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transform.c

/**
 * Navit, a modular navigation system.
 * Copyright (C) 2005-2008 Navit Team
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the
 * Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
 * Boston, MA  02110-1301, USA.
 */

#include <assert.h>
#include <stdio.h>
#include <math.h>
#include <limits.h>
#include <glib.h>
#include <string.h>
#include "config.h"
#include "coord.h"
#include "debug.h"
#include "item.h"
#include "map.h"
#include "transform.h"
#include "projection.h"
#include "point.h"

#define POST_SHIFT 8

struct transformation {
      int yaw;          /* Rotation angle */
      int pitch;
      int ddd;
      int m00,m01,m10,m11;    /* 2d transformation matrix */
      int xyscale;
      int m20,m21;            /* additional 3d parameters */
#ifdef ENABLE_ROLL
      int roll;
      int m02,m12,m22; 
      int hog;
      navit_float im02,im12,im20,im21,im22;
#endif
      navit_float im00,im01,im10,im11;    /* inverse 2d transformation matrix */
      struct map_selection *map_sel;
      struct map_selection *screen_sel;
      struct point screen_center;
      int screen_dist;
      int offx,offy,offz;
      struct coord map_center;      /* Center of source rectangle */
      enum projection pro;
      navit_float scale;            /* Scale factor */
      int scale_shift;
      int order;
      int order_base;
};



static void
transform_setup_matrix(struct transformation *t)
{
      navit_float det;
      navit_float fac;
      navit_float yawc=navit_cos(-M_PI*t->yaw/180);
      navit_float yaws=navit_sin(-M_PI*t->yaw/180);
      navit_float pitchc=navit_cos(-M_PI*t->pitch/180);
      navit_float pitchs=navit_sin(-M_PI*t->pitch/180);
#ifdef ENABLE_ROLL      
      navit_float rollc=navit_cos(M_PI*t->roll/180);
      navit_float rolls=navit_sin(M_PI*t->roll/180);
#endif

      int scale=t->scale;
      int order_dir=-1;

      dbg(1,"yaw=%d pitch=%d center=0x%x,0x%x\n", t->yaw, t->pitch, t->map_center.x, t->map_center.y);
      t->scale_shift=0;
      t->order=t->order_base;
      if (t->scale >= 1) {
            scale=t->scale;
      } else {
            scale=1.0/t->scale;
            order_dir=1;
      }
      while (scale > 1) {
            if (order_dir < 0)
                  t->scale_shift++;
            t->order+=order_dir;
            scale >>= 1;
      }
      fac=(1 << POST_SHIFT) * (1 << t->scale_shift) / t->scale;
      dbg(1,"scale_shift=%d order=%d scale=%f fac=%f\n", t->scale_shift, t->order,t->scale,fac);
      
#ifdef ENABLE_ROLL
        t->m00=rollc*yawc*fac;
        t->m01=rollc*yaws*fac;
      t->m02=-rolls*fac;
      t->m10=(pitchs*rolls*yawc-pitchc*yaws)*(-fac);
      t->m11=(pitchs*rolls*yaws+pitchc*yawc)*(-fac);
      t->m12=pitchs*rollc*(-fac);
      t->m20=(pitchc*rolls*yawc+pitchs*yaws)*fac;
      t->m21=(pitchc*rolls*yaws-pitchs*yawc)*fac;
      t->m22=pitchc*rollc*fac;
#else
        t->m00=yawc*fac;
        t->m01=yaws*fac;
      t->m10=(-pitchc*yaws)*(-fac);
      t->m11=pitchc*yawc*(-fac);
      t->m20=pitchs*yaws*fac;
      t->m21=(-pitchs*yawc)*fac;
#endif
      t->offz=0;
      t->xyscale=1;
      t->ddd=0;
      t->offx=t->screen_center.x;
      t->offy=t->screen_center.y;
      if (t->pitch) {
            t->ddd=1;
            t->offz=t->screen_dist;
            t->xyscale=t->offz;
      }
#ifdef ENABLE_ROLL
      det=(navit_float)t->m00*(navit_float)t->m11*(navit_float)t->m22+
            (navit_float)t->m01*(navit_float)t->m12*(navit_float)t->m20+
            (navit_float)t->m02*(navit_float)t->m10*(navit_float)t->m21-
            (navit_float)t->m02*(navit_float)t->m11*(navit_float)t->m20-
            (navit_float)t->m01*(navit_float)t->m10*(navit_float)t->m22-
            (navit_float)t->m00*(navit_float)t->m12*(navit_float)t->m21;

