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#define PJ_LIB__
#include <errno.h>
#include <math.h>
#include "proj.h"
#include "proj_internal.h"
PROJ_HEAD(wink2, "Winkel II") "\n\tPCyl, Sph\n\tlat_1=";
namespace { // anonymous namespace
struct pj_opaque {
double cosphi1;
};
} // anonymous namespace
#define MAX_ITER 10
#define LOOP_TOL 1e-7
static PJ_XY wink2_s_forward (PJ_LP lp, PJ *P) { /* Spheroidal, forward */
PJ_XY xy = {0.0, 0.0};
int i;
xy.y = lp.phi * M_TWO_D_PI;
const double k = M_PI * sin (lp.phi);
lp.phi *= 1.8;
for (i = MAX_ITER; i ; --i) {
const double V = (lp.phi + sin (lp.phi) - k) /
(1. + cos (lp.phi));
lp.phi -= V;
if (fabs (V) < LOOP_TOL)
break;
}
if (!i)
lp.phi = (lp.phi < 0.) ? -M_HALFPI : M_HALFPI;
else
lp.phi *= 0.5;
xy.x = 0.5 * lp.lam * (cos (lp.phi) + static_cast<struct pj_opaque*>(P->opaque)->cosphi1);
xy.y = M_FORTPI * (sin (lp.phi) + xy.y);
return xy;
}
static PJ_LP wink2_s_inverse(PJ_XY xy, PJ *P)
{
PJ_LP lpInit;
lpInit.phi = xy.y;
lpInit.lam = xy.x;
return pj_generic_inverse_2d(xy, P, lpInit);
}
PJ *PROJECTION(wink2) {
struct pj_opaque *Q = static_cast<struct pj_opaque*>(calloc (1, sizeof (struct pj_opaque)));
if (nullptr==Q)
return pj_default_destructor(P, ENOMEM);
P->opaque = Q;
static_cast<struct pj_opaque*>(P->opaque)->cosphi1 = cos(pj_param(P->ctx, P->params, "rlat_1").f);
P->es = 0.;
P->fwd = wink2_s_forward;
P->inv = wink2_s_inverse;
return P;
}
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