t->im01+in->z*t->im02;
 520         out->y=in->x*t->im10+in->y*t->im11+in->z*t->im12;
 521         out->z=in->x*t->im20+in->y*t->im21+in->z*t->im22;
 522 }
 523
 524 static int
 525 transform_zplane_intersection(struct coord_geo_cart *p1, struct coord_geo_cart *p2, navit_float z, struct coord_geo_cart *result)
 526 {
 527         navit_float dividend=z-p1->z;
 528         navit_float divisor=p2->z-p1->z;
 529         navit_float q;
 530         if (!divisor) {
 531                 if (dividend)
 532                         return 0;       /* no intersection */
 533                 else
 534                         return 3;       /* identical planes */
 535         }
 536         q=dividend/divisor;
 537         result->x=p1->x+q*(p2->x-p1->x);
 538         result->y=p1->y+q*(p2->y-p1->y);
 539         result->z=z;
 540         if (q >= 0 && q <= 1)
 541                 return 1;       /* intersection within [p1,p2] */
 542         return 2; /* intersection without [p1,p2] */
 543 }
 544
 545 static void
 546 transform_screen_to_3d(struct transformation *t, struct point *p, navit_float z, struct coord_geo_cart *cg)
 547 {
 548         double xc,yc;
 549         double offz=t->offz << POST_SHIFT;
 550         xc=p->x - t->offx;
 551         yc=p->y - t->offy;
 552         z+=offz;
 553         cg->x=xc*z/t->xscale;
 554         cg->y=yc*z/t->yscale;
 555         cg->z=z-offz;
 556 }
 557
 558 static int
 559 transform_reverse_near_far(struct transformation *t, struct point *p, struct coord *c, int near, int far)
 560 {
 561         double xc,yc;
 562         dbg(1,"%d,%d\n",p->x,p->y);
 563         if (t->ddd) {
 564                 struct coord_geo_cart nearc,farc,nears,fars,intersection;
 565                 transform_screen_to_3d(t, p, near, &nearc);
 566                 transform_screen_to_3d(t, p, far, &farc);
 567                 transform_apply_inverse_matrix(t, &nearc, &nears);
 568                 transform_apply_inverse_matrix(t, &farc, &fars);
 569                 if (transform_zplane_intersection(&nears, &fars, t->hog, &intersection) != 1)
 570                         return 0;
 571                 xc=intersection.x;
 572                 yc=intersection.y;
 573         } else {
 574                 double xcn,ycn;
 575                 xcn=p->x - t->offx;
 576                 ycn=p->y - t->offy;
 577                 xc=(xcn*t->im00+ycn*t->im01)*(1 << POST_SHIFT);
 578                 yc=(xcn*t->im10+ycn*t->im11)*(1 << POST_SHIFT);
 579         }
 580         c->x=xc*(1 << t->scale_shift)+t->map_center.x;
 581         c->y=yc*(1 << t->scale_shift)+t->map_center.y;
 582         return 1;
 583 }
 584
 585 int
 586 transform_reverse(struct transformation *t, struct point *p, struct coord *c)
 587 {
 588         return transform_reverse_near_far(t, p, c, t->znear, t->zfar);
 589 }
 590
 591 enum projection
 592 transform_get_projection(struct transformation *this_)
 593 {
 594         return this_->pro;
 595 }
 596
 597 void
 598 transform_set_projection(struct transformation *this_, enum projection pro)
 599 {
 600         this_->pro=pro;
 601 }
 602
 603 static int
 604 min4(int v1,int v2, int v3, int v4)
 605 {
 606         int res=v1;
 607         if (v2 < res)
 608                 res=v2;
 609         if (v3 < res)
 610                 res=v3;
 611         if (v4 < res)
 612                 res=v4;
 613         return res;
 614 }
 615
 616 static int
 617 max4(int v1,int v2, int v3, int v4)
 618 {
 619         int res=v1;
 620         if (v2 > res)
 621                 res=v2;
 622         if (v3 > res)
 623                 res=v3;
 624         if (v4 > res)
 625                 res=v4;
 626         return res;
