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.Units;
8 import org.djunits.unit.scale.GradeScale;
9 import org.djunits.unit.scale.IdentityScale;
10 import org.djunits.unit.scale.LinearScale;
11 import org.djunits.unit.scale.Scale;
12 import org.djunits.unit.si.SIUnit;
13 import org.djunits.unit.system.UnitSystem;
14
15 /**
16 * Angle is the measure of rotation between two intersecting lines, expressed in radians (rad) or degrees.
17 * <p>
18 * Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved. See
19 * for project information <a href="https://djunits.org" target="_blank">https://djunits.org</a>. The DJUNITS project is
20 * distributed under a <a href="https://djunits.org/docs/license.html" target="_blank">three-clause BSD-style license</a>.
21 * @author Alexander Verbraeck
22 */
23 public class Angle extends Quantity<Angle, Angle.Unit>
24 {
25 /** Constant with value zero radians. */
26 public static final Angle ZERO = Angle.ofSi(0.0);
27
28 /** Constant with value pi radians. */
29 public static final Angle PI = Angle.ofSi(Math.PI);
30
31 /** Constant with value pi/2 radians. */
32 public static final Angle HALF_PI = Angle.ofSi(Math.PI / 2.0);
33
34 /** Constant with value 2 pi radians. */
35 public static final Angle TWO_PI = Angle.ofSi(Math.PI * 2.0);
36
37 /** Constant with value tau radians. */
38 public static final Angle TAU = Angle.ofSi(Math.PI * 2.0);
39
40 /** Constant with value one radian. */
41 public static final Angle ONE = Angle.ofSi(1.0);
42
43 /** Constant with value NaN. */
44 @SuppressWarnings("checkstyle:constantname")
45 public static final Angle NaN = Angle.ofSi(Double.NaN);
46
47 /** Constant with value POSITIVE_INFINITY. */
48 public static final Angle POSITIVE_INFINITY = Angle.ofSi(Double.POSITIVE_INFINITY);
49
50 /** Constant with value NEGATIVE_INFINITY. */
51 public static final Angle NEGATIVE_INFINITY = Angle.ofSi(Double.NEGATIVE_INFINITY);
52
53 /** Constant with value MAX_VALUE. */
54 public static final Angle POS_MAXVALUE = Angle.ofSi(Double.MAX_VALUE);
55
56 /** Constant with value -MAX_VALUE. */
57 public static final Angle NEG_MAXVALUE = Angle.ofSi(-Double.MAX_VALUE);
58
59 /** */
60 private static final long serialVersionUID = 600L;
61
62 /**
63 * Instantiate a Angle quantity with a unit.
64 * @param value the value, expressed in the unit
65 * @param unit the unit in which the value is expressed
66 */
67 public Angle(final double value, final Angle.Unit unit)
68 {
69 super(value, unit);
70 }
71
72 /**
73 * Instantiate a Angle quantity with a unit, expressed as a String.
74 * @param value the value, expressed in the unit
75 * @param abbreviation the String abbreviation of the unit in which the value is expressed
76 */
77 public Angle(final double value, final String abbreviation)
78 {
79 this(value, Units.resolve(Angle.Unit.class, abbreviation));
80 }
81
82 /**
83 * Construct Angle quantity.
84 * @param value Scalar from which to construct this instance
85 */
86 public Angle(final Angle value)
87 {
88 super(value.si(), Angle.Unit.SI);
89 setDisplayUnit(value.getDisplayUnit());
90 }
91
92 /**
93 * Return a Angle instance based on an SI value.
94 * @param si the si value
95 * @return the Angle instance based on an SI value
96 */
97 public static Angle ofSi(final double si)
98 {
99 return new Angle(si, Angle.Unit.SI);
100 }
101
102 @Override
103 public Angle instantiate(final double si)
104 {
105 return ofSi(si);
106 }
107
108 @Override
109 public SIUnit siUnit()
110 {
111 return Angle.Unit.SI_UNIT;
112 }
113
114 /**
115 * Returns a Angle representation of a textual representation of a value with a unit. The String representation that can be
116 * parsed is the double value in the unit, followed by a localized or English abbreviation of the unit. Spaces are allowed,
117 * but not required, between the value and the unit.
