jquery.scrollify.js

/*!
 * jQuery Scrollify
 * Version 1.0.17
 *
 * Requires:
 * - jQuery 1.7 or higher
 *
 * https://github.com/lukehaas/Scrollify
 *
 * Copyright 2016, Luke Haas
 * Permission is hereby granted, free of charge, to any person obtaining a copy of
 * this software and associated documentation files (the "Software"), to deal in
 * the Software without restriction, including without limitation the rights to
 * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
 * the Software, and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
 * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
 * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
 * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.



if touchScroll is false - update index

 */
(function (global,factory) {
	"use strict";
	if (typeof define === 'function' && define.amd) {
		// AMD. Register as an anonymous module.
		define(['jquery'], function($) {
			return factory($, global, global.document);
		});
	} else if (typeof module === 'object' && module.exports) {
		// Node/CommonJS
		module.exports = factory(require('jquery'), global, global.document);
	} else {
		// Browser globals
		factory(jQuery, global, global.document);
	}
}(typeof window !== 'undefined' ? window : this, function ($, window, document, undefined) {
	"use strict";
	var heights = [],
		names = [],
		elements = [],
		overflow = [],
		index = 0,
		currentIndex = 0,
		interstitialIndex = 1,
		hasLocation = false,
		timeoutId,
		timeoutId2,
		$window = $(window),
		top = $window.scrollTop(),
		scrollable = false,
		locked = false,
		scrolled = false,
		manualScroll,
		swipeScroll,
		util,
		disabled = false,
		scrollSamples = [],
		scrollTime = new Date().getTime(),
		firstLoad = true,
		initialised = false,
		destination = 0,
		wheelEvent = 'onwheel' in document ? 'wheel' : document.onmousewheel !== undefined ? 'mousewheel' : 'DOMMouseScroll',
		settings = {
			//section should be an identifier that is the same for each section
			section: ".section",
			sectionName: "section-name",
			interstitialSection: "",
			easing: "easeOutExpo",
			scrollSpeed: 1100,
			offset: 0,
			scrollbars: true,
			target:"html,body",
			standardScrollElements: false,
			setHeights: true,
			overflowScroll:true,
			updateHash: true,
			touchScroll:true,
			before:function() {},
			after:function() {},
			afterResize:function() {},
			afterRender:function() {}
		};
	function animateScroll(index,instant,callbacks,toTop) {
		if(currentIndex===index) {
			callbacks = false;
		}
		if(disabled===true) {
			return true;
		}
		if(names[index]) {
			scrollable = false;
			if(callbacks) {
				settings.before(index,elements);
			}
			interstitialIndex = 1;
			destination = heights[index];
			if(firstLoad===false && currentIndex>index && toTop===false) {
				//We're going backwards
				if(overflow[index]) {

					interstitialIndex = parseInt(elements[index].outerHeight()/$window.height());

					destination = parseInt(heights[index])+(elements[index].outerHeight()-$window.height());
				}
			}


			if(settings.updateHash && settings.sectionName && !(firstLoad===true && index===0)) {
				if(history.pushState) {
				    try {
							history.replaceState(null, null, names[index]);
				    } catch (e) {
				    	if(window.console) {
				    		console.warn("Scrollify warning: Page must be hosted to manipulate the hash value.");
				    	}
				    }

				} else {
					window.location.hash = names[index];
				}
			}
			if(firstLoad) {
					settings.afterRender();
					firstLoad = false;
			}


			currentIndex = index;
			if(instant) {
				$(settings.target).stop().scrollTop(destination);
				if(callbacks) {
					settings.after(index,elements);
				}
			} else {
				locked = true;
				if( $().velocity ) {
					$(settings.target).stop().velocity('scroll', {
					  duration: settings.scrollSpeed,
					  easing: settings.easing,
					  offset: destination,
					  mobileHA: false
				  });
				} else {
					$(settings.target).stop().animate({
						scrollTop: destination
					}, settings.scrollSpeed,settings.easing);
				}

				if(window.location.hash.length && settings.sectionName && window.console) {
					try {
						if($(window.location.hash).length) {
							console.warn("Scrollify warning: ID matches hash value - this will cause the page to anchor.");
						}
					} catch (e) {}
				}
				$(settings.target).promise().done(function(){
					locked = false;
					firstLoad = false;
					if(callbacks) {
						settings.after(index,elements);
					}
				});
			}

