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 static int _download ( VikMapSource *self, MapCoord *src, const gchar *dest_fn, void *handle );
  58 static void * _download_handle_init ( VikMapSource *self);
  59 static void _download_handle_cleanup ( VikMapSource *self, void *handle);
  60 static gboolean _supports_download_only_new (VikMapSource *self );
  61
  62 static gchar *_get_uri( VikSlippyMapSource *self, MapCoord *src );
  63 static gchar *_get_hostname( VikSlippyMapSource *self );
  64 static DownloadMapOptions *_get_download_options( VikSlippyMapSource *self );
  65
  66 typedef struct _VikSlippyMapSourcePrivate VikSlippyMapSourcePrivate;
  67 struct _VikSlippyMapSourcePrivate
  68 {
  69   gchar *hostname;
  70   gchar *url;
  71   DownloadMapOptions options;
  72 };
  73
  74 #define VIK_SLIPPY_MAP_SOURCE_PRIVATE(o)  (G_TYPE_INSTANCE_GET_PRIVATE ((o), VIK_TYPE_SLIPPY_MAP_SOURCE, VikSlippyMapSourcePrivate))
  75
  76 /* properties */
  77 enum
  78 {
  79   PROP_0,
  80
  81   PROP_HOSTNAME,
  82   PROP_URL,
  83   PROP_REFERER,
  84   PROP_FOLLOW_LOCATION,
  85   PROP_CHECK_FILE_SERVER_TIME,
  86   PROP_USE_ETAG,
  87 };
  88
  89 G_DEFINE_TYPE (VikSlippyMapSource, vik_slippy_map_source, VIK_TYPE_MAP_SOURCE_DEFAULT);
  90
  91 static void
  92 vik_slippy_map_source_init (VikSlippyMapSource *self)
  93 {
  94   /* initialize the object here */
  95   VikSlippyMapSourcePrivate *priv = VIK_SLIPPY_MAP_SOURCE_PRIVATE (self);
  96
  97   priv->hostname = NULL;
  98   priv->url = NULL;
  99   priv->options.referer = NULL;
 100   priv->options.follow_location = 0;
 101   priv->options.check_file = a_check_map_file;
 102   priv->options.check_file_server_time = FALSE;
 103
 104   g_object_set (G_OBJECT (self),
 105                 "tilesize-x", 256,
 106                 "tilesize-y", 256,
 107                 "drawmode", VIK_VIEWPORT_DRAWMODE_MERCATOR,
 108                 NULL);
 109 }
 110
 111 static void
 112 vik_slippy_map_source_finalize (GObject *object)
 113 {
 114   VikSlippyMapSource *self = VIK_SLIPPY_MAP_SOURCE (object);
 115   VikSlippyMapSourcePrivate *priv = VIK_SLIPPY_MAP_SOURCE_PRIVATE (self);
 116
 117   g_free (priv->hostname);
 118   priv->hostname = NULL;
 119   g_free (priv->url);
 120   priv->url = NULL;
 121   g_free (priv->options.referer);
 122   priv->options.referer = NULL;
 123
 124   G_OBJECT_CLASS (vik_slippy_map_source_parent_class)->finalize (object);
 125 }
 126
 127 static void
 128 vik_slippy_map_source_set_property (GObject      *object,
 129                                     guint         property_id,
 130                                     const GValue *value,
 131                                     GParamSpec   *pspec)
 132 {
 133   VikSlippyMapSource *self = VIK_SLIPPY_MAP_SOURCE (object);
 134   VikSlippyMapSourcePrivate *priv = VIK_SLIPPY_MAP_SOURCE_PRIVATE (self);
 135
 136   switch (property_id)
 137     {
 138     case PROP_HOSTNAME:
 139       g_free (priv->hostname);
 140       priv->hostname = g_value_dup_string (value);
 141       break;
 142
 143     case PROP_URL:
 144       g_free (priv->url);
 145       priv->url = g_value_dup_string (value);
 146       break;
 147
 148     case PROP_REFERER:
 149       g_free (priv->options.referer);
 150       priv->options.referer = g_value_dup_string (value);
 151       break;
 152
 153     case PROP_FOLLOW_LOCATION:
 154       priv->options.follow_location = g_value_get_long (value);
 155       break;
 156
 157     case PROP_CHECK_FILE_SERVER_TIME:
 158       priv->options.check_file_server_time = g_value_get_boolean (value);
 159       break;
 160
 161     case PROP_USE_ETAG:
 162       priv->options.use_etag = g_value_get_boolean (value);
 163       break;
 164
 165     default:
 166       /* We don't have any other property... */
 167       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