118 * @param text the textual representation to parse into a Angle
119 * @return the Scalar representation of the value in its unit
120 * @throws IllegalArgumentException when the text cannot be parsed
121 * @throws NullPointerException when the text argument is null
122 */
123 public static Angle valueOf(final String text)
124 {
125 return Quantity.valueOf(text, ZERO);
126 }
127
128 /**
129 * Returns a Angle based on a value and the textual representation of the unit, which can be localized.
130 * @param value the value to use
131 * @param unitString the textual representation of the unit
132 * @return the Scalar representation of the value in its unit
133 * @throws IllegalArgumentException when the unit cannot be parsed or is incorrect
134 * @throws NullPointerException when the unitString argument is null
135 */
136 public static Angle of(final double value, final String unitString)
137 {
138 return Quantity.of(value, unitString, ZERO);
139 }
140
141 /**
142 * Add an (absolute) direction to this angle, and return a direction. The unit of the return value will be the unit of this
143 * angle, and the reference of the return value will be the reference belonging to the given direction.
144 * <code>R.add(A)</code> = unit of R and reference value of A.
145 * @param direction the absolute direction to add
146 * @return the absolute direction plus this angle
147 */
148 public final Direction add(final Direction direction)
149 {
150 return direction.add(this).setDisplayUnit(getDisplayUnit());
151 }
152
153 /**
154 * Calculate the division of Angle and Angle, which results in a Dimensionless scalar.
155 * @param v scalar
156 * @return scalar as a division of Angle and Angle
157 */
158 public final Dimensionless divide(final Angle v)
159 {
160 return new Dimensionless(this.si() / v.si(), Unitless.BASE);
161 }
162
163 /**
164 * Calculate the multiplication of Angle and Frequency, which results in a AngularVelocity scalar.
165 * @param v scalar
166 * @return scalar as a multiplication of Angle and Frequency
167 */
168 public final AngularVelocity multiply(final Frequency v)
169 {
170 return new AngularVelocity(this.si() * v.si(), AngularVelocity.Unit.SI);
171 }
172
173 /**
174 * Calculate the division of Angle and Duration, which results in a AngularVelocity scalar.
175 * @param v scalar
176 * @return scalar as a division of Angle and Duration
177 */
178 public final AngularVelocity divide(final Duration v)
179 {
180 return new AngularVelocity(this.si() / v.si(), AngularVelocity.Unit.SI);
181 }
182
183 /**
184 * Calculate the division of Angle and AngularVelocity, which results in a Duration scalar.
185 * @param v scalar
186 * @return scalar as a division of Angle and AngularVelocity
187 */
188 public final Duration divide(final AngularVelocity v)
189 {
190 return new Duration(this.si() / v.si(), Duration.Unit.SI);
191 }
192
193 /**
194 * Normalize an angle between 0 and 2 * PI.
195 * @param angle original angle.
196 * @return angle between 0 and 2 * PI.
197 */
198 public static double normalize(final double angle)
199 {
200 double normalized = angle % (2 * Math.PI);
201 if (normalized < 0.0)
202 {
203 normalized += 2 * Math.PI;
204 }
205 return normalized;
206 }
207
208 /**
209 * Normalize an angle between 0 and 2 * PI.
210 * @param angle original angle.
211 * @return a new Angle object with angle between 0 and 2 * PI.
212 */
213 public static Angle normalize(final Angle angle)
214 {
215 return new Angle(normalize(angle.si()), Angle.Unit.rad);
216 }
217
218 /******************************************************************************************************/
219 /********************************************** UNIT CLASS ********************************************/
220 /******************************************************************************************************/
221
222 /**
223 * Angle.Unit encodes the units of angle (radians, degrees).
224 * <p>
225 * Copyright (c) 2025-2026 Delft University of Technology, Jaffalaan 5, 2628 BX Delft, the Netherlands. All rights reserved.
226 * See for project information <a href="https://djunits.org" target="_blank">https://djunits.org</a>. The DJUNITS project is
227 * distributed under a <a href="https://djunits.org/docs/license.html" target="_blank">three-clause BSD-style license</a>.
