websch/editor/taphold.js

136 lines
4.3 KiB
JavaScript

/**
* Copyright (c) 2011 Zauber S.A. <http://www.zaubersoftware.com/>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* @author Guido Marucci Blas - guido@zaubersoftware.com
* @description Adds a handler for a custom event 'taphold' that handles a
* tap and hold on touch interfaces.
*/
(function($) {
var TAP_AND_HOLD_TRIGGER_TIMER = 1000;
var MAX_DISTANCE_ALLOWED_IN_TAP_AND_HOLD_EVENT = 5;
var TOUCHSTART = "touchstart";
var TOUCHEND = "touchend";
var TOUCHMOVE = "touchmove";
// For debugging only
// var TOUCHSTART = "mousedown";
// var TOUCHEND = "mouseup";
// var TOUCHMOVE = "mousemove";
var tapAndHoldTimer = null;
function calculateEuclideanDistance(x1, y1, x2, y2) {
var diffX = (x2 - x1);
var diffY = (y2 - y1);
return Math.sqrt((diffX * diffX) + (diffY * diffY));
};
function onTouchStart(event) {
var e = event.originalEvent;
// Only start detector if and only if one finger is over the widget
if (!e.touches || (e.targetTouches.length === 1 && e.touches.length === 1)) {
startTapAndHoldDetector.call(this, event)
var element = $(this);
element.bind(TOUCHMOVE, onTouchMove);
element.bind(TOUCHEND, onTouchEnd);
} else {
stopTapAndHoldDetector.call(this);
}
};
function onTouchMove(event) {
if (tapAndHoldTimer == null) {
return;
}
var e = event.originalEvent;
var x = (e.changedTouches) ? e.changedTouches[0].pageX: e.pageX;
var y = (e.changedTouches) ? e.changedTouches[0].pageY: e.pageY;
var tapAndHoldPoint = $(this).data("taphold.point");
var euclideanDistance = calculateEuclideanDistance(tapAndHoldPoint.x, tapAndHoldPoint.y, x, y);
if (euclideanDistance > MAX_DISTANCE_ALLOWED_IN_TAP_AND_HOLD_EVENT) {
stopTapAndHoldDetector.call(this);
}
};
function onTouchEnd(event) {
stopTapAndHoldDetector.call(this);
};
function onTapAndHold(event) {
clear.call(this);
$(this).data("taphold.handler").call(this, event);
};
function clear() {
tapAndHoldTimer = null;
$(this).unbind(TOUCHMOVE, onTouchMove);
$(this).unbind(TOUCHEND, onTouchEnd);
};
function startTapAndHoldDetector(event) {
if (tapAndHoldTimer != null) {
return;
}
var self = this;
tapAndHoldTimer = setTimeout(function(){
onTapAndHold.call(self, event)
}, TAP_AND_HOLD_TRIGGER_TIMER);
// Stores tap x & y
var e = event.originalEvent;
var tapAndHoldPoint = {};
tapAndHoldPoint.x = (e.changedTouches) ? e.changedTouches[0].pageX: e.pageX;
tapAndHoldPoint.y = (e.changedTouches) ? e.changedTouches[0].pageY: e.pageY;
$(this).data("taphold.point", tapAndHoldPoint);
};
function stopTapAndHoldDetector() {
clearTimeout(tapAndHoldTimer);
clear.call(this);
};
$.event.special["taphold"] = {
setup: function() {
},
add: function(handleObj) {
$(this).data("taphold.handler", handleObj.handler);
if (handleObj.data) {
$(this).bind(TOUCHSTART, handleObj.data, onTouchStart);
} else {
$(this).bind(TOUCHSTART, onTouchStart);
}
},
remove: function(handleObj) {
stopTapAndHoldDetector.call(this);
if (handleObj.data) {
$(this).unbind(TOUCHSTART, handleObj.data, onTouchStart);
} else {
$(this).unbind(TOUCHSTART, onTouchStart);
}
},
teardown: function() {
}
};
})(jQuery);