src/acquire.c

   1 /*
   2  * viking -- GPS Data and Topo Analyzer, Explorer, and Manager
   3  *
   4  * Copyright (C) 2003-2005, Evan Battaglia <gtoevan@gmx.net>
   5  * Copyright (C) 2013-2015, 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 #ifdef HAVE_CONFIG_H
  23 #include "config.h"
  24 #endif
  25
  26 #include <stdio.h>
  27 #include <string.h>
  28 #include <glib/gprintf.h>
  29 #include <glib/gi18n.h>
  30
  31 #include "viking.h"
  32 #include "babel.h"
  33 #include "gpx.h"
  34 #include "acquire.h"
  35
  36 /************************ FILTER LIST *******************/
  37 // extern VikDataSourceInterface vik_datasource_gps_interface;
  38
  39 /*** Input is TRWLayer ***/
  40 extern VikDataSourceInterface vik_datasource_bfilter_simplify_interface;
  41 extern VikDataSourceInterface vik_datasource_bfilter_compress_interface;
  42 extern VikDataSourceInterface vik_datasource_bfilter_dup_interface;
  43 extern VikDataSourceInterface vik_datasource_bfilter_manual_interface;
  44
  45 /*** Input is a track and a TRWLayer ***/
  46 extern VikDataSourceInterface vik_datasource_bfilter_polygon_interface;
  47 extern VikDataSourceInterface vik_datasource_bfilter_exclude_polygon_interface;
  48
  49 /*** Input is a track ***/
  50
  51 const VikDataSourceInterface *filters[] = {
  52   &vik_datasource_bfilter_simplify_interface,
  53   &vik_datasource_bfilter_compress_interface,
  54   &vik_datasource_bfilter_dup_interface,
  55   &vik_datasource_bfilter_manual_interface,
  56   &vik_datasource_bfilter_polygon_interface,
  57   &vik_datasource_bfilter_exclude_polygon_interface,
  58 };
  59
  60 const guint N_FILTERS = sizeof(filters) / sizeof(filters[0]);
  61
  62 VikTrack *filter_track = NULL;
  63
  64 /********************************************************/
  65
  66 /* passed along to worker thread */
  67 typedef struct {
  68   acq_dialog_widgets_t *w;
  69   ProcessOptions *po;
  70   gboolean creating_new_layer;
  71   VikTrwLayer *vtl;
  72   DownloadFileOptions *options;
  73 } w_and_interface_t;
  74
  75
  76 /*********************************************************
  77  * Definitions and routines for acquiring data from Data Sources in general
  78  *********************************************************/
  79
  80 static void progress_func ( BabelProgressCode c, gpointer data, acq_dialog_widgets_t *w )
  81 {
  82   if ( w->source_interface->is_thread ) {
  83     gdk_threads_enter ();
  84     if ( !w->running ) {
  85       if ( w->source_interface->cleanup_func )
  86         w->source_interface->cleanup_func ( w->user_data );
  87       gdk_threads_leave ();
  88       g_thread_exit ( NULL );
  89     }
  90     gdk_threads_leave ();
  91   }
  92
  93   if ( w->source_interface->progress_func )
  94     w->source_interface->progress_func ( c, data, w );
  95 }
  96
  97 /**
  98  * Some common things to do on completion of a datasource process
  99  *  . Update layer
 100  *  . Update dialog info
 101  *  . Update main dsisplay
 102  */
 103 static void on_complete_process (w_and_interface_t *wi)
 104 {
 105   if (wi->w->running) {
 106     gtk_label_set_text ( GTK_LABEL(wi->w->status), _("Done.") );
 107     if ( wi->creating_new_layer ) {
