lib/ephy-zoom.c

   1 /*
   2  *  Copyright © 2003 Christian Persch
   3  *
   4  *  This program is free software; you can redistribute it and/or modify
   5  *  it under the terms of the GNU General Public License as published by
   6  *  the Free Software Foundation; either version 2, or (at your option)
   7  *  any later version.
   8  *
   9  *  This program is distributed in the hope that it will be useful,
  10  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *  GNU General Public License for more details.
  13  *
  14  *  You should have received a copy of the GNU General Public License
  15  *  along with this program; if not, write to the Free Software
  16  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
  17  *
  18  *  $Id: ephy-zoom.c 6952 2007-03-11 19:42:02Z chpe $
  19  */
  20
  21 #include "config.h"
  22
  23 #include "ephy-zoom.h"
  24
  25 #include <math.h>
  26
  27 int
  28 ephy_zoom_get_zoom_level_index (float level)
  29 {
  30         guint i;
  31         float previous, current, mean;
  32
  33         previous = zoom_levels[0].level;
  34
  35         for (i = 1; i < n_zoom_levels; i++)
  36         {
  37                 current = zoom_levels[i].level;
  38                 mean = sqrt (previous * current);
  39
  40                 if (level <= mean) return i - 1;
  41
  42                 previous = current;
  43         }
  44
  45         return n_zoom_levels - 1;
  46 }
  47
  48
  49 float
  50 ephy_zoom_get_changed_zoom_level (float level, int steps)
  51 {
  52         int index;
  53
  54         index = ephy_zoom_get_zoom_level_index (level);
  55         return zoom_levels[CLAMP(index + steps, 0, (int) n_zoom_levels - 1)].level;
  56 }
  57
  58 float   ephy_zoom_get_nearest_zoom_level (float level)
  59 {
  60         return ephy_zoom_get_changed_zoom_level (level, 0);
  61 }