content: /*
   * Copyright (C) 2021 The Android Open Source Project
   *
   * Licensed 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.
   */
  
  package com.anod.appwatcher.utils.color;
  
  /**
   * Utility methods for mathematical operations.
   *
   */
  public class MathUtils {
    private MathUtils() {}
  
    /**
     * The signum function.
     *
     * @return 1 if num > 0, -1 if num < 0, and 0 if num = 0
     */
    public static int signum(double num) {
      if (num < 0) {
        return -1;
      } else if (num == 0) {
        return 0;
      } else {
        return 1;
      }
    }
  
    /**
     * The linear interpolation function.
     *
     * @return start if amount = 0 and stop if amount = 1
     */
    public static double lerp(double start, double stop, double amount) {
      return (1.0 - amount) * start + amount * stop;
    }
  
    /**
     * Clamps an integer between two integers.
     *
     * @return input when min <= input <= max, and either min or max otherwise.
     */
    public static int clampInt(int min, int max, int input) {
      if (input < min) {
        return min;
      } else if (input > max) {
        return max;
      }
  
      return input;
    }
  
    /**
     * Clamps an integer between two floating-point numbers.
     *
     * @return input when min <= input <= max, and either min or max otherwise.
     */
    public static double clampDouble(double min, double max, double input) {
      if (input < min) {
        return min;
      } else if (input > max) {
        return max;
      }
  
      return input;
    }
  
    /**
     * Sanitizes a degree measure as an integer.
     *
     * @return a degree measure between 0 (inclusive) and 360 (exclusive).
     */
    public static int sanitizeDegreesInt(int degrees) {
      degrees = degrees % 360;
      if (degrees < 0) {
        degrees = degrees + 360;
      }
      return degrees;
    }
  
    /**
     * Sanitizes a degree measure as a floating-point number.
     *
     * @return a degree measure between 0.0 (inclusive) and 360.0 (exclusive).
     */
    public static double sanitizeDegreesDouble(double degrees) {
      degrees = degrees % 360.0;
      if (degrees < 0) {
        degrees = degrees + 360.0;
      }
      return degrees;
    }
  
    /**
     * Sign of direction change needed to travel from one angle to another.
     *
     * <p>For angles that are 180 degrees apart from each other, both directions have the same travel
     * distance, so either direction is shortest. The value 1.0 is returned in this case.
     *
     * @param from The angle travel starts from, in degrees.
     * @param to The angle travel ends at, in degrees.
     * @return -1 if decreasing from leads to the shortest travel distance, 1 if increasing from leads
     *     to the shortest travel distance.
     */
    public static double rotationDirection(double from, double to) {
      double increasingDifference = sanitizeDegreesDouble(to - from);
      return increasingDifference <= 180.0 ? 1.0 : -1.0;
    }
  
    /** Distance of two points on a circle, represented using degrees. */
    public static double differenceDegrees(double a, double b) {
      return 180.0 - Math.abs(Math.abs(a - b) - 180.0);
    }
  
    /** Multiplies a 1x3 row vector with a 3x3 matrix. */
    public static double[] matrixMultiply(double[] row, double[][] matrix) {
      double a = row[0] * matrix[0][0] + row[1] * matrix[0][1] + row[2] * matrix[0][2];
      double b = row[0] * matrix[1][0] + row[1] * matrix[1][1] + row[2] * matrix[1][2];
      double c = row[0] * matrix[2][0] + row[1] * matrix[2][1] + row[2] * matrix[2][2];
      return new double[] {a, b, c};
    }
  }