zxing-js/library

/*
 * Copyright 2012 ZXing authors
 *
 * 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.
 */

/*namespace com.google.zxing.common.detector {*/

/**
 * General math-related and numeric utility functions.
 */
export default class MathUtils {
  private constructor() {}

  /**
   * Ends up being a bit faster than {@link Math#round(float)}. This merely rounds its
   * argument to the nearest int, where x.5 rounds up to x+1. Semantics of this shortcut
   * differ slightly from {@link Math#round(float)} in that half rounds down for negative
   * values. -2.5 rounds to -3, not -2. For purposes here it makes no difference.
   *
   * @param d real value to round
   * @return nearest {@code int}
   */
  public static round(d: number/*float*/): number /*int*/ {
    if (isNaN(d)) return 0;
    if (d <= Number.MIN_SAFE_INTEGER) return Number.MIN_SAFE_INTEGER;
    if (d >= Number.MAX_SAFE_INTEGER) return Number.MAX_SAFE_INTEGER;
    return /*(int) */ (d + (d < 0.0 ? -0.5 : 0.5)) | 0;
  }
  // TYPESCRIPTPORT: maybe remove round method and call directly Math.round, it looks like it doesn't make sense for js

  /**
   * @param aX point A x coordinate
   * @param aY point A y coordinate
   * @param bX point B x coordinate
   * @param bY point B y coordinate
   * @return Euclidean distance between points A and B
   */
  public static distance(
    aX: number /*float|int*/,
    aY: number /*float|int*/,
    bX: number /*float|int*/,
    bY: number /*float|int*/
  ): number /*float*/ {
    const xDiff = aX - bX;
    const yDiff = aY - bY;
    return /*(float) */ Math.sqrt(xDiff * xDiff + yDiff * yDiff);
  }

  /**
   * @param aX point A x coordinate
   * @param aY point A y coordinate
   * @param bX point B x coordinate
   * @param bY point B y coordinate
   * @return Euclidean distance between points A and B
   */
  // public static distance(aX: number /*int*/, aY: number /*int*/, bX: number /*int*/, bY: number /*int*/): float {
  //   const xDiff = aX - bX
  //   const yDiff = aY - bY
  //   return (float) Math.sqrt(xDiff * xDiff + yDiff * yDiff);
  // }

  /**
   * @param array values to sum
   * @return sum of values in array
   */
  public static sum(array: Int32Array): number /*int*/ {
    let count = 0;
    for (let i = 0, length = array.length; i !== length; i++) {
      const a = array[i];
      count += a;
    }
    return count;
  }
}