      t->im00=(t->m11*t->m22-t->m12*t->m21)/det;
      t->im01=(t->m02*t->m21-t->m01*t->m22)/det;
      t->im02=(t->m01*t->m12-t->m02*t->m11)/det;
      t->im10=(t->m12*t->m20-t->m10*t->m22)/det;
      t->im11=(t->m00*t->m22-t->m02*t->m20)/det;
      t->im12=(t->m02*t->m10-t->m00*t->m12)/det;
      t->im20=(t->m10*t->m21-t->m11*t->m20)/det;
      t->im21=(t->m01*t->m20-t->m00*t->m21)/det;
      t->im22=(t->m00*t->m11-t->m01*t->m10)/det;
#else
      det=((navit_float)t->m00*(navit_float)t->m11-(navit_float)t->m01*(navit_float)t->m10);
      t->im00=t->m11/det;
      t->im01=-t->m01/det;
      t->im10=-t->m10/det;
      t->im11=t->m00/det;
#endif
}

struct transformation *
transform_new(void)
{
      struct transformation *this_;

      this_=g_new0(struct transformation, 1);
      this_->screen_dist=100;
      this_->order_base=14;
#if 0
      this_->pitch=20;
#endif
#if 0
      this_->roll=30;
      this_->hog=1000;
#endif
      transform_setup_matrix(this_);
      return this_;
}

#ifdef ENABLE_ROLL

int
transform_get_hog(struct transformation *this_)
{
      return this_->hog;
}

void
transform_set_hog(struct transformation *this_, int hog)
{
      this_->hog=hog;
}

#else

int
transform_get_hog(struct transformation *this_)
{
      return 0;
}

void
transform_set_hog(struct transformation *this_, int hog)
{
      dbg(0,"not supported\n");
}

#endif

int
transformation_get_order_base(struct transformation *this_)
{
      return this_->order_base;
}

void
transform_set_order_base(struct transformation *this_, int order_base)
{
      this_->order_base=order_base;
}


struct transformation *
transform_dup(struct transformation *t)
{
      struct transformation *ret=g_new0(struct transformation, 1);
      *ret=*t;
      return ret;
}

static const navit_float gar2geo_units = 360.0/(1<<24);
static const navit_float geo2gar_units = 1/(360.0/(1<<24));

void
transform_to_geo(enum projection pro, struct coord *c, struct coord_geo *g)
{
      int x,y,northern,zone;
      switch (pro) {
      case projection_mg:
            g->lng=c->x/6371000.0/M_PI*180;
            g->lat=navit_atan(exp(c->y/6371000.0))/M_PI*360-90;
            break;
      case projection_garmin:
            g->lng=c->x*gar2geo_units;
            g->lat=c->y*gar2geo_units;
            break;
      case projection_utm:
            x=c->x;
            y=c->y;
            northern=y >= 0;
            if (!northern) {
                  y+=10000000;
            }
            zone=(x/1000000);
            x=x%1000000;
            transform_utm_to_geo(x, y, zone, northern, g);
            break;      
      default:
            break;
      }
}

void
transform_from_geo(enum projection pro, struct coord_geo *g, struct coord *c)
{
      switch (pro) {
      case projection_mg:
            c->x=g->lng*6371000.0*M_PI/180;
            c->y=log(navit_tan(M_PI_4+g->lat*M_PI/360))*6371000.0;
            break;
      case projection_garmin:
            c->x=g->lng*geo2gar_units;
            c->y=g->lat*geo2gar_units;
            break;
      default:
            break;
      }
}

void
transform_from_to(struct coord *cfrom, enum projection from, struct coord *cto, enum projection to)
{
      struct coord_geo g;
      transform_to_geo(from, cfrom, &g);
      transform_from_geo(to, &g, cto);
}

void
transform_geo_to_cart(struct coord_geo *geo, navit_float a, navit_float b, struct coord_geo_cart *cart)
{
      navit_float n,ee=1-b*b/(a*a);
      n = a/sqrtf(1-ee*navit_sin(geo->lat)*navit_sin(geo->lat));
        cart->x=n*navit_cos(geo->lat)*navit_cos(geo->lng);
        cart->y=n*navit_cos(geo->lat)*navit_sin(geo->lng);
        cart->z=n*(1-ee)*navit_sin(geo->lat);
}

void
transform_cart_to_geo(struct coord_geo_cart *cart, navit_float a, navit_float b, struct coord_geo *geo)
{
      navit_float lat,lati,n,ee=1-b*b/(a*a), lng = navit_tan(cart->y/cart->x);

        lat = navit_tan(cart->z / navit_sqrt((cart->x * cart->x) + (cart->y * cart->y)));
        do
        {
                lati = lat;

                n = a / navit_sqrt(1-ee*navit_sin(lat)*navit_sin(lat));
                lat = navit_atan((cart->z + ee * n * navit_sin(lat)) / navit_sqrt(cart->x * cart->x + cart->y * cart->y));
        }
        while (fabs(lat - lati) >= 0.000000000000001);

