Add Tile Map Service downloading

[grits] / src / data / grits-tms.c

diff --git a/src/data/grits-tms.c b/src/data/grits-tms.c
new file mode 100644 (file)
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+++ b/src/data/grits-tms.c
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+/*
+ * Copyright (C) 2009, 2012 Andy Spencer <spenceal@rose-hulman.edu>
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+
+#include <config.h>
+#include <stdio.h>
+#include <math.h>
+#include <glib.h>
+
+#include "grits-tms.h"
+
+static gchar *_make_uri(GritsTms *tms, GritsTile *tile)
+{
+
+#if 0
+       /* This doesn't make any sense.. */
+       gdouble lon_rad = deg2rad(tile->edge.n + tile->edge.s)/2;
+       gdouble lat_rad = deg2rad(tile->edge.e + tile->edge.w)/2;
+       g_message("%lf,%lf", lat_rad, lon_rad);
+
+       /* Reproject the coordinates to the Mercator projection: */
+       gdouble x = lon_rad;
+       gdouble y = log(tan(lat_rad) + 1.0/cos(lat_rad));
+
+       /* Transform range of x and y to 0 - 1 and shift origin to top left */
+       x = (1.0 + (x / G_PI)) / 2.0;
+       y = (1.0 - (y / G_PI)) / 2.0;
+
+       /* Calculate the number of tiles across the map, n, using 2^zoom */
+       gint zoom = 0;
+       for (GritsTile *tmp = tile->parent; tmp; tmp = tmp->parent)
+               zoom++;
+       gint n = pow(2, zoom);
+
+       /* Multiply x and y by n. Round results down to give tilex and tiley. */
+       gint xtile = x * n;
+       gint ytile = y * n;
+
+       g_message("xy=%f,%f  zoom=%d  n=%d  xy_tiles=%d,%d",
+                       x, y, zoom, n, xtile, ytile);
+#endif
+
+#if 1
+       /* This is broken */
+       gint zoom = 0;
+       for (GritsTile *tmp = tile->parent; tmp; tmp = tmp->parent)
+               zoom++;
+       gint breath = pow(2,zoom);
+
+       gdouble lon_pos =  (tile->edge.e+tile->edge.w)/2 + 180;
+       gdouble lat_pos = -(tile->edge.n+tile->edge.s)/2 +  90 - 4.9489;
+
+       gdouble lon_total = 360;
+       gdouble lat_total = 85.0511*2;
+
+       gdouble lon_pct = lon_pos / lon_total;
+       gdouble lat_pct = lat_pos / lat_total;
+
+       gint xtile = lon_pct * breath;
+       gint ytile = lat_pct * breath;
+
+       //g_message("bbok=%f,%f,%f,%f",
+       //              tile->edge.n, tile->edge.s,
+       //              tile->edge.e, tile->edge.w);
+       //g_message("pos=%f,%f total=%f,%f pct=%f,%f tile=%d,%d",
+       //              lon_pos,   lat_pos,
+       //              lon_total, lat_total,
+       //              lon_pct,   lat_pct,
+       //              xtile,     ytile);
+#endif
+
+       // http://tile.openstreetmap.org/<zoom>/<xtile>/<ytile>.png
+       return g_strdup_printf("%s/%d/%d/%d.%s",
+                       tms->uri_prefix, zoom, xtile, ytile, tms->extension);
+}
+
+gchar *grits_tms_fetch(GritsTms *tms, GritsTile *tile, GritsCacheType mode,
+               GritsChunkCallback callback, gpointer user_data)
+{
+       /* Get file path */
+       gchar *uri   = _make_uri(tms, tile);
+       gchar *tilep = grits_tile_get_path(tile);
+       gchar *local = g_strdup_printf("%s%s", tilep, tms->extension);
+       gchar *path  = grits_http_fetch(tms->http, uri, local,
+                       mode, callback, user_data);
+       g_free(uri);
+       g_free(tilep);
+       g_free(local);
+       return path;
+}
+
+GritsTms *grits_tms_new(const gchar *uri_prefix,
+               const gchar *prefix, const gchar *extension)
+{
+       GritsTms *tms = g_new0(GritsTms, 1);
+       tms->http         = grits_http_new(prefix);
+       tms->uri_prefix   = g_strdup(uri_prefix);
+       tms->extension    = g_strdup(extension);
+       return tms;
+}
+
+void grits_tms_free(GritsTms *tms)
+{
+       grits_http_free(tms->http);
+       g_free(tms->uri_prefix);
+       g_free(tms->extension);
+       g_free(tms);
+}