utility.ts

// SOURCE https://stackoverflow.com/questions/36721830/convert-hsl-to-rgb-and-hex
export function hslToHex(h: number, s: number, l: number) {
  l /= 100;
  const a = (s * Math.min(l, 1 - l)) / 100;
  const f = (n: number) => {
    const k = (n + h / 30) % 12;
    const color = l - a * Math.max(Math.min(k - 3, 9 - k, 1), -1);
    return Math.round(255 * color)
      .toString(16)
      .padStart(2, "0"); // convert to Hex and prefix "0" if needed
  };
  return `#${f(0)}${f(8)}${f(4)}`;
}

// SOURCE https://stackoverflow.com/questions/46432335/hex-to-hsl-convert-javascript
export function hexToHSL(hex: string): [number, number, number] {
  var result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);

  var r = parseInt(result[1], 16);
  var g = parseInt(result[2], 16);
  var b = parseInt(result[3], 16);

  (r /= 255), (g /= 255), (b /= 255);
  var max = Math.max(r, g, b),
    min = Math.min(r, g, b);
  var h,
    s,
    l = (max + min) / 2;

  if (max == min) {
    h = s = 0; // achromatic
  } else {
    var d = max - min;
    s = l > 0.5 ? d / (2 - max - min) : d / (max + min);
    switch (max) {
      case r:
        h = (g - b) / d + (g < b ? 6 : 0);
        break;
      case g:
        h = (b - r) / d + 2;
        break;
      case b:
        h = (r - g) / d + 4;
        break;
    }
    h /= 6;
  }

  s = s * 100;
  s = Math.round(s);
  l = l * 100;
  l = Math.round(l);
  h = Math.round(360 * h);

  return [h, s, l];
}

// SOURCE https://gist.github.com/borismus/1032746
export function convertDataURIToBinary(dataURI: string) {
  const base64Index: number = dataURI.indexOf(";base64,") + ";base64,".length;
  const base64: string = dataURI.substring(base64Index);
  const raw = window.atob(base64);
  const rawLength = raw.length;
  let array = new Uint8Array(new ArrayBuffer(rawLength));
  for (let i = 0; i < rawLength; i++) {
    array[i] = raw.charCodeAt(i);
  }
  return array;
}

export function sumRows(array: number[][]) {
  const result: number[] = [];
  array.forEach((row, i) => {
    row.reduce((a, b) => (result[i] = a + b));
  });
  return result;
}
export function normalise(array: number[]) {
  const max = Math.max(...array);
  return array.map((x) => x / max);
}