src/vikslippymapsource.c

   1 /* -*- Mode: C; indent-tabs-mode: t; c-basic-offset: 4; tab-width: 4 -*- */
   2 /*
   3  * viking
   4  * Copyright (C) 2009, Guilhem Bonnefille <guilhem.bonnefille@gmail.com>
   5  *
   6  * viking is free software: you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License as published by the
   8  * Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * viking is distributed in the hope that it will be useful, but
  12  * WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  14  * See the GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License along
  17  * with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20  /**
  21   * SECTION:vikslippymapsource
  22   * @short_description: the class for SlippyMap oriented map sources
  23   *
  24   * The #VikSlippyMapSource class handles slippy map oriented map sources.
  25   * The related service is tile oriented, à la Google.
  26   *
  27   * The tiles are in 'google spherical mercator', which is
  28   * basically a mercator projection that assumes a spherical earth.
  29   * http://docs.openlayers.org/library/spherical_mercator.html
  30   *
  31   * Such service is also a type of TMS (Tile Map Service) as defined in
  32   * OSGeo's wiki.
  33   * http://wiki.osgeo.org/wiki/Tile_Map_Service_Specification
  34   * But take care that the Y axis is inverted, ie the origin is at top-left
  35   * corner.
  36   * Following this specification, the protocol handled by this class
  37   * follows the global-mercator profile.
  38   *
  39   * You can also find many interesting information on the OSM's wiki.
  40   * http://wiki.openstreetmap.org/wiki/Slippy_map_tilenames
  41   * http://wiki.openstreetmap.org/wiki/Setting_up_TMS
  42   */
  43
  44 #ifdef HAVE_CONFIG_H
  45 #include "config.h"
  46 #endif
  47
  48 #ifdef HAVE_MATH_H
  49 #include <math.h>
  50 #endif
  51
  52 #include "globals.h"
  53 #include "vikslippymapsource.h"
  54
  55 static gboolean _coord_to_mapcoord ( VikMapSource *self, const VikCoord *src, gdouble xzoom, gdouble yzoom, MapCoord *dest );
  56 static void _mapcoord_to_center_coord ( VikMapSource *self, MapCoord *src, VikCoord *dest );
  57
  58 static gboolean _supports_download_only_new (VikMapSource *self );
  59
  60 static gchar *_get_uri( VikMapSourceDefault *self, MapCoord *src );
  61 static gchar *_get_hostname( VikMapSourceDefault *self );
  62 static DownloadMapOptions *_get_download_options( VikMapSourceDefault *self );
  63
  64 typedef struct _VikSlippyMapSourcePrivate VikSlippyMapSourcePrivate;
  65 struct _VikSlippyMapSourcePrivate
  66 {
  67   gchar *hostname;
  68   gchar *url;
  69   DownloadMapOptions options;
  70 };
  71
  72 #define VIK_SLIPPY_MAP_SOURCE_PRIVATE(o)  (G_TYPE_INSTANCE_GET_PRIVATE ((o), VIK_TYPE_SLIPPY_MAP_SOURCE, VikSlippyMapSourcePrivate))
  73
  74 /* properties */
  75 enum
  76 {
  77   PROP_0,
  78
  79   PROP_HOSTNAME,
  80   PROP_URL,
  81   PROP_REFERER,
  82   PROP_FOLLOW_LOCATION,
  83   PROP_CHECK_FILE_SERVER_TIME,
  84   PROP_USE_ETAG,
  85 };
  86
  87 G_DEFINE_TYPE (VikSlippyMapSource, vik_slippy_map_source, VIK_TYPE_MAP_SOURCE_DEFAULT);
  88
  89 static void
  90 vik_slippy_map_source_init (VikSlippyMapSource *self)
  91 {
  92   /* initialize the object here */
  93   VikSlippyMapSourcePrivate *priv = VIK_SLIPPY_MAP_SOURCE_PRIVATE (self);
  94
  95   priv->hostname = NULL;
  96   priv->url = NULL;
  97   priv->options.referer = NULL;
  98   priv->options.follow_location = 0;
  99   priv->options.check_file = a_check_map_file;
 100   priv->options.check_file_server_time = FALSE;
 101
 102   g_object_set (G_OBJECT (self),
 103                 "tilesize-x", 256,
 104                 "tilesize-y", 256,
