touch.js

//     Zepto.js
//     (c) 2010-2013 Thomas Fuchs
//     Zepto.js may be freely distributed under the MIT license.

;(function($){
  var touch = {},
    touchTimeout, tapTimeout, swipeTimeout, longTapTimeout,
    longTapDelay = 750,
    gesture

  function swipeDirection(x1, x2, y1, y2) {
    return Math.abs(x1 - x2) >=
      Math.abs(y1 - y2) ? (x1 - x2 > 0 ? 'Left' : 'Right') : (y1 - y2 > 0 ? 'Up' : 'Down')
  }

  function longTap() {
    longTapTimeout = null
    if (touch.last) {
      touch.el.trigger('longTap')
      touch = {}
    }
  }

  function cancelLongTap() {
    if (longTapTimeout) clearTimeout(longTapTimeout)
    longTapTimeout = null
  }

  function cancelAll() {
    if (touchTimeout) clearTimeout(touchTimeout)
    if (tapTimeout) clearTimeout(tapTimeout)
    if (swipeTimeout) clearTimeout(swipeTimeout)
    if (longTapTimeout) clearTimeout(longTapTimeout)
    touchTimeout = tapTimeout = swipeTimeout = longTapTimeout = null
    touch = {}
  }

  function isPrimaryTouch(event){
    return event.pointerType == event.MSPOINTER_TYPE_TOUCH && event.isPrimary
  }

  $(document).ready(function(){
    var now, delta, firstTouch

    if ('MSGesture' in window) {
      gesture = new MSGesture()
      gesture.target = document.body
    }

    $(document)
      .bind('MSGestureEnd', function(e){
        var swipeDirectionFromVelocity =
          e.velocityX > 1 ? 'Right' : e.velocityX < -1 ? 'Left' : e.velocityY > 1 ? 'Down' : e.velocityY < -1 ? 'Up' : null;
        if (swipeDirectionFromVelocity) {
          touch.el.trigger('swipe')
          touch.el.trigger('swipe'+ swipeDirectionFromVelocity)
        }
      })
      .on('touchstart MSPointerDown', function(e){
        if(e.type == 'MSPointerDown' && !isPrimaryTouch(e)) return;
        firstTouch = e.type == 'MSPointerDown' ? e : e.touches[0]
        now = Date.now()
        delta = now - (touch.last || now)
        touch.el = $('tagName' in firstTouch.target ?
          firstTouch.target : firstTouch.target.parentNode)
        touchTimeout && clearTimeout(touchTimeout)
        touch.x1 = firstTouch.pageX
        touch.y1 = firstTouch.pageY
        if (delta > 0 && delta <= 250) touch.isDoubleTap = true
        touch.last = now
        longTapTimeout = setTimeout(longTap, longTapDelay)
        // adds the current touch contact for IE gesture recognition
        if (gesture && e.type == 'MSPointerDown') gesture.addPointer(e.pointerId);
      })
      .on('touchmove MSPointerMove', function(e){
        if(e.type == 'MSPointerMove' && !isPrimaryTouch(e)) return;
        firstTouch = e.type == 'MSPointerMove' ? e : e.touches[0]
        cancelLongTap()
        touch.x2 = firstTouch.pageX
        touch.y2 = firstTouch.pageY
      })
      .on('touchend MSPointerUp', function(e){
        if(e.type == 'MSPointerUp' && !isPrimaryTouch(e)) return;
        cancelLongTap()

        // swipe
        if ((touch.x2 && Math.abs(touch.x1 - touch.x2) > 30) ||
            (touch.y2 && Math.abs(touch.y1 - touch.y2) > 30))

          swipeTimeout = setTimeout(function() {
            touch.el.trigger('swipe')
            touch.el.trigger('swipe' + (swipeDirection(touch.x1, touch.x2, touch.y1, touch.y2)))
            touch = {}
          }, 0)

        // normal tap
        else if ('last' in touch)
          // delay by one tick so we can cancel the 'tap' event if 'scroll' fires
          // ('tap' fires before 'scroll')
          tapTimeout = setTimeout(function() {

            // trigger universal 'tap' with the option to cancelTouch()
            // (cancelTouch cancels processing of single vs double taps for faster 'tap' response)
            var event = $.Event('tap')
            event.cancelTouch = cancelAll
            touch.el.trigger(event)

            // trigger double tap immediately
            if (touch.isDoubleTap) {
              touch.el.trigger('doubleTap')
              touch = {}
            }

            // trigger single tap after 250ms of inactivity
            else
              touchTimeout = setTimeout(function(){
                touchTimeout = null
                touch.el.trigger('singleTap')
                touch = {}
              }, 250)

          }, 0)
      })
      // when the browser window loses focus,
      // for example when a modal dialog is shown,
      // cancel all ongoing events
      .on('touchcancel MSPointerCancel', cancelAll)

    // scrolling the window indicates intention of the user
    // to scroll, not tap or swipe, so cancel all ongoing events
    $(window).on('scroll', cancelAll)
  })

  ;['swipe', 'swipeLeft', 'swipeRight', 'swipeUp', 'swipeDown',
    'doubleTap', 'tap', 'singleTap', 'longTap'].forEach(function(eventName){
    $.fn[eventName] = function(callback){ return this.on(eventName, callback) }
  })
})(Zepto)