vczero.github.io/meitu/js/lib/fastclick.js

define('lib/fastclick', function(require, exports, module) {
function FastClick(layer) {
	'use strict';
	var oldOnClick;
	this.trackingClick = false;
	this.trackingClickStart = 0;
	this.targetElement = null;
	this.touchStartX = 0;
	this.touchStartY = 0;
	this.lastTouchIdentifier = 0;
	this.touchBoundary = 10;
	this.layer = layer;

	if (FastClick.notNeeded(layer)) {
		return;
	}
	function bind(method, context) {
		return function() { return method.apply(context, arguments); };
	}
	if (deviceIsAndroid) {
		layer.addEventListener('mouseover', bind(this.onMouse, this), true);
		layer.addEventListener('mousedown', bind(this.onMouse, this), true);
		layer.addEventListener('mouseup', bind(this.onMouse, this), true);
	}

	layer.addEventListener('click', bind(this.onClick, this), true);
	layer.addEventListener('touchstart', bind(this.onTouchStart, this), false);
	layer.addEventListener('touchmove', bind(this.onTouchMove, this), false);
	layer.addEventListener('touchend', bind(this.onTouchEnd, this), false);
	layer.addEventListener('touchcancel', bind(this.onTouchCancel, this), false);

	if (!Event.prototype.stopImmediatePropagation) {
		layer.removeEventListener = function(type, callback, capture) {
			var rmv = Node.prototype.removeEventListener;
			if (type === 'click') {
				rmv.call(layer, type, callback.hijacked || callback, capture);
			} else {
				rmv.call(layer, type, callback, capture);
			}
		};

		layer.addEventListener = function(type, callback, capture) {
			var adv = Node.prototype.addEventListener;
			if (type === 'click') {
				adv.call(layer, type, callback.hijacked || (callback.hijacked = function(event) {
					if (!event.propagationStopped) {
						callback(event);
					}
				}), capture);
			} else {
				adv.call(layer, type, callback, capture);
			}
		};
	}
	if (typeof layer.onclick === 'function') {
		oldOnClick = layer.onclick;
		layer.addEventListener('click', function(event) {
			oldOnClick(event);
		}, false);
		layer.onclick = null;
	}
}

var deviceIsAndroid = navigator.userAgent.indexOf('Android') > 0;
var deviceIsIOS = /iP(ad|hone|od)/.test(navigator.userAgent);
var deviceIsIOS4 = deviceIsIOS && (/OS 4_\d(_\d)?/).test(navigator.userAgent);
var deviceIsIOSWithBadTarget = deviceIsIOS && (/OS ([6-9]|\d{2})_\d/).test(navigator.userAgent);
FastClick.prototype.needsClick = function(target) {
	'use strict';
	switch (target.nodeName.toLowerCase()) {
	case 'button':
	case 'select':
	case 'textarea':
		if (target.disabled) {
			return true;
		}

		break;
	case 'input':
		if ((deviceIsIOS && target.type === 'file') || target.disabled) {
			return true;
		}

		break;
	case 'label':
	case 'video':
		return true;
	}

	return (/\bneedsclick\b/).test(target.className);
};

FastClick.prototype.needsFocus = function(target) {
	'use strict';
	switch (target.nodeName.toLowerCase()) {
	case 'textarea':
		return true;
	case 'select':
		return !deviceIsAndroid;
	case 'input':
		switch (target.type) {
		case 'button':
		case 'checkbox':
		case 'file':
		case 'image':
		case 'radio':
		case 'submit':
			return false;
		}

		// No point in attempting to focus disabled inputs
		return !target.disabled && !target.readOnly;
	default:
		return (/\bneedsfocus\b/).test(target.className);
	}
};
FastClick.prototype.sendClick = function(targetElement, event) {
	'use strict';
	var clickEvent, touch;
	if (document.activeElement && document.activeElement !== targetElement) {
		document.activeElement.blur();
	}

	touch = event.changedTouches[0];
	clickEvent = document.createEvent('MouseEvents');
	clickEvent.initMouseEvent(this.determineEventType(targetElement), true, true, window, 1, touch.screenX, touch.screenY, touch.clientX, touch.clientY, false, false, false, false, 0, null);
	clickEvent.forwardedTouchEvent = true;
	targetElement.dispatchEvent(clickEvent);
};

