Read zip files contents which are stored with no compression.

[andy/viking.git] / src / vikmapslayer.c

/*
 * viking -- GPS Data and Topo Analyzer, Explorer, and Manager
 *
 * Copyright (C) 2005, Evan Battaglia <viking@greentorch.org>
 * Copyright (C) 2010, Guilhem Bonnefille <guilhem.bonnefille@gmail.com>
 * Copyright (c) 2013, Rob Norris <rw_norris@hotmail.com>
 * UTM multi-zone stuff by Kit Transue <notlostyet@didactek.com>
 * Dynamic map type by Guilhem Bonnefille <guilhem.bonnefille@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <gtk/gtk.h>
#include <gdk-pixbuf/gdk-pixdata.h>
#include <glib.h>
#include <glib/gstdio.h>
#include <glib/gi18n.h>

#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_MATH_H
#include <math.h>
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#include "viking.h"
#include "vikmapsourcedefault.h"
#include "vikutils.h"
#include "maputils.h"
#include "mapcache.h"
#include "background.h"
#include "preferences.h"
#include "vikmapslayer.h"
#include "icons/icons.h"
#include "metatile.h"
#include "ui_util.h"
#include "map_ids.h"

#ifdef HAVE_SQLITE3_H
#include "sqlite3.h"
#include <gio/gio.h>
#endif

#define VIK_SETTINGS_MAP_MAX_TILES "maps_max_tiles"
static gint MAX_TILES = 1000;

#define VIK_SETTINGS_MAP_MIN_SHRINKFACTOR "maps_min_shrinkfactor"
#define VIK_SETTINGS_MAP_MAX_SHRINKFACTOR "maps_max_shrinkfactor"
static gdouble MAX_SHRINKFACTOR = 8.0000001; /* zoom 1 viewing 8-tiles */
static gdouble MIN_SHRINKFACTOR = 0.0312499; /* zoom 32 viewing 1-tiles */

#define VIK_SETTINGS_MAP_REAL_MIN_SHRINKFACTOR "maps_real_min_shrinkfactor"
static gdouble REAL_MIN_SHRINKFACTOR = 0.0039062499; /* if shrinkfactor is between MAX and REAL_MAX, will only check for existence */

#define VIK_SETTINGS_MAP_SCALE_INC_UP "maps_scale_inc_up"
static guint SCALE_INC_UP = 2;
#define VIK_SETTINGS_MAP_SCALE_INC_DOWN "maps_scale_inc_down"
static guint SCALE_INC_DOWN = 4;
#define VIK_SETTINGS_MAP_SCALE_SMALLER_ZOOM_FIRST "maps_scale_smaller_zoom_first"
static gboolean SCALE_SMALLER_ZOOM_FIRST = TRUE;

/****** MAP TYPES ******/

static GList *__map_types = NULL;

#define NUM_MAP_TYPES g_list_length(__map_types)

/* List of label for each map type */
static gchar **params_maptypes = NULL;

/* Corresponding IDS. (Cf. field uniq_id in VikMapsLayer struct) */
static guint *params_maptypes_ids = NULL;

/******** MAPZOOMS *********/

static gchar *params_mapzooms[] = { N_("Use Viking Zoom Level"), "0.25", "0.5", "1", "2", "4", "8", "16", "32", "64", "128", "256", "512", "1024", "USGS 10k", "USGS 24k", "USGS 25k", "USGS 50k", "USGS 100k", "USGS 200k", "USGS 250k", NULL };
static gdouble __mapzooms_x[] = { 0.0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0, 32.0, 64.0, 128.0, 256.0, 512.0, 1024.0, 1.016, 2.4384, 2.54, 5.08, 10.16, 20.32, 25.4 };
static gdouble __mapzooms_y[] = { 0.0, 0.25, 0.5, 1.0, 2.0, 4.0, 8.0, 16.0, 32.0, 64.0, 128.0, 256.0, 512.0, 1024.0, 1.016, 2.4384, 2.54, 5.08, 10.16, 20.32, 25.4 };

#define NUM_MAPZOOMS (sizeof(params_mapzooms)/sizeof(params_mapzooms[0]) - 1)

/**************************/


static void maps_layer_post_read (VikLayer *vl, VikViewport *vp, gboolean from_file);
static const gchar* maps_layer_tooltip ( VikMapsLayer *vml );
static void maps_layer_marshall( VikMapsLayer *vml, guint8 **data, gint *len );
static VikMapsLayer *maps_layer_unmarshall( guint8 *data, gint len, VikViewport *vvp );
static gboolean maps_layer_set_param ( VikMapsLayer *vml, guint16 id, VikLayerParamData data, VikViewport *vvp, gboolean is_file_operation );
static VikLayerParamData maps_layer_get_param ( VikMapsLayer *vml, guint16 id, gboolean is_file_operation );
static void maps_layer_change_param ( GtkWidget *widget, ui_change_values values );
static void maps_layer_draw ( VikMapsLayer *vml, VikViewport *vvp );
static VikMapsLayer *maps_layer_new ( VikViewport *vvp );
static void maps_layer_free ( VikMapsLayer *vml );
static gboolean maps_layer_download_release ( VikMapsLayer *vml, GdkEventButton *event, VikViewport *vvp );
static gboolean maps_layer_download_click ( VikMapsLayer *vml, GdkEventButton *event, VikViewport *vvp );
static gpointer maps_layer_download_create ( VikWindow *vw, VikViewport *vvp );
static void maps_layer_set_cache_dir ( VikMapsLayer *vml, const gchar *dir );
static void start_download_thread ( VikMapsLayer *vml, VikViewport *vvp, const VikCoord *ul, const VikCoord *br, gint redownload );
static void maps_layer_add_menu_items ( VikMapsLayer *vml, GtkMenu *menu, VikLayersPanel *vlp );
static guint map_uniq_id_to_index ( guint uniq_id );


static VikLayerParamScale params_scales[] = {
  /* min, max, step, digits (decimal places) */
 { 0, 255, 3, 0 }, /* alpha */
};

static VikLayerParamData id_default ( void ) { return VIK_LPD_UINT ( MAP_ID_MAPQUEST_OSM ); }
static VikLayerParamData directory_default ( void )
{
  VikLayerParamData data;
  VikLayerParamData *pref = a_preferences_get(VIKING_PREFERENCES_NAMESPACE "maplayer_default_dir");
  if (pref) data.s = g_strdup ( pref->s ); else data.s = "";
  return data;
}
static VikLayerParamData file_default ( void )
{
  VikLayerParamData data;
  data.s = "";
  return data;
}
static VikLayerParamData alpha_default ( void ) { return VIK_LPD_UINT ( 255 ); }
static VikLayerParamData mapzoom_default ( void ) { return VIK_LPD_UINT ( 0 ); }

static gchar *cache_types[] = { "Viking", N_("OSM"), NULL };
static VikMapsCacheLayout cache_layout_default_value = VIK_MAPS_CACHE_LAYOUT_VIKING;
static VikLayerParamData cache_layout_default ( void ) { return VIK_LPD_UINT ( cache_layout_default_value ); }

VikLayerParam maps_layer_params[] = {
  // NB mode => id - But can't break file format just to rename something better
  { VIK_LAYER_MAPS, "mode", VIK_LAYER_PARAM_UINT, VIK_LAYER_GROUP_NONE, N_("Map Type:"), VIK_LAYER_WIDGET_COMBOBOX, NULL, NULL, NULL, id_default, NULL, NULL },
  { VIK_LAYER_MAPS, "directory", VIK_LAYER_PARAM_STRING, VIK_LAYER_GROUP_NONE, N_("Maps Directory:"), VIK_LAYER_WIDGET_FOLDERENTRY, NULL, NULL, NULL, directory_default, NULL, NULL },
  { VIK_LAYER_MAPS, "cache_type", VIK_LAYER_PARAM_UINT, VIK_LAYER_GROUP_NONE, N_("Cache Layout:"), VIK_LAYER_WIDGET_COMBOBOX, cache_types, NULL, 
    N_("This determines the tile storage layout on disk"), cache_layout_default, NULL, NULL },
  { VIK_LAYER_MAPS, "mapfile", VIK_LAYER_PARAM_STRING, VIK_LAYER_GROUP_NONE, N_("Map File:"), VIK_LAYER_WIDGET_FILEENTRY, GINT_TO_POINTER(VF_FILTER_MBTILES), NULL,
    N_("An MBTiles file. Only applies when the map type method is 'MBTiles'"), file_default, NULL, NULL },
  { VIK_LAYER_MAPS, "alpha", VIK_LAYER_PARAM_UINT, VIK_LAYER_GROUP_NONE, N_("Alpha:"), VIK_LAYER_WIDGET_HSCALE, params_scales, NULL,
    N_("Control the Alpha value for transparency effects"), alpha_default, NULL, NULL },
  { VIK_LAYER_MAPS, "autodownload", VIK_LAYER_PARAM_BOOLEAN, VIK_LAYER_GROUP_NONE, N_("Autodownload maps:"), VIK_LAYER_WIDGET_CHECKBUTTON, NULL, NULL, NULL, vik_lpd_true_default, NULL, NULL },
  { VIK_LAYER_MAPS, "adlonlymissing", VIK_LAYER_PARAM_BOOLEAN, VIK_LAYER_GROUP_NONE, N_("Autodownload Only Gets Missing Maps:"), VIK_LAYER_WIDGET_CHECKBUTTON, NULL, NULL,
    N_("Using this option avoids attempting to update already acquired tiles. This can be useful if you want to restrict the network usage, without having to resort to manual control. Only applies when 'Autodownload Maps' is on."), vik_lpd_false_default, NULL, NULL },
  { VIK_LAYER_MAPS, "mapzoom", VIK_LAYER_PARAM_UINT, VIK_LAYER_GROUP_NONE, N_("Zoom Level:"), VIK_LAYER_WIDGET_COMBOBOX, params_mapzooms, NULL,
    N_("Determines the method of displaying map tiles for the current zoom level. 'Viking Zoom Level' uses the best matching level, otherwise setting a fixed value will always use map tiles of the specified value regardless of the actual zoom level."),
    mapzoom_default, NULL, NULL },
};

enum {
  PARAM_MAPTYPE=0,
  PARAM_CACHE_DIR,
  PARAM_CACHE_LAYOUT,
  PARAM_FILE,
  PARAM_ALPHA,
  PARAM_AUTODOWNLOAD,
  PARAM_ONLYMISSING,
  PARAM_MAPZOOM,
  NUM_PARAMS
};

void maps_layer_set_autodownload_default ( gboolean autodownload )
{
  // Set appropriate function
  if ( autodownload )
    maps_layer_params[PARAM_AUTODOWNLOAD].default_value = vik_lpd_true_default;
  else
    maps_layer_params[PARAM_AUTODOWNLOAD].default_value = vik_lpd_false_default;
}

void maps_layer_set_cache_default ( VikMapsCacheLayout layout )
{
  // Override default value returned by the default param function
  cache_layout_default_value = layout;
}

static VikToolInterface maps_tools[] = {
  { { "MapsDownload", "vik-icon-Maps Download", N_("_Maps Download"), NULL, N_("Maps Download"), 0 },
    (VikToolConstructorFunc) maps_layer_download_create,
    NULL,
    NULL,
    NULL,
    (VikToolMouseFunc) maps_layer_download_click,
    NULL,
    (VikToolMouseFunc) maps_layer_download_release,
    NULL,
    FALSE,
    GDK_CURSOR_IS_PIXMAP, &cursor_mapdl_pixbuf, NULL },
};

VikLayerInterface vik_maps_layer_interface = {
  "Map",
  N_("Map"),
  "<control><shift>M",
  &vikmapslayer_pixbuf,

  maps_tools,
  sizeof(maps_tools) / sizeof(maps_tools[0]),

  maps_layer_params,
  NUM_PARAMS,
  NULL,
  0,

  VIK_MENU_ITEM_ALL,

  (VikLayerFuncCreate)                  maps_layer_new,
  (VikLayerFuncRealize)                 NULL,
  (VikLayerFuncPostRead)                maps_layer_post_read,
  (VikLayerFuncFree)                    maps_layer_free,

  (VikLayerFuncProperties)              NULL,
  (VikLayerFuncDraw)                    maps_layer_draw,
  (VikLayerFuncChangeCoordMode)         NULL,

  (VikLayerFuncGetTimestamp)            NULL,

  (VikLayerFuncSetMenuItemsSelection)   NULL,
  (VikLayerFuncGetMenuItemsSelection)   NULL,

  (VikLayerFuncAddMenuItems)            maps_layer_add_menu_items,
  (VikLayerFuncSublayerAddMenuItems)    NULL,

  (VikLayerFuncSublayerRenameRequest)   NULL,
  (VikLayerFuncSublayerToggleVisible)   NULL,
  (VikLayerFuncSublayerTooltip)         NULL,
  (VikLayerFuncLayerTooltip)            maps_layer_tooltip,
  (VikLayerFuncLayerSelected)           NULL,

  (VikLayerFuncMarshall)		maps_layer_marshall,
  (VikLayerFuncUnmarshall)		maps_layer_unmarshall,

  (VikLayerFuncSetParam)                maps_layer_set_param,
  (VikLayerFuncGetParam)                maps_layer_get_param,
  (VikLayerFuncChangeParam)             maps_layer_change_param,

  (VikLayerFuncReadFileData)            NULL,
  (VikLayerFuncWriteFileData)           NULL,

  (VikLayerFuncDeleteItem)              NULL,
  (VikLayerFuncCutItem)                 NULL,
  (VikLayerFuncCopyItem)                NULL,
  (VikLayerFuncPasteItem)               NULL,
  (VikLayerFuncFreeCopiedItem)          NULL,
  (VikLayerFuncDragDropRequest)		NULL,

  (VikLayerFuncSelectClick)             NULL,
  (VikLayerFuncSelectMove)              NULL,
  (VikLayerFuncSelectRelease)           NULL,
  (VikLayerFuncSelectedViewportMenu)    NULL,
};

struct _VikMapsLayer {
  VikLayer vl;
  guint maptype;
  gchar *cache_dir;
  VikMapsCacheLayout cache_layout;
  guint8 alpha;
  guint mapzoom_id;
  gdouble xmapzoom, ymapzoom;

  gboolean autodownload;
  gboolean adl_only_missing;
  VikCoord *last_center;
  gdouble last_xmpp;
  gdouble last_ympp;

  gint dl_tool_x, dl_tool_y;