 627 }
 628
 629 struct map_selection *
 630 transform_get_selection(struct transformation *this_, enum projection pro, int order)
 631 {
 632
 633         struct map_selection *ret,*curri,*curro;
 634         struct coord_geo g;
 635
 636         ret=map_selection_dup(this_->map_sel);
 637         curri=this_->map_sel;
 638         curro=ret;
 639         while (curri) {
 640                 if (this_->pro != pro) {
 641                         transform_to_geo(this_->pro, &curri->u.c_rect.lu, &g);
 642                         transform_from_geo(pro, &g, &curro->u.c_rect.lu);
 643                         dbg(1,"%f,%f", g.lat, g.lng);
 644                         transform_to_geo(this_->pro, &curri->u.c_rect.rl, &g);
 645                         transform_from_geo(pro, &g, &curro->u.c_rect.rl);
 646                         dbg(1,": - %f,%f\n", g.lat, g.lng);
 647                 }
 648                 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);
 649                 curro->order+=order;
 650                 curro->u.c_rect.lu.x-=500;
 651                 curro->u.c_rect.lu.y+=500;
 652                 curro->u.c_rect.rl.x+=500;
 653                 curro->u.c_rect.rl.y-=500;
 654                 curro->range=item_range_all;
 655                 curri=curri->next;
 656                 curro=curro->next;
 657         }
 658         return ret;
 659 }
 660
 661 struct coord *
 662 transform_center(struct transformation *this_)
 663 {
 664         return &this_->map_center;
 665 }
 666
 667 struct coord *
 668 transform_get_center(struct transformation *this_)
 669 {
 670         return &this_->map_center;
 671 }
 672
 673 void
 674 transform_set_center(struct transformation *this_, struct coord *c)
 675 {
 676         this_->map_center=*c;
 677 }
 678
 679
 680 void
 681 transform_set_yaw(struct transformation *t,int yaw)
 682 {
 683         t->yaw=yaw;
 684         transform_setup_matrix(t);
 685 }
 686
 687 int
 688 transform_get_yaw(struct transformation *this_)
 689 {
 690         return this_->yaw;
 691 }
 692
 693 void
 694 transform_set_pitch(struct transformation *this_,int pitch)
 695 {
 696         this_->pitch=pitch;
 697         transform_setup_matrix(this_);
 698 }
 699 int
 700 transform_get_pitch(struct transformation *this_)
 701 {
 702         return this_->pitch;
 703 }
 704
 705 #ifdef ENABLE_ROLL
 706 void
 707 transform_set_roll(struct transformation *this_,int roll)
 708 {
 709         this_->roll=roll;
 710         transform_setup_matrix(this_);
 711 }
 712
 713 int
 714 transform_get_roll(struct transformation *this_)
 715 {
 716         return this_->roll;
 717 }
 718
 719 #else
 720
 721 void
 722 transform_set_roll(struct transformation *this_,int roll)
 723 {
 724         dbg(0,"not supported\n");
 725 }
 726
 727 int
 728 transform_get_roll(struct transformation *this_)
 729 {
 730         return 0;
 731 }
 732
 733 #endif
 734
 735 void
 736 transform_set_distance(struct transformation *this_,int distance)
 737 {
 738         this_->screen_dist=distance;
 739         transform_setup_matrix(this_);
 740 }
 741
 742 int
 743 transform_get_distance(struct transformation *this_)
 744 {
 745         return this_->screen_dist;
 746 }
 747
 748 void
 749 transform_set_screen_selection(struct transformation *t, struct map_selection *sel)
 750 {
 751         map_selection_destroy(t->screen_sel);
 752         t->screen_sel=map_selection_dup(sel);
 753         if (sel) {
 754                 t->screen_center.x=(sel->u.p_rect.rl.x-sel->u.p_rect.lu.x)/2;
 755                 t->screen_center.y=(sel->u.p_rect.rl.y-sel->u.p_rect.lu.y)/2;
 756                 transform_setup_matrix(t);
