From e4cd684027f14da2301fe6ff4d004ee36b79558a Mon Sep 17 00:00:00 2001
From: Kaj-Michael Lang <milang@onion.tal.org>
Date: Fri, 26 Oct 2007 12:37:36 +0300
Subject: [PATCH] Move and add new functions to latlon.c : - Add quadtile
 functions from OSM. - Move distance to line function from osm-db.c to
 latlon.c.

---
 src/latlon.c | 84 ++++++++++++++++++++++++++++++++++++++++++++++++++--
 src/latlon.h |  7 +++++
 src/osm-db.c | 34 ---------------------
 3 files changed, 88 insertions(+), 37 deletions(-)

diff --git a/src/latlon.c b/src/latlon.c
index a9e0beb..1d4e44f 100644
--- a/src/latlon.c
+++ b/src/latlon.c
@@ -1,11 +1,13 @@
 /*
- * Different Lat/Lon related function (conversion, distances, etc)
+ * Different Lat/Lon and related functions
+ * (conversion, distances, etc)
  */
 #define _GNU_SOURCE
 
 #include <math.h>
 #include <glib.h>
 
+#include "latlon.h"
 #include "osm.h"
 
 /* Int ranges for integerized lat/lon */
@@ -14,7 +16,72 @@
 
 #define EARTH_RADIUS (3440.06479f)
 
-/* Convert latitude to integerized+mercator projected value */
+static inline gdouble 
+magnitude(gdouble x1, gdouble y1, gdouble x2, gdouble y2)
+{
+gdouble x,y;
+x=x2-x1;
+y=y2-y1;
+
+return sqrt((x*x)+(y*y));
+}
+
+gboolean 
+distance_point_to_line(gdouble x, gdouble y, gdouble x1, gdouble y1, gdouble x2, gdouble y2, gdouble *d)
+{
+gdouble lm,u,tmp;
+gdouble ix,iy;
+
+lm=magnitude(x1,y1,x2,y2);
+if (lm==0.0f)
+	return FALSE;
+
+tmp=((x-x1)*(x2-x1))+((y-y1)*(y2-y1));
+u=tmp/(lm*lm);
+
+if (u<0.0f || u>1.0f)
+	return FALSE;
+ 
+ix=x1+u*(x2-x1);
+iy=y1+u*(y2-y1);
+ 
+*d=magnitude(x,y, ix, iy);
+ 
+return TRUE;
+}
+
+/*
+ * QuadTile calculation functions, from:
+ * http://trac.openstreetmap.org/browser/sites/rails_port/lib/quad_tile/quad_tile.h 
+ */
+guint32 
+xy2tile(guint x, guint y)
+{
+guint32 tile=0;
+gint i;
+
+for (i=15;i>=0;i--) {
+	tile=(tile << 1) | ((x >> i) & 1);
+	tile=(tile << 1) | ((y >> i) & 1);
+}
+return tile;
+}
+
+guint32
+lon2x(gdouble lon)
+{
+return round((lon + 180.0) * 65535.0 / 360.0);
+}
+
+guint32 
+lat2y(gdouble lat)
+{
+return round((lat + 90.0) * 65535.0 / 180.0);
+}
+
+/* 
+ * Convert latitude to integerized+mercator projected value 
+ */
 gint32
 lat2mp_int(gdouble lat)
 {
@@ -22,7 +89,9 @@ return lat > 85.051128779 ? LATLON_MAX : lat < -85.051128779 ? LATLON_MIN :
 	lrint(log(tan(M_PI_4l+lat*M_PIl/360))/M_PIl*LATLON_MAX);
 }
 
-/* Convert longitude to integerized+mercator projected value */
+/* 
+ * Convert longitude to integerized+mercator projected value 
+ */
 gint32
 lon2mp_int(gdouble lon)
 {
@@ -41,12 +110,21 @@ mp_int2lat(gint lat)
 return 0;
 }
 
+/**
+ * Quick distance calculation, (does not handle earth curvature, so use for quick non exact needs only)
+ */
 gulong
 calculate_idistance(gint lat1, gint lon1, gint lat2, gint lon2)
 {
 return lrint(sqrt((double)((lat1-lat2)*(lat1-lat2)+(lon1-lon2)*(lon1-lon2))));
 }
 
+gdouble
+calculate_ddistance(gint lat1, gint lon1, gint lat2, gint lon2)
+{
+return sqrt((double)((lat1-lat2)*(lat1-lat2)+(lon1-lon2)*(lon1-lon2)));
+}
+
 /**
  * Quick distance for comparing, skips the final square root
  */
diff --git a/src/latlon.h b/src/latlon.h
index 162b4bf..5ac94ae 100644
--- a/src/latlon.h
+++ b/src/latlon.h
@@ -11,8 +11,15 @@
 gint32 lon2mp_int(gdouble lon);
 gint32 lat2mp_int(gdouble lat);
 gdouble calculate_distance(gdouble lat1, gdouble lon1, gdouble lat2, gdouble lon2);
+gdouble calculate_ddistance(gint lat1, gint lon1, gint lat2, gint lon2);
 gulong calculate_idistance(gint lat1, gint lon1, gint lat2, gint lon2);
 gulong calculate_idistance_cmp(gint lat1, gint lon1, gint lat2, gint lon2);
 gdouble calculate_course(gdouble lat1, gdouble lon1, gdouble lat2, gdouble lon2);
 
+gboolean distance_point_to_line(gdouble x, gdouble y, gdouble x1, gdouble y1, gdouble x2, gdouble y2, gdouble *d);
+
+guint32 xy2tile(guint x, guint y);
+guint32 lon2x(gdouble lon);
+guint32 lat2y(gdouble lat);
+
 #endif
diff --git a/src/osm-db.c b/src/osm-db.c
index 204737f..6fdf2e7 100644
--- a/src/osm-db.c
+++ b/src/osm-db.c
@@ -489,40 +489,6 @@ return ways;
 
 /*****************************************************************************/
 
-static inline gdouble 
-magnitude(gdouble x1, gdouble y1, gdouble x2, gdouble y2)
-{
-gdouble x,y;
-x=x2-x1;
-y=y2-y1;
-
-return sqrt((x*x)+(y*y));
-}
-
-static gboolean 
-distance_point_to_line(gdouble x, gdouble y, gdouble x1, gdouble y1, gdouble x2, gdouble y2, gdouble *d)
-{
-gdouble lm,u,tmp;
-gdouble ix,iy;
-
-lm=magnitude(x1,y1,x2,y2);
-if (lm==0.0f)
-	return FALSE;
-
-tmp=((x-x1)*(x2-x1))+((y-y1)*(y2-y1));
-u=tmp/(lm*lm);
-
-if (u<0.0f || u>1.0f)
-	return FALSE;
- 
-ix=x1+u*(x2-x1);
-iy=y1+u*(y2-y1);
- 
-*d=magnitude(x,y, ix, iy);
- 
-return TRUE;
-}
-
 gboolean 
 osm_way_distance(gint lat, gint lon, osm_way_node *f, osm_way_node *t, gdouble *d)
 {
-- 
2.39.5