      geo->lng=lng/M_PI*180;
      geo->lat=lat/M_PI*180;
}


void
transform_utm_to_geo(const double UTMEasting, const double UTMNorthing, int ZoneNumber, int NorthernHemisphere, struct coord_geo *geo)
{
//converts UTM coords to lat/long.  Equations from USGS Bulletin 1532 
//East Longitudes are positive, West longitudes are negative. 
//North latitudes are positive, South latitudes are negative
//Lat and Long are in decimal degrees. 
      //Written by Chuck Gantz- chuck.gantz@globalstar.com

      double Lat, Long;
      double k0 = 0.99960000000000004;
      double a = 6378137;
      double eccSquared = 0.0066943799999999998;
      double eccPrimeSquared;
      double e1 = (1-sqrt(1-eccSquared))/(1+sqrt(1-eccSquared));
      double N1, T1, C1, R1, D, M;
      double LongOrigin;
      double mu, phi1, phi1Rad;
      double x, y;
      double rad2deg = 180/M_PI;

      x = UTMEasting - 500000.0; //remove 500,000 meter offset for longitude
      y = UTMNorthing;

      if (!NorthernHemisphere) {
            y -= 10000000.0;//remove 10,000,000 meter offset used for southern hemisphere
      }

      LongOrigin = (ZoneNumber - 1)*6 - 180 + 3;  //+3 puts origin in middle of zone

      eccPrimeSquared = (eccSquared)/(1-eccSquared);

      M = y / k0;
      mu = M/(a*(1-eccSquared/4-3*eccSquared*eccSquared/64-5*eccSquared*eccSquared*eccSquared/256));
      phi1Rad = mu      + (3*e1/2-27*e1*e1*e1/32)*sin(2*mu) 
                        + (21*e1*e1/16-55*e1*e1*e1*e1/32)*sin(4*mu)
                        +(151*e1*e1*e1/96)*sin(6*mu);
      phi1 = phi1Rad*rad2deg;

      N1 = a/sqrt(1-eccSquared*sin(phi1Rad)*sin(phi1Rad));
      T1 = tan(phi1Rad)*tan(phi1Rad);
      C1 = eccPrimeSquared*cos(phi1Rad)*cos(phi1Rad);
      R1 = a*(1-eccSquared)/pow(1-eccSquared*sin(phi1Rad)*sin(phi1Rad), 1.5);
      D = x/(N1*k0);

      Lat = phi1Rad - (N1*tan(phi1Rad)/R1)*(D*D/2-(5+3*T1+10*C1-4*C1*C1-9*eccPrimeSquared)*D*D*D*D/24
                              +(61+90*T1+298*C1+45*T1*T1-252*eccPrimeSquared-3*C1*C1)*D*D*D*D*D*D/720);
      Lat = Lat * rad2deg;

      Long = (D-(1+2*T1+C1)*D*D*D/6+(5-2*C1+28*T1-3*C1*C1+8*eccPrimeSquared+24*T1*T1)
                              *D*D*D*D*D/120)/cos(phi1Rad);
      Long = LongOrigin + Long * rad2deg;

      geo->lat=Lat;
      geo->lng=Long;
}

void
transform_datum(struct coord_geo *from, enum map_datum from_datum, struct coord_geo *to, enum map_datum to_datum)
{
}

int
transform(struct transformation *t, enum projection pro, struct coord *c, struct point *p, int count, int unique, int width, int *width_return)
{
      struct coord c1;
      int xcn, ycn; 
      struct coord_geo g;
      int xc, yc, zc=0, xco=0, yco=0, zco=0;
      int xm,ym,zct;
      int zlimit=1000;
      int visible, visibleo=-1;
      int i,j = 0;
      dbg(1,"count=%d\n", count);
      for (i=0; i < count; i++) {
            if (pro == t->pro) {
                  xc=c[i].x;
                  yc=c[i].y;
            } else {
                  transform_to_geo(pro, &c[i], &g);
                  transform_from_geo(t->pro, &g, &c1);
                  xc=c1.x;
                  yc=c1.y;
            }
            xm=xc;
            ym=yc;
//          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);
//          ret=coord_rect_contains(&t->r, c);
            xc-=t->map_center.x;
            yc-=t->map_center.y;
            xc >>= t->scale_shift;
            yc >>= t->scale_shift;
#ifdef ENABLE_ROLL            
            xcn=xc*t->m00+yc*t->m01+t->hog*t->m02;
            ycn=xc*t->m10+yc*t->m11+t->hog*t->m12;
#else
            xcn=xc*t->m00+yc*t->m01;
            ycn=xc*t->m10+yc*t->m11;
#endif