 108       /* Only create the layer if it actually contains anything useful */
 109       // TODO: create function for this operation to hide detail:
 110       if ( ! vik_trw_layer_is_empty ( wi->vtl ) ) {
 111         vik_layer_post_read ( VIK_LAYER(wi->vtl), wi->w->vvp, TRUE );
 112         vik_aggregate_layer_add_layer ( vik_layers_panel_get_top_layer(wi->w->vlp), VIK_LAYER(wi->vtl), TRUE );
 113       }
 114       else
 115         gtk_label_set_text ( GTK_LABEL(wi->w->status), _("No data.") );
 116     }
 117     if ( wi->w->source_interface->keep_dialog_open ) {
 118       gtk_dialog_set_response_sensitive ( GTK_DIALOG(wi->w->dialog), GTK_RESPONSE_ACCEPT, TRUE );
 119       gtk_dialog_set_response_sensitive ( GTK_DIALOG(wi->w->dialog), GTK_RESPONSE_REJECT, FALSE );
 120     } else {
 121       gtk_dialog_response ( GTK_DIALOG(wi->w->dialog), GTK_RESPONSE_ACCEPT );
 122     }
 123     // Main display update
 124     if ( wi->vtl ) {
 125       vik_layer_post_read ( VIK_LAYER(wi->vtl), wi->w->vvp, TRUE );
 126       // View this data if desired - must be done after post read (so that the bounds are known)
 127       if ( wi->w->source_interface->autoview ) {
 128         vik_trw_layer_auto_set_view ( wi->vtl, vik_layers_panel_get_viewport(wi->w->vlp) );
 129       }
 130       vik_layers_panel_emit_update ( wi->w->vlp );
 131     }
 132   } else {
 133     /* cancelled */
 134     if ( wi->creating_new_layer )
 135       g_object_unref(wi->vtl);
 136   }
 137 }
 138
 139 static void free_process_options ( ProcessOptions *po )
 140 {
 141   if ( po ) {
 142     g_free ( po->babelargs );
 143     g_free ( po->filename );
 144     g_free ( po->input_file_type );
 145     g_free ( po->babel_filters );
 146     g_free ( po->url );
 147     g_free ( po->shell_command );
 148     g_free ( po );
 149   }
 150 }
 151
 152 /* this routine is the worker thread.  there is only one simultaneous download allowed */
 153 static void get_from_anything ( w_and_interface_t *wi )
 154 {
 155   gboolean result = TRUE;
 156
 157   VikDataSourceInterface *source_interface = wi->w->source_interface;
 158
 159   if ( source_interface->process_func ) {
 160     result = source_interface->process_func ( wi->vtl, wi->po, (BabelStatusFunc)progress_func, wi->w, wi->options );
 161   }
 162   free_process_options ( wi->po );
 163   g_free ( wi->options );
 164
 165   if (wi->w->running && !result) {
 166     gdk_threads_enter();
 167     gtk_label_set_text ( GTK_LABEL(wi->w->status), _("Error: acquisition failed.") );
 168     if ( wi->creating_new_layer )
 169       g_object_unref ( G_OBJECT ( wi->vtl ) );
 170     gdk_threads_leave();
 171   }
 172   else {
 173     gdk_threads_enter();
 174     on_complete_process ( wi );
 175     gdk_threads_leave();
 176   }
 177
 178   if ( source_interface->cleanup_func )
 179     source_interface->cleanup_func ( wi->w->user_data );
 180
 181   if ( wi->w->running ) {
 182     wi->w->running = FALSE;
 183   }
 184   else {
 185     g_free ( wi->w );
 186     g_free ( wi );
 187     wi = NULL;
 188   }
 189
 190   g_thread_exit ( NULL );
 191 }
 192
 193 /* depending on type of filter, often only vtl or track will be given.
 194  * the other can be NULL.
