gsap/src/ScrollTrigger.js

GSAP is a framework-agnostic JavaScript animation library that turns developers into animation superheroes. Build high-performance animations that work in **every** major browser. Animate CSS, SVG, canvas, React, Vue, WebGL, colors, strings, motion paths,

/*!
 * ScrollTrigger 3.13.0
 * https://gsap.com
 *
 * @license Copyright 2008-2025, GreenSock. All rights reserved.
 * Subject to the terms at https://gsap.com/standard-license
 * @author: Jack Doyle, jack@greensock.com
*/
/* eslint-disable */

import { Observer, _getTarget, _vertical, _horizontal, _scrollers, _proxies, _getScrollFunc, _getProxyProp, _getVelocityProp } from "./Observer.js";

let gsap, _coreInitted, _win, _doc, _docEl, _body, _root, _resizeDelay, _toArray, _clamp, _time2, _syncInterval, _refreshing, _pointerIsDown, _transformProp, _i, _prevWidth, _prevHeight, _autoRefresh, _sort, _suppressOverwrites, _ignoreResize, _normalizer, _ignoreMobileResize, _baseScreenHeight, _baseScreenWidth, _fixIOSBug, _context, _scrollRestoration, _div100vh, _100vh, _isReverted, _clampingMax,
	_limitCallbacks, // if true, we'll only trigger callbacks if the active state toggles, so if you scroll immediately past both the start and end positions of a ScrollTrigger (thus inactive to inactive), neither its onEnter nor onLeave will be called. This is useful during startup.
	_startup = 1,
	_getTime = Date.now,
	_time1 = _getTime(),
	_lastScrollTime = 0,
	_enabled = 0,
	_parseClamp = (value, type, self) => {
		let clamp = (_isString(value) && (value.substr(0, 6) === "clamp(" || value.indexOf("max") > -1));
		self["_" + type + "Clamp"] = clamp;
		return clamp ? value.substr(6, value.length - 7) : value;
	},
	_keepClamp = (value, clamp) => clamp && (!_isString(value) || value.substr(0, 6) !== "clamp(") ? "clamp(" + value + ")" : value,
	_rafBugFix = () => _enabled && requestAnimationFrame(_rafBugFix), // in some browsers (like Firefox), screen repaints weren't consistent unless we had SOMETHING queued up in requestAnimationFrame()! So this just creates a super simple loop to keep it alive and smooth out repaints.
	_pointerDownHandler = () => _pointerIsDown = 1,
	_pointerUpHandler = () => _pointerIsDown = 0,
	_passThrough = v => v,
	_round = value => Math.round(value * 100000) / 100000 || 0,
	_windowExists = () => typeof(window) !== "undefined",
	_getGSAP = () => gsap || (_windowExists() && (gsap = window.gsap) && gsap.registerPlugin && gsap),
	_isViewport = e => !!~_root.indexOf(e),
	_getViewportDimension = dimensionProperty => (dimensionProperty === "Height" ? _100vh : _win["inner" + dimensionProperty]) || _docEl["client" + dimensionProperty] || _body["client" + dimensionProperty],
	_getBoundsFunc = element => _getProxyProp(element, "getBoundingClientRect") || (_isViewport(element) ? () => {_winOffsets.width = _win.innerWidth; _winOffsets.height = _100vh; return _winOffsets;} : () => _getBounds(element)),
	_getSizeFunc = (scroller, isViewport, {d, d2, a}) => (a = _getProxyProp(scroller, "getBoundingClientRect")) ? () => a()[d] : () => (isViewport ? _getViewportDimension(d2) : scroller["client" + d2]) || 0,
	_getOffsetsFunc = (element, isViewport) => !isViewport || ~_proxies.indexOf(element) ? _getBoundsFunc(element) : () => _winOffsets,
	_maxScroll = (element, {s, d2, d, a}) => Math.max(0, (s = "scroll" + d2) && (a = _getProxyProp(element, s)) ? a() - _getBoundsFunc(element)()[d] : _isViewport(element) ? (_docEl[s] || _body[s]) - _getViewportDimension(d2) : element[s] - element["offset" + d2]),
	_iterateAutoRefresh = (func, events) => {
		for (let i = 0; i < _autoRefresh.length; i += 3) {
			(!events || ~events.indexOf(_autoRefresh[i+1])) && func(_autoRefresh[i], _autoRefresh[i+1], _autoRefresh[i+2]);
		}
	},
	_isString = value => typeof(value) === "string",
	_isFunction = value => typeof(value) === "function",
	_isNumber = value => typeof(value) === "number",
	_isObject = value => typeof(value) === "object",
	_endAnimation = (animation, reversed, pause) => animation && animation.progress(reversed ? 0 : 1) && pause && animation.pause(),
	_callback = (self, func) => {
		if (self.enabled) {