		}
	}

	function isAccelerating(samples) {
				function average(num) {
					var sum = 0;

					var lastElements = samples.slice(Math.max(samples.length - num, 1));

          for(var i = 0; i < lastElements.length; i++){
              sum += lastElements[i];
          }

          return Math.ceil(sum/num);
				}

				var avEnd = average(10);
        var avMiddle = average(70);

        if(avEnd >= avMiddle) {
					return true;
				} else {
					return false;
				}
	}
	var scrollify = function(options) {
		initialised = true;
		$.easing['easeOutExpo'] = function(x, t, b, c, d) {
			return (t==d) ? b+c : c * (-Math.pow(2, -10 * t/d) + 1) + b;
		};

		manualScroll = {
			handleMousedown:function() {
				if(disabled===true) {
					return true;
				}
				scrollable = false;
				scrolled = false;
			},
			handleMouseup:function() {
				if(disabled===true) {
					return true;
				}
				scrollable = true;
				if(scrolled) {
					//instant,callbacks
					manualScroll.calculateNearest(false,true);
				}
			},
			handleScroll:function() {
				if(disabled===true) {
					return true;
				}
				if(timeoutId){
					clearTimeout(timeoutId);
				}

				timeoutId = setTimeout(function(){
					scrolled = true;
					if(scrollable===false) {
						return false;
					}
					scrollable = false;
					//instant,callbacks
					manualScroll.calculateNearest(false,true);
				}, 200);
			},
			calculateNearest:function(instant,callbacks) {
				top = $window.scrollTop();
				var i =1,
					max = heights.length,
					closest = 0,
					prev = Math.abs(heights[0] - top),
					diff;
				for(;i<max;i++) {
					diff = Math.abs(heights[i] - top);

					if(diff < prev) {
						prev = diff;
						closest = i;
					}
				}
				if((atBottom() && closest>index) || atTop()) {
					index = closest;
					//index, instant, callbacks, toTop
					animateScroll(closest,instant,callbacks,false);
				}
			},
			wheelHandler:function(e) {
				if(disabled===true) {
					return true;
				} else if(settings.standardScrollElements) {
					if($(e.target).is(settings.standardScrollElements) || $(e.target).closest(settings.standardScrollElements).length) {
						return true;
					}
				}
				if(!overflow[index]) {
					e.preventDefault();
				}
				var currentScrollTime = new Date().getTime();



				e = e || window.event;
				var value = e.originalEvent.wheelDelta || -e.originalEvent.deltaY || -e.originalEvent.detail;
				var delta = Math.max(-1, Math.min(1, value));



				//delta = delta || -e.originalEvent.detail / 3 || e.originalEvent.wheelDelta / 120;


				if(scrollSamples.length > 149){
					scrollSamples.shift();
				}
				//scrollSamples.push(Math.abs(delta*10));
				scrollSamples.push(Math.abs(value));

				if((currentScrollTime-scrollTime) > 200){
					scrollSamples = [];
				}
				scrollTime = currentScrollTime;


				if(locked) {
					return false;
				}
				if(delta<0) {
					if(index<heights.length-1) {
						if(atBottom()) {
							if(isAccelerating(scrollSamples)) {
								e.preventDefault();
								index++;
								locked = true;
								//index, instant, callbacks, toTop
								animateScroll(index,false,true, false);
							} else {
								return false;
							}
						}
					}
				} else if(delta>0) {
					if(index>0) {
						if(atTop()) {
							if(isAccelerating(scrollSamples)) {
								e.preventDefault();
								index--;
								locked = true;
								//index, instant, callbacks, toTop
								animateScroll(index,false,true, false);
							} else {
								return false
							}
						}
					}
				}

			},
			keyHandler:function(e) {
				if(disabled===true || document.activeElement.readOnly===false) {
					return true;
				}
				if(locked===true) {
					return false;
				}
				if(e.keyCode==38 || e.keyCode==33) {
					if(index>0) {
						if(atTop()) {
							e.preventDefault();
							index--;
							//index, instant, callbacks, toTop
							animateScroll(index,false,true,false);
						}
					}
				} else if(e.keyCode==40 || e.keyCode==34) {
					if(index<heights.length-1) {
						if(atBottom()) {
							e.preventDefault();
							index++;
							//index, instant, callbacks, toTop
							animateScroll(index,false,true,false);
						}
					}
				}
			},
			init:function() {
				if(settings.scrollbars) {
					$window.on('mousedown', manualScroll.handleMousedown);
					$window.on('mouseup', manualScroll.handleMouseup);
					$window.on('scroll', manualScroll.handleScroll);
				} else {
					$("body").css({"overflow":"hidden"});
				}
				$window.on(wheelEvent,manualScroll.wheelHandler);
				//$(document).bind(wheelEvent,manualScroll.wheelHandler);
				$window.on('keydown', manualScroll.keyHandler);
			}
		};

