path: root/lib/ephy-zoom.c

/*
 *  Copyright © 2003 Christian Persch
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2, or (at your option)
 *  any later version.
 *
 *  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.
 *
 *  $Id$
 */

#include "config.h"

#include "ephy-zoom.h"

#include <math.h>

int
ephy_zoom_get_zoom_level_index (float level)
{
    guint i;
    float previous, current, mean;

    previous = zoom_levels[0].level;

    for (i = 1; i < n_zoom_levels; i++)
    {
        current = zoom_levels[i].level;
        mean = sqrt (previous * current);

        if (level <= mean) return i - 1;

        previous = current;
    }

    return n_zoom_levels - 1;
}


float
ephy_zoom_get_changed_zoom_level (float level, int steps)
{
    int index;

    index = ephy_zoom_get_zoom_level_index (level);
    return zoom_levels[CLAMP(index + steps, 0, (int) n_zoom_levels - 1)].level;
}

float   ephy_zoom_get_nearest_zoom_level (float level)
{
    return ephy_zoom_get_changed_zoom_level (level, 0);
}