			let result = self._ctx ? self._ctx.add(() => func(self)) : func(self);
			result && result.totalTime && (self.callbackAnimation = result);
		}
	},
	_abs = Math.abs,
	_left = "left",
	_top = "top",
	_right = "right",
	_bottom = "bottom",
	_width = "width",
	_height = "height",
	_Right = "Right",
	_Left = "Left",
	_Top = "Top",
	_Bottom = "Bottom",
	_padding = "padding",
	_margin = "margin",
	_Width = "Width",
	_Height = "Height",
	_px = "px",
	_getComputedStyle = element => _win.getComputedStyle(element),
	_makePositionable = element => { // if the element already has position: absolute or fixed, leave that, otherwise make it position: relative
		let position = _getComputedStyle(element).position;
		element.style.position = (position === "absolute" || position === "fixed") ? position : "relative";
	},
	_setDefaults = (obj, defaults) => {
		for (let p in defaults) {
			(p in obj) || (obj[p] = defaults[p]);
		}
		return obj;
	},
	_getBounds = (element, withoutTransforms) => {
		let tween = withoutTransforms && _getComputedStyle(element)[_transformProp] !== "matrix(1, 0, 0, 1, 0, 0)" && gsap.to(element, {x: 0, y: 0, xPercent: 0, yPercent: 0, rotation: 0, rotationX: 0, rotationY: 0, scale: 1, skewX: 0, skewY: 0}).progress(1),
			bounds = element.getBoundingClientRect();
		tween && tween.progress(0).kill();
		return bounds;
	},
	_getSize = (element, {d2}) => element["offset" + d2] || element["client" + d2] || 0,
	_getLabelRatioArray = timeline => {
		let a = [],
			labels = timeline.labels,
			duration = timeline.duration(),
			p;
		for (p in labels) {
			a.push(labels[p] / duration);
		}
		return a;
	},
	_getClosestLabel = animation => value => gsap.utils.snap(_getLabelRatioArray(animation), value),
	_snapDirectional = snapIncrementOrArray => {
		let snap = gsap.utils.snap(snapIncrementOrArray),
			a = Array.isArray(snapIncrementOrArray) && snapIncrementOrArray.slice(0).sort((a, b) => a - b);
		return a ? (value, direction, threshold= 1e-3) => {
			let i;
			if (!direction) {
				return snap(value);
			}
			if (direction > 0) {
				value -= threshold; // to avoid rounding errors. If we're too strict, it might snap forward, then immediately again, and again.
				for (i = 0; i < a.length; i++) {
					if (a[i] >= value) {
						return a[i];
					}
				}
				return a[i-1];
			} else {
				i = a.length;
				value += threshold;
				while (i--) {
					if (a[i] <= value) {
						return a[i];
					}
				}
			}
			return a[0];
		} : (value, direction, threshold= 1e-3) => {
			let snapped = snap(value);
			return !direction || Math.abs(snapped - value) < threshold || ((snapped - value < 0) === direction < 0) ? snapped : snap(direction < 0 ? value - snapIncrementOrArray : value + snapIncrementOrArray);
		};
	},
	_getLabelAtDirection = timeline => (value, st) => _snapDirectional(_getLabelRatioArray(timeline))(value, st.direction),
	_multiListener = (func, element, types, callback) => types.split(",").forEach(type => func(element, type, callback)),
	_addListener = (element, type, func, nonPassive, capture) => element.addEventListener(type, func, {passive: !nonPassive, capture: !!capture}),
	_removeListener = (element, type, func, capture) => element.removeEventListener(type, func, !!capture),
	_wheelListener = (func, el, scrollFunc) => {
		scrollFunc = scrollFunc && scrollFunc.wheelHandler
		if (scrollFunc) {
			func(el, "wheel", scrollFunc);
			func(el, "touchmove", scrollFunc);
		}
	},
	_markerDefaults = {startColor: "green", endColor: "red", indent: 0, fontSize: "16px", fontWeight:"normal"},
	_defaults = {toggleActions: "play", anticipatePin: 0},
	_keywords = {top: 0, left: 0, center: 0.5, bottom: 1, right: 1},
	_offsetToPx = (value, size) => {
		if (_isString(value)) {
			let eqIndex = value.indexOf("="),
				relative = ~eqIndex ? +(value.charAt(eqIndex-1) + 1) * parseFloat(value.substr(eqIndex + 1)) : 0;
			if (~eqIndex) {
				(value.indexOf("%") > eqIndex) && (relative *= size / 100);
				value = value.substr(0, eqIndex-1);
			}
			value = relative + ((value in _keywords) ? _keywords[value] * size : ~value.indexOf("%") ? parseFloat(value) * size / 100 : parseFloat(value) || 0);
		}
		return value;
	},