		swipeScroll = {
			touches : {
				"touchstart": {"y":-1,"x":-1},
				"touchmove" : {"y":-1,"x":-1},
				"touchend"  : false,
				"direction" : "undetermined"
			},
			options:{
				"distance" : 30,
				"timeGap" : 800,
				"timeStamp" : new Date().getTime()
			},
			touchHandler: function(event) {
				if(disabled===true) {
					return true;
				} else if(settings.standardScrollElements) {
					if($(event.target).is(settings.standardScrollElements) || $(event.target).closest(settings.standardScrollElements).length) {
						return true;
					}
				}
				var touch;
				if (typeof event !== 'undefined'){
					if (typeof event.touches !== 'undefined') {
						touch = event.touches[0];
						switch (event.type) {
							case 'touchstart':
								swipeScroll.touches.touchstart.y = touch.pageY;
								swipeScroll.touches.touchmove.y = -1;

								swipeScroll.touches.touchstart.x = touch.pageX;
								swipeScroll.touches.touchmove.x = -1;

								swipeScroll.options.timeStamp = new Date().getTime();
								swipeScroll.touches.touchend = false;
							case 'touchmove':
								swipeScroll.touches.touchmove.y = touch.pageY;
								swipeScroll.touches.touchmove.x = touch.pageX;
								if(swipeScroll.touches.touchstart.y!==swipeScroll.touches.touchmove.y && (Math.abs(swipeScroll.touches.touchstart.y-swipeScroll.touches.touchmove.y)>Math.abs(swipeScroll.touches.touchstart.x-swipeScroll.touches.touchmove.x))) {
									//if(!overflow[index]) {
										event.preventDefault();
									//}
									swipeScroll.touches.direction = "y";
									if((swipeScroll.options.timeStamp+swipeScroll.options.timeGap)<(new Date().getTime()) && swipeScroll.touches.touchend == false) {

										swipeScroll.touches.touchend = true;
										if (swipeScroll.touches.touchstart.y > -1) {

											if(Math.abs(swipeScroll.touches.touchmove.y-swipeScroll.touches.touchstart.y)>swipeScroll.options.distance) {
												if(swipeScroll.touches.touchstart.y < swipeScroll.touches.touchmove.y) {

													swipeScroll.up();

												} else {
													swipeScroll.down();

												}
											}
										}
									}
								}
								break;
							case 'touchend':
								if(swipeScroll.touches[event.type]===false) {
									swipeScroll.touches[event.type] = true;
									if (swipeScroll.touches.touchstart.y > -1 && swipeScroll.touches.touchmove.y > -1 && swipeScroll.touches.direction==="y") {

										if(Math.abs(swipeScroll.touches.touchmove.y-swipeScroll.touches.touchstart.y)>swipeScroll.options.distance) {
											if(swipeScroll.touches.touchstart.y < swipeScroll.touches.touchmove.y) {
												swipeScroll.up();

											} else {
												swipeScroll.down();

											}
										}
										swipeScroll.touches.touchstart.y = -1;
										swipeScroll.touches.touchstart.x = -1;
										swipeScroll.touches.direction = "undetermined";
									}
								}
							default:
								break;
						}
					}
				}
			},
			down: function() {

				if(index<heights.length) {

					if(atBottom() && index<heights.length-1) {

						index++;
						//index, instant, callbacks, toTop
						animateScroll(index,false,true,false);
					} else {
						if(Math.floor(elements[index].height()/$window.height())>interstitialIndex) {

							interstitialScroll(parseInt(heights[index])+($window.height()*interstitialIndex));
							interstitialIndex += 1;

						} else {
							interstitialScroll(parseInt(heights[index])+(elements[index].outerHeight()-$window.height()));
						}