 195  */
 196 static void acquire ( VikWindow *vw,
 197                       VikLayersPanel *vlp,
 198                       VikViewport *vvp,
 199                       vik_datasource_mode_t mode,
 200                       VikDataSourceInterface *source_interface,
 201                       VikTrwLayer *vtl,
 202                       VikTrack *track,
 203                       gpointer userdata,
 204                       VikDataSourceCleanupFunc cleanup_function )
 205 {
 206   /* for manual dialogs */
 207   GtkWidget *dialog = NULL;
 208   GtkWidget *status;
 209   gchar *args_off = NULL;
 210   gchar *fd_off = NULL;
 211   acq_dialog_widgets_t *w;
 212   gpointer user_data;
 213   DownloadFileOptions *options = g_malloc0 ( sizeof(DownloadFileOptions) );
 214
 215   acq_vik_t avt;
 216   avt.vlp = vlp;
 217   avt.vvp = vvp;
 218   avt.vw = vw;
 219   avt.userdata = userdata;
 220
 221   /* for UI builder */
 222   gpointer pass_along_data;
 223   VikLayerParamData *paramdatas = NULL;
 224
 225   w_and_interface_t *wi;
 226
 227   /*** INIT AND CHECK EXISTENCE ***/
 228   if ( source_interface->init_func )
 229     user_data = source_interface->init_func(&avt);
 230   else
 231     user_data = NULL;
 232   pass_along_data = user_data;
 233
 234   if ( source_interface->check_existence_func ) {
 235     gchar *error_str = source_interface->check_existence_func();
 236     if ( error_str ) {
 237       a_dialog_error_msg ( GTK_WINDOW(vw), error_str );
 238       g_free ( error_str );
 239       return;
 240     }
 241   }
 242
 243   /* BUILD UI & GET OPTIONS IF NECESSARY. */
 244
 245   /* POSSIBILITY 0: NO OPTIONS. DO NOTHING HERE. */
 246   /* POSSIBILITY 1: ADD_SETUP_WIDGETS_FUNC */
 247   if ( source_interface->add_setup_widgets_func ) {
 248     dialog = gtk_dialog_new_with_buttons ( "", GTK_WINDOW(vw), 0, GTK_STOCK_OK, GTK_RESPONSE_ACCEPT, GTK_STOCK_CANCEL, GTK_RESPONSE_REJECT, NULL );
 249
 250     gtk_dialog_set_default_response ( GTK_DIALOG(dialog), GTK_RESPONSE_ACCEPT );
 251     GtkWidget *response_w = NULL;
 252 #if GTK_CHECK_VERSION (2, 20, 0)
 253     response_w = gtk_dialog_get_widget_for_response ( GTK_DIALOG(dialog), GTK_RESPONSE_ACCEPT );
 254 #endif
 255
 256     source_interface->add_setup_widgets_func(dialog, vvp, user_data);
 257     gtk_window_set_title ( GTK_WINDOW(dialog), _(source_interface->window_title) );
 258
 259     if ( response_w )
 260       gtk_widget_grab_focus ( response_w );
 261
 262     if ( gtk_dialog_run ( GTK_DIALOG(dialog) ) != GTK_RESPONSE_ACCEPT ) {
 263       source_interface->cleanup_func(user_data);
 264       gtk_widget_destroy(dialog);
 265       return;
 266     }
 267   }
 268   /* POSSIBILITY 2: UI BUILDER */
 269   else if ( source_interface->params ) {
 270     paramdatas = a_uibuilder_run_dialog ( source_interface->window_title, GTK_WINDOW(vw),
 271                         source_interface->params, source_interface->params_count,
 272                         source_interface->params_groups, source_interface->params_groups_count,
 273                         source_interface->params_defaults );
 274     if ( paramdatas )
 275       pass_along_data = paramdatas;
 276     else
 277       return; /* TODO: do we have to free anything here? */
 278   }
 279
 280   /* CREATE INPUT DATA & GET OPTIONS */
 281   ProcessOptions *po = g_malloc0 ( sizeof(ProcessOptions) );
 282
 283   if ( source_interface->inputtype == VIK_DATASOURCE_INPUTTYPE_TRWLAYER ) {
 284     gchar *name_src = a_gpx_write_tmp_file ( vtl, NULL );
 285
 286     source_interface->get_process_options_func ( pass_along_data, po, NULL, name_src, NULL );
 287
 288     util_add_to_deletion_list ( name_src );
 289
 290     g_free ( name_src );
 291   } else if ( source_interface->inputtype == VIK_DATASOURCE_INPUTTYPE_TRWLAYER_TRACK ) {
 292     gchar *name_src = a_gpx_write_tmp_file ( vtl, NULL );
 293     gchar *name_src_track = a_gpx_write_track_tmp_file ( track, NULL );
 294
 295     source_interface->get_process_options_func ( pass_along_data, po, NULL, name_src, name_src_track );
 296
 297     util_add_to_deletion_list ( name_src );
 298     util_add_to_deletion_list ( name_src_track );
 299
 300     g_free ( name_src );
 301     g_free ( name_src_track );
 302   } else if ( source_interface->inputtype == VIK_DATASOURCE_INPUTTYPE_TRACK ) {
