/******************************************************************************

 * Project:  PROJ.4

 * Purpose:  Implementation of the Times projection.

 * Author:   Kristian Evers <kristianevers@gmail.com>

 *

 ******************************************************************************

 * Copyright (c) 2016, Kristian Evers

 *

 * Permission is hereby granted, free of charge, to any person obtaining a

 * copy of this software and associated documentation files (the "Software"),

 * to deal in the Software without restriction, including without limitation

 * the rights to use, copy, modify, merge, publish, distribute, sublicense,

 * and/or sell copies of the Software, and to permit persons to whom the

 * Software is furnished to do so, subject to the following conditions:

 *

 * The above copyright notice and this permission notice shall be included

 * in all copies or substantial portions of the Software.

 *

 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS

 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL

 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER

 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING

 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER

 * DEALINGS IN THE SOFTWARE.

 *****************************************************************************

 * Based on description of the Times Projection in

 *

 * Flattening the Earth, Snyder, J.P., 1993, p.213-214.

 *****************************************************************************/

#include <math.h>

#include "proj.h"

#include "proj_internal.h"

PROJ_HEAD(times, "Times") "\n\tCyl, Sph";

static PJ_XY times_s_forward(PJ_LP lp, PJ *P) { /* Spheroidal, forward */

    double T, S, S2;

    PJ_XY xy = {0.0, 0.0};

    (void)P;

    T = tan(lp.phi / 2.0);

    S = sin(M_FORTPI * T);

    S2 = S * S;

    xy.x = lp.lam * (0.74482 - 0.34588 * S2);

    xy.y = 1.70711 * T;

    return xy;

}

static PJ_LP times_s_inverse(PJ_XY xy, PJ *P) { /* Spheroidal, inverse */

    double T, S, S2;

    PJ_LP lp = {0.0, 0.0};

    (void)P;

    T = xy.y / 1.70711;

    S = sin(M_FORTPI * T);

    S2 = S * S;

    lp.lam = xy.x / (0.74482 - 0.34588 * S2);

    lp.phi = 2 * atan(T);

    return lp;

}

PJ *PJ_PROJECTION(times) {

    P->es = 0.0;

    P->inv = times_s_inverse;

    P->fwd = times_s_forward;

    return P;

}