            if (t->ddd) {
#ifdef ENABLE_ROLL            
                  zc=(xc*t->m20+yc*t->m21+t->hog*t->m22);
#else
                  zc=(xc*t->m20+yc*t->m21);
#endif
                  zct=zc;
                  zc+=t->offz << POST_SHIFT;
                  dbg(1,"zc=%d\n", zc);
                  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);
                  /* visibility */
                  visible=(zc < zlimit ? 0:1);
                  dbg(1,"visible=%d old %d\n", visible, visibleo);
                  if (visible != visibleo && visibleo != -1) { 
                        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);
                        if (zco != zc) {
                              xcn=xcn+(long long)(xco-xcn)*(zlimit-zc)/(zco-zc);
                              ycn=ycn+(long long)(yco-ycn)*(zlimit-zc)/(zco-zc);
                        }
                        dbg(1,"result (%d,%d,%d) * %d / %d\n", xcn,ycn,zc,zlimit-zc,zco-zc);
                        zc=zlimit;
                        xco=xcn;
                        yco=ycn;
                        zco=zc;
                        if (visible)
                              i--;
                        visibleo=visible;
                  } else {
                        xco=xcn;
                        yco=ycn;
                        zco=zc;
                        visibleo=visible;
                        if (! visible)
                              continue;
                  }
                  dbg(1,"zc=%d\n", zc);
                  dbg(1,"xcn %d ycn %d\n", xcn, ycn);
                  dbg(1,"%d,%d %d\n",xc,yc,zc);
#if 0
                  dbg(0,"%d/%d=%d %d/%d=%d\n",xcn,xc,xcn/xc,ycn,yc,ycn/yc);
#endif
#if 1
                  xc=(long long)xcn*t->xyscale/zc;
                  yc=(long long)ycn*t->xyscale/zc;
#else
                  xc=xcn/(1000+zc);
                  yc=ycn/(1000+zc);
#endif
                  dbg(1,"%d,%d %d\n",xc,yc,zc);
            } else {
                  xc=xcn;
                  yc=ycn;
                  xc>>=POST_SHIFT;
                  yc>>=POST_SHIFT;
            }
            xc+=t->offx;
            yc+=t->offy;
            dbg(1,"xc=%d yc=%d\n", xc, yc);
            if (j == 0 || !unique || p[j-1].x != xc || p[j-1].y != yc) {
                  p[j].x=xc;
                  p[j].y=yc;
                  if (width_return) {
                        if (t->ddd) 
                              width_return[j]=width*(t->offz << POST_SHIFT)/zc;
                        else 
                              width_return[j]=width;
                  }
                  j++;
            }
      }
      return j;
}

void
transform_reverse(struct transformation *t, struct point *p, struct coord *c)
{
        double zc,xc,yc,xcn,ycn,q;
      double offz=t->offz << POST_SHIFT;
      xc=p->x - t->offx;
      yc=p->y - t->offy;
      if (t->ddd) {
            xc/=t->xyscale;
            yc/=t->xyscale;
            double f00=xc*t->im00*t->m20;
            double f01=yc*t->im01*t->m20;
            double f10=xc*t->im10*t->m21;
            double f11=yc*t->im11*t->m21;
#ifdef ENABLE_ROLL      
            q=(1-f00-f01-t->im02*t->m20-f10-f11-t->im12*t->m21);
            if (q < 0) 
                  q=0.15;
            zc=(offz*((f00+f01+f10+f11))+t->hog*t->m22)/q;
#else
            q=(1-f00-f01-f10-f11);
                if (q < 0) 
                  q=0.15;
            zc=offz*(f00+f01+f10+f11)/q;
#endif
            xcn=xc*(zc+offz);
            ycn=yc*(zc+offz);
#ifdef ENABLE_ROLL      
            xc=xcn*t->im00+ycn*t->im01+zc*t->im02;
            yc=xcn*t->im10+ycn*t->im11+zc*t->im12;
#else
            xc=xcn*t->im00+ycn*t->im01;
            yc=xcn*t->im10+ycn*t->im11;
#endif

      } else {
            xcn=xc;
            ycn=yc;
            xc=(xcn*t->im00+ycn*t->im01)*(1 << POST_SHIFT);
            yc=(xcn*t->im10+ycn*t->im11)*(1 << POST_SHIFT);
      }
      c->x=xc*(1 << t->scale_shift)+t->map_center.x;
      c->y=yc*(1 << t->scale_shift)+t->map_center.y;
}

enum projection
transform_get_projection(struct transformation *this_)
{
      return this_->pro;
}

void
transform_set_projection(struct transformation *this_, enum projection pro)
{
      this_->pro=pro;
}

static int
min4(int v1,int v2, int v3, int v4)
{
      int res=v1;
      if (v2 < res)
            res=v2;
      if (v3 < res)
            res=v3;
      if (v4 < res)
            res=v4;
      return res;
}

static int
max4(int v1,int v2, int v3, int v4)
{
      int res=v1;
      if (v2 > res)
            res=v2;
      if (v3 > res)
            res=v3;
      if (v4 > res)
            res=v4;
      return res;
}