 303     gchar *name_src_track = a_gpx_write_track_tmp_file ( track, NULL );
 304
 305     source_interface->get_process_options_func ( pass_along_data, po, NULL, NULL, name_src_track );
 306
 307     g_free ( name_src_track );
 308   } else if ( source_interface->get_process_options_func )
 309     source_interface->get_process_options_func ( pass_along_data, po, options, NULL, NULL );
 310
 311   /* Get data for Off command */
 312   if ( source_interface->off_func ) {
 313     source_interface->off_func ( pass_along_data, &args_off, &fd_off );
 314   }
 315
 316   /* cleanup for option dialogs */
 317   if ( source_interface->add_setup_widgets_func ) {
 318     gtk_widget_destroy(dialog);
 319     dialog = NULL;
 320   } else if ( source_interface->params ) {
 321     a_uibuilder_free_paramdatas ( paramdatas, source_interface->params, source_interface->params_count );
 322   }
 323
 324   w = g_malloc(sizeof(*w));
 325   wi = g_malloc(sizeof(*wi));
 326   wi->w = w;
 327   wi->w->source_interface = source_interface;
 328   wi->po = po;
 329   wi->options = options;
 330   wi->vtl = vtl;
 331   wi->creating_new_layer = (!vtl); // Default if Auto Layer Management is passed in
 332
 333   dialog = gtk_dialog_new_with_buttons ( "", GTK_WINDOW(vw), 0, GTK_STOCK_OK, GTK_RESPONSE_ACCEPT, GTK_STOCK_CANCEL, GTK_RESPONSE_REJECT, NULL );
 334   gtk_dialog_set_response_sensitive ( GTK_DIALOG(dialog), GTK_RESPONSE_ACCEPT, FALSE );
 335   gtk_window_set_title ( GTK_WINDOW(dialog), _(source_interface->window_title) );
 336
 337   w->dialog = dialog;
 338   w->running = TRUE;
 339   status = gtk_label_new (_("Working..."));
 340   gtk_box_pack_start ( GTK_BOX(gtk_dialog_get_content_area(GTK_DIALOG(dialog))), status, FALSE, FALSE, 5 );
 341   gtk_dialog_set_default_response ( GTK_DIALOG(dialog), GTK_RESPONSE_ACCEPT );
 342   // May not want to see the dialog at all
 343   if ( source_interface->is_thread || source_interface->keep_dialog_open )
 344     gtk_widget_show_all(dialog);
 345   w->status = status;
 346
 347   w->vw = vw;
 348   w->vlp = vlp;
 349   w->vvp = vvp;
 350   if ( source_interface->add_progress_widgets_func ) {
 351     source_interface->add_progress_widgets_func ( dialog, user_data );
 352   }
 353   w->user_data = user_data;
 354
 355   if ( mode == VIK_DATASOURCE_ADDTOLAYER ) {
 356     VikLayer *current_selected = vik_layers_panel_get_selected ( w->vlp );
 357     if ( IS_VIK_TRW_LAYER(current_selected) ) {
 358       wi->vtl = VIK_TRW_LAYER(current_selected);
 359       wi->creating_new_layer = FALSE;
 360     }
 361   }
 362   else if ( mode == VIK_DATASOURCE_CREATENEWLAYER ) {
 363     wi->creating_new_layer = TRUE;
 364   }
 365   else if ( mode == VIK_DATASOURCE_MANUAL_LAYER_MANAGEMENT ) {
 366     // Don't create in acquire - as datasource will perform the necessary actions
 367     wi->creating_new_layer = FALSE;
 368     VikLayer *current_selected = vik_layers_panel_get_selected ( w->vlp );
 369     if ( IS_VIK_TRW_LAYER(current_selected) )
 370       wi->vtl = VIK_TRW_LAYER(current_selected);
 371   }
 372   if ( wi->creating_new_layer ) {
 373     wi->vtl = VIK_TRW_LAYER ( vik_layer_create ( VIK_LAYER_TRW, w->vvp, FALSE ) );
 374     vik_layer_rename ( VIK_LAYER ( wi->vtl ), _(source_interface->layer_title) );
 375   }
 376
 377   if ( source_interface->is_thread ) {
 378     if ( po->babelargs || po->url || po->shell_command ) {
 379 #if GLIB_CHECK_VERSION (2, 32, 0)
 380       g_thread_try_new ( "get_from_anything", (GThreadFunc)get_from_anything, wi, NULL );
 381 #else
 382       g_thread_create ( (GThreadFunc)get_from_anything, wi, FALSE, NULL );
 383 #endif
 384       gtk_dialog_run ( GTK_DIALOG(dialog) );
 385       if (w->running) {
 386         // Cancel and mark for thread to finish
 387         w->running = FALSE;
 388         // NB Thread will free memory
 389       } else {
 390         if ( args_off ) {
 391           /* Turn off */
 392           ProcessOptions off_po = { args_off, fd_off, NULL, NULL, NULL };
 393           a_babel_convert_from (NULL, &off_po, NULL, NULL, NULL);
 394           g_free ( args_off );
 395         }
 396         if ( fd_off )
 397           g_free ( fd_off );
 398
 399         // Thread finished by normal completion - free memory
 400         g_free ( w );
 401         g_free ( wi );
 402       }
 403     }
 404     else {
 405       // This shouldn't happen...
