Mega Code Archive
Normalize an angle in a 2&pi wide interval around a center value
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import java.io.File;
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
public class Main {
/** 2 π. */
private static final double TWO_PI = 2 * Math.PI;
/**
* Normalize an angle in a 2&pi wide interval around a center value.
* This method has three main uses:
* <ul>
* <li>normalize an angle between 0 and 2π:<br/>
* <code>a = MathUtils.normalizeAngle(a, Math.PI);</code></li>
* <li>normalize an angle between -π and +π<br/>
* <code>a = MathUtils.normalizeAngle(a, 0.0);</code></li>
* <li>compute the angle between two defining angular positions:<br>
* <code>angle = MathUtils.normalizeAngle(end, start) - start;</code></li>
* </ul>
* Note that due to numerical accuracy and since π cannot be represented
* exactly, the result interval is <em>closed</em>, it cannot be half-closed
* as would be more satisfactory in a purely mathematical view.
* @param a angle to normalize
* @param center center of the desired 2π interval for the result
* @return a-2kπ with integer k and center-π <= a-2kπ <= center+π
* @since 1.2
*/
public static double normalizeAngle(double a, double center) {
return a - TWO_PI * Math.floor((a + Math.PI - center) / TWO_PI);
}
}
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