	_createMarker = (type, name, container, direction, {startColor, endColor, fontSize, indent, fontWeight}, offset, matchWidthEl, containerAnimation) => {
		let e = _doc.createElement("div"),
			useFixedPosition = _isViewport(container) || _getProxyProp(container, "pinType") === "fixed",
			isScroller = type.indexOf("scroller") !== -1,
			parent = useFixedPosition ? _body : container,
			isStart = type.indexOf("start") !== -1,
			color = isStart ? startColor : endColor,
			css = "border-color:" + color + ";font-size:" + fontSize + ";color:" + color + ";font-weight:" + fontWeight + ";pointer-events:none;white-space:nowrap;font-family:sans-serif,Arial;z-index:1000;padding:4px 8px;border-width:0;border-style:solid;";
		css += "position:" + ((isScroller || containerAnimation) && useFixedPosition ? "fixed;" : "absolute;");
		(isScroller || containerAnimation || !useFixedPosition) && (css += (direction === _vertical ? _right : _bottom) + ":" + (offset + parseFloat(indent)) + "px;");
		matchWidthEl && (css += "box-sizing:border-box;text-align:left;width:" + matchWidthEl.offsetWidth + "px;");
		e._isStart = isStart;
		e.setAttribute("class", "gsap-marker-" + type + (name ? " marker-" + name : ""));
		e.style.cssText = css;
		e.innerText = name || name === 0 ? type + "-" + name : type;
		parent.children[0] ? parent.insertBefore(e, parent.children[0]) : parent.appendChild(e);
		e._offset = e["offset" + direction.op.d2];
		_positionMarker(e, 0, direction, isStart);
		return e;
	},
	_positionMarker = (marker, start, direction, flipped) => {
		let vars = {display: "block"},
			side = direction[flipped ? "os2" : "p2"],
			oppositeSide = direction[flipped ? "p2" : "os2"];
		marker._isFlipped = flipped;
		vars[direction.a + "Percent"] = flipped ? -100 : 0;
		vars[direction.a] = flipped ? "1px" : 0;
		vars["border" + side + _Width] = 1;
		vars["border" + oppositeSide + _Width] = 0;
		vars[direction.p] = start + "px";
		gsap.set(marker, vars);
	},
	_triggers = [],
	_ids = {},
	_rafID,
	_sync = () => _getTime() - _lastScrollTime > 34 && (_rafID || (_rafID = requestAnimationFrame(_updateAll))),
	_onScroll = () => { // previously, we tried to optimize performance by batching/deferring to the next requestAnimationFrame(), but discovered that Safari has a few bugs that make this unworkable (especially on iOS). See https://codepen.io/GreenSock/pen/16c435b12ef09c38125204818e7b45fc?editors=0010 and https://codepen.io/GreenSock/pen/JjOxYpQ/3dd65ccec5a60f1d862c355d84d14562?editors=0010 and https://codepen.io/GreenSock/pen/ExbrPNa/087cef197dc35445a0951e8935c41503?editors=0010
		if (!_normalizer || !_normalizer.isPressed || _normalizer.startX > _body.clientWidth) { // if the user is dragging the scrollbar, allow it.
			_scrollers.cache++;
			if (_normalizer) {
				_rafID || (_rafID = requestAnimationFrame(_updateAll));
			} else {
				_updateAll(); // Safari in particular (on desktop) NEEDS the immediate update rather than waiting for a requestAnimationFrame() whereas iOS seems to benefit from waiting for the requestAnimationFrame() tick, at least when normalizing. See https://codepen.io/GreenSock/pen/qBYozqO?editors=0110
			}
			_lastScrollTime || _dispatch("scrollStart");
			_lastScrollTime = _getTime();
		}
	},
	_setBaseDimensions = () => {
		_baseScreenWidth = _win.innerWidth;
		_baseScreenHeight = _win.innerHeight;
	},
	_onResize = (force) => {
		_scrollers.cache++;
		(force === true || (!_refreshing && !_ignoreResize && !_doc.fullscreenElement && !_doc.webkitFullscreenElement && (!_ignoreMobileResize || _baseScreenWidth !== _win.innerWidth || Math.abs(_win.innerHeight - _baseScreenHeight) > _win.innerHeight * 0.25))) && _resizeDelay.restart(true);
	}, // ignore resizes triggered by refresh()
	_listeners = {},
	_emptyArray = [],
	_softRefresh = () => _removeListener(ScrollTrigger, "scrollEnd", _softRefresh) || _refreshAll(true),
	_dispatch = type => (_listeners[type] && _listeners[type].map(f => f())) || _emptyArray,
	_savedStyles = [], // when ScrollTrigger.saveStyles() is called, the inline styles are recorded in this Array in a sequential format like [element, cssText, gsCache, media]. This keeps it very memory-efficient and fast to iterate through.