 168       break;
 169     }
 170 }
 171
 172 static void
 173 vik_slippy_map_source_get_property (GObject    *object,
 174                                     guint       property_id,
 175                                     GValue     *value,
 176                                     GParamSpec *pspec)
 177 {
 178   VikSlippyMapSource *self = VIK_SLIPPY_MAP_SOURCE (object);
 179   VikSlippyMapSourcePrivate *priv = VIK_SLIPPY_MAP_SOURCE_PRIVATE (self);
 180
 181   switch (property_id)
 182     {
 183     case PROP_HOSTNAME:
 184       g_value_set_string (value, priv->hostname);
 185       break;
 186
 187     case PROP_URL:
 188       g_value_set_string (value, priv->url);
 189       break;
 190
 191     case PROP_REFERER:
 192       g_value_set_string (value, priv->options.referer);
 193       break;
 194
 195     case PROP_FOLLOW_LOCATION:
 196       g_value_set_long (value, priv->options.follow_location);
 197       break;
 198
 199     case PROP_CHECK_FILE_SERVER_TIME:
 200       g_value_set_boolean (value, priv->options.check_file_server_time);
 201       break;
 202
 203     case PROP_USE_ETAG:
 204       g_value_set_boolean (value, priv->options.use_etag);
 205       break;
 206
 207     default:
 208       /* We don't have any other property... */
 209       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
 210       break;
 211     }
 212 }
 213
 214 static void
 215 vik_slippy_map_source_class_init (VikSlippyMapSourceClass *klass)
 216 {
 217         GObjectClass* object_class = G_OBJECT_CLASS (klass);
 218         VikMapSourceClass* parent_class = VIK_MAP_SOURCE_CLASS (klass);
 219         GParamSpec *pspec = NULL;
 220
 221         object_class->set_property = vik_slippy_map_source_set_property;
 222     object_class->get_property = vik_slippy_map_source_get_property;
 223
 224         /* Overiding methods */
 225         parent_class->coord_to_mapcoord =        _coord_to_mapcoord;
 226         parent_class->mapcoord_to_center_coord = _mapcoord_to_center_coord;
 227         parent_class->download =                 _download;
 228         parent_class->download_handle_init =     _download_handle_init;
 229         parent_class->download_handle_cleanup =  _download_handle_cleanup;
 230         parent_class->supports_download_only_new = _supports_download_only_new;
 231
 232         /* Default implementation of methods */
 233         klass->get_uri = _get_uri;
 234         klass->get_hostname = _get_hostname;
 235         klass->get_download_options = _get_download_options;
 236
 237         pspec = g_param_spec_string ("hostname",
 238                                      "Hostname",
 239                                      "The hostname of the map server",
 240                                      "<no-set>" /* default value */,
 241                                      G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE);
 242         g_object_class_install_property (object_class, PROP_HOSTNAME, pspec);
 243
 244         pspec = g_param_spec_string ("url",
 245                                      "URL",
 246                                      "The template of the tiles' URL",
 247                                      "<no-set>" /* default value */,
 248                                      G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE);
 249         g_object_class_install_property (object_class, PROP_URL, pspec);
 250
 251         pspec = g_param_spec_string ("referer",
 252                                      "Referer",
 253                                      "The REFERER string to use in HTTP request",
 254                                      NULL /* default value */,
 255                                      G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE);
