exag.c

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/*!
   \file lib/nviz/exag.c

   \brief Nviz library -- Exaggeration functions

   Based on visualization/nviz/src/exag.c

   (C) 2008, 2010 by the GRASS Development Team
   This program is free software under the GNU General Public License
   (>=v2). Read the file COPYING that comes with GRASS for details.

   \author Updated/modified by Martin Landa <landa.martin gmail.com> (Google SoC 2008/2010)
 */

#include <grass/nviz.h>

/*!
   \brief Get view height

   Call after initial data has been loaded

   \param[out] val height value
   \param[out] min min value (or NULL)
   \param[out] max max value (or NULL)

   \return 1
 */
int Nviz_get_exag_height(double *val, double *min, double *max)
{
    float longdim, exag, texag, hmin, hmax, fmin, fmax;
    int nsurfs, i, *surf_list;

    surf_list = GS_get_surf_list(&nsurfs);
    if (nsurfs) {
        GS_get_longdim(&longdim);
        GS_get_zrange_nz(&hmin, &hmax);

        exag = 0.0;
        for (i = 0; i < nsurfs; i++) {
            if (GS_get_exag_guess(surf_list[i], &texag) > -1)
                if (texag)
                    exag = texag > exag ? texag : exag;
        }
        if (exag == 0.0)
            exag = 1.0;

        fmin = hmin - (2. * longdim / exag);
        fmax = hmin + (3 * longdim / exag);
    }
    else {
        fmax = 10000.0;
        fmin = 0.0;
    }

    *val = fmin + (fmax - fmin) / 2.0;

    if (min)
        *min = fmin;

    if (max)
        *max = fmax;

    G_debug(1, "Nviz_get_exag_height(): value = %f min = %f max = %f",
            *val, min ? *min : 0.0 , max ? *max : 0.0);
    
    return 1;
}

/*!
   \brief Get view z-exag value

   Call after initial data has been loaded

   \return value
 */
double Nviz_get_exag()
{
    float exag, texag;
    int nsurfs, i, *surf_list;

    surf_list = GS_get_surf_list(&nsurfs);

    exag = 0.0;
    for (i = 0; i < nsurfs; i++) {
        if (GS_get_exag_guess(surf_list[i], &texag) > -1) {
            if (texag)
                exag = (texag > exag) ? texag : exag;
        }
    }

    if (exag == 0.0)
        exag = 1.0;

    if (nsurfs > 0)
        G_free(surf_list);

    G_debug(1, "Nviz_get_exag(): value = %f", exag);
    return exag;
}