 406       gtk_label_set_text ( GTK_LABEL(w->status), _("Unable to create command\nAcquire method failed.") );
 407       gtk_dialog_run (GTK_DIALOG (dialog));
 408     }
 409   }
 410   else {
 411     // bypass thread method malarkly - you'll just have to wait...
 412     if ( source_interface->process_func ) {
 413       gboolean result = source_interface->process_func ( wi->vtl, po, (BabelStatusFunc) progress_func, w, options );
 414       if ( !result )
 415         a_dialog_error_msg ( GTK_WINDOW(vw), _("Error: acquisition failed.") );
 416     }
 417     free_process_options ( po );
 418     g_free ( options );
 419
 420     on_complete_process ( wi );
 421     // Actually show it if necessary
 422     if ( wi->w->source_interface->keep_dialog_open )
 423       gtk_dialog_run ( GTK_DIALOG(dialog) );
 424
 425     g_free ( w );
 426     g_free ( wi );
 427   }
 428
 429   gtk_widget_destroy ( dialog );
 430
 431   if ( cleanup_function )
 432     cleanup_function ( source_interface );
 433 }
 434
 435 /**
 436  * a_acquire:
 437  * @vw: The #VikWindow to work with
 438  * @vlp: The #VikLayersPanel in which a #VikTrwLayer layer may be created/appended
 439  * @vvp: The #VikViewport defining the current view
 440  * @mode: How layers should be managed
 441  * @source_interface: The #VikDataSourceInterface determining how and what actions to take
 442  * @userdata: External data to be passed into the #VikDataSourceInterface
 443  * @cleanup_function: The function to dispose the #VikDataSourceInterface if necessary
 444  *
 445  * Process the given VikDataSourceInterface for sources with no input data.
