OrientationSensorUtil.java

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// -*- mode: java; c-basic-offset: 2; -*-
// Copyright 2009-2011 Google, All Rights reserved
// Copyright 2011-2012 MIT, All rights reserved
// Released under the Apache License, Version 2.0
// http://www.apache.org/licenses/LICENSE-2.0
 
package com.google.appinventor.components.runtime.util;
 
public class OrientationSensorUtil {
 
  private OrientationSensorUtil() {
  }
 
  //VisibleForTesting
  static float mod(float dividend, float quotient) {
    float result = dividend % quotient;
    if (result == 0 || Math.signum(dividend) == Math.signum(quotient)) {
      return result;
    } else {
      return result + quotient;
    }
  }
 
  public static float normalizeAzimuth(float azimuth) {
    return mod(azimuth, 360f);
  }
 
  public static float normalizePitch(float pitch) {
    return mod(pitch + 180f, 360f) - 180f;
  }
 
  public static float normalizeRoll(float roll) {
    // Guarantee that roll is in [-180, +180].  It could legitimately
    // be slightly outside due to floating point rounding issues.
    roll = Math.min(roll, 180f);
    roll = Math.max(roll, -180f);
 
    // If roll is in [-90, +90], we're done.
    if (roll >= -90 && roll <= 90) {
      return roll;
    }
 
    // Otherwise, reflect over x-axis to put in 1st or 4th quadrant.
    roll = 180 - roll;
 
    // Put in range [-90, +90].
    if (roll >= 270) {
      roll -= 360;
    }
    return roll;
  }
}