struct map_selection *
transform_get_selection(struct transformation *this_, enum projection pro, int order)
{

      struct map_selection *ret,*curri,*curro;
      struct coord_geo g;
      
      ret=map_selection_dup(this_->map_sel);
      curri=this_->map_sel;
      curro=ret;
      while (curri) {
            if (this_->pro != pro) {
                  transform_to_geo(this_->pro, &curri->u.c_rect.lu, &g);
                  transform_from_geo(pro, &g, &curro->u.c_rect.lu);
                  dbg(1,"%f,%f", g.lat, g.lng);
                  transform_to_geo(this_->pro, &curri->u.c_rect.rl, &g);
                  transform_from_geo(pro, &g, &curro->u.c_rect.rl);
                  dbg(1,": - %f,%f\n", g.lat, g.lng);
            }
            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);
            curro->order+=order;
            curro->range=item_range_all;
            curri=curri->next;
            curro=curro->next;
      }
      return ret;
}

struct coord *
transform_center(struct transformation *this_)
{
      return &this_->map_center;
}

struct coord *
transform_get_center(struct transformation *this_)
{
      return &this_->map_center;
}

void
transform_set_center(struct transformation *this_, struct coord *c)
{
      this_->map_center=*c;
}


void
transform_set_yaw(struct transformation *t,int yaw)
{
      t->yaw=yaw;
      transform_setup_matrix(t);
}

int
transform_get_yaw(struct transformation *this_)
{
      return this_->yaw;
}

void
transform_set_pitch(struct transformation *this_,int pitch)
{
      this_->pitch=pitch;
      transform_setup_matrix(this_);
}
int
transform_get_pitch(struct transformation *this_)
{
      return this_->pitch;
}

#ifdef ENABLE_ROLL
void
transform_set_roll(struct transformation *this_,int roll)
{
      this_->roll=roll;
      transform_setup_matrix(this_);
}

int
transform_get_roll(struct transformation *this_)
{
      return this_->roll;
}

#else

void
transform_set_roll(struct transformation *this_,int roll)
{
      dbg(0,"not supported\n");
}

int
transform_get_roll(struct transformation *this_)
{
      return 0;
}

#endif

void
transform_set_distance(struct transformation *this_,int distance)
{
      this_->screen_dist=distance;
      transform_setup_matrix(this_);
}

int
transform_get_distance(struct transformation *this_)
{
      return this_->screen_dist;
}

void
transform_set_screen_selection(struct transformation *t, struct map_selection *sel)
{
      map_selection_destroy(t->screen_sel);
      t->screen_sel=map_selection_dup(sel);
      if (sel) {
            t->screen_center.x=(sel->u.p_rect.rl.x-sel->u.p_rect.lu.x)/2;
            t->screen_center.y=(sel->u.p_rect.rl.y-sel->u.p_rect.lu.y)/2;
            transform_setup_matrix(t);
      }
}

void
transform_set_screen_center(struct transformation *t, struct point *p)
{
      t->screen_center=*p;
}

#if 0
void
transform_set_size(struct transformation *t, int width, int height)
{
      t->width=width;
      t->height=height;
}
#endif

void
transform_get_size(struct transformation *t, int *width, int *height)
{
      struct point_rect *r;
      if (t->screen_sel) {
            r=&t->screen_sel->u.p_rect;
            *width=r->rl.x-r->lu.x;
            *height=r->rl.y-r->lu.y;
      }
}

void
transform_setup(struct transformation *t, struct pcoord *c, int scale, int yaw)
{
      t->pro=c->pro;
      t->map_center.x=c->x;
      t->map_center.y=c->y;
      t->scale=scale/16.0;
      transform_set_yaw(t, yaw);
}

#if 0

void
transform_setup_source_rect_limit(struct transformation *t, struct coord *center, int limit)
{
      t->center=*center;
      t->scale=1;
      t->angle=0;
      t->r.lu.x=center->x-limit;
      t->r.rl.x=center->x+limit;
      t->r.rl.y=center->y-limit;
      t->r.lu.y=center->y+limit;
}
#endif