 105                 "drawmode", VIK_VIEWPORT_DRAWMODE_MERCATOR,
 106                 NULL);
 107 }
 108
 109 static void
 110 vik_slippy_map_source_finalize (GObject *object)
 111 {
 112   VikSlippyMapSource *self = VIK_SLIPPY_MAP_SOURCE (object);
 113   VikSlippyMapSourcePrivate *priv = VIK_SLIPPY_MAP_SOURCE_PRIVATE (self);
 114
 115   g_free (priv->hostname);
 116   priv->hostname = NULL;
 117   g_free (priv->url);
 118   priv->url = NULL;
 119   g_free (priv->options.referer);
 120   priv->options.referer = NULL;
 121
 122   G_OBJECT_CLASS (vik_slippy_map_source_parent_class)->finalize (object);
 123 }
 124
 125 static void
 126 vik_slippy_map_source_set_property (GObject      *object,
 127                                     guint         property_id,
 128                                     const GValue *value,
 129                                     GParamSpec   *pspec)
 130 {
 131   VikSlippyMapSource *self = VIK_SLIPPY_MAP_SOURCE (object);
 132   VikSlippyMapSourcePrivate *priv = VIK_SLIPPY_MAP_SOURCE_PRIVATE (self);
 133
 134   switch (property_id)
 135     {
 136     case PROP_HOSTNAME:
 137       g_free (priv->hostname);
 138       priv->hostname = g_value_dup_string (value);
 139       break;
 140
 141     case PROP_URL:
 142       g_free (priv->url);
 143       priv->url = g_value_dup_string (value);
 144       break;
 145
 146     case PROP_REFERER:
 147       g_free (priv->options.referer);
 148       priv->options.referer = g_value_dup_string (value);
 149       break;
 150
 151     case PROP_FOLLOW_LOCATION:
 152       priv->options.follow_location = g_value_get_long (value);
 153       break;
 154
 155     case PROP_CHECK_FILE_SERVER_TIME:
 156       priv->options.check_file_server_time = g_value_get_boolean (value);
 157       break;
 158
 159     case PROP_USE_ETAG:
 160       priv->options.use_etag = g_value_get_boolean (value);
 161       break;
 162
 163     default:
 164       /* We don't have any other property... */
 165       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
 166       break;
 167     }
 168 }
 169
 170 static void
 171 vik_slippy_map_source_get_property (GObject    *object,
 172                                     guint       property_id,
 173                                     GValue     *value,
 174                                     GParamSpec *pspec)
 175 {
 176   VikSlippyMapSource *self = VIK_SLIPPY_MAP_SOURCE (object);
 177   VikSlippyMapSourcePrivate *priv = VIK_SLIPPY_MAP_SOURCE_PRIVATE (self);
 178
 179   switch (property_id)
 180     {
 181     case PROP_HOSTNAME:
 182       g_value_set_string (value, priv->hostname);
 183       break;
 184
 185     case PROP_URL:
 186       g_value_set_string (value, priv->url);
 187       break;
 188
 189     case PROP_REFERER:
 190       g_value_set_string (value, priv->options.referer);
 191       break;
 192
 193     case PROP_FOLLOW_LOCATION:
 194       g_value_set_long (value, priv->options.follow_location);
 195       break;
 196
 197     case PROP_CHECK_FILE_SERVER_TIME:
 198       g_value_set_boolean (value, priv->options.check_file_server_time);
 199       break;
 200
 201     case PROP_USE_ETAG:
 202       g_value_set_boolean (value, priv->options.use_etag);
 203       break;
 204
 205     default:
 206       /* We don't have any other property... */
 207       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
 208       break;
 209     }
 210 }
 211
 212 static void
 213 vik_slippy_map_source_class_init (VikSlippyMapSourceClass *klass)
 214 {
 215         GObjectClass* object_class = G_OBJECT_CLASS (klass);
 216         VikMapSourceClass* grandparent_class = VIK_MAP_SOURCE_CLASS (klass);