  GtkMenu *dl_right_click_menu;
  VikCoord redownload_ul, redownload_br; /* right click menu only */
  VikViewport *redownload_vvp;
  gchar *filename;
#ifdef HAVE_SQLITE3_H
  sqlite3 *mbtiles;
#endif
};

enum { REDOWNLOAD_NONE = 0,    /* download only missing maps */
       REDOWNLOAD_BAD,         /* download missing and bad maps */
       REDOWNLOAD_NEW,         /* download missing maps that are newer on server only */
       REDOWNLOAD_ALL,         /* download all maps */
       DOWNLOAD_OR_REFRESH };  /* download missing maps and refresh cache */

static VikLayerParam prefs[] = {
  { VIK_LAYER_NUM_TYPES, VIKING_PREFERENCES_NAMESPACE "maplayer_default_dir", VIK_LAYER_PARAM_STRING, VIK_LAYER_GROUP_NONE, N_("Default map layer directory:"), VIK_LAYER_WIDGET_FOLDERENTRY, NULL, NULL, N_("Choose a directory to store cached Map tiles for this layer"), NULL, NULL, NULL },
};

void maps_layer_init ()
{
  VikLayerParamData tmp;
  tmp.s = maps_layer_default_dir();
  a_preferences_register(prefs, tmp, VIKING_PREFERENCES_GROUP_KEY);

  gint max_tiles = MAX_TILES;
  if ( a_settings_get_integer ( VIK_SETTINGS_MAP_MAX_TILES, &max_tiles ) )
    MAX_TILES = max_tiles;

  gdouble gdtmp;
  if ( a_settings_get_double ( VIK_SETTINGS_MAP_MIN_SHRINKFACTOR, &gdtmp ) )
    MIN_SHRINKFACTOR = gdtmp;

  if ( a_settings_get_double ( VIK_SETTINGS_MAP_MAX_SHRINKFACTOR, &gdtmp ) )
    MAX_SHRINKFACTOR = gdtmp;

  if ( a_settings_get_double ( VIK_SETTINGS_MAP_REAL_MIN_SHRINKFACTOR, &gdtmp ) )
    REAL_MIN_SHRINKFACTOR = gdtmp;

  gint gitmp = 0;
  if ( a_settings_get_integer ( VIK_SETTINGS_MAP_SCALE_INC_UP, &gitmp ) )
    SCALE_INC_UP = gitmp;

  if ( a_settings_get_integer ( VIK_SETTINGS_MAP_SCALE_INC_DOWN, &gitmp ) )
    SCALE_INC_DOWN = gitmp;

  gboolean gbtmp = TRUE;
  if ( a_settings_get_boolean ( VIK_SETTINGS_MAP_SCALE_SMALLER_ZOOM_FIRST, &gbtmp ) )
    SCALE_SMALLER_ZOOM_FIRST = gbtmp;

}

/****************************************/
/******** MAPS LAYER TYPES **************/
/****************************************/

void _add_map_source ( guint16 id, const char *label, VikMapSource *map )
{
  gsize len = 0;
  if (params_maptypes)
    len = g_strv_length (params_maptypes);
  /* Add the label */
  params_maptypes = g_realloc (params_maptypes, (len+2)*sizeof(gchar*));
  params_maptypes[len] = g_strdup (label);
  params_maptypes[len+1] = NULL;

  /* Add the id */
  params_maptypes_ids = g_realloc (params_maptypes_ids, (len+2)*sizeof(guint));
  params_maptypes_ids[len] = id;
  params_maptypes_ids[len+1] = 0;

  /* We have to clone */
  VikMapSource *clone = VIK_MAP_SOURCE(g_object_ref(map));
  /* Register the clone in the list */
  __map_types = g_list_append(__map_types, clone);

  /* Hack
     We have to ensure the mode LayerParam references the up-to-date
     GLists.
  */
  /*
  memcpy(&maps_layer_params[0].widget_data, &params_maptypes, sizeof(gpointer));
  memcpy(&maps_layer_params[0].extra_widget_data, &params_maptypes_ids, sizeof(gpointer));
  */
  maps_layer_params[0].widget_data = params_maptypes;
  maps_layer_params[0].extra_widget_data = params_maptypes_ids;
}

void _update_map_source ( const char *label, VikMapSource *map, int index )
{
  GList *item = g_list_nth (__map_types, index);
  g_object_unref (item->data);
  item->data = g_object_ref (map);
  /* Change previous data */
  g_free (params_maptypes[index]);
  params_maptypes[index] = g_strdup (label);
}

/**
 * maps_layer_register_map_source:
 * @map: the new VikMapSource
 *
 * Register a new VikMapSource.
 * Override existing one (equality of id).
 */
void maps_layer_register_map_source ( VikMapSource *map )
{
  g_assert(map != NULL);
  
  guint16 id = vik_map_source_get_uniq_id(map);
  const char *label = vik_map_source_get_label(map);
  g_assert(label != NULL);

  int previous = map_uniq_id_to_index (id);
  if (previous != NUM_MAP_TYPES)
  {
    _update_map_source (label, map, previous);
  }
  else
  {
    _add_map_source (id, label, map);
  }
}

#define MAPS_LAYER_NTH_LABEL(n) (params_maptypes[n])
#define MAPS_LAYER_NTH_ID(n) (params_maptypes_ids[n])
#define MAPS_LAYER_NTH_TYPE(n) (VIK_MAP_SOURCE(g_list_nth_data(__map_types, (n))))

/**
 * vik_maps_layer_get_map_type:
 *
 * Returns the actual map id (rather than the internal type index value)
 */
guint vik_maps_layer_get_map_type(VikMapsLayer *vml)
{
  return MAPS_LAYER_NTH_ID(vml->maptype);
}

/**
 * vik_maps_layer_set_map_type:
 *
 */
void vik_maps_layer_set_map_type(VikMapsLayer *vml, guint map_type)
{
   gint maptype = map_uniq_id_to_index(map_type);
   if ( maptype == NUM_MAP_TYPES )
      g_warning(_("Unknown map type"));
   else
      vml->maptype = maptype;
}

/**
 * vik_maps_layer_get_default_map_type:
 *
 */
guint vik_maps_layer_get_default_map_type ()
{
  VikLayerInterface *vli = vik_layer_get_interface ( VIK_LAYER_MAPS );
  VikLayerParamData vlpd = a_layer_defaults_get ( vli->fixed_layer_name, "mode", VIK_LAYER_PARAM_UINT );
  if ( vlpd.u == 0 )
    vlpd = id_default();
  return vlpd.u;
}

gchar *vik_maps_layer_get_map_label(VikMapsLayer *vml)
{
  return(g_strdup(MAPS_LAYER_NTH_LABEL(vml->maptype)));
}

/****************************************/
/******** CACHE DIR STUFF ***************/
/****************************************/

#define DIRECTDIRACCESS "%s%d" G_DIR_SEPARATOR_S "%d" G_DIR_SEPARATOR_S "%d%s"
#define DIRECTDIRACCESS_WITH_NAME "%s%s" G_DIR_SEPARATOR_S "%d" G_DIR_SEPARATOR_S "%d" G_DIR_SEPARATOR_S "%d%s"
#define DIRSTRUCTURE "%st%ds%dz%d" G_DIR_SEPARATOR_S "%d" G_DIR_SEPARATOR_S "%d"
#define MAPS_CACHE_DIR maps_layer_default_dir()

#ifdef WINDOWS
#include <io.h>
#define GLOBAL_MAPS_DIR "C:\\VIKING-MAPS\\"
#define LOCAL_MAPS_DIR "VIKING-MAPS"
#elif defined __APPLE__
#include <stdlib.h>
#define GLOBAL_MAPS_DIR "/Library/cache/Viking/maps/"
#define LOCAL_MAPS_DIR "/Library/Application Support/Viking/viking-maps"
#else /* POSIX */
#include <stdlib.h>
#define GLOBAL_MAPS_DIR "/var/cache/maps/"
#define LOCAL_MAPS_DIR ".viking-maps"
#endif

gchar *maps_layer_default_dir ()
{
  static gchar *defaultdir = NULL;
  if ( ! defaultdir )
  {
    /* Thanks to Mike Davison for the $VIKING_MAPS usage */
    const gchar *mapdir = g_getenv("VIKING_MAPS");
    if ( mapdir ) {
      defaultdir = g_strdup ( mapdir );
    } else if ( g_access ( GLOBAL_MAPS_DIR, W_OK ) == 0 ) {
      defaultdir = g_strdup ( GLOBAL_MAPS_DIR );
    } else {
      const gchar *home = g_get_home_dir();
      if (!home || g_access(home, W_OK))
        home = g_get_home_dir ();
      if ( home )
        defaultdir = g_build_filename ( home, LOCAL_MAPS_DIR, NULL );
      else
        defaultdir = g_strdup ( LOCAL_MAPS_DIR );
    }
    if (defaultdir && (defaultdir[strlen(defaultdir)-1] != G_DIR_SEPARATOR))
    {
      /* Add the separator at the end */
      gchar *tmp = defaultdir;
      defaultdir = g_strconcat(tmp, G_DIR_SEPARATOR_S, NULL);
      g_free(tmp);
    }
    g_debug("%s: defaultdir=%s", __FUNCTION__, defaultdir);
  }
  return defaultdir;
}

static void maps_layer_mkdir_if_default_dir ( VikMapsLayer *vml )
{
  if ( vml->cache_dir && strcmp ( vml->cache_dir, MAPS_CACHE_DIR ) == 0 && g_file_test ( vml->cache_dir, G_FILE_TEST_EXISTS ) == FALSE )
  {
    g_mkdir ( vml->cache_dir, 0777 );
  }
}

static void maps_layer_set_cache_dir ( VikMapsLayer *vml, const gchar *dir )
{
  g_assert ( vml != NULL);
  g_free ( vml->cache_dir );
  vml->cache_dir = NULL;
  const gchar *mydir = dir;

  if ( dir == NULL || dir[0] == '\0' )
  {
    if ( a_preferences_get(VIKING_PREFERENCES_NAMESPACE "maplayer_default_dir") )
      mydir = a_preferences_get(VIKING_PREFERENCES_NAMESPACE "maplayer_default_dir")->s;
  }

  gchar *canonical_dir = vu_get_canonical_filename ( VIK_LAYER(vml), mydir );

  // Ensure cache_dir always ends with a separator
  guint len = strlen(canonical_dir);
  if ( canonical_dir[len-1] != G_DIR_SEPARATOR )
  {
    vml->cache_dir = g_strconcat ( canonical_dir, G_DIR_SEPARATOR_S, NULL );
    g_free ( canonical_dir );
  }
  else {
    vml->cache_dir = canonical_dir;
  }

  maps_layer_mkdir_if_default_dir ( vml );
}

static void maps_layer_set_file ( VikMapsLayer *vml, const gchar *name )
{
  if ( vml->filename )
    g_free (vml->filename);
  vml->filename = g_strdup (name);
}

/****************************************/
/******** GOBJECT STUFF *****************/
/****************************************/

GType vik_maps_layer_get_type ()
{
  static GType vml_type = 0;

  if (!vml_type)
  {
    static const GTypeInfo vml_info =
    {
      sizeof (VikMapsLayerClass),
      NULL, /* base_init */
      NULL, /* base_finalize */
      NULL, /* class init */
      NULL, /* class_finalize */
      NULL, /* class_data */
      sizeof (VikMapsLayer),
      0,
      NULL /* instance init */
    };
    vml_type = g_type_register_static ( VIK_LAYER_TYPE, "VikMapsLayer", &vml_info, 0 );
  }

  return vml_type;
}

/****************************************/
/************** PARAMETERS **************/
/****************************************/

static guint map_index_to_uniq_id (guint16 index)
{
  g_assert ( index < NUM_MAP_TYPES );
  return vik_map_source_get_uniq_id(MAPS_LAYER_NTH_TYPE(index));
}

static guint map_uniq_id_to_index ( guint uniq_id )
{
  gint i;
  for ( i = 0; i < NUM_MAP_TYPES; i++ )
    if ( vik_map_source_get_uniq_id(MAPS_LAYER_NTH_TYPE(i)) == uniq_id )
      return i;
  return NUM_MAP_TYPES; /* no such thing */
}

#define VIK_SETTINGS_MAP_LICENSE_SHOWN "map_license_shown"

/**
 * Convenience function to display the license
 */
static void maps_show_license ( GtkWindow *parent, VikMapSource *map )
{
  a_dialog_license ( parent,
		     vik_map_source_get_label (map),
		     vik_map_source_get_license (map),
		     vik_map_source_get_license_url (map) );
}

static gboolean maps_layer_set_param ( VikMapsLayer *vml, guint16 id, VikLayerParamData data, VikViewport *vvp, gboolean is_file_operation )
{
  switch ( id )
  {
    case PARAM_CACHE_DIR: maps_layer_set_cache_dir ( vml, data.s ); break;
    case PARAM_CACHE_LAYOUT: if ( data.u < VIK_MAPS_CACHE_LAYOUT_NUM ) vml->cache_layout = data.u; break;
    case PARAM_FILE: maps_layer_set_file ( vml, data.s ); break;
    case PARAM_MAPTYPE: {
      gint maptype = map_uniq_id_to_index(data.u);
      if ( maptype == NUM_MAP_TYPES )
        g_warning(_("Unknown map type"));
      else {
        vml->maptype = maptype;

