Function requiresRot180

js/load-image-orientation.js:160–180

* Determines orientation combinations that require a rotation by 180°. * * The following is a list of combinations that return true: * * 2 (flip) => 5 (rot90,flip), 7 (rot90,flip), 6 (rot90), 8 (rot90) * 4 (flip) => 5 (rot90,flip), 7 (rot90,flip), 6 (rot90), 8 (rot90) * * 5 (rot

(orientation, autoOrientation)

   * @returns {boolean} Returns true if rotation by 180° is required
   */
  function requiresRot180(orientation, autoOrientation) {
    if (autoOrientation > 1 && autoOrientation < 9) {
      switch (orientation) {
        case 2:
        case 4:
          return autoOrientation > 4
        case 5:
        case 7:
          return autoOrientation % 2 === 0
        case 6:
        case 8:
          return (
            autoOrientation === 2 ||
            autoOrientation === 4 ||
            autoOrientation === 5 ||
            autoOrientation === 7
          )
      }
    }
    return false
  }

  // Determines if the target image should be a canvas element:
  loadImage.requiresCanvas = function (options) {