altoslib: Create display-independent map support code

This takes the swing-specific map code and creates a generic version.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 101 insertions, 0 deletions

diff --git a/altoslib/AltosMapTransform.java b/altoslib/AltosMapTransform.java
new file mode 100644
index 00000000..f5fc5ebe
--- /dev/null
+++ b/altoslib/AltosMapTransform.java
@@ -0,0 +1,101 @@
+/*
+ * 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_6;
+
+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 AltosPointDouble screen_point(AltosPointDouble screen) {
+		return new AltosPointDouble(screen.x + offset_x, screen.y + offset_y);
+	}
+
+	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 Rectangle screen(AltosMapRectangle map_rect) {
+//		AltosPoint2D	ul = screen(map_rect.ul);
+//		AltosPoint2D	lr = screen(map_rect.lr);
+//
+//		return new Rectangle((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;
+	}
+}