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#define PJ_LIB__
#include <float.h>
#include <math.h>
#include "proj.h"
#include "proj_internal.h"
#include <math.h>
PROJ_HEAD(merc, "Mercator") "\n\tCyl, Sph&Ell\n\tlat_ts=";
PROJ_HEAD(webmerc, "Web Mercator / Pseudo Mercator") "\n\tCyl, Ell\n\t";
static PJ_XY merc_e_forward (PJ_LP lp, PJ *P) { /* Ellipsoidal, forward */
PJ_XY xy = {0.0,0.0};
xy.x = P->k0 * lp.lam;
// Instead of calling tan and sin, call sin and cos which the compiler
// optimizes to a single call to sincos.
double sphi = sin(lp.phi);
double cphi = cos(lp.phi);
xy.y = P->k0 * (asinh(sphi/cphi) - P->e * atanh(P->e * sphi));
return xy;
}
static PJ_XY merc_s_forward (PJ_LP lp, PJ *P) { /* Spheroidal, forward */
PJ_XY xy = {0.0,0.0};
xy.x = P->k0 * lp.lam;
xy.y = P->k0 * asinh(tan(lp.phi));
return xy;
}
static PJ_LP merc_e_inverse (PJ_XY xy, PJ *P) { /* Ellipsoidal, inverse */
PJ_LP lp = {0.0,0.0};
lp.phi = atan(pj_sinhpsi2tanphi(P->ctx, sinh(xy.y / P->k0), P->e));
lp.lam = xy.x / P->k0;
return lp;
}
static PJ_LP merc_s_inverse (PJ_XY xy, PJ *P) { /* Spheroidal, inverse */
PJ_LP lp = {0.0,0.0};
lp.phi = atan(sinh(xy.y / P->k0));
lp.lam = xy.x / P->k0;
return lp;
}
PJ *PROJECTION(merc) {
double phits=0.0;
int is_phits;
if( (is_phits = pj_param(P->ctx, P->params, "tlat_ts").i) ) {
phits = fabs(pj_param(P->ctx, P->params, "rlat_ts").f);
if (phits >= M_HALFPI)
{
proj_log_error(P, _("Invalid value for lat_ts: |lat_ts| should be <= 90°"));
return pj_default_destructor(P, PROJ_ERR_INVALID_OP_ILLEGAL_ARG_VALUE);
}
}
if (P->es != 0.0) { /* ellipsoid */
if (is_phits)
P->k0 = pj_msfn(sin(phits), cos(phits), P->es);
P->inv = merc_e_inverse;
P->fwd = merc_e_forward;
}
else { /* sphere */
if (is_phits)
P->k0 = cos(phits);
P->inv = merc_s_inverse;
P->fwd = merc_s_forward;
}
return P;
}
PJ *PROJECTION(webmerc) {
/* Overriding k_0 with fixed parameter */
P->k0 = 1.0;
P->inv = merc_s_inverse;
P->fwd = merc_s_forward;
return P;
}
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