					}
				}
			},
			up: function() {
				if(index>=0) {
					if(atTop() && index>0) {

						index--;
						//index, instant, callbacks, toTop
						animateScroll(index,false,true,false);
					} else {

						if(interstitialIndex>2) {

							interstitialIndex -= 1;
							interstitialScroll(parseInt(heights[index])+($window.height()*interstitialIndex));

						} else {

							interstitialIndex = 1;
							interstitialScroll(parseInt(heights[index]));
						}
					}

				}
			},
			init: function() {
				if (document.addEventListener && settings.touchScroll) {
					document.addEventListener('touchstart', swipeScroll.touchHandler, false);
					document.addEventListener('touchmove', swipeScroll.touchHandler, false);
					document.addEventListener('touchend', swipeScroll.touchHandler, false);
				}
			}
		};


		util = {
			refresh:function(withCallback,scroll) {
				clearTimeout(timeoutId2);
				timeoutId2 = setTimeout(function() {
					//retain position
					sizePanels(true);
					//scroll, firstLoad
					calculatePositions(scroll,false);
					if(withCallback) {
							settings.afterResize();
					}
				},400);
			},
			handleUpdate:function() {
				//callbacks, scroll
				//changed from false,true to false,false
				util.refresh(false,false);
			},
			handleResize:function() {
				//callbacks, scroll
				util.refresh(true,false);
			},
			handleOrientation:function() {
				//callbacks, scroll
				util.refresh(true,true);
			}
		};
		settings = $.extend(settings, options);

		//retain position
		sizePanels(false);

		calculatePositions(false,true);

		if(true===hasLocation) {
			//index, instant, callbacks, toTop
			animateScroll(index,false,true,true);
		} else {
			setTimeout(function() {
				//instant,callbacks
				manualScroll.calculateNearest(true,false);
			},200);
		}
		if(heights.length) {
			manualScroll.init();
			swipeScroll.init();

			$window.on("resize",util.handleResize);
			if (document.addEventListener) {
				window.addEventListener("orientationchange", util.handleOrientation, false);
			}
		}
		function interstitialScroll(pos) {
			if( $().velocity ) {
				$(settings.target).stop().velocity('scroll', {
					duration: settings.scrollSpeed,
					easing: settings.easing,
					offset: pos,
					mobileHA: false
				});
			} else {
				$(settings.target).stop().animate({
					scrollTop: pos
				}, settings.scrollSpeed,settings.easing);
			}
		}

		function sizePanels(keepPosition) {
			if(keepPosition) {
				top = $window.scrollTop();
			}

			var selector = settings.section;
			overflow = [];
			if(settings.interstitialSection.length) {
				selector += "," + settings.interstitialSection;
			}
			if(settings.scrollbars===false) {
				settings.overflowScroll = false;
			}
			$(selector).each(function(i) {
				var $this = $(this);

				if(settings.setHeights) {
					if($this.is(settings.interstitialSection)) {
						overflow[i] = false;
					} else {
						if(($this.css("height","auto").outerHeight()<$window.height()) || $this.css("overflow")==="hidden") {
							$this.css({"height":$window.height()});

							overflow[i] = false;
						} else {

							$this.css({"height":$this.height()});

							if(settings.overflowScroll) {
								overflow[i] = true;
							} else {
								overflow[i] = false;
							}
						}

					}

				} else {

					if(($this.outerHeight()<$window.height()) || (settings.overflowScroll===false)) {
						overflow[i] = false;
					} else {
						overflow[i] = true;
					}
				}
			});
			if(keepPosition) {
				$window.scrollTop(top);
			}
		}
		function calculatePositions(scroll,firstLoad) {
			var selector = settings.section;
			if(settings.interstitialSection.length) {
				selector += "," + settings.interstitialSection;
			}
			heights = [];
			names = [];
			elements = [];
			$(selector).each(function(i){
					var $this = $(this);
					if(i>0) {
						heights[i] = parseInt($this.offset().top) + settings.offset;
					} else {
						heights[i] = parseInt($this.offset().top);
					}
					if(settings.sectionName && $this.data(settings.sectionName)) {
						names[i] = "#" + $this.data(settings.sectionName).toString().replace(/ /g,"-");
					} else {
						if($this.is(settings.interstitialSection)===false) {
							names[i] = "#" + (i + 1);
						} else {
							names[i] = "#";
							if(i===$(selector).length-1 && i>1) {

								heights[i] = heights[i-1]+(parseInt($($(selector)[i-1]).outerHeight())-parseInt($(window).height()))+parseInt($this.outerHeight());
							}
						}
					}
					elements[i] = $this;
					try {
						if($(names[i]).length && window.console) {
							console.warn("Scrollify warning: Section names can't match IDs - this will cause the browser to anchor.");
						}
					} catch (e) {}

					if(window.location.hash===names[i]) {
						index = i;
						hasLocation = true;
					}