 757         }
 758 }
 759
 760 void
 761 transform_set_screen_center(struct transformation *t, struct point *p)
 762 {
 763         t->screen_center=*p;
 764 }
 765
 766 #if 0
 767 void
 768 transform_set_size(struct transformation *t, int width, int height)
 769 {
 770         t->width=width;
 771         t->height=height;
 772 }
 773 #endif
 774
 775 void
 776 transform_get_size(struct transformation *t, int *width, int *height)
 777 {
 778         struct point_rect *r;
 779         if (t->screen_sel) {
 780                 r=&t->screen_sel->u.p_rect;
 781                 *width=r->rl.x-r->lu.x;
 782                 *height=r->rl.y-r->lu.y;
 783         }
 784 }
 785
 786 void
 787 transform_setup(struct transformation *t, struct pcoord *c, int scale, int yaw)
 788 {
 789         t->pro=c->pro;
 790         t->map_center.x=c->x;
 791         t->map_center.y=c->y;
 792         t->scale=scale/16.0;
 793         transform_set_yaw(t, yaw);
 794 }
 795
 796 #if 0
 797
 798 void
 799 transform_setup_source_rect_limit(struct transformation *t, struct coord *center, int limit)
 800 {
 801         t->center=*center;
 802         t->scale=1;
 803         t->angle=0;
 804         t->r.lu.x=center->x-limit;
 805         t->r.rl.x=center->x+limit;
 806         t->r.rl.y=center->y-limit;
 807         t->r.lu.y=center->y+limit;
 808 }
 809 #endif
 810
 811 void
 812 transform_setup_source_rect(struct transformation *t)
 813 {
 814         int i;
 815         struct coord screen[4];
 816         struct point screen_pnt[4];
 817         struct point_rect *pr;
 818         struct map_selection *ms,*msm,*next,**msm_last;
 819         ms=t->map_sel;
 820         while (ms) {
 821                 next=ms->next;
 822                 g_free(ms);
 823                 ms=next;
 824         }
 825         t->map_sel=NULL;
 826         msm_last=&t->map_sel;
 827         ms=t->screen_sel;
 828         while (ms) {
 829                 int valid=0;
 830                 msm=g_new0(struct map_selection, 1);
 831                 *msm=*ms;
 832                 pr=&ms->u.p_rect;
 833                 screen_pnt[0].x=pr->lu.x;       /* left upper */
 834                 screen_pnt[0].y=pr->lu.y;
 835                 screen_pnt[1].x=pr->rl.x;       /* right upper */
 836                 screen_pnt[1].y=pr->lu.y;
 837                 screen_pnt[2].x=pr->rl.x;       /* right lower */
 838                 screen_pnt[2].y=pr->rl.y;
 839                 screen_pnt[3].x=pr->lu.x;       /* left lower */
 840                 screen_pnt[3].y=pr->rl.y;
 841                 if (t->ddd) {
 842                         struct coord_geo_cart tmp,cg[8];
 843                         struct coord c;
 844                         int valid=0;
 845                         int hog=t->hog;
 846                         char edgenodes[]={
 847                                 0,1,
 848                                 1,2,
 849                                 2,3,
 850                                 3,0,
 851                                 4,5,
 852                                 5,6,
 853                                 6,7,
 854                                 7,4,
 855                                 0,4,
 856                                 1,5,
 857                                 2,6,
 858                                 3,7};
 859                         for (i = 0 ; i < 8 ; i++) {
 860                                 transform_screen_to_3d(t, &screen_pnt[i%4], (i >= 4 ? t->zfar:t->znear), &tmp);
 861                                 transform_apply_inverse_matrix(t, &tmp, &cg[i]);
 862                         }
 863                         msm->u.c_rect.lu.x=0;