 217         VikMapSourceDefaultClass* parent_class = VIK_MAP_SOURCE_DEFAULT_CLASS (klass);
 218         GParamSpec *pspec = NULL;
 219
 220         object_class->set_property = vik_slippy_map_source_set_property;
 221     object_class->get_property = vik_slippy_map_source_get_property;
 222
 223         /* Overiding methods */
 224         grandparent_class->coord_to_mapcoord =        _coord_to_mapcoord;
 225         grandparent_class->mapcoord_to_center_coord = _mapcoord_to_center_coord;
 226         grandparent_class->supports_download_only_new = _supports_download_only_new;
 227
 228         parent_class->get_uri = _get_uri;
 229         parent_class->get_hostname = _get_hostname;
 230         parent_class->get_download_options = _get_download_options;
 231
 232         pspec = g_param_spec_string ("hostname",
 233                                      "Hostname",
 234                                      "The hostname of the map server",
 235                                      "<no-set>" /* default value */,
 236                                      G_PARAM_READWRITE);
 237         g_object_class_install_property (object_class, PROP_HOSTNAME, pspec);
 238
 239         pspec = g_param_spec_string ("url",
 240                                      "URL",
 241                                      "The template of the tiles' URL",
 242                                      "<no-set>" /* default value */,
 243                                      G_PARAM_READWRITE);
 244         g_object_class_install_property (object_class, PROP_URL, pspec);
 245
 246         pspec = g_param_spec_string ("referer",
 247                                      "Referer",
 248                                      "The REFERER string to use in HTTP request",
 249                                      NULL /* default value */,
 250                                      G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE);
 251         g_object_class_install_property (object_class, PROP_REFERER, pspec);
 252
 253         pspec = g_param_spec_long ("follow-location",
 254                                    "Follow location",
 255                                "Specifies the number of retries to follow a redirect while downloading a page",
 256                                0  /* minimum value */,
 257                                G_MAXLONG /* maximum value */,
 258                                0  /* default value */,
 259                                G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE);
 260         g_object_class_install_property (object_class, PROP_FOLLOW_LOCATION, pspec);
 261
 262         pspec = g_param_spec_boolean ("check-file-server-time",
 263                                       "Check file server time",
 264                                   "Age of current cache before redownloading tile",
 265                                   FALSE  /* default value */,
 266                                   G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE);
 267         g_object_class_install_property (object_class, PROP_CHECK_FILE_SERVER_TIME, pspec);
 268
 269         pspec = g_param_spec_boolean ("use-etag",
 270                                       "Use etag values with server",
 271                                   "Store etag in a file, and send it to server to check if we have the latest file",
 272                                   FALSE  /* default value */,
 273                                   G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE);
 274         g_object_class_install_property (object_class, PROP_USE_ETAG, pspec);
 275
 276         g_type_class_add_private (klass, sizeof (VikSlippyMapSourcePrivate));
 277
 278         object_class->finalize = vik_slippy_map_source_finalize;
