// SmoothScroll v0.9.9 // Licensed under the terms of the MIT license. // People involved // - Balazs Galambosi: maintainer (CHANGELOG.txt) // - Patrick Brunner (patrickb1991@gmail.com) // - Michael Herf: ssc_pulse Algorithm // Scroll Variables (tweakable) var ssc_framerate = 150; // [Hz] var ssc_animtime = 500; // [px] //var ssc_stepsize = 72; // [px] var ssc_stepsize = 48; // [px] // ssc_pulse (less tweakable) // ratio of "tail" to "acceleration" var ssc_pulseAlgorithm = true; var ssc_pulseScale = 6; var ssc_pulseNormalize = 1; // Keyboard Settings var ssc_keyboardsupport = true; var ssc_arrowscroll = 50; // [px] // Other Variables var ssc_frame = false; var ssc_direction = { x: 0, y: 0 }; var ssc_initdone = false; var ssc_fixedback = true; var ssc_root = document.documentElement; var ssc_activeElement; var ssc_key = { left: 37, up: 38, right: 39, down: 40, spacebar: 32, pageup: 33, pagedown: 34, end: 35, home: 36 }; /*********************************************** * INITIALIZE ***********************************************/ /** * Sets up scrolls array, determines if ssc_frames are involved. */ function ssc_init() { if (!document.body) return; var body = document.body; var html = document.documentElement; var windowHeight = window.innerHeight; var scrollHeight = body.scrollHeight; // check compat mode for ssc_root element ssc_root = (document.compatMode.indexOf('CSS') >= 0) ? html : body; ssc_activeElement = body; ssc_initdone = true; // Checks if this script is running in a ssc_frame if (top != self) { ssc_frame = true; } /** * This fixes a bug where the areas left and right to * the content does not trigger the onmousewheel event * on some pages. e.g.: html, body { height: 100% } */ else if (scrollHeight > windowHeight && (body.offsetHeight <= windowHeight || html.offsetHeight <= windowHeight)) { ssc_root.style.height = "auto"; if (ssc_root.offsetHeight <= windowHeight) { var underlay = document.createElement("div"); underlay.style.clear = "both"; body.appendChild(underlay); } } if (!ssc_fixedback) { body.style.backgroundAttachment = "scroll"; html.style.backgroundAttachment = "scroll"; } if (ssc_keyboardsupport) { ssc_addEvent("keydown", ssc_keydown); } } /************************************************ * SCROLLING ************************************************/ var ssc_que = []; var ssc_pending = false; /** * Pushes scroll actions to the scrolling queue. */ function ssc_scrollArray(elem, left, top, delay) { delay || (delay = 1000); ssc_directionCheck(left, top); // push a scroll command ssc_que.push({ x: left, y: top, lastX: (left < 0) ? 0.99 : -0.99, lastY: (top < 0) ? 0.99 : -0.99, start: +new Date }); // don't act if there's a ssc_pending queue if (ssc_pending) { return; } var step = function() { var now = +new Date; var scrollX = 0; var scrollY = 0; for (var i = 0; i < ssc_que.length; i++) { var item = ssc_que[i]; var elapsed = now - item.start; var finished = (elapsed >= ssc_animtime); // scroll position: [0, 1] var position = (finished) ? 1 : elapsed / ssc_animtime; // easing [optional] if (ssc_pulseAlgorithm) { position = ssc_pulse(position); } // only need the difference var x = (item.x * position - item.lastX) >> 0; var y = (item.y * position - item.lastY) >> 0; // add this to the total scrolling scrollX += x; scrollY += y; // update last values item.lastX += x; item.lastY += y; // delete and step back if it's over if (finished) { ssc_que.splice(i, 1); i--; } } // scroll left if (left) { var lastLeft = elem.scrollLeft; elem.scrollLeft += scrollX; // scroll left failed (edge) if (scrollX && elem.scrollLeft === lastLeft) { left = 0; } } // scroll top if (top) { var lastTop = elem.scrollTop; elem.scrollTop += scrollY; // scroll top failed (edge) if (scrollY && elem.scrollTop === lastTop) { top = 0; } } // clean up if there's nothing left to do if (!left && !top) { ssc_que = []; } if (ssc_que.length) { setTimeout(step, delay / ssc_framerate + 1); } else { ssc_pending = false; } } // start a new queue of actions setTimeout(step, 0); ssc_pending = true; } /*********************************************** * EVENTS ***********************************************/ /** * Mouse ssc_wheel handler. * @param {Object} event */ function ssc_wheel(event) { if (!ssc_initdone) { init(); } var target = event.target; var overflowing = ssc_overflowingAncestor(target); // use default if there's no overflowing // element or default action is prevented if (!overflowing || event.defaultPrevented || ssc_isNodeName(ssc_activeElement, "embed") || (ssc_isNodeName(target, "embed") && /\.pdf/i.test(target.src))) { return true; } var deltaX = event.wheelDeltaX || 0; var deltaY = event.wheelDeltaY || 0; // use wheelDelta if