twis.js

/*!
 * 2-way-iScroll v2.0 ~ Copyright (c) 2011 Matteo Spinelli, http://cubiq.org
 * Released under MIT license, http://cubiq.org/license
 */

(function(){
var m = Math,
	vendor = (/webkit/i).test(navigator.appVersion) ? 'webkit' :
		(/firefox/i).test(navigator.userAgent) ? 'Moz' :
		'opera' in window ? 'O' : '',

	// Browser capabilities
	has3d = 'WebKitCSSMatrix' in window && 'm11' in new WebKitCSSMatrix(),
	hasTouch = 'ontouchstart' in window,
	hasTransform = vendor + 'Transform' in document.documentElement.style,
	isIDevice = (/iphone|ipad/gi).test(navigator.appVersion),
	isPlaybook = (/playbook/gi).test(navigator.appVersion),
	hasTransitionEnd = isIDevice || isPlaybook,
	nextFrame = (function() {
	    return window.requestAnimationFrame
			|| window.webkitRequestAnimationFrame
			|| window.mozRequestAnimationFrame
			|| window.oRequestAnimationFrame
			|| window.msRequestAnimationFrame
			|| function(callback) { return setTimeout(callback, 17); }
	})(),
	cancelFrame = (function () {
	    return window.cancelRequestAnimationFrame
			|| window.webkitCancelRequestAnimationFrame
			|| window.mozCancelRequestAnimationFrame
			|| window.oCancelRequestAnimationFrame
			|| window.msCancelRequestAnimationFrame
			|| clearTimeout
	})(),

	// Events
	RESIZE_EV = 'onorientationchange' in window ? 'orientationchange' : 'resize',
	START_EV = hasTouch ? 'touchstart' : 'mousedown',
	MOVE_EV = hasTouch ? 'touchmove' : 'mousemove',
	END_EV = hasTouch ? 'touchend' : 'mouseup',
	CANCEL_EV = hasTouch ? 'touchcancel' : 'mouseup',

	// Helpers
	trnOpen = 'translate' + (has3d ? '3d(' : '('),
	trnClose = has3d ? ',0)' : ')',

	// Constructor
	TWIS = function (wrapper, options) {
		var that = this,
			doc = document,
			i;

		that.wrapper = doc.querySelector(wrapper);
		that.wrapper.style.overflow = 'hidden';

		// Default options
		that.options = {
			slider: wrapper + ' > div',
			pages: wrapper + ' > div > div',
			hScroll: true,
			vScroll: true,
			x: 0,
			y: 0,
			bounce: true,
			bounceLock: false,
			momentum: true,
			lockDirection: true,
			useTransform: true,
			useTransition: false,

			// Events
			onRefresh: null,
			onBeforeScrollStart: function (e) { e.preventDefault(); },
			onScrollStart: null,
			onBeforeScrollMove: null,
			onScrollMove: null,
			onBeforeScrollEnd: null,
			onScrollEnd: null,
			onTouchEnd: null,
			onDestroy: null
		};

		// User defined options
		for (i in options) that.options[i] = options[i];

		that.slider = doc.querySelector(that.options.slider);
		that.pages = doc.querySelectorAll(that.options.pages);

		// Set starting position
		that.x = that.options.x;
		that.y = that.options.y;

		// Normalize options
		that.options.useTransform = hasTransform ? that.options.useTransform : false;
		that.options.hScrollbar = that.options.hScroll && that.options.hScrollbar;
		that.options.vScrollbar = that.options.vScroll && that.options.vScrollbar;
		that.options.useTransition = hasTransitionEnd && that.options.useTransition;

		// Set some default styles
		that.slider.style[vendor + 'TransitionProperty'] = that.options.useTransform ? '-' + vendor.toLowerCase() + '-transform' : 'top left';
		that.slider.style[vendor + 'TransitionDuration'] = '0';
		that.slider.style[vendor + 'TransformOrigin'] = '0 0';
		if (that.options.useTransition) that.slider.style[vendor + 'TransitionTimingFunction'] = 'cubic-bezier(0.33,0.66,0.66,1)';
		
		that.currentPage = 0;
		that.changeTarget(that.pages[that.currentPage]);

		that._bind(RESIZE_EV, window);
		that._bind(START_EV);
//		if (!hasTouch) that._bind('mouseout', that.wrapper);
	};