	_revertRecorded = media => {
		for (let i = 0; i < _savedStyles.length; i+=5) {
			if (!media || _savedStyles[i+4] && _savedStyles[i+4].query === media) {
				_savedStyles[i].style.cssText = _savedStyles[i+1];
				_savedStyles[i].getBBox && _savedStyles[i].setAttribute("transform", _savedStyles[i+2] || "");
				_savedStyles[i+3].uncache = 1;
			}
		}
	},
	_revertAll = (kill, media) => {
		let trigger;
		for (_i = 0; _i < _triggers.length; _i++) {
			trigger = _triggers[_i];
			if (trigger && (!media || trigger._ctx === media)) {
				if (kill) {
					trigger.kill(1);
				} else {
					trigger.revert(true, true);
				}
			}
		}
		_isReverted = true;
		media && _revertRecorded(media);
		media || _dispatch("revert");
	},
	_clearScrollMemory = (scrollRestoration, force) => { // zero-out all the recorded scroll positions. Don't use _triggers because if, for example, .matchMedia() is used to create some ScrollTriggers and then the user resizes and it removes ALL ScrollTriggers, and then go back to a size where there are ScrollTriggers, it would have kept the position(s) saved from the initial state.
		_scrollers.cache++;
		(force || !_refreshingAll) && _scrollers.forEach(obj => _isFunction(obj) && obj.cacheID++ && (obj.rec = 0));
		_isString(scrollRestoration) && (_win.history.scrollRestoration = _scrollRestoration = scrollRestoration);
	},
	_refreshingAll,
	_refreshID = 0,
	_queueRefreshID,
	_queueRefreshAll = () => { // we don't want to call _refreshAll() every time we create a new ScrollTrigger (for performance reasons) - it's better to batch them. Some frameworks dynamically load content and we can't rely on the window's "load" or "DOMContentLoaded" events to trigger it.
		if (_queueRefreshID !== _refreshID) {
			let id = _queueRefreshID = _refreshID;
			requestAnimationFrame(() => id === _refreshID && _refreshAll(true));
		}
	},
	_refresh100vh = () => {
		_body.appendChild(_div100vh);
		_100vh = (!_normalizer && _div100vh.offsetHeight) || _win.innerHeight;
		_body.removeChild(_div100vh);
	},
	_hideAllMarkers = hide => _toArray(".gsap-marker-start, .gsap-marker-end, .gsap-marker-scroller-start, .gsap-marker-scroller-end").forEach(el => el.style.display = hide ? "none" : "block"),
	_refreshAll = (force, skipRevert) => {
		_docEl = _doc.documentElement; // some frameworks like Astro may cache the <body> and replace it during routing, so we'll just re-record the _docEl and _body for safety (otherwise, the markers may not get added properly).
		_body = _doc.body;
		_root = [_win, _doc, _docEl, _body];
		if (_lastScrollTime && !force && !_isReverted) {
			_addListener(ScrollTrigger, "scrollEnd", _softRefresh);
			return;
		}
		_refresh100vh();
		_refreshingAll = ScrollTrigger.isRefreshing = true;
		_scrollers.forEach(obj => _isFunction(obj) && ++obj.cacheID && (obj.rec = obj())); // force the clearing of the cache because some browsers take a little while to dispatch the "scroll" event and the user may have changed the scroll position and then called ScrollTrigger.refresh() right away
		let refreshInits = _dispatch("refreshInit");
		_sort && ScrollTrigger.sort();
		skipRevert || _revertAll();
		_scrollers.forEach(obj => {
			if (_isFunction(obj)) {
				obj.smooth && (obj.target.style.scrollBehavior = "auto"); // smooth scrolling interferes
				obj(0);
			}
		});
		_triggers.slice(0).forEach(t => t.refresh()) // don't loop with _i because during a refresh() someone could call ScrollTrigger.update() which would iterate through _i resulting in a skip.
		_isReverted = false;
		_triggers.forEach((t) => { // nested pins (pinnedContainer) with pinSpacing may expand the container, so we must accommodate that here.
			if (t._subPinOffset && t.pin) {
				let prop = t.vars.horizontal ? "offsetWidth" : "offsetHeight",
					original = t.pin[prop];
				t.revert(true, 1);
				t.adjustPinSpacing(t.pin[prop] - original);
				t.refresh();
			}
		});
		_clampingMax = 1; // pinSpacing might be propping a page open, thus when we .setPositions() to clamp a ScrollTrigger's end we should leave the pinSpacing alone. That's what this flag is for.
		_hideAllMarkers(true);
		_triggers.forEach(t => { // the scroller's max scroll position may change after all the ScrollTriggers refreshed (like pinning could push it down), so we need to loop back and correct any with end: "max". Same for anything with a clamped end
			let max = _maxScroll(t.scroller, t._dir),
				endClamp = t.vars.end === "max" || (t._endClamp && t.end > max),
				startClamp = t._startClamp && t.start >= max;
			(endClamp || startClamp) && t.setPositions(startClamp ? max - 1 : t.start, endClamp ? Math.max(startClamp ? max : t.start + 1, max) : t.end, true);
		});
		_hideAllMarkers(false);
		_clampingMax = 0;
		refreshInits.forEach(result => result && result.render && result.render(-1)); // if the onRefreshInit() returns an animation (typically a gsap.set()), revert it. This makes it easy to put things in a certain spot before refreshing for measurement purposes, and then put things back.