void
transform_setup_source_rect(struct transformation *t)
{
      int i;
      struct coord screen[4];
      struct point screen_pnt[4];
      struct point_rect *pr;
      struct map_selection *ms,*msm,*next,**msm_last;
      ms=t->map_sel;
      while (ms) {
            next=ms->next;
            g_free(ms);
            ms=next;
      }
      t->map_sel=NULL;
      msm_last=&t->map_sel;
      ms=t->screen_sel;
      while (ms) {
            msm=g_new0(struct map_selection, 1);
            *msm=*ms;
            pr=&ms->u.p_rect;
            screen_pnt[0].x=pr->lu.x;
            screen_pnt[0].y=pr->lu.y;
            screen_pnt[1].x=pr->rl.x;
            screen_pnt[1].y=pr->lu.y;
            screen_pnt[2].x=pr->lu.x;
            screen_pnt[2].y=pr->rl.y;
            screen_pnt[3].x=pr->rl.x;
            screen_pnt[3].y=pr->rl.y;
            for (i = 0 ; i < 4 ; i++) {
                  transform_reverse(t, &screen_pnt[i], &screen[i]);
                  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);
            }
            msm->u.c_rect.lu.x=min4(screen[0].x,screen[1].x,screen[2].x,screen[3].x);
            msm->u.c_rect.rl.x=max4(screen[0].x,screen[1].x,screen[2].x,screen[3].x);
            msm->u.c_rect.rl.y=min4(screen[0].y,screen[1].y,screen[2].y,screen[3].y);
            msm->u.c_rect.lu.y=max4(screen[0].y,screen[1].y,screen[2].y,screen[3].y);
            dbg(1,"%dx%d\n", msm->u.c_rect.rl.x-msm->u.c_rect.lu.x,
                         msm->u.c_rect.lu.y-msm->u.c_rect.rl.y);
            *msm_last=msm;
            msm_last=&msm->next;
            ms=ms->next;
      }
}

long
transform_get_scale(struct transformation *t)
{
      return (int)(t->scale*16);
}

void
transform_set_scale(struct transformation *t, long scale)
{
      t->scale=scale/16.0;
      transform_setup_matrix(t);
}


int
transform_get_order(struct transformation *t)
{
      dbg(1,"order %d\n", t->order);
      return t->order;
}



#define TWOPI (M_PI*2)
#define GC2RAD(c) ((c) * TWOPI/(1<<24))
#define minf(a,b) ((a) < (b) ? (a) : (b))

static double
transform_distance_garmin(struct coord *c1, struct coord *c2)
{
#ifdef USE_HALVESINE
      static const int earth_radius = 6371*1000; //m change accordingly
// static const int earth_radius  = 3960; //miles
 
//Point 1 cords
      navit_float lat1  = GC2RAD(c1->y);
      navit_float long1 = GC2RAD(c1->x);

//Point 2 cords
      navit_float lat2  = GC2RAD(c2->y);
      navit_float long2 = GC2RAD(c2->x);

//Haversine Formula
      navit_float dlong = long2-long1;
      navit_float dlat  = lat2-lat1;

      navit_float sinlat  = navit_sin(dlat/2);
      navit_float sinlong = navit_sin(dlong/2);
 
      navit_float a=(sinlat*sinlat)+navit_cos(lat1)*navit_cos(lat2)*(sinlong*sinlong);
      navit_float c=2*navit_asin(minf(1,navit_sqrt(a)));
#ifdef AVOID_FLOAT
      return round(earth_radius*c);
#else
      return earth_radius*c;
#endif
#else
#define GMETER 2.3887499999999999
      navit_float dx,dy;
      dx=c1->x-c2->x;
      dy=c1->y-c2->y;
      return navit_sqrt(dx*dx+dy*dy)*GMETER;
#undef GMETER
#endif
}

double
transform_scale(int y)
{
      struct coord c;
      struct coord_geo g;
      c.x=0;
      c.y=y;
      transform_to_geo(projection_mg, &c, &g);
      return 1/navit_cos(g.lat/180*M_PI);
}

#ifdef AVOID_FLOAT
static int
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};

static int tab_int_step = 0x20000;
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};

int transform_int_scale(int y)
{
      int a=tab_int_step,i,size = sizeof(tab_int_scale)/sizeof(int);
      if (y < 0)
            y=-y;
      i=y/tab_int_step;
      if (i < size-1) 
            return tab_int_scale[i]+((tab_int_scale[i+1]-tab_int_scale[i])*(y-i*tab_int_step))/tab_int_step;
      return tab_int_scale[size-1];
}
#endif

double
transform_distance(enum projection pro, struct coord *c1, struct coord *c2)
{
      if (pro == projection_mg) {
#ifndef AVOID_FLOAT 
      double dx,dy,scale=transform_scale((c1->y+c2->y)/2);
      dx=c1->x-c2->x;
      dy=c1->y-c2->y;
      return sqrt(dx*dx+dy*dy)/scale;
#else
      int dx,dy,f,scale=transform_int_scale((c1->y+c2->y)/2);
      dx=c1->x-c2->x;
      dy=c1->y-c2->y;
      if (dx < 0)
            dx=-dx;
      if (dy < 0)
            dy=-dy;
      while (dx > 20000 || dy > 20000) {
            dx/=10;
            dy/=10;
            scale/=10;
      }
      if (! dy)
            return dx*10000/scale;
      if (! dx)
            return dy*10000/scale;
      if (dx > dy) {
            f=dx*8/dy-8;
            if (f >= 32)
                  return dx*10000/scale;
            return dx*tab_sqrt[f]/scale;
      } else {
            f=dy*8/dx-8;
            if (f >= 32)
                  return dy*10000/scale;
            return dy*tab_sqrt[f]/scale;
      }
#endif
      } else if (pro == projection_garmin) {
            return transform_distance_garmin(c1, c2);
      } else {
            dbg(0,"Unknown projection: %d\n", pro);
            return 0;
      }
}