// Prototype
TWIS.prototype = {
	enabled: true,
	x: 0,
	y: 0,
	steps: [],
	
	handleEvent: function (e) {
		var that = this;
		switch(e.type) {
			case START_EV:
				if (!hasTouch && e.button !== 0) return;
				that._start(e);
				break;
			case MOVE_EV: that._move(e); break;
			case END_EV:
			case CANCEL_EV: that._end(e); break;
			case RESIZE_EV: that._resize(); break;
			case 'mouseout': that._mouseout(e); break;
			case 'webkitTransitionEnd': that._transitionEnd(e); break;
		}
	},

	_resize: function () {
		this.refresh();
	},
	
	_pos: function (x, y) {
		if (this.options.useTransform) {
				this.slider.style[vendor + 'Transform'] = trnOpen + x + 'px,0' + trnClose;
				this.scroller.style[vendor + 'Transform'] = trnOpen + '0,' + y + 'px' + trnClose;
		} else {
			x = m.round(x);
			this.slider.style.left = x + 'px';

			y = m.round(y);
			this.scroller.style.top = y + 'px';
		}

		this.x = x;
		this.y = y;
	},

	_start: function (e) {
		var that = this,
			point = hasTouch ? e.touches[0] : e,
			matrix, x, y;

		if (!that.enabled) return;

		if (that.options.onBeforeScrollStart) that.options.onBeforeScrollStart.call(that, e);
		
		if (that.options.useTransition) that._transitionTime(0);

		that.moved = false;
		that.animating = false;
		that.zoomed = false;
		that.distX = 0;
		that.distY = 0;
		that.absDistX = 0;
		that.absDistY = 0;
		that.dirX = 0;
		that.dirY = 0;

		if (that.options.momentum) {
			if (that.options.useTransform) {
				// Very lame general purpose alternative to CSSMatrix
				matrix = getComputedStyle(that.slider, null)[vendor + 'Transform'].replace(/[^0-9-.,]/g, '').split(',');
				x = matrix[4] * 1;

				matrix = getComputedStyle(that.scroller, null)[vendor + 'Transform'].replace(/[^0-9-.,]/g, '').split(',');
				y = matrix[5] * 1;
			} else {
				x = getComputedStyle(that.slider, null).left.replace(/[^0-9-]/g, '') * 1;
				y = getComputedStyle(that.scroller, null).top.replace(/[^0-9-]/g, '') * 1;
			}
			
			if (x != that.x || y != that.y) {
				if (that.options.useTransition) that._unbind('webkitTransitionEnd', that.scroller);
				else cancelFrame(that.aniTime);
				that.steps = [];
				that._pos(x, y);
			}
		}

		that.absStartX = that.x;	// Needed by snap threshold
		that.absStartY = that.y;

		that.startX = that.x;
		that.startY = that.y;
		that.pointX = point.pageX;
		that.pointY = point.pageY;

		that.startTime = e.timeStamp || Date.now();

		if (that.options.onScrollStart) that.options.onScrollStart.call(that, e);

		that._bind(MOVE_EV);
		that._bind(END_EV);
		that._bind(CANCEL_EV);
	},
	
	_move: function (e) {
		var that = this,
			point = hasTouch ? e.touches[0] : e,
			deltaX = point.pageX - that.pointX,
			deltaY = point.pageY - that.pointY,
			newX = that.x + deltaX,
			newY = that.y + deltaY,
			timestamp = e.timeStamp || Date.now();

		if (that.options.onBeforeScrollMove) that.options.onBeforeScrollMove.call(that, e);

		that.pointX = point.pageX;
		that.pointY = point.pageY;

		// Slow down if outside of the boundaries
		if (newX > 0 || newX < that.maxScrollX) {
			newX = that.options.bounce ? that.x + (deltaX / 2) : newX >= 0 || that.maxScrollX >= 0 ? 0 : that.maxScrollX;
		}
		if (newY > 0 || newY < that.maxScrollY) { 
			newY = that.options.bounce ? that.y + (deltaY / 2) : newY >= 0 || that.maxScrollY >= 0 ? 0 : that.maxScrollY;
		}

		if (that.absDistX < 8 && that.absDistY < 8) {
			that.distX += deltaX;
			that.distY += deltaY;
			that.absDistX = m.abs(that.distX);
			that.absDistY = m.abs(that.distY);