 279 }
 280
 281 /* 1 << (x) is like a 2**(x) */
 282 #define GZ(x) ((1<<(x)))
 283
 284 static const gdouble scale_mpps[] = { GZ(0), GZ(1), GZ(2), GZ(3), GZ(4), GZ(5), GZ(6), GZ(7), GZ(8), GZ(9),
 285                                            GZ(10), GZ(11), GZ(12), GZ(13), GZ(14), GZ(15), GZ(16), GZ(17) };
 286
 287 static const gint num_scales = (sizeof(scale_mpps) / sizeof(scale_mpps[0]));
 288
 289 static const gdouble scale_neg_mpps[] = { 1.0/GZ(0), 1.0/GZ(1), 1.0/GZ(2), 1.0/GZ(3) };
 290 static const gint num_scales_neg = (sizeof(scale_neg_mpps) / sizeof(scale_neg_mpps[0]));
 291
 292 #define ERROR_MARGIN 0.01
 293 gint
 294 vik_slippy_map_source_zoom_to_scale ( gdouble mpp ) {
 295   gint i;
 296   for ( i = 0; i < num_scales; i++ ) {
 297     if ( ABS(scale_mpps[i] - mpp) < ERROR_MARGIN ) {
 298       return i;
 299     }
 300   }
 301   for ( i = 0; i < num_scales_neg; i++ ) {
 302     if ( ABS(scale_neg_mpps[i] - mpp) < 0.000001 ) {
 303       return -i;
 304     }
 305   }
 306
 307   return 255;
 308 }
 309
 310 gboolean
 311 _supports_download_only_new (VikMapSource *self)
 312 {
 313   g_return_val_if_fail (VIK_IS_SLIPPY_MAP_SOURCE(self), FALSE);
 314
 315   VikSlippyMapSourcePrivate *priv = VIK_SLIPPY_MAP_SOURCE_PRIVATE(self);
 316
 317   return priv->options.check_file_server_time || priv->options.use_etag;
 318 }
 319
 320 static gboolean
 321 _coord_to_mapcoord ( VikMapSource *self, const VikCoord *src, gdouble xzoom, gdouble yzoom, MapCoord *dest )
 322 {
 323   g_assert ( src->mode == VIK_COORD_LATLON );
 324
 325   if ( xzoom != yzoom )
 326     return FALSE;
 327
 328   dest->scale = vik_slippy_map_source_zoom_to_scale ( xzoom );
 329   if ( dest->scale == 255 )
 330     return FALSE;
 331
 332   dest->x = (src->east_west + 180) / 360 * GZ(17) / xzoom;
 333   dest->y = (180 - MERCLAT(src->north_south)) / 360 * GZ(17) / xzoom;
 334   dest->z = 0;
 335
 336   return TRUE;
 337 }
 338
 339 static void
 340 _mapcoord_to_center_coord ( VikMapSource *self, MapCoord *src, VikCoord *dest )
 341 {
 342   gdouble socalled_mpp;
 343   if (src->scale >= 0)
 344     socalled_mpp = GZ(src->scale);
 345   else
 346     socalled_mpp = 1.0/GZ(-src->scale);
 347   dest->mode = VIK_COORD_LATLON;
 348   dest->east_west = ((src->x+0.5) / GZ(17) * socalled_mpp * 360) - 180;
 349   dest->north_south = DEMERCLAT(180 - ((src->y+0.5) / GZ(17) * socalled_mpp * 360));
 350 }
 351
 352 static gchar *
 353 _get_uri( VikMapSourceDefault *self, MapCoord *src )
 354 {
 355         g_return_val_if_fail (VIK_IS_SLIPPY_MAP_SOURCE(self), NULL);
 356
 357     VikSlippyMapSourcePrivate *priv = VIK_SLIPPY_MAP_SOURCE_PRIVATE(self);
 358         gchar *uri = g_strdup_printf (priv->url, 17 - src->scale, src->x, src->y);
 359         return uri;
 360 }
 361
 362 static gchar *
 363 _get_hostname( VikMapSourceDefault *self )
 364 {
 365         g_return_val_if_fail (VIK_IS_SLIPPY_MAP_SOURCE(self), NULL);
 366
 367     VikSlippyMapSourcePrivate *priv = VIK_SLIPPY_MAP_SOURCE_PRIVATE(self);
 368         return g_strdup( priv->hostname );
 369 }
 370
 371 static DownloadMapOptions *
 372 _get_download_options( VikMapSourceDefault *self )
 373 {
 374         g_return_val_if_fail (VIK_IS_SLIPPY_MAP_SOURCE(self), NULL);
 375
 376         VikSlippyMapSourcePrivate *priv = VIK_SLIPPY_MAP_SOURCE_PRIVATE(self);
 377         return &(priv->options);
 378 }
 379
 380 VikSlippyMapSource *
 381 vik_slippy_map_source_new_with_id (guint8 id, const gchar *label, const gchar *hostname, const gchar *url)
 382 {
 383         return g_object_new(VIK_TYPE_SLIPPY_MAP_SOURCE,
 384                             "id", id, "label", label, "hostname", hostname, "url", url, NULL);
 385 }