        // When loading from a file don't need the license reminder - ensure it's saved into the 'seen' list
        if ( is_file_operation ) {
          a_settings_set_integer_list_containing ( VIK_SETTINGS_MAP_LICENSE_SHOWN, data.u );
        }
        else {
          VikMapSource *map = MAPS_LAYER_NTH_TYPE(vml->maptype);
          if (vik_map_source_get_license (map) != NULL) {
            // Check if licence for this map type has been shown before
            if ( ! a_settings_get_integer_list_contains ( VIK_SETTINGS_MAP_LICENSE_SHOWN, data.u ) ) {
              if ( vvp )
                maps_show_license ( VIK_GTK_WINDOW_FROM_WIDGET(vvp), map );
              a_settings_set_integer_list_containing ( VIK_SETTINGS_MAP_LICENSE_SHOWN, data.u );
            }
          }
        }
      }
      break;
    }
    case PARAM_ALPHA: if ( data.u <= 255 ) vml->alpha = data.u; break;
    case PARAM_AUTODOWNLOAD: vml->autodownload = data.b; break;
    case PARAM_ONLYMISSING: vml->adl_only_missing = data.b; break;
    case PARAM_MAPZOOM: if ( data.u < NUM_MAPZOOMS ) {
                          vml->mapzoom_id = data.u;
                          vml->xmapzoom = __mapzooms_x [data.u];
                          vml->ymapzoom = __mapzooms_y [data.u];
                        }else g_warning (_("Unknown Map Zoom")); break;
    default: break;
  }
  return TRUE;
}

static VikLayerParamData maps_layer_get_param ( VikMapsLayer *vml, guint16 id, gboolean is_file_operation )
{
  VikLayerParamData rv;
  switch ( id )
  {
    case PARAM_CACHE_DIR:
    {
      gboolean set = FALSE;
      /* Only save a blank when the map cache location equals the default
          On reading in, when it is blank then the default is reconstructed
          Since the default changes dependent on the user and OS, it means the resultant file is more portable */
      if ( is_file_operation && vml->cache_dir && strcmp ( vml->cache_dir, MAPS_CACHE_DIR ) == 0 ) {
        rv.s = "";
        set = TRUE;
      }
      else if ( is_file_operation ) {
        if ( a_vik_get_file_ref_format() == VIK_FILE_REF_FORMAT_RELATIVE ) {
          gchar *cwd = g_get_current_dir();
          if ( cwd ) {
            rv.s = file_GetRelativeFilename ( cwd, vml->cache_dir );
            if ( !rv.s ) rv.s = "";
            set = TRUE;
	  }
	}
      }
      if ( !set )
	rv.s = vml->cache_dir ? vml->cache_dir : "";
      break;
    }
    case PARAM_CACHE_LAYOUT: rv.u = vml->cache_layout; break;
    case PARAM_FILE: rv.s = vml->filename; break;
    case PARAM_MAPTYPE: rv.u = map_index_to_uniq_id ( vml->maptype ); break;
    case PARAM_ALPHA: rv.u = vml->alpha; break;
    case PARAM_AUTODOWNLOAD: rv.u = vml->autodownload; break;
    case PARAM_ONLYMISSING: rv.u = vml->adl_only_missing; break;
    case PARAM_MAPZOOM: rv.u = vml->mapzoom_id; break;
    default: break;
  }
  return rv;
}

static void maps_layer_change_param ( GtkWidget *widget, ui_change_values values )
{
  switch ( GPOINTER_TO_INT(values[UI_CHG_PARAM_ID]) ) {
    // Alter sensitivity of download option widgets according to the maptype setting.
    case PARAM_MAPTYPE: {
      // Get new value
      VikLayerParamData vlpd = a_uibuilder_widget_get_value ( widget, values[UI_CHG_PARAM] );
      // Is it *not* the OSM On Disk Tile Layout or the MBTiles type or the OSM Metatiles type
      gboolean sensitive = ( MAP_ID_OSM_ON_DISK != vlpd.u && MAP_ID_OSM_ON_DISK != vlpd.u && MAP_ID_OSM_ON_DISK != vlpd.u );
      GtkWidget **ww1 = values[UI_CHG_WIDGETS];
      GtkWidget **ww2 = values[UI_CHG_LABELS];
      GtkWidget *w1 = ww1[PARAM_ONLYMISSING];
      GtkWidget *w2 = ww2[PARAM_ONLYMISSING];
      GtkWidget *w3 = ww1[PARAM_AUTODOWNLOAD];
      GtkWidget *w4 = ww2[PARAM_AUTODOWNLOAD];
      // Depends on autodownload value
      gboolean missing_sense = sensitive && VIK_MAPS_LAYER(values[UI_CHG_LAYER])->autodownload;
      if ( w1 ) gtk_widget_set_sensitive ( w1, missing_sense );
      if ( w2 ) gtk_widget_set_sensitive ( w2, missing_sense );
      if ( w3 ) gtk_widget_set_sensitive ( w3, sensitive );
      if ( w4 ) gtk_widget_set_sensitive ( w4, sensitive );

      // Cache type not applicable either
      GtkWidget *w9 = ww1[PARAM_CACHE_LAYOUT];
      GtkWidget *w10 = ww2[PARAM_CACHE_LAYOUT];
      if ( w9 ) gtk_widget_set_sensitive ( w9, sensitive );
      if ( w10 ) gtk_widget_set_sensitive ( w10, sensitive );

      // File only applicable for MBTiles type
      // Directory for all other types
      sensitive = ( MAP_ID_MBTILES == vlpd.u);
      GtkWidget *w5 = ww1[PARAM_FILE];
      GtkWidget *w6 = ww2[PARAM_FILE];
      GtkWidget *w7 = ww1[PARAM_CACHE_DIR];
      GtkWidget *w8 = ww2[PARAM_CACHE_DIR];
      if ( w5 ) gtk_widget_set_sensitive ( w5, sensitive );
      if ( w6 ) gtk_widget_set_sensitive ( w6, sensitive );
      if ( w7 ) gtk_widget_set_sensitive ( w7, !sensitive );
      if ( w8 ) gtk_widget_set_sensitive ( w8, !sensitive );

      break;
    }

    // Alter sensitivity of 'download only missing' widgets according to the autodownload setting.
    case PARAM_AUTODOWNLOAD: {
      // Get new value
      VikLayerParamData vlpd = a_uibuilder_widget_get_value ( widget, values[UI_CHG_PARAM] );
      GtkWidget **ww1 = values[UI_CHG_WIDGETS];
      GtkWidget **ww2 = values[UI_CHG_LABELS];
      GtkWidget *w1 = ww1[PARAM_ONLYMISSING];
      GtkWidget *w2 = ww2[PARAM_ONLYMISSING];
      if ( w1 ) gtk_widget_set_sensitive ( w1, vlpd.b );
      if ( w2 ) gtk_widget_set_sensitive ( w2, vlpd.b );
      break;
    }
    default: break;
  }
}

/****************************************/
/****** CREATING, COPYING, FREEING ******/
/****************************************/

static VikMapsLayer *maps_layer_new ( VikViewport *vvp )
{
  VikMapsLayer *vml = VIK_MAPS_LAYER ( g_object_new ( VIK_MAPS_LAYER_TYPE, NULL ) );
  vik_layer_set_type ( VIK_LAYER(vml), VIK_LAYER_MAPS );

  vik_layer_set_defaults ( VIK_LAYER(vml), vvp );

  vml->dl_tool_x = vml->dl_tool_y = -1;
  vml->last_center = NULL;
  vml->last_xmpp = 0.0;
  vml->last_ympp = 0.0;

  vml->dl_right_click_menu = NULL;
  vml->filename = NULL;
  return vml;
}

static void maps_layer_free ( VikMapsLayer *vml )
{
  g_free ( vml->cache_dir );
  vml->cache_dir = NULL;
  if ( vml->dl_right_click_menu )
    g_object_ref_sink ( G_OBJECT(vml->dl_right_click_menu) );
  g_free(vml->last_center);
  vml->last_center = NULL;
  g_free ( vml->filename );
  vml->filename = NULL;

#ifdef HAVE_SQLITE3_H
  VikMapSource *map = MAPS_LAYER_NTH_TYPE(vml->maptype);
  if ( vik_map_source_is_mbtiles ( map ) ) {
    if ( vml->mbtiles ) {
      int ans = sqlite3_close ( vml->mbtiles );
      if ( ans != SQLITE_OK ) {
        // Only to console for information purposes only
        g_warning ( "SQL Close problem: %d", ans );
      }
    }
  }
#endif
}

static void maps_layer_post_read (VikLayer *vl, VikViewport *vp, gboolean from_file)
{
  VikMapsLayer *vml = VIK_MAPS_LAYER(vl);
  VikMapSource *map = MAPS_LAYER_NTH_TYPE(vml->maptype);

  if (!from_file)
  {
    /* If this method is not called in file reading context
     * it is called in GUI context.
     * So, we can check if we have to inform the user about inconsistency */
    VikViewportDrawMode vp_drawmode;
    vp_drawmode = vik_viewport_get_drawmode ( vp );

    if (vik_map_source_get_drawmode(map) != vp_drawmode) {
      const gchar *drawmode_name = vik_viewport_get_drawmode_name (vp, vik_map_source_get_drawmode(map));
      gchar *msg = g_strdup_printf(_("New map cannot be displayed in the current drawmode.\nSelect \"%s\" from View menu to view it."), drawmode_name);
      a_dialog_warning_msg ( VIK_GTK_WINDOW_FROM_WIDGET(vp), msg );
      g_free(msg);
    }
  }
  
  // Performed in post read as we now know the map type
#ifdef HAVE_SQLITE3_H
  // Do some SQL stuff
  if ( vik_map_source_is_mbtiles ( map ) ) {
    int ans = sqlite3_open_v2 ( vml->filename,
                                &(vml->mbtiles),
                                SQLITE_OPEN_READONLY,
                                NULL );
    if ( ans != SQLITE_OK ) {
      // That didn't work, so here's why:
      g_warning ( "%s: %s", __FUNCTION__, sqlite3_errmsg ( vml->mbtiles ) );

      a_dialog_error_msg_extra ( VIK_GTK_WINDOW_FROM_WIDGET(vp),
                                 _("Failed to open MBTiles file: %s"),
                                 vml->filename );
      vml->mbtiles = NULL;
    }
  }
#endif

  // If the on Disk OSM Tile Layout type
  if ( vik_map_source_get_uniq_id(map) == MAP_ID_OSM_ON_DISK ) {
    // Copy the directory into filename
    //  thus the mapcache look up will be unique when using more than one of these map types
    g_free ( vml->filename );
    vml->filename = g_strdup (vml->cache_dir);
  }
}

static const gchar* maps_layer_tooltip ( VikMapsLayer *vml )
{
  return vik_maps_layer_get_map_label ( vml );
}

static void maps_layer_marshall( VikMapsLayer *vml, guint8 **data, gint *len )
{
  vik_layer_marshall_params ( VIK_LAYER(vml), data, len );
}

static VikMapsLayer *maps_layer_unmarshall( guint8 *data, gint len, VikViewport *vvp )
{
  VikMapsLayer *rv = maps_layer_new ( vvp );
  vik_layer_unmarshall_params ( VIK_LAYER(rv), data, len, vvp );
  maps_layer_post_read ( VIK_LAYER(rv), vvp, FALSE );
  return rv;
}

/*********************/
/****** DRAWING ******/
/*********************/

static GdkPixbuf *pixbuf_shrink ( GdkPixbuf *pixbuf, gdouble xshrinkfactor, gdouble yshrinkfactor )
{
  GdkPixbuf *tmp;
  guint16 width = gdk_pixbuf_get_width(pixbuf), height = gdk_pixbuf_get_height(pixbuf);
  tmp = gdk_pixbuf_scale_simple(pixbuf, ceil(width * xshrinkfactor), ceil(height * yshrinkfactor), GDK_INTERP_BILINEAR);
  g_object_unref ( G_OBJECT(pixbuf) );
  return tmp;
}

#ifdef HAVE_SQLITE3_H
/*
static int sql_select_tile_dump_cb (void *data, int cols, char **fields, char **col_names )
{
  g_warning ( "Found %d columns", cols );
  int i;
  for ( i = 0; i < cols; i++ ) {
    g_warning ( "SQL processing %s = %s", col_names[i], fields[i] );
  }
  return 0;
}
*/

/**
 *
 */
static GdkPixbuf *get_pixbuf_sql_exec ( sqlite3 *sql, gint xx, gint yy, gint zoom )
{
  GdkPixbuf *pixbuf = NULL;

  // MBTiles stored internally with the flipping y thingy (i.e. TMS scheme).
  gint flip_y = (gint) pow(2, zoom)-1 - yy;
  gchar *statement = g_strdup_printf ( "SELECT tile_data FROM tiles WHERE zoom_level=%d AND tile_column=%d AND tile_row=%d;", zoom, xx, flip_y );

  gboolean finished = FALSE;

  sqlite3_stmt *sql_stmt = NULL;
  int ans = sqlite3_prepare_v2 ( sql, statement, -1, &sql_stmt, NULL );
  if ( ans != SQLITE_OK ) {
    g_warning ( "%s: %s - %d", __FUNCTION__, "prepare failure", ans );
    finished = TRUE;
  }

  while ( !finished ) {
    ans = sqlite3_step ( sql_stmt );
    switch (ans) {
      case SQLITE_ROW: {
        // Get tile_data blob
        int count = sqlite3_column_count(sql_stmt);
        if ( count != 1 )  {
          g_warning ( "%s: %s - %d", __FUNCTION__, "count not one", count );
          finished = TRUE;
        }
        else {
          const void *data = sqlite3_column_blob ( sql_stmt, 0 );
          int bytes = sqlite3_column_bytes ( sql_stmt, 0 );
          if ( bytes < 1 )  {
            g_warning ( "%s: %s (%d)", __FUNCTION__, "not enough bytes", bytes );
            finished = TRUE;
          }
          else {
            // Convert these blob bytes into a pixbuf via these streaming operations
            GInputStream *stream = g_memory_input_stream_new_from_data ( data, bytes, NULL );
            GError *error = NULL;
            pixbuf = gdk_pixbuf_new_from_stream ( stream, NULL, &error );
            if (error || (!pixbuf)) {
              g_warning ( "%s: %s", __FUNCTION__, error->message );
              g_error_free ( error );
            }
            g_input_stream_close ( stream, NULL, NULL );
          }
        }
        break;
      }
      default:
       // e.g. SQLITE_DONE | SQLITE_ERROR | SQLITE_MISUSE | etc...
       // Finished normally
       //  and give up on any errors
       if ( ans != SQLITE_DONE )
         g_warning ( "%s: %s - %d", __FUNCTION__, "step issue", ans );
       finished = TRUE;
       break;
    }
  }
  ans = sqlite3_finalize ( sql_stmt );
  
  g_free ( statement );

  return pixbuf;
}
#endif

static GdkPixbuf *get_mbtiles_pixbuf ( VikMapsLayer *vml, gint xx, gint yy, gint zoom )
{
  GdkPixbuf *pixbuf = NULL;

#ifdef HAVE_SQLITE3_H
  if ( vml->mbtiles ) {
    /*
    gchar *statement = g_strdup_printf ( "SELECT name FROM sqlite_master WHERE type='table';" );
    char *errMsg = NULL;
    int ans = sqlite3_exec ( vml->mbtiles, statement, sql_select_tile_dump_cb, pixbuf, &errMsg );
    if ( ans != SQLITE_OK ) {
      // Only to console for information purposes only
      g_warning ( "SQL problem: %d for %s - error: %s", ans, statement, errMsg );
      sqlite3_free( errMsg );
    }
    g_free ( statement );
    */