			return;
		}

		// Lock direction
		if (that.options.lockDirection) {
			if (that.absDistX > that.absDistY) {
				newY = that.y;
				deltaY = 0;
			} else {
				newX = that.x;
				deltaX = 0;
			}
		}

		that.moved = true;
		that._pos(newX, newY);
		that.dirX = deltaX > 0 ? -1 : deltaX < 0 ? 1 : 0;
		that.dirY = deltaY > 0 ? -1 : deltaY < 0 ? 1 : 0;

		if (timestamp - that.startTime > 300) {
			that.startTime = timestamp;
			that.startX = that.x;
			that.startY = that.y;
		}
		
		if (that.options.onScrollMove) that.options.onScrollMove.call(that, e);
	},
	
	_end: function (e) {
		if (hasTouch && e.touches.length != 0) return;

		var that = this,
			point = hasTouch ? e.changedTouches[0] : e,
			target, ev,
			momentumX = { dist:0, time:0 },
			momentumY = { dist:0, time:0 },
			duration = (e.timeStamp || Date.now()) - that.startTime,
			newPosX = that.x,
			newPosY = that.y,
			newDuration;

		that._unbind(MOVE_EV);
		that._unbind(END_EV);
		that._unbind(CANCEL_EV);

		if (that.options.onBeforeScrollEnd) that.options.onBeforeScrollEnd.call(that, e);

		if (!that.moved) {
			if (hasTouch) {
				// Find the last touched element
				target = point.target;
				while (target.nodeType != 1) target = target.parentNode;

				if (target.tagName != 'SELECT' && target.tagName != 'INPUT' && target.tagName != 'TEXTAREA') {
					ev = document.createEvent('MouseEvents');
					ev.initMouseEvent('click', true, true, e.view, 1,
						point.screenX, point.screenY, point.clientX, point.clientY,
						e.ctrlKey, e.altKey, e.shiftKey, e.metaKey,
						0, null);
					ev._fake = true;
					target.dispatchEvent(ev);
				}
			}

			that._resetPos(200);

			if (that.options.onTouchEnd) that.options.onTouchEnd.call(that, e);
			return;
		}
		
		if (that.dirX) {
			that.currentPage = -(that.dirX < 0
				? m.ceil(this.x / that.pageWidth)
				: m.floor(this.x / that.pageWidth));
				
			that.currentPage = that.currentPage <= 0 ? 0 : that.currentPage > that.pageCount-1 ? that.pageCount-1 : that.currentPage;

			newPosX = -that.currentPage * that.pageWidth;

			that.changeTarget(that.pages[that.currentPage]);

//			newPosX = newPosX >= 0 ? 0 : newPosX < that.maxScrollX ? that.maxScrollX : newPosX;

			that.scrollTo(newPosX, that.y, 400);

			if (that.options.onTouchEnd) that.options.onTouchEnd.call(that, e);
			return;
		}

		if (that.dirY && duration < 300 && that.options.momentum) {
			momentumY = newPosY ? that._momentum(newPosY - that.startY, duration, -that.y, (that.maxScrollY < 0 ? that.scrollerH - that.wrapperH + that.y : 0), that.options.bounce ? that.wrapperH : 0) : momentumY;

			newPosY = that.y + momentumY.dist;

			if ((that.y > 0 && newPosY > 0) || (that.y < that.maxScrollY && newPosY < that.maxScrollY)) momentumY = { dist:0, time:0 };
		}

		if (momentumY.dist) {
			newDuration = m.max(momentumY.time, 10);

			that.scrollTo(that.x, m.round(newPosY), newDuration);

			if (that.options.onTouchEnd) that.options.onTouchEnd.call(that, e);
			return;
		}

		that._resetPos(200);
		if (that.options.onTouchEnd) that.options.onTouchEnd.call(that, e);
	},
	
