1 package org.djunits.quantity;
2
3 import org.djunits.quantity.def.Quantity;
4 import org.djunits.unit.AbstractUnit;
5 import org.djunits.unit.UnitRuntimeException;
6 import org.djunits.unit.Unitless;
7 import org.djunits.unit.scale.GradeScale;
8 import org.djunits.unit.scale.IdentityScale;
9 import org.djunits.unit.scale.LinearScale;
10 import org.djunits.unit.scale.Scale;
11 import org.djunits.unit.si.SIUnit;
12 import org.djunits.unit.system.UnitSystem;
13
14 /**
15 * Angle is the measure of rotation between two intersecting lines, expressed in radians (rad) or degrees.
16 * <p>
17 * Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See
18 * for project information <a href="https://djunits.org" target="_blank">https://djunits.org</a>. The DJUNITS project is
19 * distributed under a <a href="https://djunits.org/docs/license.html" target="_blank">three-clause BSD-style license</a>.
20 * @author Alexander Verbraeck
21 */
22 public class Angle extends Quantity<Angle>
23 {
24 /** Constant with value zero radians. */
25 public static final Angle ZERO = ofSi(0.0);
26
27 /** Constant with value pi radians. */
28 public static final Angle PI = ofSi(Math.PI);
29
30 /** Constant with value pi/2 radians. */
31 public static final Angle HALF_PI = ofSi(Math.PI / 2.0);
32
33 /** Constant with value 2 pi radians. */
34 public static final Angle TWO_PI = ofSi(Math.PI * 2.0);
35
36 /** Constant with value tau radians. */
37 public static final Angle TAU = ofSi(Math.PI * 2.0);
38
39 /** Constant with value one radian. */
40 public static final Angle ONE = ofSi(1.0);
41
42 /** Constant with value NaN. */
43 @SuppressWarnings("checkstyle:constantname")
44 public static final Angle NaN = ofSi(Double.NaN);
45
46 /** Constant with value POSITIVE_INFINITY. */
47 public static final Angle POSITIVE_INFINITY = ofSi(Double.POSITIVE_INFINITY);
48
49 /** Constant with value NEGATIVE_INFINITY. */
50 public static final Angle NEGATIVE_INFINITY = ofSi(Double.NEGATIVE_INFINITY);
51
52 /** Constant with value MAX_VALUE. */
53 public static final Angle POS_MAXVALUE = ofSi(Double.MAX_VALUE);
54
55 /** Constant with value -MAX_VALUE. */
56 public static final Angle NEG_MAXVALUE = ofSi(-Double.MAX_VALUE);
57
58 /** */
59 private static final long serialVersionUID = 600L;
60
61 /**
62 * Instantiate a Angle quantity with a unit.
63 * @param valueInUnit the value, expressed in the unit
64 * @param unit the unit in which the value is expressed
65 */
66 public Angle(final double valueInUnit, final Angle.Unit unit)
67 {
68 super(valueInUnit, unit);
69 }
70
71 /**
72 * Return a Angle instance based on an SI value.
73 * @param si the si value
74 * @return the Angle instance based on an SI value
75 */
76 public static Angle ofSi(final double si)
77 {
78 return new Angle(si, Angle.Unit.SI);
79 }
80
81 @Override
82 public Angle instantiateSi(final double si)
83 {
84 return ofSi(si);
85 }
86
87 @Override
88 public SIUnit siUnit()
89 {
90 return Angle.Unit.SI_UNIT;
91 }
92
93 /**
94 * Returns a Angle representation of a textual representation of a value with a unit. The String representation that can be
95 * parsed is the double value in the unit, followed by a localized or English abbreviation of the unit. Spaces are allowed,
96 * but not required, between the value and the unit.
97 * @param text the textual representation to parse into a Angle
98 * @return the Scalar representation of the value in its unit
99 * @throws IllegalArgumentException when the text cannot be parsed
100 * @throws NullPointerException when the text argument is null
101 */
102 public static Angle valueOf(final String text)
103 {
104 return Quantity.valueOf(text, ZERO);
105 }
106
107 /**
108 * Returns a Angle based on a value and the textual representation of the unit, which can be localized.
