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@andygup
Created November 12, 2019 23:16
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touch-emulator
(function(window, document, exportName, undefined) {
"use strict";
var isMultiTouch = false;
var multiTouchStartPos;
var eventTarget;
var touchElements = {};
// polyfills
if(!document.createTouch) {
document.createTouch = function(view, target, identifier, pageX, pageY, screenX, screenY, clientX, clientY) {
// auto set
if(clientX == undefined || clientY == undefined) {
clientX = pageX - window.pageXOffset;
clientY = pageY - window.pageYOffset;
}
return new Touch(target, identifier, {
pageX: pageX,
pageY: pageY,
screenX: screenX,
screenY: screenY,
clientX: clientX,
clientY: clientY
});
};
}
if(!document.createTouchList) {
document.createTouchList = function() {
var touchList = new TouchList();
for (var i = 0; i < arguments.length; i++) {
touchList[i] = arguments[i];
}
touchList.length = arguments.length;
return touchList;
};
}
/**
* create an touch point
* @constructor
* @param target
* @param identifier
* @param pos
* @param deltaX
* @param deltaY
* @returns {Object} touchPoint
*/
function Touch(target, identifier, pos, deltaX, deltaY) {
deltaX = deltaX || 0;
deltaY = deltaY || 0;
this.identifier = identifier;
this.target = target;
this.clientX = pos.clientX + deltaX;
this.clientY = pos.clientY + deltaY;
this.screenX = pos.screenX + deltaX;
this.screenY = pos.screenY + deltaY;
this.pageX = pos.pageX + deltaX;
this.pageY = pos.pageY + deltaY;
}
/**
* create empty touchlist with the methods
* @constructor
* @returns touchList
*/
function TouchList() {
var touchList = [];
touchList.item = function(index) {
return this[index] || null;
};
// specified by Mozilla
touchList.identifiedTouch = function(id) {
return this[id + 1] || null;
};
return touchList;
}
/**
* Simple trick to fake touch event support
* this is enough for most libraries like Modernizr and Hammer
*/
function fakeTouchSupport() {
var objs = [window, document.documentElement];
var props = ['ontouchstart', 'ontouchmove', 'ontouchcancel', 'ontouchend'];
for(var o=0; o<objs.length; o++) {
for(var p=0; p<props.length; p++) {
if(objs[o] && objs[o][props[p]] == undefined) {
objs[o][props[p]] = null;
}
}
}
}
/**
* we don't have to emulate on a touch device
* @returns {boolean}
*/
function hasTouchSupport() {
return ("ontouchstart" in window) || // touch events
(window.Modernizr && window.Modernizr.touch) || // modernizr
(navigator.msMaxTouchPoints || navigator.maxTouchPoints) > 2; // pointer events
}
/**
* disable mouseevents on the page
* @param ev
*/
function preventMouseEvents(ev) {
ev.preventDefault();
ev.stopPropagation();
}
/**
* only trigger touches when the left mousebutton has been pressed
* @param touchType
* @returns {Function}
*/
function onMouse(touchType) {
return function(ev) {
// prevent mouse events
preventMouseEvents(ev);
if (ev.which !== 1) {
return;
}
// The EventTarget on which the touch point started when it was first placed on the surface,
// even if the touch point has since moved outside the interactive area of that element.
// also, when the target doesnt exist anymore, we update it
if (ev.type == 'mousedown' || !eventTarget || (eventTarget && !eventTarget.dispatchEvent)) {
eventTarget = ev.target;
}
// shiftKey has been lost, so trigger a touchend
if (isMultiTouch && !ev.shiftKey) {
triggerTouch('touchend', ev);
isMultiTouch = false;
}
triggerTouch(touchType, ev);
// we're entering the multi-touch mode!