	_resetPos: function (time) {
		var that = this,
			resetX = that.x >= 0 ? 0 : that.x < that.maxScrollX ? that.maxScrollX : that.x,
			resetY = that.y >= 0 || that.maxScrollY > 0 ? 0 : that.y < that.maxScrollY ? that.maxScrollY : that.y;

		if (resetX == that.x && resetY == that.y) {
			if (that.moved) {
				if (that.options.onScrollEnd) that.options.onScrollEnd.call(that);		// Execute custom code on scroll end
				that.moved = false;
			}

			return;
		}

		that.scrollTo(resetX, resetY, time || 0);
	},
	
	_mouseout: function (e) {
		var t = e.relatedTarget;

		if (!t) {
			this._end(e);
			return;
		}

		while (t = t.parentNode) if (t == this.wrapper) return;
		
		this._end(e);
	},

	_transitionEnd: function (e) {
		var that = this;

		if (e.target != that.scroller) return;

		that._unbind('webkitTransitionEnd', that.scroller);
		
		that._startAni();
	},

	/**
	 *
	 * Utilities
	 *
	 */
	_startAni: function () {
		var that = this,
			startX = that.x, startY = that.y,
			startTime = Date.now(),
			step, easeOut,
			animate;

		if (that.animating) return;

		if (!that.steps.length) {
			that._resetPos(400);
			return;
		}

		step = that.steps.shift();

		if (step.x == startX && step.y == startY) step.time = 0;

		that.animating = true;
		that.moved = true;

		if (that.options.useTransition) {
			that._transitionTime(step.time);
			that._pos(step.x, step.y);
			that.animating = false;
			if (step.time) that._bind('webkitTransitionEnd', that.scroller);
			else that._resetPos(0);
			return;
		}
		
		animate = function () {
			var now = Date.now(),
				newX, newY;

			if (now >= startTime + step.time) {
				that._pos(step.x, step.y);
				that.animating = false;
				if (that.options.onAnimationEnd) that.options.onAnimationEnd.call(that);			// Execute custom code on animation end
				that._startAni();
				return;
			}

			now = (now - startTime) / step.time - 1;
			easeOut = m.sqrt(1 - now * now);
			newX = (step.x - startX) * easeOut + startX;
			newY = (step.y - startY) * easeOut + startY;
			that._pos(newX, newY);
			if (that.animating) that.aniTime = nextFrame(animate);
		};
		
		animate();
	},

	_transitionTime: function (time) {
		this.scroller.style[vendor + 'TransitionDuration'] = time + 'ms';
	},
	
	_momentum: function (dist, time, maxDistUpper, maxDistLower, size) {
		var deceleration = 0.0006,
			speed = m.abs(dist) / time,
			newDist = (speed * speed) / (2 * deceleration),
			newTime = 0, outsideDist = 0;

		// Proportinally reduce speed if we are outside of the boundaries 
		if (dist > 0 && newDist > maxDistUpper) {
			outsideDist = size / (6 / (newDist / speed * deceleration));
			maxDistUpper = maxDistUpper + outsideDist;
			speed = speed * maxDistUpper / newDist;
			newDist = maxDistUpper;
		} else if (dist < 0 && newDist > maxDistLower) {
			outsideDist = size / (6 / (newDist / speed * deceleration));
			maxDistLower = maxDistLower + outsideDist;
			speed = speed * maxDistLower / newDist;
			newDist = maxDistLower;
		}

		newDist = newDist * (dist < 0 ? -1 : 1);
		newTime = speed / deceleration;

		return { dist: newDist, time: m.round(newTime) };
	},

	_offset: function (el) {
		var left = -el.offsetLeft,
			top = -el.offsetTop;
			
		while (el = el.offsetParent) {
			left -= el.offsetLeft;
			top -= el.offsetTop;
		} 

		return { left: left, top: top };
	},

	_bind: function (type, el, bubble) {
		(el || this.wrapper).addEventListener(type, this, !!bubble);
	},

	_unbind: function (type, el, bubble) {
		(el || this.wrapper).removeEventListener(type, this, !!bubble);
	},


	/**
	 *
	 * Public methods
	 *
	 */
	changeTarget: function (target) {
		var that = this, matrix;

		if (that.scroller) {
			that.stop();
			that.refresh();
		}

		that.scroller = target;

		matrix = getComputedStyle(that.scroller, null)[vendor + 'Transform'].replace(/[^0-9-.,]/g, '').split(',');
		that.y = matrix[5] * 1 || 0;

