// Constants
  var MIN_ROTATION = 20;
  var MIN_SCALE = .3;
  var MIN_SWIPE_DISTANCE = 50;

  var rotation, scale, recognized, translationX, translationY;

  function resetGesture(event) {
    rotation = 0;
    scale = 1;
    recognized = false;
    translationX = translationY = 0;
  }

  function detectGesture(event) {
    // Disable built-in inertia
    if (event.detail == event.MSGESTURE_FLAG_INERTIA) {
      return;
    }

    // Update total values
    rotation += event.rotation * 180 / Math.PI;
    scale *= event.scale;
    translationX += event.translationX;
    translationY += event.translationY;

    if (!recognized) {

      var direction;

      if (Math.abs(translationX) > MIN_SWIPE_DISTANCE) {
        // Horizontal swipe
        recognized = true;
        direction = translationX < 0 ? 'left' : 'right';
        console.log('Horizontal swipe: ', direction);
      } else if (Math.abs(translationY) > MIN_SWIPE_DISTANCE) {
        // Vertical swipe
        recognized = true;
        direction = translationY < 0 ? 'up' : 'down'
        console.log('Vertical swipe: ', direction);
      }

      if (Math.abs(rotation) >= MIN_ROTATION) {
        // Rotation
        recognized = true;
        console.log('Rotate: ', rotation < 0 ? 'left' : 'right');
      } else if (Math.abs(scale - 1) > MIN_SCALE) {
        // Pinch/Stretch
        recognized = true;
        console.log('Scale: ', scale > 1 ? 'stretch' : 'pinch');
      }
    }
  }