FastClick.prototype.determineEventType = function(targetElement) {
	'use strict';

	if (deviceIsAndroid && targetElement.tagName.toLowerCase() === 'select') {
		return 'mousedown';
	}

	return 'click';
};

FastClick.prototype.focus = function(targetElement) {
	'use strict';
	var length;
	if (deviceIsIOS && targetElement.setSelectionRange && targetElement.type.indexOf('date') !== 0 && targetElement.type !== 'time') {
		length = targetElement.value.length;
		targetElement.setSelectionRange(length, length);
	} else {
		targetElement.focus();
	}
};


/**
 * Check whether the given target element is a child of a scrollable layer and if so, set a flag on it.
 *
 * @param {EventTarget|Element} targetElement
 */
FastClick.prototype.updateScrollParent = function(targetElement) {
	'use strict';
	var scrollParent, parentElement;

	scrollParent = targetElement.fastClickScrollParent;

	// Attempt to discover whether the target element is contained within a scrollable layer. Re-check if the
	// target element was moved to another parent.
	if (!scrollParent || !scrollParent.contains(targetElement)) {
		parentElement = targetElement;
		do {
			if (parentElement.scrollHeight > parentElement.offsetHeight) {
				scrollParent = parentElement;
				targetElement.fastClickScrollParent = parentElement;
				break;
			}

			parentElement = parentElement.parentElement;
		} while (parentElement);
	}

	// Always update the scroll top tracker if possible.
	if (scrollParent) {
		scrollParent.fastClickLastScrollTop = scrollParent.scrollTop;
	}
};

FastClick.prototype.getTargetElementFromEventTarget = function(eventTarget) {
	'use strict';

	// On some older browsers (notably Safari on iOS 4.1 - see issue #56) the event target may be a text node.
	if (eventTarget.nodeType === Node.TEXT_NODE) {
		return eventTarget.parentNode;
	}

	return eventTarget;
};
FastClick.prototype.onTouchStart = function(event) {
	'use strict';
	var targetElement, touch, selection;

	// Ignore multiple touches, otherwise pinch-to-zoom is prevented if both fingers are on the FastClick element (issue #111).
	if (event.targetTouches.length > 1) {
		return true;
	}

	targetElement = this.getTargetElementFromEventTarget(event.target);
	touch = event.targetTouches[0];

	if (deviceIsIOS) {

		// Only trusted events will deselect text on iOS (issue #49)
		selection = window.getSelection();
		if (selection.rangeCount && !selection.isCollapsed) {
			return true;
		}

		if (!deviceIsIOS4) {
			if (touch.identifier === this.lastTouchIdentifier) {
				event.preventDefault();
				return false;
			}

			this.lastTouchIdentifier = touch.identifier;
			this.updateScrollParent(targetElement);
		}
	}

	this.trackingClick = true;
	this.trackingClickStart = event.timeStamp;
	this.targetElement = targetElement;

	this.touchStartX = touch.pageX;
	this.touchStartY = touch.pageY;

	// Prevent phantom clicks on fast double-tap (issue #36)
	if ((event.timeStamp - this.lastClickTime) < 200) {
		event.preventDefault();
	}

	return true;
};


/**
 * Based on a touchmove event object, check whether the touch has moved past a boundary since it started.
 *
 * @param {Event} event
 * @returns {boolean}
 */
FastClick.prototype.touchHasMoved = function(event) {
	'use strict';
	var touch = event.changedTouches[0], boundary = this.touchBoundary;

	if (Math.abs(touch.pageX - this.touchStartX) > boundary || Math.abs(touch.pageY - this.touchStartY) > boundary) {
		return true;
	}

	return false;
};