 864                         msm->u.c_rect.lu.y=0;
 865                         msm->u.c_rect.rl.x=0;
 866                         msm->u.c_rect.rl.y=0;
 867                         for (i = 0 ; i < 12 ; i++) {
 868                                 if (transform_zplane_intersection(&cg[edgenodes[i*2]], &cg[edgenodes[i*2+1]], hog, &tmp) == 1) {
 869                                         c.x=tmp.x*(1 << t->scale_shift)+t->map_center.x;
 870                                         c.y=tmp.y*(1 << t->scale_shift)+t->map_center.y;
 871                                         dbg(0,"intersection with edge %d at 0x%x,0x%x\n",i,c.x,c.y);
 872                                         if (valid)
 873                                                 coord_rect_extend(&msm->u.c_rect, &c);
 874                                         else {
 875                                                 msm->u.c_rect.lu=c;
 876                                                 msm->u.c_rect.rl=c;
 877                                                 valid=1;
 878                                         }
 879                                         dbg(0,"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);
 880                                 }
 881                         }
 882                 } else {
 883                         for (i = 0 ; i < 4 ; i++) {
 884                                 transform_reverse(t, &screen_pnt[i], &screen[i]);
 885                                 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);
 886                         }
 887                         msm->u.c_rect.lu.x=min4(screen[0].x,screen[1].x,screen[2].x,screen[3].x);
 888                         msm->u.c_rect.rl.x=max4(screen[0].x,screen[1].x,screen[2].x,screen[3].x);
 889                         msm->u.c_rect.rl.y=min4(screen[0].y,screen[1].y,screen[2].y,screen[3].y);
 890                         msm->u.c_rect.lu.y=max4(screen[0].y,screen[1].y,screen[2].y,screen[3].y);
 891                 }
 892                 dbg(1,"%dx%d\n", msm->u.c_rect.rl.x-msm->u.c_rect.lu.x,
 893                                  msm->u.c_rect.lu.y-msm->u.c_rect.rl.y);
 894                 *msm_last=msm;
 895                 msm_last=&msm->next;
 896                 ms=ms->next;
 897         }
 898 }
 899
 900 long
 901 transform_get_scale(struct transformation *t)
 902 {
 903         return (int)(t->scale*16);
 904 }
 905
 906 void
 907 transform_set_scale(struct transformation *t, long scale)
 908 {
 909         t->scale=scale/16.0;
 910         transform_setup_matrix(t);
 911 }
 912
 913
 914 int
 915 transform_get_order(struct transformation *t)
 916 {
 917         dbg(1,"order %d\n", t->order);
 918         return t->order;
 919 }
 920
 921
 922
 923 #define TWOPI (M_PI*2)
 924 #define GC2RAD(c) ((c) * TWOPI/(1<<24))
 925 #define minf(a,b) ((a) < (b) ? (a) : (b))
 926
 927 static double
 928 transform_distance_garmin(struct coord *c1, struct coord *c2)
 929 {
 930 #ifdef USE_HALVESINE
 931         static const int earth_radius = 6371*1000; //m change accordingly
 932 // static const int earth_radius  = 3960; //miles
 933
 934 //Point 1 cords
 935         navit_float lat1  = GC2RAD(c1->y);
 936         navit_float long1 = GC2RAD(c1->x);
 937
 938 //Point 2 cords
 939         navit_float lat2  = GC2RAD(c2->y);
 940         navit_float long2 = GC2RAD(c2->x);
 941
 942 //Haversine Formula
 943         navit_float dlong = long2-long1;
 944         navit_float dlat  = lat2-lat1;
 945
 946         navit_float sinlat  = navit_sin(dlat/2);
 947         navit_float sinlong = navit_sin(dlong/2);
 948
 949         navit_float a=(sinlat*sinlat)+navit_cos(lat1)*navit_cos(lat2)*(sinlong*sinlong);