109 * @param valueInUnit the value, expressed in the unit as given by unitString
110 * @param unitString the textual representation of the unit
111 * @return the Scalar representation of the value in its unit
112 * @throws IllegalArgumentException when the unit cannot be parsed or is incorrect
113 * @throws NullPointerException when the unitString argument is null
114 */
115 public static Angle of(final double valueInUnit, final String unitString)
116 {
117 return Quantity.of(valueInUnit, unitString, ZERO);
118 }
119
120 @Override
121 public Angle.Unit getDisplayUnit()
122 {
123 return (Angle.Unit) super.getDisplayUnit();
124 }
125
126 /**
127 * Add an (absolute) direction to this angle, and return a direction. The unit of the return value will be the unit of this
128 * angle, and the reference of the return value will be the reference belonging to the given direction.
129 * <code>R.add(A)</code> = unit of R and reference value of A.
130 * @param direction the absolute direction to add
131 * @return the absolute direction plus this angle
132 */
133 public final Direction add(final Direction direction)
134 {
135 return direction.add(this).setDisplayUnit(getDisplayUnit());
136 }
137
138 /**
139 * Calculate the division of Angle and Angle, which results in a Dimensionless scalar.
140 * @param v scalar
141 * @return scalar as a division of Angle and Angle
142 */
143 public final Dimensionless divide(final Angle v)
144 {
145 return new Dimensionless(this.si() / v.si(), Unitless.BASE);
146 }
147
148 /**
149 * Calculate the multiplication of Angle and Frequency, which results in a AngularVelocity scalar.
150 * @param v scalar
151 * @return scalar as a multiplication of Angle and Frequency
152 */
153 public final AngularVelocity multiply(final Frequency v)
154 {
155 return new AngularVelocity(this.si() * v.si(), AngularVelocity.Unit.SI);
156 }
157
158 /**
159 * Calculate the division of Angle and Duration, which results in a AngularVelocity scalar.
160 * @param v scalar
161 * @return scalar as a division of Angle and Duration
162 */
163 public final AngularVelocity divide(final Duration v)
164 {
165 return new AngularVelocity(this.si() / v.si(), AngularVelocity.Unit.SI);
166 }
167
168 /**
169 * Calculate the division of Angle and AngularVelocity, which results in a Duration scalar.
170 * @param v scalar
171 * @return scalar as a division of Angle and AngularVelocity
172 */
173 public final Duration divide(final AngularVelocity v)
174 {
175 return new Duration(this.si() / v.si(), Duration.Unit.SI);
176 }
177
178 /**
179 * Normalize an angle between 0 and 2 * PI.
180 * @param angle original angle.
181 * @return angle between 0 and 2 * PI.
182 */
183 public static double normalize(final double angle)
184 {
185 double normalized = angle % (2 * Math.PI);
186 if (normalized < 0.0)
187 {
188 normalized += 2 * Math.PI;
189 }
190 return normalized;
191 }
192
193 /**
194 * Normalize an angle between 0 and 2 * PI.
195 * @param angle original angle.
196 * @return a new Angle object with angle between 0 and 2 * PI.
197 */
198 public static Angle normalize(final Angle angle)
199 {
200 return new Angle(normalize(angle.si()), Angle.Unit.rad);
201 }
202
203 /******************************************************************************************************/
204 /********************************************** UNIT CLASS ********************************************/
205 /******************************************************************************************************/
206
207 /**
208 * Angle.Unit encodes the units of angle (radians, degrees).
209 * <p>
210 * Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved.
211 * See for project information <a href="https://djunits.org" target="_blank">https://djunits.org</a>. The DJUNITS project is
212 * distributed under a <a href="https://djunits.org/docs/license.html" target="_blank">three-clause BSD-style license</a>.