    // Reading BLOBS is a bit more involved and so can't use the simpler sqlite3_exec ()
    // Hence this specific function
    pixbuf = get_pixbuf_sql_exec ( vml->mbtiles, xx, yy, zoom );
  }
#endif

  return pixbuf;
}

static GdkPixbuf *get_pixbuf_from_metatile ( VikMapsLayer *vml, gint xx, gint yy, gint zz )
{
  const int tile_max = METATILE_MAX_SIZE;
  char err_msg[PATH_MAX];
  char *buf;
  int len;
  int compressed;

  buf = malloc(tile_max);
  if (!buf) {
      return NULL;
  }

  err_msg[0] = 0;
  len = metatile_read(vml->cache_dir, xx, yy, zz, buf, tile_max, &compressed, err_msg);

  if (len > 0) {
    if (compressed) {
      // Not handled yet - I don't think this is used often - so implement later if necessary
      g_warning ( "Compressed metatiles not implemented:%s\n", __FUNCTION__);
      return NULL;
    }

    // Convert these buf bytes into a pixbuf via these streaming operations
    GdkPixbuf *pixbuf = NULL;

    GInputStream *stream = g_memory_input_stream_new_from_data ( buf, len, NULL );
    GError *error = NULL;
    pixbuf = gdk_pixbuf_new_from_stream ( stream, NULL, &error );
    if (error || (!pixbuf)) {
      g_warning ( "%s: %s", __FUNCTION__, error->message );
      g_error_free ( error );
    }
    g_input_stream_close ( stream, NULL, NULL );

    free(buf);
    return pixbuf;
  }
  else {
    g_warning ( "FAILED:%s %s", __FUNCTION__, err_msg);
    return NULL;
  }
}


static GdkPixbuf *pixbuf_apply_settings ( GdkPixbuf *pixbuf, VikMapsLayer *vml, MapCoord *mapcoord, gdouble xshrinkfactor, gdouble yshrinkfactor )
{
  // Apply alpha setting
  if ( pixbuf && vml->alpha < 255 )
    pixbuf = ui_pixbuf_set_alpha ( pixbuf, vml->alpha );

  if ( pixbuf && ( xshrinkfactor != 1.0 || yshrinkfactor != 1.0 ) )
    pixbuf = pixbuf_shrink ( pixbuf, xshrinkfactor, yshrinkfactor );

  if ( pixbuf )
    a_mapcache_add ( pixbuf, (mapcache_extra_t) {0.0}, mapcoord->x, mapcoord->y,
                     mapcoord->z, vik_map_source_get_uniq_id(MAPS_LAYER_NTH_TYPE(vml->maptype)),
                     mapcoord->scale, vml->alpha, xshrinkfactor, yshrinkfactor, vml->filename );

  return pixbuf;
}

static void get_filename ( const gchar *cache_dir,
                           VikMapsCacheLayout cl,
                           guint16 id,
                           const gchar *name,
                           gint scale,
                           gint z,
                           gint x,
                           gint y,
                           gchar *filename_buf,
                           gint buf_len,
                           const gchar* file_extension )
{
  switch ( cl ) {
    case VIK_MAPS_CACHE_LAYOUT_OSM:
      if ( name ) {
        if ( g_strcmp0 ( cache_dir, MAPS_CACHE_DIR ) )
          // Cache dir not the default - assume it's been directed somewhere specific
          g_snprintf ( filename_buf, buf_len, DIRECTDIRACCESS, cache_dir, (17 - scale), x, y, file_extension );
        else
          // Using default cache - so use the map name in the directory path
          g_snprintf ( filename_buf, buf_len, DIRECTDIRACCESS_WITH_NAME, cache_dir, name, (17 - scale), x, y, file_extension );
      }
      else
        g_snprintf ( filename_buf, buf_len, DIRECTDIRACCESS, cache_dir, (17 - scale), x, y, file_extension );
      break;
    default:
      g_snprintf ( filename_buf, buf_len, DIRSTRUCTURE, cache_dir, id, scale, z, x, y );
      break;
  }
}

static GdkPixbuf *get_pixbuf( VikMapsLayer *vml, guint16 id, const gchar* mapname, MapCoord *mapcoord, gchar *filename_buf, gint buf_len, gdouble xshrinkfactor, gdouble yshrinkfactor )
{
  GdkPixbuf *pixbuf;

  /* get the thing */
  pixbuf = a_mapcache_get ( mapcoord->x, mapcoord->y, mapcoord->z,
                            id, mapcoord->scale, vml->alpha, xshrinkfactor, yshrinkfactor, vml->filename );

  if ( ! pixbuf ) {
    VikMapSource *map = MAPS_LAYER_NTH_TYPE(vml->maptype);
    if ( vik_map_source_is_direct_file_access(map) ) {
      // ATM MBTiles must be 'a direct access type'
      if ( vik_map_source_is_mbtiles(map) ) {
        pixbuf = get_mbtiles_pixbuf ( vml, mapcoord->x, mapcoord->y, (17 - mapcoord->scale) );
        pixbuf = pixbuf_apply_settings ( pixbuf, vml, mapcoord, xshrinkfactor, yshrinkfactor );
        // return now to avoid file tests that aren't appropriate for this map type
        return pixbuf;
      }
      else if ( vik_map_source_is_osm_meta_tiles(map) ) {
        pixbuf = get_pixbuf_from_metatile ( vml, mapcoord->x, mapcoord->y, (17 - mapcoord->scale) );
        pixbuf = pixbuf_apply_settings ( pixbuf, vml, mapcoord, xshrinkfactor, yshrinkfactor );
        return pixbuf;
      }
      else
        get_filename ( vml->cache_dir, VIK_MAPS_CACHE_LAYOUT_OSM, id, NULL,
                       mapcoord->scale, mapcoord->z, mapcoord->x, mapcoord->y, filename_buf, buf_len,
                       vik_map_source_get_file_extension(map) );
    }
    else
      get_filename ( vml->cache_dir, vml->cache_layout, id, mapname,
                     mapcoord->scale, mapcoord->z, mapcoord->x, mapcoord->y, filename_buf, buf_len,
                     vik_map_source_get_file_extension(map) );

    if ( g_file_test ( filename_buf, G_FILE_TEST_EXISTS ) == TRUE)
    {
      GError *gx = NULL;
      pixbuf = gdk_pixbuf_new_from_file ( filename_buf, &gx );

      /* free the pixbuf on error */
      if (gx)
      {
        if ( gx->domain != GDK_PIXBUF_ERROR || gx->code != GDK_PIXBUF_ERROR_CORRUPT_IMAGE ) {
          // Report a warning
          if ( IS_VIK_WINDOW ((VikWindow*)VIK_GTK_WINDOW_FROM_LAYER(vml)) ) {
            gchar* msg = g_strdup_printf ( _("Couldn't open image file: %s"), gx->message );
            vik_window_statusbar_update ( (VikWindow*)VIK_GTK_WINDOW_FROM_LAYER(vml), msg, VIK_STATUSBAR_INFO );
            g_free (msg);
          }
        }

        g_error_free ( gx );
        if ( pixbuf )
          g_object_unref ( G_OBJECT(pixbuf) );
        pixbuf = NULL;
      } else {
        pixbuf = pixbuf_apply_settings ( pixbuf, vml, mapcoord, xshrinkfactor, yshrinkfactor );
      }
    }
  }
  return pixbuf;
}

static gboolean should_start_autodownload(VikMapsLayer *vml, VikViewport *vvp)
{
  const VikCoord *center = vik_viewport_get_center ( vvp );

  if (vik_window_get_pan_move (VIK_WINDOW(VIK_GTK_WINDOW_FROM_WIDGET(GTK_WIDGET(vvp)))))
    /* D'n'D pan in action: do not download */
    return FALSE;

  // Don't attempt to download unsupported zoom levels
  gdouble xzoom = vik_viewport_get_xmpp ( vvp );
  VikMapSource *map = MAPS_LAYER_NTH_TYPE(vml->maptype);
  guint8 zl = map_utils_mpp_to_zoom_level ( xzoom );
  if ( zl < vik_map_source_get_zoom_min(map) || zl > vik_map_source_get_zoom_max(map) )
    return FALSE;

  if (vml->last_center == NULL) {
    VikCoord *new_center = g_malloc(sizeof(VikCoord));
    *new_center = *center;
    vml->last_center = new_center;
    vml->last_xmpp = vik_viewport_get_xmpp(vvp);
    vml->last_ympp = vik_viewport_get_ympp(vvp);
    return TRUE;
  }

  /* TODO: perhaps vik_coord_diff() */
  if (vik_coord_equals(vml->last_center, center)
      && (vml->last_xmpp == vik_viewport_get_xmpp(vvp))
      && (vml->last_ympp == vik_viewport_get_ympp(vvp)))
    return FALSE;

  *(vml->last_center) = *center;
    vml->last_xmpp = vik_viewport_get_xmpp(vvp);
    vml->last_ympp = vik_viewport_get_ympp(vvp);
  return TRUE;
}

/**
 *
 */
gboolean try_draw_scale_down (VikMapsLayer *vml, VikViewport *vvp, MapCoord ulm, gint xx, gint yy, gint tilesize_x_ceil, gint tilesize_y_ceil,
                              gdouble xshrinkfactor, gdouble yshrinkfactor, guint id, const gchar *mapname, gchar *path_buf, guint max_path_len)
{
  GdkPixbuf *pixbuf;
  int scale_inc;
  for (scale_inc = 1; scale_inc < SCALE_INC_DOWN; scale_inc ++) {
    // Try with smaller zooms
    int scale_factor = 1 << scale_inc;  /*  2^scale_inc */
    MapCoord ulm2 = ulm;
    ulm2.x = ulm.x / scale_factor;
    ulm2.y = ulm.y / scale_factor;
    ulm2.scale = ulm.scale + scale_inc;
    pixbuf = get_pixbuf ( vml, id, mapname, &ulm2, path_buf, max_path_len, xshrinkfactor * scale_factor, yshrinkfactor * scale_factor );
    if ( pixbuf ) {
      gint src_x = (ulm.x % scale_factor) * tilesize_x_ceil;
      gint src_y = (ulm.y % scale_factor) * tilesize_y_ceil;
      vik_viewport_draw_pixbuf ( vvp, pixbuf, src_x, src_y, xx, yy, tilesize_x_ceil, tilesize_y_ceil );
      return TRUE;
    }
  }
  return FALSE;
}

/**
 *
 */
gboolean try_draw_scale_up (VikMapsLayer *vml, VikViewport *vvp, MapCoord ulm, gint xx, gint yy, gint tilesize_x_ceil, gint tilesize_y_ceil,
                            gdouble xshrinkfactor, gdouble yshrinkfactor, guint id, const gchar *mapname, gchar *path_buf, guint max_path_len)
{
  GdkPixbuf *pixbuf;
  // Try with bigger zooms
  int scale_dec;
  for (scale_dec = 1; scale_dec < SCALE_INC_UP; scale_dec ++) {
    int pict_x, pict_y;
    int scale_factor = 1 << scale_dec;  /*  2^scale_dec */
    MapCoord ulm2 = ulm;
    ulm2.x = ulm.x * scale_factor;
    ulm2.y = ulm.y * scale_factor;
    ulm2.scale = ulm.scale - scale_dec;
    for (pict_x = 0; pict_x < scale_factor; pict_x ++) {
      for (pict_y = 0; pict_y < scale_factor; pict_y ++) {
        MapCoord ulm3 = ulm2;
        ulm3.x += pict_x;
        ulm3.y += pict_y;
        pixbuf = get_pixbuf ( vml, id, mapname, &ulm3, path_buf, max_path_len, xshrinkfactor / scale_factor, yshrinkfactor / scale_factor );
        if ( pixbuf ) {
          gint src_x = 0;
          gint src_y = 0;
          gint dest_x = xx + pict_x * (tilesize_x_ceil / scale_factor);
          gint dest_y = yy + pict_y * (tilesize_y_ceil / scale_factor);
          vik_viewport_draw_pixbuf ( vvp, pixbuf, src_x, src_y, dest_x, dest_y, tilesize_x_ceil / scale_factor, tilesize_y_ceil / scale_factor );
          return TRUE;
        }
      }
    }
  }
  return FALSE;
}

static void maps_layer_draw_section ( VikMapsLayer *vml, VikViewport *vvp, VikCoord *ul, VikCoord *br )
{
  MapCoord ulm, brm;
  gdouble xzoom = vik_viewport_get_xmpp ( vvp );
  gdouble yzoom = vik_viewport_get_ympp ( vvp );
  gdouble xshrinkfactor = 1.0, yshrinkfactor = 1.0;
  gboolean existence_only = FALSE;

  if ( vml->xmapzoom && (vml->xmapzoom != xzoom || vml->ymapzoom != yzoom) ) {
    xshrinkfactor = vml->xmapzoom / xzoom;
    yshrinkfactor = vml->ymapzoom / yzoom;
    xzoom = vml->xmapzoom;
    yzoom = vml->xmapzoom;
    if ( ! (xshrinkfactor > MIN_SHRINKFACTOR && xshrinkfactor < MAX_SHRINKFACTOR &&
         yshrinkfactor > MIN_SHRINKFACTOR && yshrinkfactor < MAX_SHRINKFACTOR ) ) {
      if ( xshrinkfactor > REAL_MIN_SHRINKFACTOR && yshrinkfactor > REAL_MIN_SHRINKFACTOR ) {
        g_debug ( "%s: existence_only due to SHRINKFACTORS", __FUNCTION__ );
        existence_only = TRUE;
      }
      else {
        // Report the reason for not drawing
        if ( IS_VIK_WINDOW ((VikWindow*)VIK_GTK_WINDOW_FROM_LAYER(vml)) ) {
          gchar* msg = g_strdup_printf ( _("Cowardly refusing to draw tiles or existence of tiles beyond %d zoom out factor"), (int)( 1.0/REAL_MIN_SHRINKFACTOR));
          vik_window_statusbar_update ( (VikWindow*)VIK_GTK_WINDOW_FROM_LAYER(vml), msg, VIK_STATUSBAR_INFO );
          g_free (msg);
        }
        return;
      }
    }
  }