 950         navit_float c=2*navit_asin(minf(1,navit_sqrt(a)));
 951 #ifdef AVOID_FLOAT
 952         return round(earth_radius*c);
 953 #else
 954         return earth_radius*c;
 955 #endif
 956 #else
 957 #define GMETER 2.3887499999999999
 958         navit_float dx,dy;
 959         dx=c1->x-c2->x;
 960         dy=c1->y-c2->y;
 961         return navit_sqrt(dx*dx+dy*dy)*GMETER;
 962 #undef GMETER
 963 #endif
 964 }
 965
 966 double
 967 transform_scale(int y)
 968 {
 969         struct coord c;
 970         struct coord_geo g;
 971         c.x=0;
 972         c.y=y;
 973         transform_to_geo(projection_mg, &c, &g);
 974         return 1/navit_cos(g.lat/180*M_PI);
 975 }
 976
 977 #ifdef AVOID_FLOAT
 978 static int
 979 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};
 980
 981 static int tab_int_step = 0x20000;
 982 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};
 983
 984 int transform_int_scale(int y)
 985 {
 986         int a=tab_int_step,i,size = sizeof(tab_int_scale)/sizeof(int);
 987         if (y < 0)
 988                 y=-y;
 989         i=y/tab_int_step;
 990         if (i < size-1)
 991                 return tab_int_scale[i]+((tab_int_scale[i+1]-tab_int_scale[i])*(y-i*tab_int_step))/tab_int_step;
 992         return tab_int_scale[size-1];
 993 }
 994 #endif
 995
 996 double
 997 transform_distance(enum projection pro, struct coord *c1, struct coord *c2)
 998 {
 999         if (pro == projection_mg) {
1000 #ifndef AVOID_FLOAT
1001         double dx,dy,scale=transform_scale((c1->y+c2->y)/2);
1002         dx=c1->x-c2->x;
1003         dy=c1->y-c2->y;
1004         return sqrt(dx*dx+dy*dy)/scale;
1005 #else
1006         int dx,dy,f,scale=transform_int_scale((c1->y+c2->y)/2);
1007         dx=c1->x-c2->x;
1008         dy=c1->y-c2->y;
1009         if (dx < 0)
1010                 dx=-dx;
1011         if (dy < 0)
1012                 dy=-dy;
1013         while (dx > 20000 || dy > 20000) {
1014                 dx/=10;
1015                 dy/=10;
1016                 scale/=10;
1017         }
1018         if (! dy)
1019                 return dx*10000/scale;
1020         if (! dx)
1021                 return dy*10000/scale;
1022         if (dx > dy) {
1023                 f=dx*8/dy-8;
1024                 if (f >= 32)
1025                         return dx*10000/scale;
1026                 return dx*tab_sqrt[f]/scale;
1027         } else {
1028                 f=dy*8/dx-8;
1029                 if (f >= 32)
1030                         return dy*10000/scale;
1031                 return dy*tab_sqrt[f]/scale;
1032         }
1033 #endif
1034         } else if (pro == projection_garmin) {
1035                 return transform_distance_garmin(c1, c2);
1036         } else {
1037                 dbg(0,"Unknown projection: %d\n", pro);
1038                 return 0;
1039         }
1040 }
1041
1042 void
1043 transform_project(enum projection pro, struct coord *c, int distance, int angle, struct coord *res)
1044 {
1045         double scale;
1046         switch (pro) {
1047         case projection_mg:
1048                 scale=transform_scale(c->y);
1049                 res->x=c->x+distance*sin(angle*M_PI/180)*scale;
1050                 res->y=c->y+distance*cos(angle*M_PI/180)*scale;
1051                 break;
1052         default:
1053                 dbg(0,"Unsupported projection: %d\n", pro);
1054                 return;
1055         }
1056
1057 }
1058
1059
1060 double
1061 transform_polyline_length(enum projection pro, struct coord *c, int count)
1062 {
1063         double ret=0;
1064         int i;
1065
1066         for (i = 0 ; i < count-1 ; i++)
1067                 ret+=transform_distance(pro, &c[i], &c[i+1]);