if (!isMultiTouch && ev.shiftKey) {
isMultiTouch = true;
multiTouchStartPos = {
pageX: ev.pageX,
pageY: ev.pageY,
clientX: ev.clientX,
clientY: ev.clientY,
screenX: ev.screenX,
screenY: ev.screenY
};
triggerTouch('touchstart', ev);
}
// reset
if (ev.type == 'mouseup') {
multiTouchStartPos = null;
isMultiTouch = false;
eventTarget = null;
}
}
}
/**
* trigger a touch event
* @param eventName
* @param mouseEv
*/
function triggerTouch(eventName, mouseEv) {
var touchEvent = document.createEvent('Event');
touchEvent.initEvent(eventName, true, true);
touchEvent.altKey = mouseEv.altKey;
touchEvent.ctrlKey = mouseEv.ctrlKey;
touchEvent.metaKey = mouseEv.metaKey;
touchEvent.shiftKey = mouseEv.shiftKey;
touchEvent.touches = getActiveTouches(mouseEv, eventName);
touchEvent.targetTouches = getActiveTouches(mouseEv, eventName);
touchEvent.changedTouches = getChangedTouches(mouseEv, eventName);
eventTarget.dispatchEvent(touchEvent);
}
/**
* create a touchList based on the mouse event
* @param mouseEv
* @returns {TouchList}
*/
function createTouchList(mouseEv) {
var touchList = new TouchList();
if (isMultiTouch) {
var f = TouchEmulator.multiTouchOffset;
var deltaX = multiTouchStartPos.pageX - mouseEv.pageX;
var deltaY = multiTouchStartPos.pageY - mouseEv.pageY;
touchList.push(new Touch(eventTarget, 1, multiTouchStartPos, (deltaX*-1) - f, (deltaY*-1) + f));
touchList.push(new Touch(eventTarget, 2, multiTouchStartPos, deltaX+f, deltaY-f));
} else {
touchList.push(new Touch(eventTarget, 1, mouseEv, 0, 0));
}
return touchList;
}
/**
* receive all active touches
* @param mouseEv
* @returns {TouchList}
*/
function getActiveTouches(mouseEv, eventName) {
// empty list
if (mouseEv.type == 'mouseup') {
return new TouchList();
}
var touchList = createTouchList(mouseEv);
if(isMultiTouch && mouseEv.type != 'mouseup' && eventName == 'touchend') {
touchList.splice(1, 1);
}
return touchList;
}
/**
* receive a filtered set of touches with only the changed pointers
* @param mouseEv
* @param eventName
* @returns {TouchList}
*/
function getChangedTouches(mouseEv, eventName) {
var touchList = createTouchList(mouseEv);
// we only want to return the added/removed item on multitouch
// which is the second pointer, so remove the first pointer from the touchList
//
// but when the mouseEv.type is mouseup, we want to send all touches because then
// no new input will be possible
if(isMultiTouch && mouseEv.type != 'mouseup' &&
(eventName == 'touchstart' || eventName == 'touchend')) {
touchList.splice(0, 1);
}
return touchList;
}
/**
* show the touchpoints on the screen
*/
function showTouches(ev) {
var touch, i, el, styles;
// first all visible touches
for(i = 0; i < ev.touches.length; i++) {
touch = ev.touches[i];
el = touchElements[touch.identifier];
if(!el) {
el = touchElements[touch.identifier] = document.createElement("div");
document.body.appendChild(el);
}
styles = TouchEmulator.template(touch);
for(var prop in styles) {
el.style[prop] = styles[prop];
}
}
// remove all ended touches
if(ev.type == 'touchend' || ev.type == 'touchcancel') {
for(i = 0; i < ev.changedTouches.length; i++) {
touch = ev.changedTouches[i];
el = touchElements[touch.identifier];
if(el) {
el.parentNode.removeChild(el);
delete touchElements[touch.identifier];
}
}
}
}
/**
* TouchEmulator initializer
*/
function TouchEmulator() {
if (hasTouchSupport()) {
return;
}
fakeTouchSupport();
window.addEventListener("mousedown", onMouse('touchstart'), true);
window.addEventListener("mousemove", onMouse('touchmove'), true);
window.addEventListener("mouseup", onMouse('touchend'), true);
window.addEventListener("mouseenter", preventMouseEvents, true);
window.addEventListener("mouseleave", preventMouseEvents, true);
window.addEventListener("mouseout", preventMouseEvents, true);
window.addEventListener("mouseover", preventMouseEvents, true);
// it uses itself!
window.addEventListener("touchstart", showTouches, true);
window.addEventListener("touchmove", showTouches, true);
window.addEventListener("touchend", showTouches, true);
window.addEventListener("touchcancel", showTouches, true);
}
// start distance when entering the multitouch mode
TouchEmulator.multiTouchOffset = 75;
/**
* css template for the touch rendering
* @param touch
* @returns object
*/
TouchEmulator.template = function(touch) {
var size = 30;
var transform = 'translate('+ (touch.clientX-(size/2)) +'px, '+ (touch.clientY-(size/2)) +'px)';
return {
position: 'fixed',
left: 0,
top: 0,
background: '#fff',
border: 'solid 1px #999',
opacity: .6,
borderRadius: '100%',
height: size + 'px',
width: size + 'px',
padding: 0,
margin: 0,
display: 'block',
overflow: 'hidden',
pointerEvents: 'none',
webkitUserSelect: 'none',
mozUserSelect: 'none',
userSelect: 'none',
webkitTransform: transform,
mozTransform: transform,
transform: transform,
zIndex: 100
}
};
// export
if (typeof define == "function" && define.amd) {
define(function() {
return TouchEmulator;
});
} else if (typeof module != "undefined" && module.exports) {
module.exports = TouchEmulator;
} else {
window[exportName] = TouchEmulator;
}
})(window, document, "TouchEmulator");
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