 256         g_object_class_install_property (object_class, PROP_REFERER, pspec);
 257
 258         pspec = g_param_spec_long ("follow-location",
 259                                    "Follow location",
 260                                "Specifies the number of retries to follow a redirect while downloading a page",
 261                                0  /* minimum value */,
 262                                G_MAXLONG /* maximum value */,
 263                                0  /* default value */,
 264                                G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE);
 265         g_object_class_install_property (object_class, PROP_FOLLOW_LOCATION, pspec);
 266
 267         pspec = g_param_spec_boolean ("check-file-server-time",
 268                                       "Check file server time",
 269                                   "Age of current cache before redownloading tile",
 270                                   FALSE  /* default value */,
 271                                   G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE);
 272         g_object_class_install_property (object_class, PROP_CHECK_FILE_SERVER_TIME, pspec);
 273
 274         pspec = g_param_spec_boolean ("use-etag",
 275                                       "Use etag values with server",
 276                                   "Store etag in a file, and send it to server to check if we have the latest file",
 277                                   FALSE  /* default value */,
 278                                   G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE);
 279         g_object_class_install_property (object_class, PROP_USE_ETAG, pspec);
 280
 281         g_type_class_add_private (klass, sizeof (VikSlippyMapSourcePrivate));
 282
 283         object_class->finalize = vik_slippy_map_source_finalize;
 284 }
 285
 286 /* 1 << (x) is like a 2**(x) */
 287 #define GZ(x) ((1<<(x)))
 288
 289 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),
 290                                            GZ(10), GZ(11), GZ(12), GZ(13), GZ(14), GZ(15), GZ(16), GZ(17) };
 291
 292 static const gint num_scales = (sizeof(scale_mpps) / sizeof(scale_mpps[0]));
 293
 294 static const gdouble scale_neg_mpps[] = { 1.0/GZ(0), 1.0/GZ(1), 1.0/GZ(2), 1.0/GZ(3) };
 295 static const gint num_scales_neg = (sizeof(scale_neg_mpps) / sizeof(scale_neg_mpps[0]));
 296
 297 #define ERROR_MARGIN 0.01
 298 static gint slippy_zoom ( gdouble mpp ) {
 299   gint i;
 300   for ( i = 0; i < num_scales; i++ ) {
 301     if ( ABS(scale_mpps[i] - mpp) < ERROR_MARGIN ) {
 302       return i;
 303     }
 304   }
 305   for ( i = 0; i < num_scales_neg; i++ ) {
 306     if ( ABS(scale_neg_mpps[i] - mpp) < 0.000001 ) {
 307       return -i;
 308     }
 309   }
 310
 311   return 255;
 312 }
 313
 314 gchar *
 315 vik_slippy_map_source_get_uri( VikSlippyMapSource *self, MapCoord *src )
 316 {
 317         VikSlippyMapSourceClass *klass;
 318         g_return_val_if_fail (self != NULL, 0);
 319         g_return_val_if_fail (VIK_IS_SLIPPY_MAP_SOURCE (self), 0);
 320         klass = VIK_SLIPPY_MAP_SOURCE_GET_CLASS(self);
 321
 322         g_return_val_if_fail (klass->get_uri != NULL, 0);
 323
 324         return (*klass->get_uri)(self, src);
 325 }
 326
 327 gchar *
 328 vik_slippy_map_source_get_hostname( VikSlippyMapSource *self )
 329 {
 330         VikSlippyMapSourceClass *klass;
 331         g_return_val_if_fail (self != NULL, 0);
 332         g_return_val_if_fail (VIK_IS_SLIPPY_MAP_SOURCE (self), 0);
 333         klass = VIK_SLIPPY_MAP_SOURCE_GET_CLASS(self);
 334
 335         g_return_val_if_fail (klass->get_hostname != NULL, 0);
 336
 337         return (*klass->get_hostname)(self);
 338 }
 339
 340 DownloadMapOptions *
 341 vik_slippy_map_source_get_download_options( VikSlippyMapSource *self )
 342 {
 343         VikSlippyMapSourceClass *klass;