		_scrollers.forEach(obj => {
			if (_isFunction(obj)) {
				obj.smooth && requestAnimationFrame(() => obj.target.style.scrollBehavior = "smooth");
				obj.rec && obj(obj.rec);
			}
		});
		_clearScrollMemory(_scrollRestoration, 1);
		_resizeDelay.pause();
		_refreshID++;
		_refreshingAll = 2;
		_updateAll(2);
		_triggers.forEach(t => _isFunction(t.vars.onRefresh) && t.vars.onRefresh(t));
		_refreshingAll = ScrollTrigger.isRefreshing = false;
		_dispatch("refresh");
	},
	_lastScroll = 0,
	_direction = 1,
	_primary,
	_updateAll = (force) => {
		if (force === 2 || (!_refreshingAll && !_isReverted)) { // _isReverted could be true if, for example, a matchMedia() is in the process of executing. We don't want to update during the time everything is reverted.
			ScrollTrigger.isUpdating = true;
			_primary && _primary.update(0); // ScrollSmoother uses refreshPriority -9999 to become the primary that gets updated before all others because it affects the scroll position.
			let l = _triggers.length,
				time = _getTime(),
				recordVelocity = time - _time1 >= 50,
				scroll = l && _triggers[0].scroll();
			_direction = _lastScroll > scroll ? -1 : 1;
			_refreshingAll || (_lastScroll = scroll);
			if (recordVelocity) {
				if (_lastScrollTime && !_pointerIsDown && time - _lastScrollTime > 200) {
					_lastScrollTime = 0;
					_dispatch("scrollEnd");
				}
				_time2 = _time1;
				_time1 = time;
			}
			if (_direction < 0) {
				_i = l;
				while (_i-- > 0) {
					_triggers[_i] && _triggers[_i].update(0, recordVelocity);
				}
				_direction = 1;
			} else {
				for (_i = 0; _i < l; _i++) {
					_triggers[_i] && _triggers[_i].update(0, recordVelocity);
				}
			}
			ScrollTrigger.isUpdating = false;
		}
		_rafID = 0;
	},
	_propNamesToCopy = [_left, _top, _bottom, _right, _margin + _Bottom, _margin + _Right, _margin + _Top, _margin + _Left, "display", "flexShrink", "float", "zIndex", "gridColumnStart", "gridColumnEnd", "gridRowStart", "gridRowEnd", "gridArea", "justifySelf", "alignSelf", "placeSelf", "order"],
	_stateProps = _propNamesToCopy.concat([_width, _height, "boxSizing", "max" + _Width, "max" + _Height, "position", _margin, _padding, _padding + _Top, _padding + _Right, _padding + _Bottom, _padding + _Left]),
	_swapPinOut = (pin, spacer, state) => {
		_setState(state);
		let cache = pin._gsap;
		if (cache.spacerIsNative) {
			_setState(cache.spacerState);
		} else if (pin._gsap.swappedIn) {
			let parent = spacer.parentNode;
			if (parent) {
				parent.insertBefore(pin, spacer);
				parent.removeChild(spacer);
			}
		}
		pin._gsap.swappedIn = false;
	},
	_swapPinIn = (pin, spacer, cs, spacerState) => {
		if (!pin._gsap.swappedIn) {
			let i = _propNamesToCopy.length,
				spacerStyle = spacer.style,
				pinStyle = pin.style,
				p;
			while (i--) {
				p = _propNamesToCopy[i];
				spacerStyle[p] = cs[p];
			}
			spacerStyle.position = cs.position === "absolute" ? "absolute" : "relative";
			(cs.display === "inline") && (spacerStyle.display = "inline-block");
			pinStyle[_bottom] = pinStyle[_right] = "auto";
			spacerStyle.flexBasis = cs.flexBasis || "auto";
			spacerStyle.overflow = "visible";
			spacerStyle.boxSizing = "border-box";
			spacerStyle[_width] = _getSize(pin, _horizontal) + _px;
			spacerStyle[_height] = _getSize(pin, _vertical) + _px;
			spacerStyle[_padding] = pinStyle[_margin] = pinStyle[_top] = pinStyle[_left] = "0";
			_setState(spacerState);
			pinStyle[_width] = pinStyle["max" + _Width] = cs[_width];
			pinStyle[_height] = pinStyle["max" + _Height] = cs[_height];
			pinStyle[_padding] = cs[_padding];
			if (pin.parentNode !== spacer) {
				pin.parentNode.insertBefore(spacer, pin);
				spacer.appendChild(pin);
			}
			pin._gsap.swappedIn = true;
		}
	},
	_capsExp = /([A-Z])/g,
	_setState = state => {
		if (state) {
			let style = state.t.style,
				l = state.length,
				i = 0,
				p, value;
			(state.t._gsap || gsap.core.getCache(state.t)).uncache = 1; // otherwise transforms may be off
			for (; i < l; i +=2) {
				value = state[i+1];
				p = state[i];
				if (value) {
					style[p] = value;
				} else if (style[p]) {
					style.removeProperty(p.replace(_capsExp, "-$1").toLowerCase());
				}
			}
		}
	},
	_getState = element => { // returns an Array with alternating values like [property, value, property, value] and a "t" property pointing to the target (element). Makes it fast and cheap.