 446  */
 447 void a_acquire ( VikWindow *vw,
 448                  VikLayersPanel *vlp,
 449                  VikViewport *vvp,
 450                  vik_datasource_mode_t mode,
 451                  VikDataSourceInterface *source_interface,
 452                  gpointer userdata,
 453                  VikDataSourceCleanupFunc cleanup_function )
 454 {
 455   acquire ( vw, vlp, vvp, mode, source_interface, NULL, NULL, userdata, cleanup_function );
 456 }
 457
 458 static void acquire_trwlayer_callback ( GObject *menuitem, gpointer *pass_along )
 459 {
 460   VikDataSourceInterface *iface = g_object_get_data ( menuitem, "vik_acq_iface" );
 461   VikWindow *vw =       pass_along[0];
 462   VikLayersPanel *vlp = pass_along[1];
 463   VikViewport *vvp =    pass_along[2];
 464   VikTrwLayer *vtl =    pass_along[3];
 465   VikTrack *tr =        pass_along[4];
 466
 467   acquire ( vw, vlp, vvp, iface->mode, iface, vtl, tr, NULL, NULL );
 468 }
 469
 470 static GtkWidget *acquire_build_menu ( VikWindow *vw, VikLayersPanel *vlp, VikViewport *vvp,
 471                                 VikTrwLayer *vtl, VikTrack *track, /* both passed to acquire, although for many filters only one ness */
 472                                 const gchar *menu_title, vik_datasource_inputtype_t inputtype )
 473 {
 474   static gpointer pass_along[5];
 475   GtkWidget *menu_item=NULL, *menu=NULL;
 476   GtkWidget *item=NULL;
 477   int i;
 478
 479   pass_along[0] = vw;
 480   pass_along[1] = vlp;
 481   pass_along[2] = vvp;
 482   pass_along[3] = vtl;
 483   pass_along[4] = track;
 484
 485   for ( i = 0; i < N_FILTERS; i++ ) {
 486     if ( filters[i]->inputtype == inputtype ) {
 487       if ( ! menu_item ) { /* do this just once, but return NULL if no filters */
 488         menu = gtk_menu_new();
 489         menu_item = gtk_menu_item_new_with_mnemonic ( menu_title );
 490         gtk_menu_item_set_submenu (GTK_MENU_ITEM (menu_item), menu );
 491       }
 492
 493       item = gtk_menu_item_new_with_label ( filters[i]->window_title );
 494       g_object_set_data ( G_OBJECT(item), "vik_acq_iface", (gpointer) filters[i] );
 495       g_signal_connect ( G_OBJECT(item), "activate", G_CALLBACK(acquire_trwlayer_callback), pass_along );
 496       gtk_menu_shell_append (GTK_MENU_SHELL (menu), item);
 497       gtk_widget_show ( item );
 498     }
 499   }
 500
 501   return menu_item;
 502 }
 503
 504 /**
 505  * a_acquire_trwlayer_menu:
 506  *
 507  * Create a sub menu intended for rightclicking on a TRWLayer's menu called "Filter".
 508  *
 509  * Returns: %NULL if no filters.
 510  */
 511 GtkWidget *a_acquire_trwlayer_menu (VikWindow *vw, VikLayersPanel *vlp, VikViewport *vvp, VikTrwLayer *vtl)
 512 {
 513   return acquire_build_menu ( vw, vlp, vvp, vtl, NULL, _("_Filter"), VIK_DATASOURCE_INPUTTYPE_TRWLAYER );
 514 }
 515
 516 /**
 517  * a_acquire_trwlayer_track_menu:
 518  *
 519  * Create a sub menu intended for rightclicking on a TRWLayer's menu called "Filter with Track "TRACKNAME"...".
 520  *
 521  * Returns: %NULL if no filters or no filter track has been set.
 522  */
 523 GtkWidget *a_acquire_trwlayer_track_menu (VikWindow *vw, VikLayersPanel *vlp, VikViewport *vvp, VikTrwLayer *vtl)
 524 {
 525   if ( filter_track == NULL )
 526     return NULL;
 527   else {
 528     gchar *menu_title = g_strdup_printf ( _("Filter with %s"), filter_track->name );
 529     GtkWidget *rv = acquire_build_menu ( vw, vlp, vvp, vtl, filter_track,
 530                         menu_title, VIK_DATASOURCE_INPUTTYPE_TRWLAYER_TRACK );
 531     g_free ( menu_title );
 532     return rv;
 533   }
 534 }
 535
 536 /**
 537  * a_acquire_track_menu:
 538  *
 539  * Create a sub menu intended for rightclicking on a track's menu called "Filter".
 540  *
 541  * Returns: %NULL if no applicable filters
 542  */
 543 GtkWidget *a_acquire_track_menu (VikWindow *vw, VikLayersPanel *vlp, VikViewport *vvp, VikTrack *tr)
 544 {
 545   return acquire_build_menu ( vw, vlp, vvp, NULL, tr, _("Filter"), VIK_DATASOURCE_INPUTTYPE_TRACK );
 546 }
 547
 548 /**
 549  * a_acquire_set_filter_track:
 550  *
 551  * Sets application-wide track to use with filter. references the track.
 552  */
 553 void a_acquire_set_filter_track ( VikTrack *tr )
 554 {
 555   if ( filter_track )
 556     vik_track_free ( filter_track );
 557
 558   filter_track = tr;
 559   vik_track_ref ( tr );
 560 }