		// Set some default styles
		that.scroller.style[vendor + 'TransitionProperty'] = that.options.useTransform ? '-' + vendor.toLowerCase() + '-transform' : 'top left';
		that.scroller.style[vendor + 'TransitionDuration'] = '0';
		that.scroller.style[vendor + 'TransformOrigin'] = '0 0';
		if (that.options.useTransition) that.scroller.style[vendor + 'TransitionTimingFunction'] = 'cubic-bezier(0.33,0.66,0.66,1)';

		if (that.options.useTransform) that.scroller.style[vendor + 'Transform'] = trnOpen + '0,' + that.y + 'px' + trnClose;
		else that.scroller.style.cssText += ';position:absolute;top:' + that.y + 'px;left:0px';

		that.refresh();
	},
	
	destroy: function () {
		var that = this;

		that.scroller.style[vendor + 'Transform'] = '';

		// Remove the event listeners
		that._unbind(RESIZE_EV, window);
		that._unbind(START_EV);
		that._unbind(MOVE_EV);
		that._unbind(END_EV);
		that._unbind(CANCEL_EV);
		that._unbind('mouseout', that.wrapper);
		if (that.options.useTransition) that._unbind('webkitTransitionEnd', that.scroller);
		
		if (that.options.onDestroy) that.options.onDestroy.call(that);
	},

	refresh: function () {
		var that = this,
			offset;

		that.wrapperW = that.wrapper.clientWidth;
		that.wrapperH = that.wrapper.clientHeight;
		
		that.pageWidth = that.pages[0].offsetWidth;
		that.pageCount = that.pages.length;

		that.scrollerW = that.slider.offsetWidth;
		that.scrollerH = that.scroller.offsetHeight;

		that.maxScrollX = that.wrapperW - that.scrollerW;
		that.maxScrollY = that.wrapperH - that.scrollerH;

		that.dirX = 0;
		that.dirY = 0;

		that.hScroll = that.options.hScroll && that.maxScrollX < 0;
		that.vScroll = that.options.vScroll && (!that.options.bounceLock && !that.hScroll || that.scrollerH > that.wrapperH);

		offset = that._offset(that.wrapper);
		that.wrapperOffsetLeft = -offset.left;
		that.wrapperOffsetTop = -offset.top;

		that.slider.style[vendor + 'TransitionDuration'] = '0';
		that.scroller.style[vendor + 'TransitionDuration'] = '0';

		that._resetPos(200);
	},
	
	scrollToPage: function (page, time) {
		time = time || 0;
		if (page < 0) page = 0;
		else if (page > this.pages.length-1) page = this.pages.length-1;

		this.changeTarget(this.pages[page]);

		this.scrollTo(-page*this.pageWidth, this.y, time);
	},
	
	scrollY: function (pos, time) {
		time = time || 0;
		if (pos > 0) pos = 0;
		else if (pos < this.maxScrollY) pos = this.maxScrollY;

		this.scrollTo(this.x, pos, time);
	},

	scrollTo: function (x, y, time, relative) {
		var that = this,
			step = x,
			i, l;

		that.stop();

		if (!step.length) step = [{ x: x, y: y, time: time, relative: relative }];
		
		for (i=0, l=step.length; i<l; i++) {
			if (step[i].relative) { step[i].x = that.x - step[i].x; step[i].y = that.y - step[i].y; }
			that.steps.push({ x: step[i].x, y: step[i].y, time: step[i].time || 0 });
		}

		that._startAni();
	},

	scrollToElement: function (el, time) {
		var that = this, pos;
		el = el.nodeType ? el : that.scroller.querySelector(el);
		if (!el) return;

		pos = that._offset(el);
		pos.left += that.wrapperOffsetLeft;
		pos.top += that.wrapperOffsetTop;

		pos.left = pos.left > 0 ? 0 : pos.left < that.maxScrollX ? that.maxScrollX : pos.left;
		pos.top = pos.top > 0 ? 0 : pos.top < that.maxScrollY ? that.maxScrollY : pos.top;
		time = time === undefined ? m.max(m.abs(pos.left)*2, m.abs(pos.top)*2) : time;

		that.scrollTo(pos.left, pos.top, time);
	},

	disable: function () {
		this.stop();
		this._resetPos(0);
		this.enabled = false;

		// If disabled after touchstart we make sure that there are no left over events
		this._unbind(MOVE_EV);
		this._unbind(END_EV);
		this._unbind(CANCEL_EV);
	},
	
	enable: function () {
		this.enabled = true;
	},
	
	stop: function () {
		cancelFrame(this.aniTime);
		this.steps = [];
		this.moved = false;
		this.animating = false;
	}
};

if (typeof exports !== 'undefined') exports.TWIS = TWIS;
else window.TWIS = TWIS;

})();