		let l = _stateProps.length,
			style = element.style,
			state = [],
			i = 0;
		for (; i < l; i++) {
			state.push(_stateProps[i], style[_stateProps[i]]);
		}
		state.t = element;
		return state;
	},
	_copyState = (state, override, omitOffsets) => {
		let result = [],
			l = state.length,
			i = omitOffsets ? 8 : 0, // skip top, left, right, bottom if omitOffsets is true
			p;
		for (; i < l; i += 2) {
			p = state[i];
			result.push(p, (p in override) ? override[p] : state[i+1]);
		}
		result.t = state.t;
		return result;
	},
	_winOffsets = {left:0, top:0},
	// // potential future feature (?) Allow users to calculate where a trigger hits (scroll position) like getScrollPosition("#id", "top bottom")
	// _getScrollPosition = (trigger, position, {scroller, containerAnimation, horizontal}) => {
	// 	scroller = _getTarget(scroller || _win);
	// 	let direction = horizontal ? _horizontal : _vertical,
	// 		isViewport = _isViewport(scroller);
	// 	_getSizeFunc(scroller, isViewport, direction);
	// 	return _parsePosition(position, _getTarget(trigger), _getSizeFunc(scroller, isViewport, direction)(), direction, _getScrollFunc(scroller, direction)(), 0, 0, 0, _getOffsetsFunc(scroller, isViewport)(), isViewport ? 0 : parseFloat(_getComputedStyle(scroller)["border" + direction.p2 + _Width]) || 0, 0, containerAnimation ? containerAnimation.duration() : _maxScroll(scroller), containerAnimation);
	// },
	_parsePosition = (value, trigger, scrollerSize, direction, scroll, marker, markerScroller, self, scrollerBounds, borderWidth, useFixedPosition, scrollerMax, containerAnimation, clampZeroProp) => {
		_isFunction(value) && (value = value(self));
		if (_isString(value) && value.substr(0,3) === "max") {
			value = scrollerMax + (value.charAt(4) === "=" ? _offsetToPx("0" + value.substr(3), scrollerSize) : 0);
		}
		let time = containerAnimation ? containerAnimation.time() : 0,
			p1, p2, element;
		containerAnimation && containerAnimation.seek(0);
		isNaN(value) || (value = +value); // convert a string number like "45" to an actual number
		if (!_isNumber(value)) {
			_isFunction(trigger) && (trigger = trigger(self));
			let offsets = (value || "0").split(" "),
				bounds, localOffset, globalOffset, display;
			element = _getTarget(trigger, self) || _body;
			bounds = _getBounds(element) || {};
			if ((!bounds || (!bounds.left && !bounds.top)) && _getComputedStyle(element).display === "none") { // if display is "none", it won't report getBoundingClientRect() properly
				display = element.style.display;
				element.style.display = "block";
				bounds = _getBounds(element);
				display ? (element.style.display = display) : element.style.removeProperty("display");
			}
			localOffset = _offsetToPx(offsets[0], bounds[direction.d]);
			globalOffset = _offsetToPx(offsets[1] || "0", scrollerSize);
			value = bounds[direction.p] - scrollerBounds[direction.p] - borderWidth + localOffset + scroll - globalOffset;
			markerScroller && _positionMarker(markerScroller, globalOffset, direction, (scrollerSize - globalOffset < 20 || (markerScroller._isStart && globalOffset > 20)));
			scrollerSize -= scrollerSize - globalOffset; // adjust for the marker
		} else {
			containerAnimation && (value = gsap.utils.mapRange(containerAnimation.scrollTrigger.start, containerAnimation.scrollTrigger.end, 0, scrollerMax, value));
			markerScroller && _positionMarker(markerScroller, scrollerSize, direction, true);
		}
		if (clampZeroProp) {
			self[clampZeroProp] = value || -0.001;
			value < 0 && (value = 0);
		}
		if (marker) {
			let position = value + scrollerSize,
				isStart = marker._isStart;
			p1 = "scroll" + direction.d2;
			_positionMarker(marker, position, direction, (isStart && position > 20) || (!isStart && (useFixedPosition ? Math.max(_body[p1], _docEl[p1]) : marker.parentNode[p1]) <= position + 1));
			if (useFixedPosition) {
				scrollerBounds = _getBounds(markerScroller);
				useFixedPosition && (marker.style[direction.op.p] = (scrollerBounds[direction.op.p] - direction.op.m - marker._offset) + _px);
			}
		}
		if (containerAnimation && element) {
			p1 = _getBounds(element);
			containerAnimation.seek(scrollerMax);
			p2 = _getBounds(element);
			containerAnimation._caScrollDist = p1[direction.p] - p2[direction.p];
			value = value / (containerAnimation._caScrollDist) * scrollerMax;
		}
		containerAnimation && containerAnimation.seek(time);
		return containerAnimation ? value : Math.round(value);
	},
	_prefixExp = /(webkit|moz|length|cssText|inset)/i,
	_reparent = (element, parent, top, left) => {
		if (element.parentNode !== parent) {
			let style = element.style,
				p, cs;
			if (parent === _body) {
				element._stOrig = style.cssText; // record original inline styles so we can revert them later
				cs = _getComputedStyle(element);
				for (p in cs) { // must copy all relevant styles to ensure that nothing changes visually when we reparent to the <body>. Skip the vendor prefixed ones.