/**
 * Update the last position.
 *
 * @param {Event} event
 * @returns {boolean}
 */
FastClick.prototype.onTouchMove = function(event) {
	'use strict';
	if (!this.trackingClick) {
		return true;
	}

	// If the touch has moved, cancel the click tracking
	if (this.targetElement !== this.getTargetElementFromEventTarget(event.target) || this.touchHasMoved(event)) {
		this.trackingClick = false;
		this.targetElement = null;
	}

	return true;
};


/**
 * Attempt to find the labelled control for the given label element.
 *
 * @param {EventTarget|HTMLLabelElement} labelElement
 * @returns {Element|null}
 */
FastClick.prototype.findControl = function(labelElement) {
	'use strict';

	// Fast path for newer browsers supporting the HTML5 control attribute
	if (labelElement.control !== undefined) {
		return labelElement.control;
	}

	// All browsers under test that support touch events also support the HTML5 htmlFor attribute
	if (labelElement.htmlFor) {
		return document.getElementById(labelElement.htmlFor);
	}

	// If no for attribute exists, attempt to retrieve the first labellable descendant element
	// the list of which is defined here: http://www.w3.org/TR/html5/forms.html#category-label
	return labelElement.querySelector('button, input:not([type=hidden]), keygen, meter, output, progress, select, textarea');
};


/**
 * On touch end, determine whether to send a click event at once.
 *
 * @param {Event} event
 * @returns {boolean}
 */
FastClick.prototype.onTouchEnd = function(event) {
	'use strict';
	var forElement, trackingClickStart, targetTagName, scrollParent, touch, targetElement = this.targetElement;

	if (!this.trackingClick) {
		return true;
	}

	// Prevent phantom clicks on fast double-tap (issue #36)
	if ((event.timeStamp - this.lastClickTime) < 200) {
		this.cancelNextClick = true;
		return true;
	}

	// Reset to prevent wrong click cancel on input (issue #156).
	this.cancelNextClick = false;

	this.lastClickTime = event.timeStamp;

	trackingClickStart = this.trackingClickStart;
	this.trackingClick = false;
	this.trackingClickStart = 0;

	// On some iOS devices, the targetElement supplied with the event is invalid if the layer
	// is performing a transition or scroll, and has to be re-detected manually. Note that
	// for this to function correctly, it must be called *after* the event target is checked!
	// See issue #57; also filed as rdar://13048589 .
	if (deviceIsIOSWithBadTarget) {
		touch = event.changedTouches[0];

		// In certain cases arguments of elementFromPoint can be negative, so prevent setting targetElement to null
		targetElement = document.elementFromPoint(touch.pageX - window.pageXOffset, touch.pageY - window.pageYOffset) || targetElement;
		targetElement.fastClickScrollParent = this.targetElement.fastClickScrollParent;
	}

	targetTagName = targetElement.tagName.toLowerCase();
	if (targetTagName === 'label') {
		forElement = this.findControl(targetElement);
		if (forElement) {
			this.focus(targetElement);
			if (deviceIsAndroid) {
				return false;
			}

			targetElement = forElement;
		}
	} else if (this.needsFocus(targetElement)) {

		if ((event.timeStamp - trackingClickStart) > 100 || (deviceIsIOS && window.top !== window && targetTagName === 'input')) {
			this.targetElement = null;
			return false;
		}

		this.focus(targetElement);
		this.sendClick(targetElement, event);

		// Select elements need the event to go through on iOS 4, otherwise the selector menu won't open.
		if (!deviceIsIOS4 || targetTagName !== 'select') {
			this.targetElement = null;
			event.preventDefault();
		}

		return false;
	}

	if (deviceIsIOS && !deviceIsIOS4) {
		scrollParent = targetElement.fastClickScrollParent;
		if (scrollParent && scrollParent.fastClickLastScrollTop !== scrollParent.scrollTop) {
			return true;
		}
	}
	if (!this.needsClick(targetElement)) {
		event.preventDefault();
		this.sendClick(targetElement, event);
	}

	return false;
};