			});

			if(true===scroll) {
				//index, instant, callbacks, toTop
				animateScroll(index,false,false,false);
			}
		}

		function atTop() {
			if(!overflow[index]) {
				return true;
			}
			top = $window.scrollTop();
			if(top>parseInt(heights[index])) {
				return false;
			} else {
				return true;
			}
		}
		function atBottom() {
			if(!overflow[index]) {
				return true;
			}
			top = $window.scrollTop();

			if(top<parseInt(heights[index])+(elements[index].outerHeight()-$window.height())-28) {

				return false;

			} else {
				return true;
			}
		}
	}

	function move(panel,instant) {
		var z = names.length;
		for(;z>=0;z--) {
			if(typeof panel === 'string') {
				if (names[z]===panel) {
					index = z;
					//index, instant, callbacks, toTop
					animateScroll(z,instant,true,true);
				}
			} else {
				if(z===panel) {
					index = z;
					//index, instant, callbacks, toTop
					animateScroll(z,instant,true,true);
				}
			}
		}
	}
	scrollify.move = function(panel) {
		if(panel===undefined) {
			return false;
		}
		if(panel.originalEvent) {
			panel = $(this).attr("href");
		}
		move(panel,false);
	};
	scrollify.instantMove = function(panel) {
		if(panel===undefined) {
			return false;
		}
		move(panel,true);
	};
	scrollify.next = function() {
		if(index<names.length) {
			index += 1;
			//index, instant, callbacks, toTop
			animateScroll(index,false,true,true);
		}
	};
	scrollify.previous = function() {
		if(index>0) {
			index -= 1;
			//index, instant, callbacks, toTop
			animateScroll(index,false,true,true);
		}
	};
	scrollify.instantNext = function() {
		if(index<names.length) {
			index += 1;
			//index, instant, callbacks, toTop
			animateScroll(index,true,true,true);
		}
	};
	scrollify.instantPrevious = function() {
		if(index>0) {
			index -= 1;
			//index, instant, callbacks, toTop
			animateScroll(index,true,true,true);
		}
	};
	scrollify.destroy = function() {
		if(!initialised) {
			return false;
		}
		if(settings.setHeights) {
			$(settings.section).each(function() {
				$(this).css("height","auto");
			});
		}
		$window.off("resize",util.handleResize);
		if(settings.scrollbars) {
			$window.off('mousedown', manualScroll.handleMousedown);
			$window.off('mouseup', manualScroll.handleMouseup);
			$window.off('scroll', manualScroll.handleScroll);
		}
		$window.off(wheelEvent,manualScroll.wheelHandler);
		$window.off('keydown', manualScroll.keyHandler);

		if (document.addEventListener && settings.touchScroll) {
			document.removeEventListener('touchstart', swipeScroll.touchHandler, false);
			document.removeEventListener('touchmove', swipeScroll.touchHandler, false);
			document.removeEventListener('touchend', swipeScroll.touchHandler, false);
		}
		heights = [];
		names = [];
		elements = [];
		overflow = [];
	};
	scrollify.update = function() {
		if(!initialised) {
			return false;
		}
		util.handleUpdate();
	};
	scrollify.current = function() {
		return elements[index];
	};
	scrollify.currentIndex = function() {
		return index;
	};
	scrollify.disable = function() {
		disabled = true;
	};
	scrollify.enable = function() {
		disabled = false;
		if (initialised) {
			//instant,callbacks
			manualScroll.calculateNearest(false,false);
		}
	};
	scrollify.isDisabled = function() {
		return disabled;
	};
	scrollify.setOptions = function(updatedOptions) {
		if(!initialised) {
			return false;
		}
		if(typeof updatedOptions === "object") {
			settings = $.extend(settings, updatedOptions);
			util.handleUpdate();
		} else if(window.console) {
			console.warn("Scrollify warning: setOptions expects an object.");
		}
	};
	$.scrollify = scrollify;
	return scrollify;
}));