  /* coord -> ID */
  VikMapSource *map = MAPS_LAYER_NTH_TYPE(vml->maptype);
  if ( vik_map_source_coord_to_mapcoord ( map, ul, xzoom, yzoom, &ulm ) &&
       vik_map_source_coord_to_mapcoord ( map, br, xzoom, yzoom, &brm ) ) {

    /* loop & draw */
    gint x, y;
    gint xmin = MIN(ulm.x, brm.x), xmax = MAX(ulm.x, brm.x);
    gint ymin = MIN(ulm.y, brm.y), ymax = MAX(ulm.y, brm.y);
    guint16 id = vik_map_source_get_uniq_id(map);
    const gchar *mapname = vik_map_source_get_name(map);

    VikCoord coord;
    gint xx, yy, width, height;
    GdkPixbuf *pixbuf;

    // Prevent the program grinding to a halt if trying to deal with thousands of tiles
    //  which can happen when using a small fixed zoom level and viewing large areas.
    // Also prevents very large number of tile download requests
    gint tiles = (xmax-xmin) * (ymax-ymin);
    if ( tiles > MAX_TILES ) {
      g_debug ( "%s: existence_only due to wanting too many tiles (%d)", __FUNCTION__, tiles );
      existence_only = TRUE;
    }

    guint max_path_len = strlen(vml->cache_dir) + 40;
    gchar *path_buf = g_malloc ( max_path_len * sizeof(char) );

    if ( (!existence_only) && vml->autodownload  && should_start_autodownload(vml, vvp)) {
      g_debug("%s: Starting autodownload", __FUNCTION__);
      if ( !vml->adl_only_missing && vik_map_source_supports_download_only_new (map) )
        // Try to download newer tiles
        start_download_thread ( vml, vvp, ul, br, REDOWNLOAD_NEW );
      else
        // Download only missing tiles
        start_download_thread ( vml, vvp, ul, br, REDOWNLOAD_NONE );
    }

    if ( vik_map_source_get_tilesize_x(map) == 0 && !existence_only ) {
      for ( x = xmin; x <= xmax; x++ ) {
        for ( y = ymin; y <= ymax; y++ ) {
          ulm.x = x;
          ulm.y = y;
          pixbuf = get_pixbuf ( vml, id, mapname, &ulm, path_buf, max_path_len, xshrinkfactor, yshrinkfactor );
          if ( pixbuf ) {
            width = gdk_pixbuf_get_width ( pixbuf );
            height = gdk_pixbuf_get_height ( pixbuf );

            vik_map_source_mapcoord_to_center_coord ( map, &ulm, &coord );
            vik_viewport_coord_to_screen ( vvp, &coord, &xx, &yy );
            xx -= (width/2);
            yy -= (height/2);

            vik_viewport_draw_pixbuf ( vvp, pixbuf, 0, 0, xx, yy, width, height );
          }
        }
      }
    } else { /* tilesize is known, don't have to keep converting coords */
      gdouble tilesize_x = vik_map_source_get_tilesize_x(map) * xshrinkfactor;
      gdouble tilesize_y = vik_map_source_get_tilesize_y(map) * yshrinkfactor;
      /* ceiled so tiles will be maximum size in the case of funky shrinkfactor */
      gint tilesize_x_ceil = ceil ( tilesize_x );
      gint tilesize_y_ceil = ceil ( tilesize_y );
      gint8 xinc = (ulm.x == xmin) ? 1 : -1;
      gint8 yinc = (ulm.y == ymin) ? 1 : -1;
      gint xx_tmp, yy_tmp;
      gint base_yy, xend, yend;

      xend = (xinc == 1) ? (xmax+1) : (xmin-1);
      yend = (yinc == 1) ? (ymax+1) : (ymin-1);

      vik_map_source_mapcoord_to_center_coord ( map, &ulm, &coord );
      vik_viewport_coord_to_screen ( vvp, &coord, &xx_tmp, &yy_tmp );
      xx = xx_tmp; yy = yy_tmp;
      /* above trick so xx,yy doubles. this is so shrinkfactors aren't rounded off
       * eg if tile size 128, shrinkfactor 0.333 */
      xx -= (tilesize_x/2);
      base_yy = yy - (tilesize_y/2);

      for ( x = ((xinc == 1) ? xmin : xmax); x != xend; x+=xinc ) {
        yy = base_yy;
        for ( y = ((yinc == 1) ? ymin : ymax); y != yend; y+=yinc ) {
          ulm.x = x;
          ulm.y = y;

          if ( existence_only ) {
            if ( vik_map_source_is_direct_file_access (MAPS_LAYER_NTH_TYPE(vml->maptype)) )
              get_filename ( vml->cache_dir, VIK_MAPS_CACHE_LAYOUT_OSM, id, vik_map_source_get_name(map),
                             ulm.scale, ulm.z, ulm.x, ulm.y, path_buf, max_path_len, vik_map_source_get_file_extension(map) );
            else
              get_filename ( vml->cache_dir, vml->cache_layout, id, vik_map_source_get_name(map),
                             ulm.scale, ulm.z, ulm.x, ulm.y, path_buf, max_path_len, vik_map_source_get_file_extension(map) );

            if ( g_file_test ( path_buf, G_FILE_TEST_EXISTS ) == TRUE ) {
	      GdkGC *black_gc = gtk_widget_get_style(GTK_WIDGET(vvp))->black_gc;
              vik_viewport_draw_line ( vvp, black_gc, xx+tilesize_x_ceil, yy, xx, yy+tilesize_y_ceil );
            }
          } else {
            // Try correct scale first
            int scale_factor = 1;
            pixbuf = get_pixbuf ( vml, id, mapname, &ulm, path_buf, max_path_len, xshrinkfactor * scale_factor, yshrinkfactor * scale_factor );
            if ( pixbuf ) {
              gint src_x = (ulm.x % scale_factor) * tilesize_x_ceil;
              gint src_y = (ulm.y % scale_factor) * tilesize_y_ceil;
              vik_viewport_draw_pixbuf ( vvp, pixbuf, src_x, src_y, xx, yy, tilesize_x_ceil, tilesize_y_ceil );
            }
            else {
              // Otherwise try different scales
              if ( SCALE_SMALLER_ZOOM_FIRST ) {
                if ( !try_draw_scale_down(vml,vvp,ulm,xx,yy,tilesize_x_ceil,tilesize_y_ceil,xshrinkfactor,yshrinkfactor,id,mapname,path_buf,max_path_len) ) {
                  try_draw_scale_up(vml,vvp,ulm,xx,yy,tilesize_x_ceil,tilesize_y_ceil,xshrinkfactor,yshrinkfactor,id,mapname,path_buf,max_path_len);
                }
              }
              else {
                if ( !try_draw_scale_up(vml,vvp,ulm,xx,yy,tilesize_x_ceil,tilesize_y_ceil,xshrinkfactor,yshrinkfactor,id,mapname,path_buf,max_path_len) ) {
                  try_draw_scale_down(vml,vvp,ulm,xx,yy,tilesize_x_ceil,tilesize_y_ceil,xshrinkfactor,yshrinkfactor,id,mapname,path_buf,max_path_len);
                }
              }
            }
          }

          yy += tilesize_y;
        }
        xx += tilesize_x;
      }

      // ATM Only show tile grid lines in extreme debug mode
      if ( vik_debug && vik_verbose ) {
        /* Grid drawing here so it gets drawn on top of the map */
        /* Thus loop around x & y again, but this time separately */
        /* Only showing grid for the current scale */
        GdkGC *black_gc = GTK_WIDGET(vvp)->style->black_gc;
        /* Draw single grid lines across the whole screen */
        gint width = vik_viewport_get_width(vvp);
        gint height = vik_viewport_get_height(vvp);
        xx = xx_tmp; yy = yy_tmp;
        gint base_xx = xx - (tilesize_x/2);
        base_yy = yy - (tilesize_y/2);

        xx = base_xx;
        for ( x = ((xinc == 1) ? xmin : xmax); x != xend; x+=xinc ) {
          vik_viewport_draw_line ( vvp, black_gc, xx, base_yy, xx, height );
          xx += tilesize_x;
        }

        yy = base_yy;
        for ( y = ((yinc == 1) ? ymin : ymax); y != yend; y+=yinc ) {
          vik_viewport_draw_line ( vvp, black_gc, base_xx, yy, width, yy );
          yy += tilesize_y;
        }
      }

    }
    g_free ( path_buf );
  }
}

static void maps_layer_draw ( VikMapsLayer *vml, VikViewport *vvp )
{
  if ( vik_map_source_get_drawmode(MAPS_LAYER_NTH_TYPE(vml->maptype)) == vik_viewport_get_drawmode ( vvp ) )
  {
    VikCoord ul, br;

    /* Copyright */
    gdouble level = vik_viewport_get_zoom ( vvp );
    LatLonBBox bbox;
    vik_viewport_get_min_max_lat_lon ( vvp, &bbox.south, &bbox.north, &bbox.west, &bbox.east );
    vik_map_source_get_copyright ( MAPS_LAYER_NTH_TYPE(vml->maptype), bbox, level, vik_viewport_add_copyright, vvp );

    /* Logo */
    const GdkPixbuf *logo = vik_map_source_get_logo ( MAPS_LAYER_NTH_TYPE(vml->maptype) );
    vik_viewport_add_logo ( vvp, logo );

    /* get corner coords */
    if ( vik_viewport_get_coord_mode ( vvp ) == VIK_COORD_UTM && ! vik_viewport_is_one_zone ( vvp ) ) {
      /* UTM multi-zone stuff by Kit Transue */
      gchar leftmost_zone, rightmost_zone, i;
      leftmost_zone = vik_viewport_leftmost_zone( vvp );
      rightmost_zone = vik_viewport_rightmost_zone( vvp );
      for ( i = leftmost_zone; i <= rightmost_zone; ++i ) {
        vik_viewport_corners_for_zonen ( vvp, i, &ul, &br );
        maps_layer_draw_section ( vml, vvp, &ul, &br );
      }
    }
    else {
      vik_viewport_screen_to_coord ( vvp, 0, 0, &ul );
      vik_viewport_screen_to_coord ( vvp, vik_viewport_get_width(vvp), vik_viewport_get_height(vvp), &br );

      maps_layer_draw_section ( vml, vvp, &ul, &br );
    }
  }
}

/*************************/
/****** DOWNLOADING ******/
/*************************/

/* pass along data to thread, exists even if layer is deleted. */
typedef struct {
  gchar *cache_dir;
  gchar *filename_buf;
  VikMapsCacheLayout cache_layout;
  gint x0, y0, xf, yf;
  MapCoord mapcoord;
  gint maptype;
  gint maxlen;
  gint mapstoget;
  gint redownload;
  gboolean refresh_display;
  VikMapsLayer *vml;
  VikViewport *vvp;
  gboolean map_layer_alive;
  GMutex *mutex;
} MapDownloadInfo;

static void mdi_free ( MapDownloadInfo *mdi )
{
  vik_mutex_free(mdi->mutex);
  g_free ( mdi->cache_dir );
  mdi->cache_dir = NULL;
  g_free ( mdi->filename_buf );
  mdi->filename_buf = NULL;
  g_free ( mdi );
}

static void weak_ref_cb(gpointer ptr, GObject * dead_vml)
{
  MapDownloadInfo *mdi = ptr;
  g_mutex_lock(mdi->mutex);
  mdi->map_layer_alive = FALSE;
  g_mutex_unlock(mdi->mutex);
}

static gboolean is_in_area (VikMapSource *map, MapCoord mc)
{
  VikCoord vc;
  vik_map_source_mapcoord_to_center_coord ( map, &mc, &vc );

  struct LatLon tl;
  tl.lat = vik_map_source_get_lat_max(map);
  tl.lon = vik_map_source_get_lon_min(map);
  struct LatLon br;
  br.lat = vik_map_source_get_lat_min(map);
  br.lon = vik_map_source_get_lon_max(map);
  VikCoord vctl;
  vik_coord_load_from_latlon (&vctl, VIK_COORD_LATLON, &tl);
  VikCoord vcbr;
  vik_coord_load_from_latlon (&vcbr, VIK_COORD_LATLON, &br);

  return vik_coord_inside ( &vc, &vctl, &vcbr );
}

static int map_download_thread ( MapDownloadInfo *mdi, gpointer threaddata )
{
  void *handle = vik_map_source_download_handle_init(MAPS_LAYER_NTH_TYPE(mdi->maptype));
  guint donemaps = 0;
  MapCoord mcoord = mdi->mapcoord;
  gint x, y;
  for ( x = mdi->x0; x <= mdi->xf; x++ )
  {
    mcoord.x = x;
    for ( y = mdi->y0; y <= mdi->yf; y++ )
    {
      mcoord.y = y;
      // Only attempt to download a tile from supported areas
      if ( is_in_area ( MAPS_LAYER_NTH_TYPE(mdi->maptype), mcoord ) )
      {
        gboolean remove_mem_cache = FALSE;
        gboolean need_download = FALSE;

        get_filename ( mdi->cache_dir, mdi->cache_layout,
                       vik_map_source_get_uniq_id(MAPS_LAYER_NTH_TYPE(mdi->maptype)),
                       vik_map_source_get_name(MAPS_LAYER_NTH_TYPE(mdi->maptype)),
                       mdi->mapcoord.scale, mdi->mapcoord.z, x, y, mdi->filename_buf, mdi->maxlen,
                       vik_map_source_get_file_extension(MAPS_LAYER_NTH_TYPE(mdi->maptype)) );

        donemaps++;
        int res = a_background_thread_progress ( threaddata, ((gdouble)donemaps) / mdi->mapstoget ); /* this also calls testcancel */
        if (res != 0) {
          vik_map_source_download_handle_cleanup(MAPS_LAYER_NTH_TYPE(mdi->maptype), handle);
          return -1;
        }

        if ( g_file_test ( mdi->filename_buf, G_FILE_TEST_EXISTS ) == FALSE ) {
          need_download = TRUE;
          remove_mem_cache = TRUE;

        } else {  /* in case map file already exists */
          switch (mdi->redownload) {
            case REDOWNLOAD_NONE:
              continue;

            case REDOWNLOAD_BAD:
            {
              /* see if this one is bad or what */
              GError *gx = NULL;
              GdkPixbuf *pixbuf = gdk_pixbuf_new_from_file ( mdi->filename_buf, &gx );
              if (gx || (!pixbuf)) {
                g_remove ( mdi->filename_buf );
                need_download = TRUE;
                remove_mem_cache = TRUE;
                g_error_free ( gx );