deltaX/Y is not available if (!deltaX && !deltaY) { deltaY = event.wheelDelta || 0; } // scale by step size // delta is 120 most of the time // synaptics seems to send 1 sometimes if (Math.abs(deltaX) > 1.2) { deltaX *= ssc_stepsize / 120; } if (Math.abs(deltaY) > 1.2) { deltaY *= ssc_stepsize / 120; } ssc_scrollArray(overflowing, -deltaX, -deltaY); event.preventDefault(); } /** * ssc_keydown event handler. * @param {Object} event */ function ssc_keydown(event) { var target = event.target; var modifier = event.ctrlKey || event.altKey || event.metaKey; // do nothing if user is editing text // or using a modifier ssc_key (except shift) if ( /input|textarea|embed/i.test(target.nodeName) || target.isContentEditable || event.defaultPrevented || modifier ) { return true; } // spacebar should trigger button press if (ssc_isNodeName(target, "button") && event.keyCode === ssc_key.spacebar) { return true; } var shift, x = 0, y = 0; var elem = ssc_overflowingAncestor(ssc_activeElement); var clientHeight = elem.clientHeight; if (elem == document.body) { clientHeight = window.innerHeight; } switch (event.keyCode) { case ssc_key.up: y = -ssc_arrowscroll; break; case ssc_key.down: y = ssc_arrowscroll; break; case ssc_key.spacebar: // (+ shift) shift = event.shiftKey ? 1 : -1; y = -shift * clientHeight * 0.9; break; case ssc_key.pageup: y = -clientHeight * 0.9; break; case ssc_key.pagedown: y = clientHeight * 0.9; break; case ssc_key.home: y = -elem.scrollTop; break; case ssc_key.end: var damt = elem.scrollHeight - elem.scrollTop - clientHeight; y = (damt > 0) ? damt+10 : 0; break; case ssc_key.left: x = -ssc_arrowscroll; break; case ssc_key.right: x = ssc_arrowscroll; break; default: return true; // a ssc_key we don't care about } ssc_scrollArray(elem, x, y); event.preventDefault(); } /** * ssc_mousedown event only for updating ssc_activeElement */ function ssc_mousedown(event) { ssc_activeElement = event.target; } /*********************************************** * OVERFLOW ***********************************************/ var ssc_cache = {}; // cleared out every once in while setInterval(function(){ ssc_cache = {}; }, 10 * 1000); var ssc_uniqueID = (function() { var i = 0; return function (el) { return el.ssc_uniqueID || (el.ssc_uniqueID = i++); }; })(); function ssc_setCache(elems, overflowing) { for (var i = elems.length; i--;) ssc_cache[ssc_uniqueID(elems[i])] = overflowing; return overflowing; } function ssc_overflowingAncestor(el) { var elems = []; var ssc_rootScrollHeight = ssc_root.scrollHeight; do { var cached = ssc_cache[ssc_uniqueID(el)]; if (cached) { return ssc_setCache(elems, cached); } elems.push(el); if (ssc_rootScrollHeight === el.scrollHeight) { if (!ssc_frame || ssc_root.clientHeight + 10 < ssc_rootScrollHeight) { return ssc_setCache(elems, document.body); // scrolling ssc_root in WebKit } } else if (el.clientHeight + 10 < el.scrollHeight) { overflow = getComputedStyle(el, "").getPropertyValue("overflow"); if (overflow === "scroll" || overflow === "auto") { return ssc_setCache(elems, el); } } } while (el = el.parentNode); } /*********************************************** * HELPERS ***********************************************/ function ssc_addEvent(type, fn, bubble) { window.addEventListener(type, fn, (bubble||false)); } function ssc_removeEvent(type, fn, bubble) { window.removeEventListener(type, fn, (bubble||false)); } function ssc_isNodeName(el, tag) { return el.nodeName.toLowerCase() === tag.toLowerCase(); } function ssc_directionCheck(x, y) { x = (x > 0) ? 1 : -1; y = (y > 0) ? 1 : -1; if (ssc_direction.x !== x || ssc_direction.y !== y) { ssc_direction.x = x; ssc_direction.y = y; ssc_que = []; } } /*********************************************** * ssc_pulse ***********************************************/ /** * Viscous fluid with a ssc_pulse for part and decay for the rest. * - Applies a fixed force over an interval (a damped acceleration), and * - Lets the exponential bleed away the velocity over a longer interval * - Michael Herf, http://stereopsis.com/stopping/ */ function ssc_pulse_(x) { var val, start, expx; // test x = x * ssc_pulseScale; if (x < 1) { // acceleartion val = x - (1 - Math.exp(-x)); } else { // tail // the previous animation ended here: start = Math.exp(-1); // simple viscous drag x -= 1; expx = 1 - Math.exp(-x); val = start + (expx * (1 - start)); } return val * ssc_pulseNormalize; } function ssc_pulse(x) { if (x >= 1) return 1; if (x <= 0) return 0; if (ssc_pulseNormalize == 1) { ssc_pulseNormalize /= ssc_pulse_(1); } return ssc_pulse_(x); } if(!$.browser.msie){ ssc_addEvent("mousedown", ssc_mousedown); ssc_addEvent("mousewheel", ssc_wheel); ssc_addEvent("load", ssc_init); }