213 * @author Alexander Verbraeck
214 */
215 @SuppressWarnings("checkstyle:constantname")
216 public static class Unit extends AbstractUnit<Angle.Unit, Angle>
217 {
218 /** The dimensions of Angle: rad. */
219 public static final SIUnit SI_UNIT = SIUnit.of("rad");
220
221 /** radian. */
222 public static final Angle.Unit rad = new Angle.Unit("rad", "rad", "radian", IdentityScale.SCALE, UnitSystem.SI_DERIVED);
223
224 /** The SI or BASE unit. */
225 public static final Angle.Unit SI = rad;
226
227 /** percent (non-linear, 100% is 45 degrees; 90 degrees is infinite). */
228 public static final Angle.Unit percent = new Angle.Unit("%", "%", "percent", new GradeScale(0.01), UnitSystem.OTHER);
229
230 /** degree. */
231 public static final Angle.Unit deg = rad.deriveUnit("deg", "\u00b0", "degree", Math.PI / 180.0, UnitSystem.SI_ACCEPTED);
232
233 /** arcminute. */
234 public static final Angle.Unit arcmin = deg.deriveUnit("arcmin", "'", "arcminute", 1.0 / 60.0, UnitSystem.OTHER);
235
236 /** arcsecond. */
237 public static final Angle.Unit arcsec = deg.deriveUnit("arcsec", "\"", "arcsecond", 1.0 / 3600.0, UnitSystem.OTHER);
238
239 /** grad. */
240 public static final Angle.Unit grad = rad.deriveUnit("grad", "gradian", 2.0 * Math.PI / 400.0, UnitSystem.OTHER);
241
242 /** centesimal arcminute. */
243 public static final Angle.Unit cdm =
244 grad.deriveUnit("cdm", "c'", "centesimal arcminute", 1.0 / 100.0, UnitSystem.OTHER);
245
246 /** centesimal arcsecond. */
247 public static final Angle.Unit cds =
248 grad.deriveUnit("cds", "c\"", "centesimal arcsecond", 1.0 / 10000.0, UnitSystem.OTHER);
249
250 /**
251 * Create a new Angle unit.
252 * @param id the id or main abbreviation of the unit
253 * @param name the full name of the unit
254 * @param scaleFactorToBaseUnit the scale factor of the unit to convert it TO the base (SI) unit
255 * @param unitSystem the unit system such as SI or IMPERIAL
256 */
257 public Unit(final String id, final String name, final double scaleFactorToBaseUnit, final UnitSystem unitSystem)
258 {
259 super(id, name, new LinearScale(scaleFactorToBaseUnit), unitSystem);
260 }
261
262 /**
263 * Return a derived unit for this unit, with textual abbreviation(s) and a display abbreviation.
264 * @param textualAbbreviation the textual abbreviation of the unit, which doubles as the id
265 * @param displayAbbreviation the display abbreviation of the unit
266 * @param name the full name of the unit
267 * @param scale the scale to use to convert between this unit and the standard (e.g., SI, BASE) unit
268 * @param unitSystem unit system, e.g. SI or Imperial
269 */
270 public Unit(final String textualAbbreviation, final String displayAbbreviation, final String name, final Scale scale,
271 final UnitSystem unitSystem)
272 {
273 super(textualAbbreviation, displayAbbreviation, name, scale, unitSystem);
274 }
275
276 @Override
277 public SIUnit siUnit()
278 {
279 return SI_UNIT;
280 }
281
282 @Override
283 public Unit getBaseUnit()
284 {
285 return SI;
286 }
287
288 /** {@inheritDoc} */
289 @Override
290 public Angle ofSi(final double si)
291 {
292 return Angle.ofSi(si);
293 }
294
295 @Override
296 public Unit deriveUnit(final String textualAbbreviation, final String displayAbbreviation, final String name,
297 final double scaleFactor, final UnitSystem unitSystem)
298 {
299 if (getScale() instanceof LinearScale ls)
300 {
301 return new Angle.Unit(textualAbbreviation, displayAbbreviation, name,
302 new LinearScale(ls.getScaleFactorToBaseUnit() * scaleFactor), unitSystem);
303 }
304 throw new UnitRuntimeException("Only possible to derive a unit from a unit with a linear scale");
305 }
306
307 }
308 }