              } else {
                g_object_unref ( pixbuf );
              }
              break;
            }

            case REDOWNLOAD_NEW:
              need_download = TRUE;
              remove_mem_cache = TRUE;
              break;

            case REDOWNLOAD_ALL:
              /* FIXME: need a better way than to erase file in case of server/network problem */
              g_remove ( mdi->filename_buf );
              need_download = TRUE;
              remove_mem_cache = TRUE;
              break;

            case DOWNLOAD_OR_REFRESH:
              remove_mem_cache = TRUE;
              break;

            default:
              g_warning ( "redownload state %d unknown\n", mdi->redownload);
          }
        }

        mdi->mapcoord.x = x; mdi->mapcoord.y = y;

        if (need_download) {
          DownloadResult_t dr = vik_map_source_download( MAPS_LAYER_NTH_TYPE(mdi->maptype), &(mdi->mapcoord), mdi->filename_buf, handle);
          switch ( dr ) {
            case DOWNLOAD_HTTP_ERROR:
            case DOWNLOAD_CONTENT_ERROR: {
              // TODO: ?? count up the number of download errors somehow...
              gchar* msg = g_strdup_printf ( "%s: %s", vik_maps_layer_get_map_label (mdi->vml), _("Failed to download tile") );
              vik_window_statusbar_update ( (VikWindow*)VIK_GTK_WINDOW_FROM_LAYER(mdi->vml), msg, VIK_STATUSBAR_INFO );
              g_free (msg);
              break;
            }
            case DOWNLOAD_FILE_WRITE_ERROR: {
              gchar* msg = g_strdup_printf ( "%s: %s", vik_maps_layer_get_map_label (mdi->vml), _("Unable to save tile") );
              vik_window_statusbar_update ( (VikWindow*)VIK_GTK_WINDOW_FROM_LAYER(mdi->vml), msg, VIK_STATUSBAR_INFO );
              g_free (msg);
              break;
            }
            case DOWNLOAD_SUCCESS:
            case DOWNLOAD_NOT_REQUIRED:
            default:
              break;
          }
        }

        g_mutex_lock(mdi->mutex);
        if (remove_mem_cache)
            a_mapcache_remove_all_shrinkfactors ( x, y, mdi->mapcoord.z, vik_map_source_get_uniq_id(MAPS_LAYER_NTH_TYPE(mdi->maptype)), mdi->mapcoord.scale, mdi->vml->filename );
        if (mdi->refresh_display && mdi->map_layer_alive) {
          /* TODO: check if it's on visible area */
          vik_layer_emit_update ( VIK_LAYER(mdi->vml) ); // NB update display from background
        }
        g_mutex_unlock(mdi->mutex);
        mdi->mapcoord.x = mdi->mapcoord.y = 0; /* we're temporarily between downloads */
      }
    }
  }
  vik_map_source_download_handle_cleanup(MAPS_LAYER_NTH_TYPE(mdi->maptype), handle);
  g_mutex_lock(mdi->mutex);
  if (mdi->map_layer_alive)
    g_object_weak_unref(G_OBJECT(mdi->vml), weak_ref_cb, mdi);
  g_mutex_unlock(mdi->mutex); 
  return 0;
}

static void mdi_cancel_cleanup ( MapDownloadInfo *mdi )
{
  if ( mdi->mapcoord.x || mdi->mapcoord.y )
  {
    get_filename ( mdi->cache_dir, mdi->cache_layout,
                   vik_map_source_get_uniq_id(MAPS_LAYER_NTH_TYPE(mdi->maptype)),
                   vik_map_source_get_name(MAPS_LAYER_NTH_TYPE(mdi->maptype)),
                   mdi->mapcoord.scale, mdi->mapcoord.z, mdi->mapcoord.x, mdi->mapcoord.y, mdi->filename_buf, mdi->maxlen,
                   vik_map_source_get_file_extension(MAPS_LAYER_NTH_TYPE(mdi->maptype)) );
    if ( g_file_test ( mdi->filename_buf, G_FILE_TEST_EXISTS ) == TRUE)
    {
      g_remove ( mdi->filename_buf );
    }
  }
}

static void start_download_thread ( VikMapsLayer *vml, VikViewport *vvp, const VikCoord *ul, const VikCoord *br, gint redownload )
{
  gdouble xzoom = vml->xmapzoom ? vml->xmapzoom : vik_viewport_get_xmpp ( vvp );
  gdouble yzoom = vml->ymapzoom ? vml->ymapzoom : vik_viewport_get_ympp ( vvp );
  MapCoord ulm, brm;
  VikMapSource *map = MAPS_LAYER_NTH_TYPE(vml->maptype);

  // Don't ever attempt download on direct access
  if ( vik_map_source_is_direct_file_access ( map ) )
    return;

  if ( vik_map_source_coord_to_mapcoord ( map, ul, xzoom, yzoom, &ulm ) 
    && vik_map_source_coord_to_mapcoord ( map, br, xzoom, yzoom, &brm ) )
  {
    MapDownloadInfo *mdi = g_malloc ( sizeof(MapDownloadInfo) );
    gint a, b;

    mdi->vml = vml;
    mdi->vvp = vvp;
    mdi->map_layer_alive = TRUE;
    mdi->mutex = vik_mutex_new();
    mdi->refresh_display = TRUE;

    /* cache_dir and buffer for dest filename */
    mdi->cache_dir = g_strdup ( vml->cache_dir );
    mdi->maxlen = strlen ( vml->cache_dir ) + 40;
    mdi->filename_buf = g_malloc ( mdi->maxlen * sizeof(gchar) );
    mdi->cache_layout = vml->cache_layout;
    mdi->maptype = vml->maptype;

    mdi->mapcoord = ulm;
    mdi->redownload = redownload;

    mdi->x0 = MIN(ulm.x, brm.x);
    mdi->xf = MAX(ulm.x, brm.x);
    mdi->y0 = MIN(ulm.y, brm.y);
    mdi->yf = MAX(ulm.y, brm.y);

    mdi->mapstoget = 0;

    MapCoord mcoord = mdi->mapcoord;

    if ( mdi->redownload ) {
      mdi->mapstoget = (mdi->xf - mdi->x0 + 1) * (mdi->yf - mdi->y0 + 1);
    } else {
      /* calculate how many we need */
      for ( a = mdi->x0; a <= mdi->xf; a++ )
      {
        mcoord.x = a;
        for ( b = mdi->y0; b <= mdi->yf; b++ )
        {
          mcoord.y = b;
          // Only count tiles from supported areas
          if ( is_in_area (map, mcoord) )
          {
            get_filename ( mdi->cache_dir, mdi->cache_layout,
                           vik_map_source_get_uniq_id(map),
                           vik_map_source_get_name(map),
                           ulm.scale, ulm.z, a, b, mdi->filename_buf, mdi->maxlen,
                           vik_map_source_get_file_extension(map) );
            if ( g_file_test ( mdi->filename_buf, G_FILE_TEST_EXISTS ) == FALSE )
              mdi->mapstoget++;
          }
        }
      }
    }

    mdi->mapcoord.x = mdi->mapcoord.y = 0; /* for cleanup -- no current map */

    if ( mdi->mapstoget )
    {
      const gchar *tmp_str;
      gchar *tmp;

      if (redownload) 
      {
        if (redownload == REDOWNLOAD_BAD)
          tmp_str = ngettext("Redownloading up to %d %s map...", "Redownloading up to %d %s maps...", mdi->mapstoget);
        else
          tmp_str = ngettext("Redownloading %d %s map...", "Redownloading %d %s maps...", mdi->mapstoget);
      } 
      else 
      {
        tmp_str = ngettext("Downloading %d %s map...", "Downloading %d %s maps...", mdi->mapstoget);
      }
      tmp = g_strdup_printf ( tmp_str, mdi->mapstoget, MAPS_LAYER_NTH_LABEL(vml->maptype));
 
      g_object_weak_ref(G_OBJECT(mdi->vml), weak_ref_cb, mdi);
      /* launch the thread */
      a_background_thread ( BACKGROUND_POOL_REMOTE,
                            VIK_GTK_WINDOW_FROM_LAYER(vml), /* parent window */
                            tmp,                                              /* description string */
                            (vik_thr_func) map_download_thread,               /* function to call within thread */
                            mdi,                                              /* pass along data */
                            (vik_thr_free_func) mdi_free,                     /* function to free pass along data */
                            (vik_thr_free_func) mdi_cancel_cleanup,
                            mdi->mapstoget );
      g_free ( tmp );
    }
    else
      mdi_free ( mdi );
  }
}

static void maps_layer_download_section ( VikMapsLayer *vml, VikViewport *vvp, VikCoord *ul, VikCoord *br, gdouble zoom, gint download_method )
{
  MapCoord ulm, brm;
  VikMapSource *map = MAPS_LAYER_NTH_TYPE(vml->maptype);

  // Don't ever attempt download on direct access
  if ( vik_map_source_is_direct_file_access ( map ) )
    return;

  if (!vik_map_source_coord_to_mapcoord(map, ul, zoom, zoom, &ulm) 
    || !vik_map_source_coord_to_mapcoord(map, br, zoom, zoom, &brm)) {
    g_warning("%s() coord_to_mapcoord() failed", __PRETTY_FUNCTION__);
    return;
  }

  MapDownloadInfo *mdi = g_malloc(sizeof(MapDownloadInfo));
  gint i, j;

  mdi->vml = vml;
  mdi->vvp = vvp;
  mdi->map_layer_alive = TRUE;
  mdi->mutex = vik_mutex_new();
  mdi->refresh_display = TRUE;

  mdi->cache_dir = g_strdup ( vml->cache_dir );
  mdi->maxlen = strlen ( vml->cache_dir ) + 40;
  mdi->filename_buf = g_malloc ( mdi->maxlen * sizeof(gchar) );
  mdi->maptype = vml->maptype;
  mdi->cache_layout = vml->cache_layout;

  mdi->mapcoord = ulm;
  mdi->redownload = download_method;

  mdi->x0 = MIN(ulm.x, brm.x);
  mdi->xf = MAX(ulm.x, brm.x);
  mdi->y0 = MIN(ulm.y, brm.y);
  mdi->yf = MAX(ulm.y, brm.y);

  mdi->mapstoget = 0;

  MapCoord mcoord = mdi->mapcoord;

  for (i = mdi->x0; i <= mdi->xf; i++) {
    mcoord.x = i;
    for (j = mdi->y0; j <= mdi->yf; j++) {
      mcoord.y = j;
      // Only count tiles from supported areas
      if ( is_in_area (map, mcoord) ) {
        get_filename ( mdi->cache_dir, mdi->cache_layout,
                       vik_map_source_get_uniq_id(map),
                       vik_map_source_get_name(map),
                       ulm.scale, ulm.z, i, j, mdi->filename_buf, mdi->maxlen,
                       vik_map_source_get_file_extension(map) );
        if ( g_file_test ( mdi->filename_buf, G_FILE_TEST_EXISTS ) == FALSE )
              mdi->mapstoget++;
      }
    }
  }

  mdi->mapcoord.x = mdi->mapcoord.y = 0; /* for cleanup -- no current map */

  if (mdi->mapstoget) {
    gchar *tmp;
    const gchar *fmt;
    fmt = ngettext("Downloading %d %s map...",
                   "Downloading %d %s maps...",
		   mdi->mapstoget);
    tmp = g_strdup_printf ( fmt, mdi->mapstoget, MAPS_LAYER_NTH_LABEL(vml->maptype) );

    g_object_weak_ref(G_OBJECT(mdi->vml), weak_ref_cb, mdi);

    // launch the thread
    a_background_thread ( BACKGROUND_POOL_REMOTE,
                          VIK_GTK_WINDOW_FROM_LAYER(vml), /* parent window */
                          tmp,                                /* description string */
                          (vik_thr_func) map_download_thread, /* function to call within thread */
                          mdi,                                /* pass along data */
                          (vik_thr_free_func) mdi_free,       /* function to free pass along data */
                          (vik_thr_free_func) mdi_cancel_cleanup,
                          mdi->mapstoget );
    g_free ( tmp );
  }
  else
    mdi_free ( mdi );
}

/**
 * vik_maps_layer_download_section:
 * @vml:  The Map Layer
 * @vvp:  The Viewport that the map is on
 * @ul:   Upper left coordinate of the area to be downloaded
 * @br:   Bottom right coordinate of the area to be downloaded
 * @zoom: The zoom level at which the maps are to be download
 *
 * Download a specified map area at a certain zoom level
 */
void vik_maps_layer_download_section ( VikMapsLayer *vml, VikViewport *vvp, VikCoord *ul, VikCoord *br, gdouble zoom )
{
  maps_layer_download_section (vml, vvp, ul, br, zoom, REDOWNLOAD_NONE);
}

static void maps_layer_redownload_bad ( VikMapsLayer *vml )
{
  start_download_thread ( vml, vml->redownload_vvp, &(vml->redownload_ul), &(vml->redownload_br), REDOWNLOAD_BAD );
}

static void maps_layer_redownload_all ( VikMapsLayer *vml )
{
  start_download_thread ( vml, vml->redownload_vvp, &(vml->redownload_ul), &(vml->redownload_br), REDOWNLOAD_ALL );
}

static void maps_layer_redownload_new ( VikMapsLayer *vml )
{
  start_download_thread ( vml, vml->redownload_vvp, &(vml->redownload_ul), &(vml->redownload_br), REDOWNLOAD_NEW );
}