 344         g_return_val_if_fail (self != NULL, 0);
 345         g_return_val_if_fail (VIK_IS_SLIPPY_MAP_SOURCE (self), 0);
 346         klass = VIK_SLIPPY_MAP_SOURCE_GET_CLASS(self);
 347
 348         g_return_val_if_fail (klass->get_download_options != NULL, 0);
 349
 350         return (*klass->get_download_options)(self);
 351 }
 352
 353 gboolean
 354 _supports_download_only_new (VikMapSource *self)
 355 {
 356   g_return_val_if_fail (VIK_IS_SLIPPY_MAP_SOURCE(self), FALSE);
 357
 358   VikSlippyMapSourcePrivate *priv = VIK_SLIPPY_MAP_SOURCE_PRIVATE(self);
 359
 360   return priv->options.check_file_server_time || priv->options.use_etag;
 361 }
 362 static gboolean
 363 _coord_to_mapcoord ( VikMapSource *self, const VikCoord *src, gdouble xzoom, gdouble yzoom, MapCoord *dest )
 364 {
 365   g_assert ( src->mode == VIK_COORD_LATLON );
 366
 367   if ( xzoom != yzoom )
 368     return FALSE;
 369
 370   dest->scale = slippy_zoom ( xzoom );
 371   if ( dest->scale == 255 )
 372     return FALSE;
 373
 374   dest->x = (src->east_west + 180) / 360 * GZ(17) / xzoom;
 375   dest->y = (180 - MERCLAT(src->north_south)) / 360 * GZ(17) / xzoom;
 376   dest->z = 0;
 377
 378   return TRUE;
 379 }
 380
 381 static void
 382 _mapcoord_to_center_coord ( VikMapSource *self, MapCoord *src, VikCoord *dest )
 383 {
 384   gdouble socalled_mpp;
 385   if (src->scale >= 0)
 386     socalled_mpp = GZ(src->scale);
 387   else
 388     socalled_mpp = 1.0/GZ(-src->scale);
 389   dest->mode = VIK_COORD_LATLON;
 390   dest->east_west = ((src->x+0.5) / GZ(17) * socalled_mpp * 360) - 180;
 391   dest->north_south = DEMERCLAT(180 - ((src->y+0.5) / GZ(17) * socalled_mpp * 360));
 392 }
 393
 394 static int
 395 _download ( VikMapSource *self, MapCoord *src, const gchar *dest_fn, void *handle )
 396 {
 397    int res;
 398    gchar *uri = vik_slippy_map_source_get_uri(VIK_SLIPPY_MAP_SOURCE(self), src);
 399    gchar *host = vik_slippy_map_source_get_hostname(VIK_SLIPPY_MAP_SOURCE(self));
 400    DownloadMapOptions *options = vik_slippy_map_source_get_download_options(VIK_SLIPPY_MAP_SOURCE(self));
 401    res = a_http_download_get_url ( host, uri, dest_fn, options, handle );
 402    g_free ( uri );
 403    g_free ( host );
 404    return res;
 405 }
 406
 407 static void *
 408 _download_handle_init ( VikMapSource *self )
 409 {
 410    return a_download_handle_init ();
 411 }
 412
 413
 414 static void
 415 _download_handle_cleanup ( VikMapSource *self, void *handle )
 416 {
 417    return a_download_handle_cleanup ( handle );
 418 }
 419
 420 static gchar *
 421 _get_uri( VikSlippyMapSource *self, MapCoord *src )
 422 {
 423         g_return_val_if_fail (VIK_IS_SLIPPY_MAP_SOURCE(self), NULL);
 424
 425     VikSlippyMapSourcePrivate *priv = VIK_SLIPPY_MAP_SOURCE_PRIVATE(self);
 426         gchar *uri = g_strdup_printf (priv->url, 17 - src->scale, src->x, src->y);
 427         return uri;
 428 }
 429
 430 static gchar *
 431 _get_hostname( VikSlippyMapSource *self )
 432 {
 433         g_return_val_if_fail (VIK_IS_SLIPPY_MAP_SOURCE(self), NULL);
 434
 435     VikSlippyMapSourcePrivate *priv = VIK_SLIPPY_MAP_SOURCE_PRIVATE(self);
 436         return g_strdup( priv->hostname );
 437 }
 438
 439 static DownloadMapOptions *
 440 _get_download_options( VikSlippyMapSource *self )
 441 {
 442         g_return_val_if_fail (VIK_IS_SLIPPY_MAP_SOURCE(self), NULL);
 443
 444         VikSlippyMapSourcePrivate *priv = VIK_SLIPPY_MAP_SOURCE_PRIVATE(self);
 445         return &(priv->options);
 446 }
 447
 448 VikSlippyMapSource *
 449 vik_slippy_map_source_new_with_id (guint8 id, const gchar *label, const gchar *hostname, const gchar *url)
 450 {
 451         return g_object_new(VIK_TYPE_SLIPPY_MAP_SOURCE,
 452                             "id", id, "label", label, "hostname", hostname, "url", url, NULL);
 453 }