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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; 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
* 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_14;
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;
int width, height;
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(double lat, double lon) {
double x, y;
double e;
x = lon * scale_x;
e = Math.sin(Math.toRadians(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 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);
}
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));
}
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() {
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);
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;
}
}
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