228 * @author Alexander Verbraeck
229 */
230 @SuppressWarnings("checkstyle:constantname")
231 public static class Unit extends AbstractUnit<Angle.Unit, Angle>
232 {
233 /** The dimensions of Angle: rad. */
234 public static final SIUnit SI_UNIT = SIUnit.of("rad");
235
236 /** radian. */
237 public static final Angle.Unit rad = new Angle.Unit("rad", "rad", "radian", IdentityScale.SCALE, UnitSystem.SI_DERIVED);
238
239 /** The SI or BASE unit. */
240 public static final Angle.Unit SI = rad;
241
242 /** percent (non-linear, 100% is 45 degrees; 90 degrees is infinite). */
243 public static final Angle.Unit percent = new Angle.Unit("%", "%", "percent", new GradeScale(0.01), UnitSystem.OTHER);
244
245 /** degree. */
246 public static final Angle.Unit deg = rad.deriveUnit("deg", "\u00b0", "degree", Math.PI / 180.0, UnitSystem.SI_ACCEPTED);
247
248 /** arcminute. */
249 public static final Angle.Unit arcmin = deg.deriveUnit("arcmin", "'", "arcminute", 1.0 / 60.0, UnitSystem.OTHER);
250
251 /** arcsecond. */
252 public static final Angle.Unit arcsec = deg.deriveUnit("arcsec", "\"", "arcsecond", 1.0 / 3600.0, UnitSystem.OTHER);
253
254 /** grad. */
255 public static final Angle.Unit grad = rad.deriveUnit("grad", "gradian", 2.0 * Math.PI / 400.0, UnitSystem.OTHER);
256
257 /** centesimal arcminute. */
258 public static final Angle.Unit cdm =
259 grad.deriveUnit("cdm", "c'", "centesimal arcminute", 1.0 / 100.0, UnitSystem.OTHER);
260
261 /** centesimal arcsecond. */
262 public static final Angle.Unit cds =
263 grad.deriveUnit("cds", "c\"", "centesimal arcsecond", 1.0 / 10000.0, UnitSystem.OTHER);
264
265 /**
266 * Create a new Angle unit.
267 * @param id the id or main abbreviation of the unit
268 * @param name the full name of the unit
269 * @param scaleFactorToBaseUnit the scale factor of the unit to convert it TO the base (SI) unit
270 * @param unitSystem the unit system such as SI or IMPERIAL
271 */
272 public Unit(final String id, final String name, final double scaleFactorToBaseUnit, final UnitSystem unitSystem)
273 {
274 super(id, name, new LinearScale(scaleFactorToBaseUnit), unitSystem);
275 }
276
277 /**
278 * Return a derived unit for this unit, with textual abbreviation(s) and a display abbreviation.
279 * @param textualAbbreviation the textual abbreviation of the unit, which doubles as the id
280 * @param displayAbbreviation the display abbreviation of the unit
281 * @param name the full name of the unit
282 * @param scale the scale to use to convert between this unit and the standard (e.g., SI, BASE) unit
283 * @param unitSystem unit system, e.g. SI or Imperial
284 */
285 public Unit(final String textualAbbreviation, final String displayAbbreviation, final String name, final Scale scale,
286 final UnitSystem unitSystem)
287 {
288 super(textualAbbreviation, displayAbbreviation, name, scale, unitSystem);
289 }
290
291 @Override
292 public SIUnit siUnit()
293 {
294 return SI_UNIT;
295 }
296
297 @Override
298 public Unit getBaseUnit()
299 {
300 return SI;
301 }
302
303 /** {@inheritDoc} */
304 @Override
305 public Angle ofSi(final double si)
306 {
307 return Angle.ofSi(si);
308 }
309
310 @Override
311 public Unit deriveUnit(final String textualAbbreviation, final String displayAbbreviation, final String name,
312 final double scaleFactor, final UnitSystem unitSystem)
313 {
314 if (getScale() instanceof LinearScale ls)
315 {
316 return new Angle.Unit(textualAbbreviation, displayAbbreviation, name,
317 new LinearScale(ls.getScaleFactorToBaseUnit() * scaleFactor), unitSystem);
318 }
319 throw new UnitRuntimeException("Only possible to derive a unit from a unit with a linear scale");
320 }
321
322 }
323 }