/**
 * Display a simple dialog with information about this particular map tile
 */
static void maps_layer_tile_info ( VikMapsLayer *vml )
{
  VikMapSource *map = MAPS_LAYER_NTH_TYPE(vml->maptype);

  gdouble xzoom = vml->xmapzoom ? vml->xmapzoom : vik_viewport_get_xmpp ( vml->redownload_vvp );
  gdouble yzoom = vml->ymapzoom ? vml->ymapzoom : vik_viewport_get_ympp ( vml->redownload_vvp );
  MapCoord ulm;

  if ( !vik_map_source_coord_to_mapcoord ( map, &(vml->redownload_ul), xzoom, yzoom, &ulm ) )
    return;

  gchar *filename = NULL;
  gchar *source = NULL;

  if ( vik_map_source_is_direct_file_access ( map ) ) {
    if ( vik_map_source_is_mbtiles ( map ) ) {
      filename = g_strdup ( vml->filename );
#ifdef HAVE_SQLITE3_H
      // And whether to bother going into the SQL to check it's really there or not...
      gchar *exists = NULL;
      gint zoom = 17 - ulm.scale;
      if ( vml->mbtiles ) {
        GdkPixbuf *pixbuf = get_pixbuf_sql_exec ( vml->mbtiles, ulm.x, ulm.y, zoom );
        if ( pixbuf ) {
          exists = g_strdup ( _("YES") );
          g_object_unref ( G_OBJECT(pixbuf) );
        }
        else {
          exists = g_strdup ( _("NO") );
        }
      }
      else
        exists = g_strdup ( _("NO") );
      gint flip_y = (gint) pow(2, zoom)-1 - ulm.y;
      // NB Also handles .jpg automatically due to pixbuf_new_from () support - although just print png for now.
      source = g_strdup_printf ( "Source: %s (%d%s%d%s%d.%s %s)", filename, zoom, G_DIR_SEPARATOR_S, ulm.x, G_DIR_SEPARATOR_S, flip_y, "png", exists );
      g_free ( exists );
#else
      source = g_strdup ( _("Source: Not available") );
#endif
    }
    else if ( vik_map_source_is_osm_meta_tiles ( map ) ) {
      char path[PATH_MAX];
      xyz_to_meta(path, sizeof(path), vml->cache_dir, ulm.x, ulm.y, 17-ulm.scale );
      source = g_strdup ( path );
      filename = g_strdup ( path );
    }
    else {
      guint max_path_len = strlen(vml->cache_dir) + 40;
      filename = g_malloc ( max_path_len * sizeof(char) );
      get_filename ( vml->cache_dir, VIK_MAPS_CACHE_LAYOUT_OSM,
                     vik_map_source_get_uniq_id(map),
                     NULL,
                     ulm.scale, ulm.z, ulm.x, ulm.y, filename, max_path_len,
                     vik_map_source_get_file_extension(map) );
      source = g_strconcat ( "Source: file://", filename, NULL );
    }
  }
  else {
    guint max_path_len = strlen(vml->cache_dir) + 40;
    filename = g_malloc ( max_path_len * sizeof(char) );
    get_filename ( vml->cache_dir, vml->cache_layout,
                   vik_map_source_get_uniq_id(map),
                   vik_map_source_get_name(map),
                   ulm.scale, ulm.z, ulm.x, ulm.y, filename, max_path_len,
                   vik_map_source_get_file_extension(map) );
    source = g_markup_printf_escaped ( "Source: http://%s%s",
                                       vik_map_source_default_get_hostname ( VIK_MAP_SOURCE_DEFAULT(map) ),
                                       vik_map_source_default_get_uri ( VIK_MAP_SOURCE_DEFAULT(map), &ulm ) );
  }

  GArray *array = g_array_new (FALSE, TRUE, sizeof(gchar*));
  g_array_append_val ( array, source );

  gchar *filemsg = NULL;
  gchar *timemsg = NULL;

  if ( g_file_test ( filename, G_FILE_TEST_EXISTS ) ) {
    filemsg = g_strconcat ( "Tile File: ", filename, NULL );
    // Get some timestamp information of the tile
    struct stat stat_buf;
    if ( g_stat ( filename, &stat_buf ) == 0 ) {
      gchar time_buf[64];
      strftime ( time_buf, sizeof(time_buf), "%c", gmtime((const time_t *)&stat_buf.st_mtime) );
      timemsg = g_strdup_printf ( _("Tile File Timestamp: %s"), time_buf );
    }
    else {
      timemsg = g_strdup ( _("Tile File Timestamp: Not Available") );
    }
    g_array_append_val ( array, filemsg );
    g_array_append_val ( array, timemsg );
  }
  else {
    filemsg = g_strdup_printf ( "Tile File: %s [Not Available]", filename );
    g_array_append_val ( array, filemsg );
  }

  a_dialog_list (  VIK_GTK_WINDOW_FROM_LAYER(vml), _("Tile Information"), array, 5 );
  g_array_free ( array, FALSE );

  g_free ( timemsg );
  g_free ( filemsg );
  g_free ( source );
  g_free ( filename );
}

static gboolean maps_layer_download_release ( VikMapsLayer *vml, GdkEventButton *event, VikViewport *vvp )
{
  if (!vml || vml->vl.type != VIK_LAYER_MAPS)
    return FALSE;
  if ( vml->dl_tool_x != -1 && vml->dl_tool_y != -1 )
  {
    if ( event->button == 1 )
    {
      VikCoord ul, br;
      vik_viewport_screen_to_coord ( vvp, MAX(0, MIN(event->x, vml->dl_tool_x)), MAX(0, MIN(event->y, vml->dl_tool_y)), &ul );
      vik_viewport_screen_to_coord ( vvp, MIN(vik_viewport_get_width(vvp), MAX(event->x, vml->dl_tool_x)), MIN(vik_viewport_get_height(vvp), MAX ( event->y, vml->dl_tool_y ) ), &br );
      start_download_thread ( vml, vvp, &ul, &br, DOWNLOAD_OR_REFRESH );
      vml->dl_tool_x = vml->dl_tool_y = -1;
      return TRUE;
    }
    else
    {
      vik_viewport_screen_to_coord ( vvp, MAX(0, MIN(event->x, vml->dl_tool_x)), MAX(0, MIN(event->y, vml->dl_tool_y)), &(vml->redownload_ul) );
      vik_viewport_screen_to_coord ( vvp, MIN(vik_viewport_get_width(vvp), MAX(event->x, vml->dl_tool_x)), MIN(vik_viewport_get_height(vvp), MAX ( event->y, vml->dl_tool_y ) ), &(vml->redownload_br) );

      vml->redownload_vvp = vvp;

      vml->dl_tool_x = vml->dl_tool_y = -1;

      if ( ! vml->dl_right_click_menu ) {
        GtkWidget *item;
        vml->dl_right_click_menu = GTK_MENU ( gtk_menu_new () );

        item = gtk_menu_item_new_with_mnemonic ( _("Redownload _Bad Map(s)") );
        g_signal_connect_swapped ( G_OBJECT(item), "activate", G_CALLBACK(maps_layer_redownload_bad), vml );
        gtk_menu_shell_append ( GTK_MENU_SHELL(vml->dl_right_click_menu), item );

        item = gtk_menu_item_new_with_mnemonic ( _("Redownload _New Map(s)") );
        g_signal_connect_swapped ( G_OBJECT(item), "activate", G_CALLBACK(maps_layer_redownload_new), vml );
        gtk_menu_shell_append ( GTK_MENU_SHELL(vml->dl_right_click_menu), item );

        item = gtk_menu_item_new_with_mnemonic ( _("Redownload _All Map(s)") );
        g_signal_connect_swapped ( G_OBJECT(item), "activate", G_CALLBACK(maps_layer_redownload_all), vml );
        gtk_menu_shell_append ( GTK_MENU_SHELL(vml->dl_right_click_menu), item );

        item = gtk_image_menu_item_new_with_mnemonic ( _("_Show Tile Information") );
        gtk_image_menu_item_set_image ( (GtkImageMenuItem*)item, gtk_image_new_from_stock (GTK_STOCK_INFO, GTK_ICON_SIZE_MENU) );
        g_signal_connect_swapped ( G_OBJECT(item), "activate", G_CALLBACK(maps_layer_tile_info), vml );
        gtk_menu_shell_append (GTK_MENU_SHELL(vml->dl_right_click_menu), item);
      }

      gtk_menu_popup ( vml->dl_right_click_menu, NULL, NULL, NULL, NULL, event->button, event->time );
      gtk_widget_show_all ( GTK_WIDGET(vml->dl_right_click_menu) );
    }
  }
  return FALSE;
}

static gpointer maps_layer_download_create ( VikWindow *vw, VikViewport *vvp)
{
  return vvp;
}

static gboolean maps_layer_download_click ( VikMapsLayer *vml, GdkEventButton *event, VikViewport *vvp )
{
  MapCoord tmp;
  if (!vml || vml->vl.type != VIK_LAYER_MAPS)
    return FALSE;
  VikMapSource *map = MAPS_LAYER_NTH_TYPE(vml->maptype);
  if ( vik_map_source_get_drawmode(map) == vik_viewport_get_drawmode ( vvp ) &&
       vik_map_source_coord_to_mapcoord ( map, vik_viewport_get_center ( vvp ),
           vml->xmapzoom ? vml->xmapzoom : vik_viewport_get_xmpp ( vvp ),
           vml->ymapzoom ? vml->ymapzoom : vik_viewport_get_ympp ( vvp ),
           &tmp ) ) {
    vml->dl_tool_x = event->x, vml->dl_tool_y = event->y;
    return TRUE;
  }
  return FALSE;
}

// A slightly better way of defining the menu callback information
// This should be easier to extend/rework compared to previously
typedef enum {
  MA_VML = 0,
  MA_VVP,
  MA_LAST
} menu_array_index;

typedef gpointer menu_array_values[MA_LAST];

static void download_onscreen_maps ( menu_array_values values, gint redownload )
{
  VikMapsLayer *vml = VIK_MAPS_LAYER(values[MA_VML]);
  VikViewport *vvp = VIK_VIEWPORT(values[MA_VVP]);
  VikViewportDrawMode vp_drawmode = vik_viewport_get_drawmode ( vvp );

  gdouble xzoom = vml->xmapzoom ? vml->xmapzoom : vik_viewport_get_xmpp ( vvp );
  gdouble yzoom = vml->ymapzoom ? vml->ymapzoom : vik_viewport_get_ympp ( vvp );

  VikCoord ul, br;
  MapCoord ulm, brm;

  vik_viewport_screen_to_coord ( vvp, 0, 0, &ul );
  vik_viewport_screen_to_coord ( vvp, vik_viewport_get_width(vvp), vik_viewport_get_height(vvp), &br );

  VikMapSource *map = MAPS_LAYER_NTH_TYPE(vml->maptype);
  if ( vik_map_source_get_drawmode(map) == vp_drawmode &&
       vik_map_source_coord_to_mapcoord ( map, &ul, xzoom, yzoom, &ulm ) &&
       vik_map_source_coord_to_mapcoord ( map, &br, xzoom, yzoom, &brm ) )
    start_download_thread ( vml, vvp, &ul, &br, redownload );
  else if (vik_map_source_get_drawmode(map) != vp_drawmode) {
    const gchar *drawmode_name = vik_viewport_get_drawmode_name (vvp, vik_map_source_get_drawmode(map));
    gchar *err = g_strdup_printf(_("Wrong drawmode for this map.\nSelect \"%s\" from View menu and try again."), _(drawmode_name));
    a_dialog_error_msg ( VIK_GTK_WINDOW_FROM_LAYER(vml), err );
    g_free(err);
  }
  else
    a_dialog_error_msg ( VIK_GTK_WINDOW_FROM_LAYER(vml), _("Wrong zoom level for this map.") );

}

static void maps_layer_download_missing_onscreen_maps ( menu_array_values values )
{
  download_onscreen_maps( values, REDOWNLOAD_NONE);
}

static void maps_layer_download_new_onscreen_maps ( menu_array_values values )
{
  download_onscreen_maps( values, REDOWNLOAD_NEW);
}

static void maps_layer_redownload_all_onscreen_maps ( menu_array_values values )
{
  download_onscreen_maps( values, REDOWNLOAD_ALL);
}

static void maps_layer_about ( gpointer vml_vvp[2] )
{
  VikMapsLayer *vml = vml_vvp[0];
  VikMapSource *map = MAPS_LAYER_NTH_TYPE(vml->maptype);

  if ( vik_map_source_get_license (map) )
    maps_show_license ( VIK_GTK_WINDOW_FROM_LAYER(vml), map );
  else
    a_dialog_info_msg ( VIK_GTK_WINDOW_FROM_LAYER(vml),
                        vik_map_source_get_label (map) );
}

/**
 * maps_layer_how_many_maps:
 * Copied from maps_layer_download_section but without the actual download and this returns a value
 */
static gint maps_layer_how_many_maps ( VikMapsLayer *vml, VikViewport *vvp, VikCoord *ul, VikCoord *br, gdouble zoom, gint redownload )
{
  MapCoord ulm, brm;
  VikMapSource *map = MAPS_LAYER_NTH_TYPE(vml->maptype);

  if ( vik_map_source_is_direct_file_access ( map ) )
    return 0;

  if (!vik_map_source_coord_to_mapcoord(map, ul, zoom, zoom, &ulm)
    || !vik_map_source_coord_to_mapcoord(map, br, zoom, zoom, &brm)) {
    g_warning("%s() coord_to_mapcoord() failed", __PRETTY_FUNCTION__);
    return 0;
  }

