js/reveal.js
/**
	 * Handler for the document level 'touchstart' event,
	 * enables support for swipe and pinch gestures.
	 */
Handler for the document level 'touchstart' event,
enables support for swipe and pinch gestures.
Handler for the document level ' touchstart ' event enables support for swipe and pinch gestures .
function onDocumentTouchStart( event ) {
		touch.startX = event.touches[0].clientX;
		touch.startY = event.touches[0].clientY;
		touch.startCount = event.touches.length;
		if( event.touches.length === 2 && config.overview ) {
			touch.startSpan = distanceBetween( {
				x: event.touches[1].clientX,
				y: event.touches[1].clientY
			}, {
				x: touch.startX,
				y: touch.startY
			} );
		}
	}
function onDocumentTouchStart ( event ) { touch . startX = event . touches [ 0 ] . clientX ; touch . startY = event . touches [ 0 ] . clientY ; touch . startCount = event . touches . length ; if ( event . touches . length === 2 && config . overview ) { touch . startSpan = distanceBetween ( { x : event . touches [ 1 ] . clientX , y : event . touches [ 1 ] . clientY } , { x : touch . startX , y : touch . startY } ) ; } }
Handler for the document level 'touchstart' event,
 enables support for swipe and pinch gestures.
Handler for the document level ' touchstart ' event enables support for swipe and pinch gestures .
// If there's two touches we need to memorize the distance // between those two points to detect pinching