double
transform_polyline_length(enum projection pro, struct coord *c, int count)
{
      double ret=0;
      int i;

      for (i = 0 ; i < count-1 ; i++) 
            ret+=transform_distance(pro, &c[i], &c[i+1]);
      return ret;
}

int
transform_distance_sq(struct coord *c1, struct coord *c2)
{
      int dx=c1->x-c2->x;
      int dy=c1->y-c2->y;

      if (dx > 32767 || dy > 32767 || dx < -32767 || dy < -32767)
            return INT_MAX;
      else
            return dx*dx+dy*dy;
}

int
transform_distance_sq_pc(struct pcoord *c1, struct pcoord *c2)
{
      struct coord p1,p2;
      p1.x = c1->x; p1.y = c1->y;
      p2.x = c2->x; p2.y = c2->y;
      return transform_distance_sq(&p1, &p2);
}

int
transform_distance_line_sq(struct coord *l0, struct coord *l1, struct coord *ref, struct coord *lpnt)
{
      int vx,vy,wx,wy;
      int c1,c2;
      int climit=1000000;
      struct coord l;

      vx=l1->x-l0->x;
      vy=l1->y-l0->y;
      wx=ref->x-l0->x;
      wy=ref->y-l0->y;

      c1=vx*wx+vy*wy;
      if ( c1 <= 0 ) {
            if (lpnt)
                  *lpnt=*l0;
            return transform_distance_sq(l0, ref);
      }
      c2=vx*vx+vy*vy;
      if ( c2 <= c1 ) {
            if (lpnt)
                  *lpnt=*l1;
            return transform_distance_sq(l1, ref);
      }
      while (c1 > climit || c2 > climit) {
            c1/=256;
            c2/=256;
      }
      l.x=l0->x+vx*c1/c2;
      l.y=l0->y+vy*c1/c2;
      if (lpnt)
            *lpnt=l;
      return transform_distance_sq(&l, ref);
}

int
transform_distance_polyline_sq(struct coord *c, int count, struct coord *ref, struct coord *lpnt, int *pos)
{
      int i,dist,distn;
      struct coord lp;
      if (count < 2)
            return INT_MAX;
      if (pos)
            *pos=0;
      dist=transform_distance_line_sq(&c[0], &c[1], ref, lpnt);
      for (i=2 ; i < count ; i++) {
            distn=transform_distance_line_sq(&c[i-1], &c[i], ref, &lp);
            if (distn < dist) {
                  dist=distn;
                  if (lpnt)
                        *lpnt=lp;
                  if (pos)
                        *pos=i-1;
            }
      }
      return dist;
}


void
transform_print_deg(double deg)
{
      printf("%2.0f:%2.0f:%2.4f", floor(deg), fmod(deg*60,60), fmod(deg*3600,60));
}

#ifdef AVOID_FLOAT
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};

static int
atan2_int_lookup(int val)
{
      int len=sizeof(tab_atan)/sizeof(int);
      int i=len/2;
      int p=i-1;
      for (;;) {
            i>>=1;
            if (val < tab_atan[p])
                  p-=i;
            else
                  if (val < tab_atan[p+1])
                        return p+(p>>1);
                  else
                        p+=i;
      }
}

static int
atan2_int(int dx, int dy)
{
      int f,mul=1,add=0,ret;
      if (! dx) {
            return dy < 0 ? 180 : 0;
      }
      if (! dy) {
            return dx < 0 ? -90 : 90;
      }
      if (dx < 0) {
            dx=-dx;
            mul=-1;
      }
      if (dy < 0) {
            dy=-dy;
            add=180*mul;
            mul*=-1;
      }
      while (dx > 20000 || dy > 20000) {
            dx/=10;
            dy/=10;
      }
      if (dx > dy) {
            ret=90-atan2_int_lookup(dy*10000/dx);
      } else {
            ret=atan2_int_lookup(dx*10000/dy);
      }
      return ret*mul+add;
}
#endif

int
transform_get_angle_delta(struct coord *c1, struct coord *c2, int dir)
{
      int dx=c2->x-c1->x;
      int dy=c2->y-c1->y;
#ifndef AVOID_FLOAT 
      double angle;
      angle=atan2(dx,dy);
      angle*=180/M_PI;
#else
      int angle;
      angle=atan2_int(dx,dy);
#endif
      if (dir == -1)
            angle=angle-180;
      if (angle < 0)
            angle+=360;
      return angle;
}