1068         return ret;
1069 }
1070
1071 int
1072 transform_distance_sq(struct coord *c1, struct coord *c2)
1073 {
1074         int dx=c1->x-c2->x;
1075         int dy=c1->y-c2->y;
1076
1077         if (dx > 32767 || dy > 32767 || dx < -32767 || dy < -32767)
1078                 return INT_MAX;
1079         else
1080                 return dx*dx+dy*dy;
1081 }
1082
1083 int
1084 transform_distance_sq_pc(struct pcoord *c1, struct pcoord *c2)
1085 {
1086         struct coord p1,p2;
1087         p1.x = c1->x; p1.y = c1->y;
1088         p2.x = c2->x; p2.y = c2->y;
1089         return transform_distance_sq(&p1, &p2);
1090 }
1091
1092 int
1093 transform_distance_line_sq(struct coord *l0, struct coord *l1, struct coord *ref, struct coord *lpnt)
1094 {
1095         int vx,vy,wx,wy;
1096         int c1,c2;
1097         int climit=1000000;
1098         struct coord l;
1099
1100         vx=l1->x-l0->x;
1101         vy=l1->y-l0->y;
1102         wx=ref->x-l0->x;
1103         wy=ref->y-l0->y;
1104
1105         c1=vx*wx+vy*wy;
1106         if ( c1 <= 0 ) {
1107                 if (lpnt)
1108                         *lpnt=*l0;
1109                 return transform_distance_sq(l0, ref);
1110         }
1111         c2=vx*vx+vy*vy;
1112         if ( c2 <= c1 ) {
1113                 if (lpnt)
1114                         *lpnt=*l1;
1115                 return transform_distance_sq(l1, ref);
1116         }
1117         while (c1 > climit || c2 > climit) {
1118                 c1/=256;
1119                 c2/=256;
1120         }
1121         l.x=l0->x+vx*c1/c2;
1122         l.y=l0->y+vy*c1/c2;
1123         if (lpnt)
1124                 *lpnt=l;
1125         return transform_distance_sq(&l, ref);
1126 }
1127
1128 int
1129 transform_distance_polyline_sq(struct coord *c, int count, struct coord *ref, struct coord *lpnt, int *pos)
1130 {
1131         int i,dist,distn;
1132         struct coord lp;
1133         if (count < 2)
1134                 return INT_MAX;
1135         if (pos)
1136                 *pos=0;
1137         dist=transform_distance_line_sq(&c[0], &c[1], ref, lpnt);
1138         for (i=2 ; i < count ; i++) {
1139                 distn=transform_distance_line_sq(&c[i-1], &c[i], ref, &lp);
1140                 if (distn < dist) {
1141                         dist=distn;
1142                         if (lpnt)
1143                                 *lpnt=lp;
1144                         if (pos)
1145                                 *pos=i-1;
1146                 }
1147         }
1148         return dist;
1149 }
1150
1151 int
1152 transform_douglas_peucker(struct coord *in, int count, int dist_sq, struct coord *out)
1153 {
1154         int ret=0;
1155         int i,d,dmax=0, idx=0;
1156         for (i = 1; i < count-1 ; i++) {
1157                 d=transform_distance_line_sq(&in[0], &in[count-1], &in[i], NULL);
1158                 if (d > dmax) {
1159                         idx=i;
1160                         dmax=d;
1161                 }
1162         }
1163         if (dmax > dist_sq) {
1164                 ret=transform_douglas_peucker(in, idx+1, dist_sq, out)-1;
1165                 ret+=transform_douglas_peucker(in+idx, count-idx, dist_sq, out+ret);
1166         } else {
1167                 if (count > 0)
1168                         out[ret++]=in[0];
1169                 if (count > 1)
1170                         out[ret++]=in[count-1];
1171         }
1172         return ret;
1173 }
1174
1175
1176 void
1177 transform_print_deg(double deg)
1178 {
1179         printf("%2.0f:%2.0f:%2.4f", floor(deg), fmod(deg*60,60), fmod(deg*3600,60));
1180 }
1181
1182 #ifdef AVOID_FLOAT
1183 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};
