X-Git-Url: https://git.street.me.uk/andy/viking.git/blobdiff_plain/983bb64fcf20abf3445f82969c33a5e679ab5f3f..b529dc9c00bbafad3671e76e719277d4deecddbc:/src/vikslippymapsource.c?ds=sidebyside

diff --git a/src/vikslippymapsource.c b/src/vikslippymapsource.c
index 2c878047..c04ef485 100644
--- a/src/vikslippymapsource.c
+++ b/src/vikslippymapsource.c
@@ -36,14 +36,14 @@ static gboolean _supports_if_modified_since (VikMapSource *self );
 
 static gchar *_get_uri( VikSlippyMapSource *self, MapCoord *src );
 static gchar *_get_hostname( VikSlippyMapSource *self );
-static DownloadOptions *_get_download_options( VikSlippyMapSource *self );
+static DownloadMapOptions *_get_download_options( VikSlippyMapSource *self );
 
 typedef struct _VikSlippyMapSourcePrivate VikSlippyMapSourcePrivate;
 struct _VikSlippyMapSourcePrivate
 {
   gchar *hostname;
   gchar *url;
-  DownloadOptions options;
+  DownloadMapOptions options;
 };
 
 #define VIK_SLIPPY_MAP_SOURCE_PRIVATE(o)  (G_TYPE_INSTANCE_GET_PRIVATE ((o), VIK_TYPE_SLIPPY_MAP_SOURCE, VikSlippyMapSourcePrivate))
@@ -250,13 +250,23 @@ static const gdouble scale_mpps[] = { GZ(0), GZ(1), GZ(2), GZ(3), GZ(4), GZ(5),
 
 static const gint num_scales = (sizeof(scale_mpps) / sizeof(scale_mpps[0]));
 
+static const gdouble scale_neg_mpps[] = { 1.0/GZ(0), 1.0/GZ(1), 1.0/GZ(2), 1.0/GZ(3) };
+static const gint num_scales_neg = (sizeof(scale_neg_mpps) / sizeof(scale_neg_mpps[0]));
+
 #define ERROR_MARGIN 0.01
-static guint8 slippy_zoom ( gdouble mpp ) {
+static gint slippy_zoom ( gdouble mpp ) {
   gint i;
   for ( i = 0; i < num_scales; i++ ) {
-    if ( ABS(scale_mpps[i] - mpp) < ERROR_MARGIN )
+    if ( ABS(scale_mpps[i] - mpp) < ERROR_MARGIN ) {
       return i;
+    }
   }
+  for ( i = 0; i < num_scales_neg; i++ ) {
+    if ( ABS(scale_neg_mpps[i] - mpp) < 0.000001 ) {
+      return -i;
+    }
+  }
+
   return 255;
 }
 
@@ -286,7 +296,7 @@ vik_slippy_map_source_get_hostname( VikSlippyMapSource *self )
 	return (*klass->get_hostname)(self);
 }
 
-DownloadOptions *
+DownloadMapOptions *
 vik_slippy_map_source_get_download_options( VikSlippyMapSource *self )
 {
 	VikSlippyMapSourceClass *klass;
@@ -330,7 +340,11 @@ _coord_to_mapcoord ( VikMapSource *self, const VikCoord *src, gdouble xzoom, gdo
 static void
 _mapcoord_to_center_coord ( VikMapSource *self, MapCoord *src, VikCoord *dest )
 {
-  gdouble socalled_mpp = GZ(src->scale);
+  gdouble socalled_mpp;
+  if (src->scale >= 0)
+    socalled_mpp = GZ(src->scale);
+  else
+    socalled_mpp = 1.0/GZ(-src->scale);
   dest->mode = VIK_COORD_LATLON;
   dest->east_west = ((src->x+0.5) / GZ(17) * socalled_mpp * 360) - 180;
   dest->north_south = DEMERCLAT(180 - ((src->y+0.5) / GZ(17) * socalled_mpp * 360));
@@ -342,7 +356,7 @@ _download ( VikMapSource *self, MapCoord *src, const gchar *dest_fn, void *handl
    int res;
    gchar *uri = vik_slippy_map_source_get_uri(VIK_SLIPPY_MAP_SOURCE(self), src);
    gchar *host = vik_slippy_map_source_get_hostname(VIK_SLIPPY_MAP_SOURCE(self));
-   DownloadOptions *options = vik_slippy_map_source_get_download_options(VIK_SLIPPY_MAP_SOURCE(self));
+   DownloadMapOptions *options = vik_slippy_map_source_get_download_options(VIK_SLIPPY_MAP_SOURCE(self));
    res = a_http_download_get_url ( host, uri, dest_fn, options, handle );
    g_free ( uri );
    g_free ( host );
@@ -381,7 +395,7 @@ _get_hostname( VikSlippyMapSource *self )
 	return g_strdup( priv->hostname );
 }
 
-static DownloadOptions *
+static DownloadMapOptions *
 _get_download_options( VikSlippyMapSource *self )
 {
 	g_return_val_if_fail (VIK_IS_SLIPPY_MAP_SOURCE(self), NULL);