Merge branch 'master' of ssh://git.gag.com/scm/git/fw/altos

[fw/altos] / altoslib / AltosMapTransform.java

diff --git a/altoslib/AltosMapTransform.java b/altoslib/AltosMapTransform.java
new file mode 100644 (file)
index 0000000..7615c83
--- /dev/null
+++ b/altoslib/AltosMapTransform.java
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+/*
+ * Copyright © 2014 Keith Packard <keithp@keithp.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; version 2 of the License.
+ *
+ * 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.
+ */
+
+package org.altusmetrum.altoslib_7;
+
+import java.io.*;
+import java.lang.Math;
+import java.util.*;
+import java.util.concurrent.*;
+
+public class AltosMapTransform {
+
+       double  scale_x, scale_y;
+
+       double  offset_x, offset_y;
+
+       public AltosLatLon lat_lon (AltosPointDouble point) {
+               double lat, lon;
+               double rads;
+
+               lon = point.x/scale_x;
+               rads = 2 * Math.atan(Math.exp(-point.y/scale_y));
+               lat = Math.toDegrees(rads - Math.PI/2);
+
+               return new AltosLatLon(lat,lon);
+       }
+
+       public AltosLatLon lat_lon (AltosPointInt point) {
+               return lat_lon(new AltosPointDouble(point.x, point.y));
+       }
+
+       public AltosPointDouble screen_point(AltosPointInt screen) {
+               return new AltosPointDouble(screen.x + offset_x, screen.y + offset_y);
+       }
+
+       public AltosPointDouble screen_point(AltosPointDouble screen) {
+               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));
+       }
+
+       public AltosLatLon screen_lat_lon(AltosPointDouble screen) {
+               return lat_lon(screen_point(screen));
+       }
+
+       public AltosPointDouble point(AltosLatLon lat_lon) {
+               double x, y;
+               double e;
+
+               x = lat_lon.lon * scale_x;
+
+               e = Math.sin(Math.toRadians(lat_lon.lat));
+               e = Math.max(e,-(1-1.0E-15));
+               e = Math.min(e,  1-1.0E-15 );
+
+               y = 0.5*Math.log((1+e)/(1-e))*-scale_y;
+
+               return new AltosPointDouble(x, y);
+       }
+
+       public AltosPointDouble screen(AltosPointDouble point) {
+               return new AltosPointDouble(point.x - offset_x, point.y - offset_y);
+       }
+
+       public AltosPointInt screen(AltosPointInt point) {
+               return new AltosPointInt((int) (point.x - offset_x + 0.5),
+                                        (int) (point.y - offset_y + 0.5));
+       }
+
+       public AltosRectangle screen(AltosMapRectangle map_rect) {
+               AltosPointDouble        ul = screen(map_rect.ul);
+               AltosPointDouble        lr = screen(map_rect.lr);
+
+               return new AltosRectangle((int) ul.x, (int) ul.y, (int) (lr.x - ul.x), (int) (lr.y - ul.y));
+       }
+
+       public AltosPointDouble screen(AltosLatLon lat_lon) {
+               return screen(point(lat_lon));
+       }
+
+       private boolean has_location;
+
+       public boolean has_location() {
+               return has_location;
+       }
+
+       public AltosMapTransform(int width, int height, int zoom, AltosLatLon centre_lat_lon) {
+               scale_x = 256/360.0 * Math.pow(2, zoom);
+               scale_y = 256/(2.0*Math.PI) * Math.pow(2, zoom);
+
+               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;
+       }
+}