1184
1185 static int
1186 atan2_int_lookup(int val)
1187 {
1188         int len=sizeof(tab_atan)/sizeof(int);
1189         int i=len/2;
1190         int p=i-1;
1191         for (;;) {
1192                 i>>=1;
1193                 if (val < tab_atan[p])
1194                         p-=i;
1195                 else
1196                         if (val < tab_atan[p+1])
1197                                 return p+(p>>1);
1198                         else
1199                                 p+=i;
1200         }
1201 }
1202
1203 static int
1204 atan2_int(int dx, int dy)
1205 {
1206         int f,mul=1,add=0,ret;
1207         if (! dx) {
1208                 return dy < 0 ? 180 : 0;
1209         }
1210         if (! dy) {
1211                 return dx < 0 ? -90 : 90;
1212         }
1213         if (dx < 0) {
1214                 dx=-dx;
1215                 mul=-1;
1216         }
1217         if (dy < 0) {
1218                 dy=-dy;
1219                 add=180*mul;
1220                 mul*=-1;
1221         }
1222         while (dx > 20000 || dy > 20000) {
1223                 dx/=10;
1224                 dy/=10;
1225         }
1226         if (dx > dy) {
1227                 ret=90-atan2_int_lookup(dy*10000/dx);
1228         } else {
1229                 ret=atan2_int_lookup(dx*10000/dy);
1230         }
1231         return ret*mul+add;
1232 }
1233 #endif
1234
1235 int
1236 transform_get_angle_delta(struct coord *c1, struct coord *c2, int dir)
1237 {
1238         int dx=c2->x-c1->x;
1239         int dy=c2->y-c1->y;
1240 #ifndef AVOID_FLOAT
1241         double angle;
1242         angle=atan2(dx,dy);
1243         angle*=180/M_PI;
1244 #else
1245         int angle;
1246         angle=atan2_int(dx,dy);
1247 #endif
1248         if (dir == -1)
1249                 angle=angle-180;
1250         if (angle < 0)
1251                 angle+=360;
1252         return angle;
1253 }
1254
1255 int
1256 transform_within_border(struct transformation *this_, struct point *p, int border)
1257 {
1258         struct map_selection *ms=this_->screen_sel;
1259         while (ms) {
1260                 struct point_rect *r=&ms->u.p_rect;
1261                 if (p->x >= r->lu.x+border && p->x <= r->rl.x-border &&
1262                     p->y >= r->lu.y+border && p->y <= r->rl.y-border)
1263                         return 1;
1264                 ms=ms->next;
1265         }
1266         return 0;
1267 }
1268
1269 int
1270 transform_within_dist_point(struct coord *ref, struct coord *c, int dist)
1271 {
1272         if (c->x-dist > ref->x)
1273                 return 0;
1274         if (c->x+dist < ref->x)
1275                 return 0;
1276         if (c->y-dist > ref->y)
1277                 return 0;
1278         if (c->y+dist < ref->y)
1279                 return 0;
1280         if ((c->x-ref->x)*(c->x-ref->x) + (c->y-ref->y)*(c->y-ref->y) <= dist*dist)
1281                 return 1;
1282         return 0;
1283 }
1284
1285 int
1286 transform_within_dist_line(struct coord *ref, struct coord *c0, struct coord *c1, int dist)
1287 {
1288         int vx,vy,wx,wy;
1289         int n1,n2;
1290         struct coord lc;
1291
1292         if (c0->x < c1->x) {
1293                 if (c0->x-dist > ref->x)
1294                         return 0;
1295                 if (c1->x+dist < ref->x)
1296                         return 0;
1297         } else {
1298                 if (c1->x-dist > ref->x)
1299                         return 0;
1300                 if (c0->x+dist < ref->x)
1301                         return 0;
1302         }
1303         if (c0->y < c1->y) {
1304                 if (c0->y-dist > ref->y)