  MapDownloadInfo *mdi = g_malloc(sizeof(MapDownloadInfo));
  gint i, j;

  mdi->vml = vml;
  mdi->vvp = vvp;
  mdi->map_layer_alive = TRUE;
  mdi->mutex = vik_mutex_new();
  mdi->refresh_display = FALSE;

  mdi->cache_dir = g_strdup ( vml->cache_dir );
  mdi->maxlen = strlen ( vml->cache_dir ) + 40;
  mdi->filename_buf = g_malloc ( mdi->maxlen * sizeof(gchar) );
  mdi->maptype = vml->maptype;
  mdi->cache_layout = vml->cache_layout;

  mdi->mapcoord = ulm;
  mdi->redownload = redownload;

  mdi->x0 = MIN(ulm.x, brm.x);
  mdi->xf = MAX(ulm.x, brm.x);
  mdi->y0 = MIN(ulm.y, brm.y);
  mdi->yf = MAX(ulm.y, brm.y);

  mdi->mapstoget = 0;

  if ( mdi->redownload == REDOWNLOAD_ALL ) {
    mdi->mapstoget = (mdi->xf - mdi->x0 + 1) * (mdi->yf - mdi->y0 + 1);
  }
  else {
    /* calculate how many we need */
    MapCoord mcoord = mdi->mapcoord;
    for (i = mdi->x0; i <= mdi->xf; i++) {
      mcoord.x = i;
      for (j = mdi->y0; j <= mdi->yf; j++) {
        mcoord.y = j;
        // Only count tiles from supported areas
        if ( is_in_area ( map, mcoord ) ) {
          get_filename ( mdi->cache_dir, mdi->cache_layout,
                         vik_map_source_get_uniq_id(map),
                         vik_map_source_get_name(map),
                         ulm.scale, ulm.z, i, j, mdi->filename_buf, mdi->maxlen,
                         vik_map_source_get_file_extension(map) );
          if ( mdi->redownload == REDOWNLOAD_NEW ) {
            // Assume the worst - always a new file
            // Absolute value would require a server lookup - but that is too slow
            mdi->mapstoget++;
          }
          else {
            if ( g_file_test ( mdi->filename_buf, G_FILE_TEST_EXISTS ) == FALSE ) {
              // Missing
              mdi->mapstoget++;
            }
            else {
              if ( mdi->redownload == REDOWNLOAD_BAD ) {
                /* see if this one is bad or what */
                GError *gx = NULL;
                GdkPixbuf *pixbuf = gdk_pixbuf_new_from_file ( mdi->filename_buf, &gx );
                if (gx || (!pixbuf)) {
                  mdi->mapstoget++;
                }
                break;
                // Other download cases already considered or just ignored
              }
            }
          }
        }
      }
    }
  }

  gint rv = mdi->mapstoget;

  mdi_free ( mdi );

  return rv;
}

/**
 * maps_dialog_zoom_between:
 * This dialog is specific to the map layer, so it's here rather than in dialog.c
 */
gboolean maps_dialog_zoom_between ( GtkWindow *parent,
                                    gchar *title,
                                    gchar *zoom_list[],
                                    gint default_zoom1,
                                    gint default_zoom2,
                                    gint *selected_zoom1,
                                    gint *selected_zoom2,
                                    gchar *download_list[],
                                    gint default_download,
                                    gint *selected_download )
{
  GtkWidget *dialog = gtk_dialog_new_with_buttons ( title,
                                                    parent,
                                                    GTK_DIALOG_MODAL | GTK_DIALOG_DESTROY_WITH_PARENT,
                                                    GTK_STOCK_OK, GTK_RESPONSE_ACCEPT,
                                                    GTK_STOCK_CANCEL, GTK_RESPONSE_REJECT,
                                                    NULL );
  gtk_dialog_set_default_response ( GTK_DIALOG(dialog), GTK_RESPONSE_ACCEPT );
  GtkWidget *response_w = NULL;
#if GTK_CHECK_VERSION (2, 20, 0)
  response_w = gtk_dialog_get_widget_for_response ( GTK_DIALOG(dialog), GTK_RESPONSE_ACCEPT );
#endif
  GtkWidget *zoom_label1 = gtk_label_new ( _("Zoom Start:") );
  GtkWidget *zoom_combo1 = vik_combo_box_text_new();
  gchar **s;
  for (s = zoom_list; *s; s++)
    vik_combo_box_text_append ( zoom_combo1, *s );
  gtk_combo_box_set_active ( GTK_COMBO_BOX(zoom_combo1), default_zoom1 );

  GtkWidget *zoom_label2 = gtk_label_new ( _("Zoom End:") );
  GtkWidget *zoom_combo2 = vik_combo_box_text_new();
  for (s = zoom_list; *s; s++)
    vik_combo_box_text_append ( zoom_combo2, *s );
  gtk_combo_box_set_active ( GTK_COMBO_BOX(zoom_combo2), default_zoom2 );

  GtkWidget *download_label = gtk_label_new(_("Download Maps Method:"));
  GtkWidget *download_combo = vik_combo_box_text_new();
  for (s = download_list; *s; s++)
    vik_combo_box_text_append ( download_combo, *s );
  gtk_combo_box_set_active ( GTK_COMBO_BOX(download_combo), default_download );

  GtkTable *box = GTK_TABLE(gtk_table_new(3, 2, FALSE));
  gtk_table_attach_defaults (box, GTK_WIDGET(zoom_label1), 0, 1, 0, 1);
  gtk_table_attach_defaults (box, GTK_WIDGET(zoom_combo1), 1, 2, 0, 1);
  gtk_table_attach_defaults (box, GTK_WIDGET(zoom_label2), 0, 1, 1, 2);
  gtk_table_attach_defaults (box, GTK_WIDGET(zoom_combo2), 1, 2, 1, 2);
  gtk_table_attach_defaults (box, GTK_WIDGET(download_label), 0, 1, 2, 3);
  gtk_table_attach_defaults (box, GTK_WIDGET(download_combo), 1, 2, 2, 3);

  gtk_box_pack_start ( GTK_BOX(gtk_dialog_get_content_area(GTK_DIALOG(dialog))), GTK_WIDGET(box), FALSE, FALSE, 5 );

  if ( response_w )
    gtk_widget_grab_focus ( response_w );

  gtk_widget_show_all ( dialog );
  if ( gtk_dialog_run ( GTK_DIALOG(dialog) ) != GTK_RESPONSE_ACCEPT ) {
    gtk_widget_destroy(dialog);
    return FALSE;
  }

  // Return selected options
  *selected_zoom1 = gtk_combo_box_get_active ( GTK_COMBO_BOX(zoom_combo1) );
  *selected_zoom2 = gtk_combo_box_get_active ( GTK_COMBO_BOX(zoom_combo2) );
  *selected_download = gtk_combo_box_get_active ( GTK_COMBO_BOX(download_combo) );

  gtk_widget_destroy(dialog);
  return TRUE;
}

// My best guess of sensible limits
#define REALLY_LARGE_AMOUNT_OF_TILES 5000
#define CONFIRM_LARGE_AMOUNT_OF_TILES 500

/**
 * Get all maps in the region for zoom levels specified by the user
 * Sort of similar to trw_layer_download_map_along_track_cb function
 */
static void maps_layer_download_all ( menu_array_values values )
{
  VikMapsLayer *vml = VIK_MAPS_LAYER(values[MA_VML]);
  VikViewport *vvp = VIK_VIEWPORT(values[MA_VVP]);

  // I don't think we should allow users to hammer the servers too much...
  // Delibrately not allowing lowest zoom levels
  // Still can give massive numbers to download
  // A screen size of 1600x1200 gives around 300,000 tiles between 1..128 when none exist before !!
  gchar *zoom_list[] = {"1", "2", "4", "8", "16", "32", "64", "128", "256", "512", "1024", NULL };
  gdouble zoom_vals[] = {1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024};

  gint selected_zoom1, selected_zoom2, default_zoom, lower_zoom;
  gint selected_download_method;
  
  gdouble cur_zoom = vik_viewport_get_zoom(vvp);

  for (default_zoom = 0; default_zoom < sizeof(zoom_vals)/sizeof(gdouble); default_zoom++) {
    if (cur_zoom == zoom_vals[default_zoom])
      break;
  }
  default_zoom = (default_zoom == sizeof(zoom_vals)/sizeof(gdouble)) ? sizeof(zoom_vals)/sizeof(gdouble) - 1 : default_zoom;

  // Default to only 2 zoom levels below the current one
  if (default_zoom > 1 )
    lower_zoom = default_zoom - 2;
  else
    lower_zoom = default_zoom;

  // redownload method - needs to align with REDOWNLOAD* macro values
  gchar *download_list[] = { _("Missing"), _("Bad"), _("New"), _("Reload All"), NULL };

  gchar *title = g_strdup_printf ( ("%s: %s"), vik_maps_layer_get_map_label (vml), _("Download for Zoom Levels") );

  if ( ! maps_dialog_zoom_between ( VIK_GTK_WINDOW_FROM_LAYER(vml),
                                    title,
                                    zoom_list,
                                    lower_zoom,
                                    default_zoom,
                                    &selected_zoom1,
                                    &selected_zoom2,
                                    download_list,
                                    REDOWNLOAD_NONE, // AKA Missing
                                    &selected_download_method ) ) {
    // Cancelled
    g_free ( title );
    return;
  }
  g_free ( title );

  // Find out new current positions
  gdouble min_lat, max_lat, min_lon, max_lon;
  VikCoord vc_ul, vc_br;
  vik_viewport_get_min_max_lat_lon ( vvp, &min_lat, &max_lat, &min_lon, &max_lon );
  struct LatLon ll_ul = { max_lat, min_lon };
  struct LatLon ll_br = { min_lat, max_lon };
  vik_coord_load_from_latlon ( &vc_ul, vik_viewport_get_coord_mode (vvp), &ll_ul );
  vik_coord_load_from_latlon ( &vc_br, vik_viewport_get_coord_mode (vvp), &ll_br );

  // Get Maps Count - call for each zoom level (in reverse)
  // With REDOWNLOAD_NEW this is a possible maximum
  // With REDOWNLOAD_NONE this only missing ones - however still has a server lookup per tile
  gint map_count = 0;
  gint zz;
  for ( zz = selected_zoom2; zz >= selected_zoom1; zz-- ) {
    map_count = map_count + maps_layer_how_many_maps ( vml, vvp, &vc_ul, &vc_br, zoom_vals[zz], selected_download_method );
  }

  g_debug ("vikmapslayer: download request map count %d for method %d", map_count, selected_download_method);

  // Absolute protection of hammering a map server
  if ( map_count > REALLY_LARGE_AMOUNT_OF_TILES ) {
    gchar *str = g_strdup_printf (_("You are not allowed to download more than %d tiles in one go (requested %d)"), REALLY_LARGE_AMOUNT_OF_TILES, map_count);
    a_dialog_error_msg ( VIK_GTK_WINDOW_FROM_LAYER(vml), str );
    g_free (str);
    return;
  }

  // Confirm really want to do this
  if ( map_count > CONFIRM_LARGE_AMOUNT_OF_TILES ) {
    gchar *str = g_strdup_printf (_("Do you really want to download %d tiles?"), map_count);
    gboolean ans = a_dialog_yes_or_no ( VIK_GTK_WINDOW_FROM_LAYER(vml), str, NULL );
    g_free (str);
    if ( ! ans )
      return;
  }

  // Get Maps - call for each zoom level (in reverse)
  for ( zz = selected_zoom2; zz >= selected_zoom1; zz-- ) {
    maps_layer_download_section ( vml, vvp, &vc_ul, &vc_br, zoom_vals[zz], selected_download_method );
  }
}

/**
 *
 */
static void maps_layer_flush ( menu_array_values values )
{
  VikMapsLayer *vml = VIK_MAPS_LAYER(values[MA_VML]);
  a_mapcache_flush_type ( vik_map_source_get_uniq_id(MAPS_LAYER_NTH_TYPE(vml->maptype)) );
}

static void maps_layer_add_menu_items ( VikMapsLayer *vml, GtkMenu *menu, VikLayersPanel *vlp )
{
  GtkWidget *item;
  static menu_array_values values;
  values[MA_VML] = vml;
  values[MA_VVP] = vik_layers_panel_get_viewport( VIK_LAYERS_PANEL(vlp) );

  item = gtk_menu_item_new();
  gtk_menu_shell_append ( GTK_MENU_SHELL(menu), item );
  gtk_widget_show ( item );

  /* Now with icons */
  item = gtk_image_menu_item_new_with_mnemonic ( _("Download _Missing Onscreen Maps") );
    gtk_image_menu_item_set_image ( (GtkImageMenuItem*)item, gtk_image_new_from_stock (GTK_STOCK_ADD, GTK_ICON_SIZE_MENU) );
  g_signal_connect_swapped ( G_OBJECT(item), "activate", G_CALLBACK(maps_layer_download_missing_onscreen_maps), values );
  gtk_menu_shell_append (GTK_MENU_SHELL (menu), item);
  gtk_widget_show ( item );

  if ( vik_map_source_supports_download_only_new (MAPS_LAYER_NTH_TYPE(vml->maptype)) ) {
    item = gtk_image_menu_item_new_with_mnemonic ( _("Download _New Onscreen Maps") );
    gtk_image_menu_item_set_image ( (GtkImageMenuItem*)item, gtk_image_new_from_stock (GTK_STOCK_REDO, GTK_ICON_SIZE_MENU) );
    g_signal_connect_swapped ( G_OBJECT(item), "activate", G_CALLBACK(maps_layer_download_new_onscreen_maps), values );
    gtk_menu_shell_append (GTK_MENU_SHELL (menu), item);
    gtk_widget_show ( item );
  }

  item = gtk_image_menu_item_new_with_mnemonic ( _("Reload _All Onscreen Maps") );
  gtk_image_menu_item_set_image ( (GtkImageMenuItem*)item, gtk_image_new_from_stock (GTK_STOCK_REFRESH, GTK_ICON_SIZE_MENU) );
  g_signal_connect_swapped ( G_OBJECT(item), "activate", G_CALLBACK(maps_layer_redownload_all_onscreen_maps), values );
  gtk_menu_shell_append (GTK_MENU_SHELL (menu), item);
  gtk_widget_show ( item );

  item = gtk_image_menu_item_new_with_mnemonic ( _("Download Maps in _Zoom Levels...") );
  gtk_image_menu_item_set_image ( (GtkImageMenuItem*)item, gtk_image_new_from_stock (GTK_STOCK_DND_MULTIPLE, GTK_ICON_SIZE_MENU) );
  g_signal_connect_swapped ( G_OBJECT(item), "activate", G_CALLBACK(maps_layer_download_all), values );
  gtk_menu_shell_append (GTK_MENU_SHELL (menu), item);
  gtk_widget_show ( item );

  item = gtk_image_menu_item_new_from_stock ( GTK_STOCK_ABOUT, NULL );
  g_signal_connect_swapped ( G_OBJECT(item), "activate", G_CALLBACK(maps_layer_about), values );
  gtk_menu_shell_append (GTK_MENU_SHELL (menu), item);
  gtk_widget_show ( item );

  // Typical users shouldn't need to use this functionality - so debug only ATM
  if ( vik_debug ) {
    item = gtk_image_menu_item_new_with_mnemonic ( _("Flush Map Cache") );
    gtk_image_menu_item_set_image ( (GtkImageMenuItem*)item, gtk_image_new_from_stock (GTK_STOCK_REMOVE, GTK_ICON_SIZE_MENU) );
    g_signal_connect_swapped ( G_OBJECT(item), "activate", G_CALLBACK(maps_layer_flush), values );
    gtk_menu_shell_append (GTK_MENU_SHELL (menu), item);
    gtk_widget_show ( item );
  }
}

/**
 * Enable downloading maps of the current screen area either 'new' or 'everything'
 */
void vik_maps_layer_download ( VikMapsLayer *vml, VikViewport *vvp, gboolean only_new )
{
  if ( !vml ) return;
  if ( !vvp ) return;

  static menu_array_values values;
  values[MA_VML] = vml;
  values[MA_VVP] = vvp;

  if ( only_new )
    // Get only new maps
    maps_layer_download_new_onscreen_maps ( values );
  else
    // Redownload everything
    maps_layer_redownload_all_onscreen_maps ( values );
}