int
transform_within_border(struct transformation *this_, struct point *p, int border)
{
      struct map_selection *ms=this_->screen_sel;
      while (ms) {
            struct point_rect *r=&ms->u.p_rect;
            if (p->x >= r->lu.x+border && p->x <= r->rl.x-border &&
                p->y >= r->lu.y+border && p->y <= r->rl.y-border)
                  return 1;
            ms=ms->next;
      }
      return 0;
}

int
transform_within_dist_point(struct coord *ref, struct coord *c, int dist)
{
      if (c->x-dist > ref->x)
            return 0;
      if (c->x+dist < ref->x)
            return 0;
      if (c->y-dist > ref->y)
            return 0;
      if (c->y+dist < ref->y)
            return 0;
      if ((c->x-ref->x)*(c->x-ref->x) + (c->y-ref->y)*(c->y-ref->y) <= dist*dist) 
            return 1;
        return 0;
}

int
transform_within_dist_line(struct coord *ref, struct coord *c0, struct coord *c1, int dist)
{
      int vx,vy,wx,wy;
      int n1,n2;
      struct coord lc;

      if (c0->x < c1->x) {
            if (c0->x-dist > ref->x)
                  return 0;
            if (c1->x+dist < ref->x)
                  return 0;
      } else {
            if (c1->x-dist > ref->x)
                  return 0;
            if (c0->x+dist < ref->x)
                  return 0;
      }
      if (c0->y < c1->y) {
            if (c0->y-dist > ref->y)
                  return 0;
            if (c1->y+dist < ref->y)
                  return 0;
      } else {
            if (c1->y-dist > ref->y)
                  return 0;
            if (c0->y+dist < ref->y)
                  return 0;
      }
      vx=c1->x-c0->x;
      vy=c1->y-c0->y;
      wx=ref->x-c0->x;
      wy=ref->y-c0->y;

      n1=vx*wx+vy*wy;
      if ( n1 <= 0 )
            return transform_within_dist_point(ref, c0, dist);
      n2=vx*vx+vy*vy;
      if ( n2 <= n1 )
            return transform_within_dist_point(ref, c1, dist);

      lc.x=c0->x+vx*n1/n2;
      lc.y=c0->y+vy*n1/n2;
      return transform_within_dist_point(ref, &lc, dist);
}

int
transform_within_dist_polyline(struct coord *ref, struct coord *c, int count, int close, int dist)
{
      int i;
      for (i = 0 ; i < count-1 ; i++) {
            if (transform_within_dist_line(ref,c+i,c+i+1,dist)) {
                  return 1;
            }
      }
      if (close)
            return (transform_within_dist_line(ref,c,c+count-1,dist));
      return 0;
}

int
transform_within_dist_polygon(struct coord *ref, struct coord *c, int count, int dist)
{
      int i, j, ci = 0;
      for (i = 0, j = count-1; i < count; j = i++) {
            if ((((c[i].y <= ref->y) && ( ref->y < c[j].y )) ||
            ((c[j].y <= ref->y) && ( ref->y < c[i].y))) &&
            (ref->x < (c[j].x - c[i].x) * (ref->y - c[i].y) / (c[j].y - c[i].y) + c[i].x))
                  ci = !ci;
      }
      if (! ci) {
            if (dist)
                  return transform_within_dist_polyline(ref, c, count, dist, 1);
            else
                  return 0;
      }
      return 1;
}

int
transform_within_dist_item(struct coord *ref, enum item_type type, struct coord *c, int count, int dist)
{
      if (type < type_line)
            return transform_within_dist_point(ref, c, dist);
      if (type < type_area)
            return transform_within_dist_polyline(ref, c, count, 0, dist);
      return transform_within_dist_polygon(ref, c, count, dist);
}

void
transform_destroy(struct transformation *t)
{
      g_free(t);
}


/*
Note: there are many mathematically equivalent ways to express these formulas. As usual, not all of them are computationally equivalent.

L = latitude in radians (positive north)
Lo = longitude in radians (positive east)
E = easting (meters)
N = northing (meters)

For the sphere

E = r Lo
N = r ln [ tan (pi/4 + L/2) ]

where 

r = radius of the sphere (meters)
ln() is the natural logarithm

For the ellipsoid

E = a Lo
N = a * ln ( tan (pi/4 + L/2) * ( (1 - e * sin (L)) / (1 + e * sin (L))) ** (e/2)  )


                                               e
                                               -
                   pi     L     1 - e sin(L)   2
    =  a ln( tan( ---- + ---) (--------------)   )
                   4      2     1 + e sin(L) 


where

a = the length of the semi-major axis of the ellipsoid (meters)
e = the first eccentricity of the ellipsoid


*/



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