001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.data.coor;
003
004/**
005 * Northing, Easting of the projected coordinates.
006 *
007 * This class is immutable.
008 *
009 * @author Imi
010 */
011public class EastNorth extends Coordinate {
012
013    private static final long serialVersionUID = 1L;
014
015    /**
016     * A zero constant
017     */
018    public static final EastNorth ZERO = new EastNorth(0, 0);
019
020    /**
021     * Constructs a new {@code EastNorth}.
022     * @param east easting
023     * @param north northing
024     */
025    public EastNorth(double east, double north) {
026        super(east, north);
027    }
028
029    /**
030     * Returns easting.
031     * @return easting
032     */
033    public double east() {
034        return x;
035    }
036
037    /**
038     * Returns northing.
039     * @return northing
040     */
041    public double north() {
042        return y;
043    }
044
045    /**
046     * Adds an offset to this {@link EastNorth} instance and returns the result.
047     * @param dEast The offset to add in east direction.
048     * @param dNorth The offset to add in north direction.
049     * @return The result.
050     */
051    public EastNorth add(double dEast, double dNorth) {
052        return new EastNorth(east()+dEast, north()+dNorth);
053    }
054
055    /**
056     * Adds the coordinates of an other EastNorth instance to this one.
057     * @param other The other instance.
058     * @return The new EastNorth position.
059     */
060    public EastNorth add(EastNorth other) {
061        return new EastNorth(x+other.x, y+other.y);
062    }
063
064    /**
065     * Subtracts an east/north value from this point.
066     * @param other The other value to subtract from this.
067     * @return A point with the new coordinates.
068     */
069    public EastNorth subtract(EastNorth other) {
070        return new EastNorth(x-other.x, y-other.y);
071    }
072
073    /**
074     * Scales this {@link EastNorth} instance to a given factor and returns the result.
075     * @param s factor
076     * @return The result.
077     */
078    public EastNorth scale(double s) {
079        return new EastNorth(s * x, s * y);
080    }
081
082    /**
083     * Does a linear interpolation between two EastNorth instances.
084     * @param en2 The other EstNort instance.
085     * @param proportion The proportion the other instance influences the result.
086     * @return The new {@link EastNorth} position.
087     */
088    public EastNorth interpolate(EastNorth en2, double proportion) {
089        // this is an alternate form of this.x + proportion * (en2.x - this.x) that is slightly faster
090        return new EastNorth((1 - proportion) * this.x + proportion * en2.x,
091                (1 - proportion) * this.y + proportion * en2.y);
092    }
093
094    /**
095     * Gets the center between two {@link EastNorth} instances.
096     * @param en2 The other instance.
097     * @return The center between this and the other instance.
098     */
099    public EastNorth getCenter(EastNorth en2) {
100        // The JIT will inline this for us, it is as fast as the normal /2 approach
101        return interpolate(en2, .5);
102    }
103
104    /**
105     * Returns the euclidean distance from this {@code EastNorth} to a specified {@code EastNorth}.
106     *
107     * @param en the specified coordinate to be measured against this {@code EastNorth}
108     * @return the euclidean distance from this {@code EastNorth} to a specified {@code EastNorth}
109     * @since 6166
110     */
111    public double distance(final EastNorth en) {
112        return super.distance(en);
113    }
114
115    /**
116     * Returns the square of the euclidean distance from this {@code EastNorth} to a specified {@code EastNorth}.
117     *
118     * @param en the specified coordinate to be measured against this {@code EastNorth}
119     * @return the square of the euclidean distance from this {@code EastNorth} to a specified {@code EastNorth}
120     * @since 6166
121     */
122    public double distanceSq(final EastNorth en) {
123        return super.distanceSq(en);
124    }
125
126    /**
127     * Counts length (distance from [0,0]) of this.
128     *
129     * @return length of this
130     */
131    public double length() {
132        return Math.sqrt(x*x + y*y);
133    }
134
135    /**
136     * Returns the heading, in radians, that you have to use to get from
137     * this EastNorth to another. Heading is mapped into [0, 2pi)
138     *
139     * @param other the "destination" position
140     * @return heading
141     */
142    public double heading(EastNorth other) {
143        double hd = Math.atan2(other.east() - east(), other.north() - north());
144        if (hd < 0) {
145            hd = 2 * Math.PI + hd;
146        }
147        return hd;
148    }
149
150    /**
151     * Replies true if east and north are different from Double.NaN and not infinite
152     *
153     * @return true if east and north are different from Double.NaN and not infinite
154     */
155    public boolean isValid() {
156        return !Double.isNaN(x) && !Double.isNaN(y) && !Double.isInfinite(x) && !Double.isInfinite(y);
157    }
158
159    /**
160     * Returns an EastNorth representing the this EastNorth rotated around
161     * a given EastNorth by a given angle
162     * @param pivot the center of the rotation
163     * @param angle the angle of the rotation
164     * @return EastNorth rotated object
165     */
166    public EastNorth rotate(EastNorth pivot, double angle) {
167        double cosPhi = Math.cos(angle);
168        double sinPhi = Math.sin(angle);
169        double x = east() - pivot.east();
170        double y = north() - pivot.north();
171        // CHECKSTYLE.OFF: SingleSpaceSeparator
172        double nx =  cosPhi * x + sinPhi * y + pivot.east();
173        double ny = -sinPhi * x + cosPhi * y + pivot.north();
174        // CHECKSTYLE.ON: SingleSpaceSeparator
175        return new EastNorth(nx, ny);
176    }
177
178    @Override
179    public String toString() {
180        return "EastNorth[e="+x+", n="+y+']';
181    }
182
183    /**
184     * Compares two EastNorth values
185     * @param other other east.north
186     * @param e epsilon
187     *
188     * @return true if "x" and "y" values are within epsilon {@code e} of each other
189     */
190    public boolean equalsEpsilon(EastNorth other, double e) {
191        return Math.abs(x - other.x) < e && Math.abs(y - other.y) < e;
192    }
193}