					if (!+p && !_prefixExp.test(p) && cs[p] && typeof style[p] === "string" && p !== "0") {
						style[p] = cs[p];
					}
				}
				style.top = top;
				style.left = left;
			} else {
				style.cssText = element._stOrig;
			}
			gsap.core.getCache(element).uncache = 1;
			parent.appendChild(element);
		}
	},
	_interruptionTracker = (getValueFunc, initialValue, onInterrupt) => {
		let last1 = initialValue,
			last2 = last1;
		return value => {
			let current = Math.round(getValueFunc()); // round because in some [very uncommon] Windows environments, scroll can get reported with decimals even though it was set without.
			if (current !== last1 && current !== last2 && Math.abs(current - last1) > 3 && Math.abs(current - last2) > 3) { // if the user scrolls, kill the tween. iOS Safari intermittently misreports the scroll position, it may be the most recently-set one or the one before that! When Safari is zoomed (CMD-+), it often misreports as 1 pixel off too! So if we set the scroll position to 125, for example, it'll actually report it as 124.
				value = current;
				onInterrupt && onInterrupt();
			}
			last2 = last1;
			last1 = Math.round(value);
			return last1;
		};
	},
	_shiftMarker = (marker, direction, value) => {
		let vars = {};
		vars[direction.p] = "+=" + value;
		gsap.set(marker, vars);
	},
	// _mergeAnimations = animations => {
	// 	let tl = gsap.timeline({smoothChildTiming: true}).startTime(Math.min(...animations.map(a => a.globalTime(0))));
	// 	animations.forEach(a => {let time = a.totalTime(); tl.add(a); a.totalTime(time); });
	// 	tl.smoothChildTiming = false;
	// 	return tl;
	// },

	// returns a function that can be used to tween the scroll position in the direction provided, and when doing so it'll add a .tween property to the FUNCTION itself, and remove it when the tween completes or gets killed. This gives us a way to have multiple ScrollTriggers use a central function for any given scroller and see if there's a scroll tween running (which would affect if/how things get updated)
	_getTweenCreator = (scroller, direction) => {
		let getScroll = _getScrollFunc(scroller, direction),
			prop = "_scroll" + direction.p2, // add a tweenable property to the scroller that's a getter/setter function, like _scrollTop or _scrollLeft. This way, if someone does gsap.killTweensOf(scroller) it'll kill the scroll tween.
			getTween = (scrollTo, vars, initialValue, change1, change2) => {
				let tween = getTween.tween,
					onComplete = vars.onComplete,
					modifiers = {};
				initialValue = initialValue || getScroll();
				let checkForInterruption = _interruptionTracker(getScroll, initialValue, () => {
					tween.kill();
					getTween.tween = 0;
				});
				change2 = (change1 && change2) || 0; // if change1 is 0, we set that to the difference and ignore change2. Otherwise, there would be a compound effect.
				change1 = change1 || (scrollTo - initialValue);
				tween && tween.kill();
				vars[prop] = scrollTo;
				vars.inherit = false;
				vars.modifiers = modifiers;
				modifiers[prop] = () => checkForInterruption(initialValue + change1 * tween.ratio + change2 * tween.ratio * tween.ratio);
				vars.onUpdate = () => {
					_scrollers.cache++;
					getTween.tween && _updateAll(); // if it was interrupted/killed, like in a context.revert(), don't force an updateAll()
				};
				vars.onComplete = () => {
					getTween.tween = 0;
					onComplete && onComplete.call(tween);
				};
				tween = getTween.tween = gsap.to(scroller, vars);
				return tween;
			};
		scroller[prop] = getScroll;
		getScroll.wheelHandler = () => getTween.tween && getTween.tween.kill() && (getTween.tween = 0);
		_addListener(scroller, "wheel", getScroll.wheelHandler); // Windows machines handle mousewheel scrolling in chunks (like "3 lines per scroll") meaning the typical strategy for cancelling the scroll isn't as sensitive. It's much more likely to match one of the previous 2 scroll event positions. So we kill any snapping as soon as there's a wheel event.
