projects / andy / viking.git / blame
| Commit | Line | Data |
|---|---|---|
| e1dde2a6 RN |
1 | /* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 4; tab-width: 4 -*- */ |
| 2 | /* | |
| 3 | * viking -- GPS Data and Topo Analyzer, Explorer, and Manager | |
| 4 | * | |
| 5 | * Copyright (C) 2013, Rob Norris <rw_norris@hotmail.com> | |
| 6 | * | |
| 7 | * This program is free software; you can redistribute it and/or modify | |
| 8 | * it under the terms of the GNU General Public License as published by | |
| 9 | * the Free Software Foundation; either version 2 of the License, or | |
| 10 | * (at your option) any later version. | |
| 11 | * | |
| 12 | * This program is distributed in the hope that it will be useful, | |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
| 15 | * GNU General Public License for more details. | |
| 16 | * | |
| 17 | * You should have received a copy of the GNU General Public License | |
| 18 | * along with this program; if not, write to the Free Software | |
| 19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
| 20 | * | |
| 21 | */ | |
| 22 | #include "maputils.h" | |
| 23 | ||
| 24 | // World Scale: VIK_GZ(17) | |
| 25 | // down to | |
| 26 | // Submeter scale: 1/VIK_GZ(5) | |
| 27 | // No map provider is going to have tiles at the highest zoom in level - but we can interpolate to that. | |
| 28 | ||
| 29 | static const gdouble scale_mpps[] = { VIK_GZ(0), VIK_GZ(1), VIK_GZ(2), VIK_GZ(3), VIK_GZ(4), VIK_GZ(5), | |
| 30 | VIK_GZ(6), VIK_GZ(7), VIK_GZ(8), VIK_GZ(9), VIK_GZ(10), VIK_GZ(11), | |
| 31 | VIK_GZ(12), VIK_GZ(13), VIK_GZ(14), VIK_GZ(15), VIK_GZ(16), VIK_GZ(17) }; | |
| 32 | static const gint num_scales = (sizeof(scale_mpps) / sizeof(scale_mpps[0])); | |
| 33 | ||
| 34 | static const gdouble scale_neg_mpps[] = { 1.0/VIK_GZ(0), 1.0/VIK_GZ(1), 1.0/VIK_GZ(2), | |
| 35 | 1.0/VIK_GZ(3), 1.0/VIK_GZ(4), 1.0/VIK_GZ(5) }; | |
| 36 | static const gint num_scales_neg = (sizeof(scale_neg_mpps) / sizeof(scale_neg_mpps[0])); | |
| 37 | ||
| 38 | #define ERROR_MARGIN 0.01 | |
| 39 | /** | |
| 40 | * map_utils_mpp_to_scale: | |
| 41 | * @mpp: The so called 'mpp' | |
| 42 | * | |
| 43 | * Returns: the zoom scale value which may be negative. | |
| 44 | */ | |
| 45 | gint map_utils_mpp_to_scale ( gdouble mpp ) { | |
| 46 | gint i; | |
| 47 | for ( i = 0; i < num_scales; i++ ) { | |
| 48 | if ( ABS(scale_mpps[i] - mpp) < ERROR_MARGIN ) { | |
| 49 | return i; | |
| 50 | } | |
| 51 | } | |
| 52 | for ( i = 0; i < num_scales_neg; i++ ) { | |
| 53 | if ( ABS(scale_neg_mpps[i] - mpp) < 0.000001 ) { | |
| 54 | return -i; | |
| 55 | } | |
| 56 | } | |
| 57 | ||
| 58 | return 255; | |
| 59 | } | |
| 60 | ||
| 61 | /** | |
| 62 | * map_utils_mpp_to_zoom_level: | |
| 63 | * @mpp: The so called 'mpp' | |
| 64 | * | |
| 65 | * Returns: a Zoom Level | |
| 66 | * See: http://wiki.openstreetmap.org/wiki/Zoom_levels | |
| 67 | */ | |
| 68 | guint8 map_utils_mpp_to_zoom_level ( gdouble mpp ) | |
| 69 | { | |
| 70 | gint answer = 17 - map_utils_mpp_to_scale ( mpp ); | |
| 71 | if ( answer < 0 ) | |
| 72 | answer = 17; | |
| 73 | return answer; | |
| 74 | } |