/**
 * On touch cancel, stop tracking the click.
 *
 * @returns {void}
 */
FastClick.prototype.onTouchCancel = function() {
	'use strict';
	this.trackingClick = false;
	this.targetElement = null;
};


/**
 * Determine mouse events which should be permitted.
 *
 * @param {Event} event
 * @returns {boolean}
 */
FastClick.prototype.onMouse = function(event) {
	'use strict';

	// If a target element was never set (because a touch event was never fired) allow the event
	if (!this.targetElement) {
		return true;
	}

	if (event.forwardedTouchEvent) {
		return true;
	}

	// Programmatically generated events targeting a specific element should be permitted
	if (!event.cancelable) {
		return true;
	}

	// Derive and check the target element to see whether the mouse event needs to be permitted;
	// unless explicitly enabled, prevent non-touch click events from triggering actions,
	// to prevent ghost/doubleclicks.
	if (!this.needsClick(this.targetElement) || this.cancelNextClick) {

		// Prevent any user-added listeners declared on FastClick element from being fired.
		if (event.stopImmediatePropagation) {
			event.stopImmediatePropagation();
		} else {

			// Part of the hack for browsers that don't support Event#stopImmediatePropagation (e.g. Android 2)
			event.propagationStopped = true;
		}

		// Cancel the event
		event.stopPropagation();
		event.preventDefault();

		return false;
	}

	// If the mouse event is permitted, return true for the action to go through.
	return true;
};
FastClick.prototype.onClick = function(event) {
	'use strict';
	var permitted;
	if (this.trackingClick) {
		this.targetElement = null;
		this.trackingClick = false;
		return true;
	}
	if (event.target.type === 'submit' && event.detail === 0) {
		return true;
	}

	permitted = this.onMouse(event);
	if (!permitted) {
		this.targetElement = null;
	}
	return permitted;
};
FastClick.prototype.destroy = function() {
	'use strict';
	var layer = this.layer;

	if (deviceIsAndroid) {
		layer.removeEventListener('mouseover', this.onMouse, true);
		layer.removeEventListener('mousedown', this.onMouse, true);
		layer.removeEventListener('mouseup', this.onMouse, true);
	}

	layer.removeEventListener('click', this.onClick, true);
	layer.removeEventListener('touchstart', this.onTouchStart, false);
	layer.removeEventListener('touchmove', this.onTouchMove, false);
	layer.removeEventListener('touchend', this.onTouchEnd, false);
	layer.removeEventListener('touchcancel', this.onTouchCancel, false);
};
FastClick.notNeeded = function(layer) {
	'use strict';
	var metaViewport;
	var chromeVersion;
	if (typeof window.ontouchstart === 'undefined') {
		return true;
	}
	chromeVersion = +(/Chrome\/([0-9]+)/.exec(navigator.userAgent) || [,0])[1];

	if (chromeVersion) {

		if (deviceIsAndroid) {
			metaViewport = document.querySelector('meta[name=viewport]');

			if (metaViewport) {
				// Chrome on Android with user-scalable="no" doesn't need FastClick (issue #89)
				if (metaViewport.content.indexOf('user-scalable=no') !== -1) {
					return true;
				}
				// Chrome 32 and above with width=device-width or less don't need FastClick
				if (chromeVersion > 31 && window.innerWidth <= window.screen.width) {
					return true;
				}
			}

		// Chrome desktop doesn't need FastClick (issue #15)
		} else {
			return true;
		}
	}
	if (layer.style.msTouchAction === 'none') {
		return true;
	}

	return false;
};

FastClick.attach = function(layer) {
	'use strict';
	return new FastClick(layer);
};

module.exports = FastClick.attach;
module.exports.FastClick = FastClick;

});