1305                         return 0;
1306                 if (c1->y+dist < ref->y)
1307                         return 0;
1308         } else {
1309                 if (c1->y-dist > ref->y)
1310                         return 0;
1311                 if (c0->y+dist < ref->y)
1312                         return 0;
1313         }
1314         vx=c1->x-c0->x;
1315         vy=c1->y-c0->y;
1316         wx=ref->x-c0->x;
1317         wy=ref->y-c0->y;
1318
1319         n1=vx*wx+vy*wy;
1320         if ( n1 <= 0 )
1321                 return transform_within_dist_point(ref, c0, dist);
1322         n2=vx*vx+vy*vy;
1323         if ( n2 <= n1 )
1324                 return transform_within_dist_point(ref, c1, dist);
1325
1326         lc.x=c0->x+vx*n1/n2;
1327         lc.y=c0->y+vy*n1/n2;
1328         return transform_within_dist_point(ref, &lc, dist);
1329 }
1330
1331 int
1332 transform_within_dist_polyline(struct coord *ref, struct coord *c, int count, int close, int dist)
1333 {
1334         int i;
1335         for (i = 0 ; i < count-1 ; i++) {
1336                 if (transform_within_dist_line(ref,c+i,c+i+1,dist)) {
1337                         return 1;
1338                 }
1339         }
1340         if (close)
1341                 return (transform_within_dist_line(ref,c,c+count-1,dist));
1342         return 0;
1343 }
1344
1345 int
1346 transform_within_dist_polygon(struct coord *ref, struct coord *c, int count, int dist)
1347 {
1348         int i, j, ci = 0;
1349         for (i = 0, j = count-1; i < count; j = i++) {
1350                 if ((((c[i].y <= ref->y) && ( ref->y < c[j].y )) ||
1351                 ((c[j].y <= ref->y) && ( ref->y < c[i].y))) &&
1352                 (ref->x < (c[j].x - c[i].x) * (ref->y - c[i].y) / (c[j].y - c[i].y) + c[i].x))
1353                         ci = !ci;
1354         }
1355         if (! ci) {
1356                 if (dist)
1357                         return transform_within_dist_polyline(ref, c, count, dist, 1);
1358                 else
1359                         return 0;
1360         }
1361         return 1;
1362 }
1363
1364 int
1365 transform_within_dist_item(struct coord *ref, enum item_type type, struct coord *c, int count, int dist)
1366 {
1367         if (type < type_line)
1368                 return transform_within_dist_point(ref, c, dist);
1369         if (type < type_area)
1370                 return transform_within_dist_polyline(ref, c, count, 0, dist);
1371         return transform_within_dist_polygon(ref, c, count, dist);
1372 }
1373
1374 void
1375 transform_destroy(struct transformation *t)
1376 {
1377         g_free(t);
1378 }
1379
1380
1381 /*
1382 Note: there are many mathematically equivalent ways to express these formulas. As usual, not all of them are computationally equivalent.
1383
1384 L = latitude in radians (positive north)
1385 Lo = longitude in radians (positive east)
1386 E = easting (meters)
1387 N = northing (meters)
1388
1389 For the sphere
1390
1391 E = r Lo
1392 N = r ln [ tan (pi/4 + L/2) ]
1393
1394 where
1395
1396 r = radius of the sphere (meters)
1397 ln() is the natural logarithm
1398
1399 For the ellipsoid
1400
1401 E = a Lo
1402 N = a * ln ( tan (pi/4 + L/2) * ( (1 - e * sin (L)) / (1 + e * sin (L))) ** (e/2)  )
1403
1404
1405                                                e
1406                                                -
1407                    pi     L     1 - e sin(L)   2
1408     =  a ln( tan( ---- + ---) (--------------)   )
1409                    4      2     1 + e sin(L)
1410
1411
1412 where
1413
1414 a = the length of the semi-major axis of the ellipsoid (meters)
1415 e = the first eccentricity of the ellipsoid
1416
1417
1418 */
1419
1420