code: function(animData) {
  		// calculate swipe speed for Y axis (paanning)
  		animData.calculateSwipeSpeed('y');
  
  		_currPanBounds = self.currItem.bounds;
  		
  		animData.backAnimDestination = {};
  		animData.backAnimStarted = {};
  
  		// Avoid acceleration animation if speed is too low
  		if(Math.abs(animData.lastFlickSpeed.x) <= 0.05 && Math.abs(animData.lastFlickSpeed.y) <= 0.05 ) {
  			animData.speedDecelerationRatioAbs.x = animData.speedDecelerationRatioAbs.y = 0;
  
  			// Run pan drag release animation. E.g. if you drag image and release finger without momentum.
  			animData.calculateOverBoundsAnimOffset('x');
  			animData.calculateOverBoundsAnimOffset('y');
  			return true;
  		}
  
  		// Animation loop that controls the acceleration after pan gesture ends
  		_registerStartAnimation('zoomPan');
  		animData.lastNow = _getCurrentTime();
  		animData.panAnimLoop();
  	}
docs: amount of pixels to drag to determine direction of swipe