X-Git-Url: https://git.gag.com/?p=fw%2Faltos;a=blobdiff_plain;f=altoslib%2FAltosMapTransform.java;h=9eac2654220150ac29ea114bf04b23015b41e45a;hp=30994ecb60bc2dc826f50f6fffbc546b07882e24;hb=HEAD;hpb=3882e358b6f2970cb1afebcf2a71da34a57002df

diff --git a/altoslib/AltosMapTransform.java b/altoslib/AltosMapTransform.java
index 30994ecb..3f8f290c 100644
--- a/altoslib/AltosMapTransform.java
+++ b/altoslib/AltosMapTransform.java
@@ -3,7 +3,8 @@
  *
  * 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; version 2 of the License.
+ * 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
@@ -15,7 +16,7 @@
  * 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
  */
 
-package org.altusmetrum.altoslib_7;
+package org.altusmetrum.altoslib_14;
 
 import java.io.*;
 import java.lang.Math;
@@ -28,6 +29,8 @@ public class AltosMapTransform {
 
 	double	offset_x, offset_y;
 
+	int	width, height;
+
 	public AltosLatLon lat_lon (AltosPointDouble point) {
 		double lat, lon;
 		double rads;
@@ -51,6 +54,13 @@ public class AltosMapTransform {
 		return new AltosPointDouble(screen.x + offset_x, screen.y + offset_y);
 	}
 
+	public double hypot(AltosLatLon a, AltosLatLon b) {
+		AltosPointDouble	a_pt = point(a);
+		AltosPointDouble	b_pt = point(b);
+
+		return Math.hypot(a_pt.x - b_pt.x, a_pt.y - b_pt.y);
+	}
+
 	public AltosLatLon screen_lat_lon(AltosPointInt screen) {
 		return lat_lon(screen_point(screen));
 	}
@@ -59,13 +69,13 @@ public class AltosMapTransform {
 		return lat_lon(screen_point(screen));
 	}
 
-	public AltosPointDouble point(AltosLatLon lat_lon) {
+	public  AltosPointDouble point(double lat, double lon) {
 		double x, y;
 		double e;
 
-		x = lat_lon.lon * scale_x;
+		x = lon * scale_x;
 
-		e = Math.sin(Math.toRadians(lat_lon.lat));
+		e = Math.sin(Math.toRadians(lat));
 		e = Math.max(e,-(1-1.0E-15));
 		e = Math.min(e,  1-1.0E-15 );
 
@@ -74,6 +84,10 @@ public class AltosMapTransform {
 		return new AltosPointDouble(x, y);
 	}
 
+	public AltosPointDouble point(AltosLatLon lat_lon) {
+		return point(lat_lon.lat, lat_lon.lon);
+	}
+
 	public AltosPointDouble screen(AltosPointDouble point) {
 		return new AltosPointDouble(point.x - offset_x, point.y - offset_y);
 	}
@@ -94,6 +108,43 @@ public class AltosMapTransform {
 		return screen(point(lat_lon));
 	}
 
+	public AltosPointDouble screen(double lat, double lon) {
+		return screen(point(lat, lon));
+	}
+
+	/* Return first longitude value which ends up on-screen */
+	public double first_lon(double lon) {
+		/* Find a longitude left of the screen */
+		for (;;) {
+			double x = lon * scale_x - offset_x;
+			if (x < 0)
+				break;
+			lon -= 360.0;
+		}
+		/* Find the first longitude on the screen */
+		for (;;) {
+			double x = lon * scale_x - offset_x;
+			if (x >= 0)
+				break;
+			lon += 360.0;
+		}
+		return lon;
+	}
+
+	/* Return last longitude value which ends up on-screen */
+	public double last_lon(double lon) {
+		lon = first_lon(lon);
+
+		for(;;) {
+			double next_lon = lon + 360.0;
+			double next_x = next_lon * scale_x - offset_x;
+			if (next_x >= width)
+				break;
+			lon = next_lon;
+		}
+		return lon;
+	}
+
 	private boolean has_location;
 
 	public boolean has_location() {
@@ -104,10 +155,21 @@ public class AltosMapTransform {
 		scale_x = 256/360.0 * Math.pow(2, zoom);
 		scale_y = 256/(2.0*Math.PI) * Math.pow(2, zoom);
 
+		this.width = width;
+		this.height = height;
+
 		AltosPointDouble centre_pt = point(centre_lat_lon);
 
 		has_location = (centre_lat_lon.lat != 0 || centre_lat_lon.lon != 0);
 		offset_x = centre_pt.x - width / 2.0;
 		offset_y = centre_pt.y - height / 2.0;
 	}
+
+	public static double lon_from_distance(double lat, double distance) {
+		double c = AltosGreatCircle.earth_radius * Math.cos(lat * Math.PI / 180) * 2 * Math.PI;
+
+		if (c < 10)
+			return 0;
+		return distance/c * 360.0;
+	}
 }