image-js/src/util/matrix.js

Image processing and manipulation in JavaScript

export default function Matrix(width, height, defaultValue) {
  const matrix = new Array(width);
  for (let x = 0; x < width; x++) {
    matrix[x] = new Array(height);
  }
  if (defaultValue) {
    for (let x = 0; x < width; x++) {
      for (let y = 0; y < height; y++) {
        matrix[x][y] = defaultValue;
      }
    }
  }
  matrix.width = width;
  matrix.height = height;
  Object.setPrototypeOf(matrix, Matrix.prototype);
  return matrix;
}

Matrix.prototype.localMin = function (x, y) {
  let min = this[x][y];
  let position = [x, y];
  for (let i = Math.max(0, x - 1); i < Math.min(this.length, x + 2); i++) {
    for (let j = Math.max(0, y - 1); j < Math.min(this[0].length, y + 2); j++) {
      if (this[i][j] < min) {
        min = this[i][j];
        position = [i, j];
      }
    }
  }
  return {
    position: position,
    value: min,
  };
};

Matrix.prototype.localMax = function (x, y) {
  let max = this[x][y];
  let position = [x, y];
  for (let i = Math.max(0, x - 1); i < Math.min(this.length, x + 2); i++) {
    for (let j = Math.max(0, y - 1); j < Math.min(this[0].length, y + 2); j++) {
      if (this[i][j] > max) {
        max = this[i][j];
        position = [i, j];
      }
    }
  }
  return {
    position: position,
    value: max,
  };
};

Matrix.prototype.localSearch = function (x, y, value) {
  let results = [];
  for (let i = Math.max(0, x - 1); i < Math.min(this.length, x + 2); i++) {
    for (let j = Math.max(0, y - 1); j < Math.min(this[0].length, y + 2); j++) {
      if (this[i][j] === value) {
        results.push([i, j]);
      }
    }
  }
  return results;
};