		ScrollTrigger.isTouch && _addListener(scroller, "touchmove", getScroll.wheelHandler);
		return getTween;
	};




export class ScrollTrigger {

	constructor(vars, animation) {
		_coreInitted || ScrollTrigger.register(gsap) || console.warn("Please gsap.registerPlugin(ScrollTrigger)");
		_context(this);
		this.init(vars, animation);
	}

	init(vars, animation) {
		this.progress = this.start = 0;
		this.vars && this.kill(true, true); // in case it's being initted again
		if (!_enabled) {
			this.update = this.refresh = this.kill = _passThrough;
			return;
		}
		vars = _setDefaults((_isString(vars) || _isNumber(vars) || vars.nodeType) ? {trigger: vars} : vars, _defaults);
		let {onUpdate, toggleClass, id, onToggle, onRefresh, scrub, trigger, pin, pinSpacing, invalidateOnRefresh, anticipatePin, onScrubComplete, onSnapComplete, once, snap, pinReparent, pinSpacer, containerAnimation, fastScrollEnd, preventOverlaps} = vars,
			direction = vars.horizontal || (vars.containerAnimation && vars.horizontal !== false) ? _horizontal : _vertical,
			isToggle = !scrub && scrub !== 0,
			scroller = _getTarget(vars.scroller || _win),
			scrollerCache = gsap.core.getCache(scroller),
			isViewport = _isViewport(scroller),
			useFixedPosition = ("pinType" in vars ? vars.pinType : _getProxyProp(scroller, "pinType") || (isViewport && "fixed")) === "fixed",
			callbacks = [vars.onEnter, vars.onLeave, vars.onEnterBack, vars.onLeaveBack],
			toggleActions = isToggle && vars.toggleActions.split(" "),
			markers = "markers" in vars ? vars.markers : _defaults.markers,
			borderWidth = isViewport ? 0 : parseFloat(_getComputedStyle(scroller)["border" + direction.p2 + _Width]) || 0,
			self = this,
			onRefreshInit = vars.onRefreshInit && (() => vars.onRefreshInit(self)),
			getScrollerSize = _getSizeFunc(scroller, isViewport, direction),
			getScrollerOffsets = _getOffsetsFunc(scroller, isViewport),
			lastSnap = 0,
			lastRefresh = 0,
			prevProgress = 0,
			scrollFunc = _getScrollFunc(scroller, direction),
			tweenTo, pinCache, snapFunc, scroll1, scroll2, start, end, markerStart, markerEnd, markerStartTrigger, markerEndTrigger, markerVars, executingOnRefresh,
			change, pinOriginalState, pinActiveState, pinState, spacer, offset, pinGetter, pinSetter, pinStart, pinChange, spacingStart, spacerState, markerStartSetter, pinMoves,
			markerEndSetter, cs, snap1, snap2, scrubTween, scrubSmooth, snapDurClamp, snapDelayedCall, prevScroll, prevAnimProgress, caMarkerSetter, customRevertReturn;

		// for the sake of efficiency, _startClamp/_endClamp serve like a truthy value indicating that clamping was enabled on the start/end, and ALSO store the actual pre-clamped numeric value. We tap into that in ScrollSmoother for speed effects. So for example, if start="clamp(top bottom)" results in a start of -100 naturally, it would get clamped to 0 but -100 would be stored in _startClamp.
		self._startClamp = self._endClamp = false;
		self._dir = direction;
		anticipatePin *= 45;
		self.scroller = scroller;
		self.scroll = containerAnimation ? containerAnimation.time.bind(containerAnimation) : scrollFunc;
		scroll1 = scrollFunc();
		self.vars = vars;
		animation = animation || vars.animation;
		if ("refreshPriority" in vars) {
			_sort = 1;
			vars.refreshPriority === -9999 && (_primary = self); // used by ScrollSmoother
		}
		scrollerCache.tweenScroll = scrollerCache.tweenScroll || {
			top: _getTweenCreator(scroller, _vertical),
			left: _getTweenCreator(scroller, _horizontal)
		};
		self.tweenTo = tweenTo = scrollerCache.tweenScroll[direction.p];
		self.scrubDuration = value => {
			scrubSmooth = _isNumber(value) && value;
			if (!scrubSmooth) {
				scrubTween && scrubTween.progress(1).kill();
				scrubTween = 0;
			} else {
				scrubTween ? scrubTween.duration(value) : (scrubTween = gsap.to(animation, {ease: "expo", totalProgress: "+=0", inherit: false, duration: scrubSmooth, paused: true, onComplete: () => onScrubComplete && onScrubComplete(self)}));
			}
		};
		if (animation) {
			animation.vars.lazy = false;
			(animation._initted && !self.isReverted) || (animation.vars.immediateRender !== false && vars.immediateRender !== false && animation.duration() && animation.render(0, true, true)); // special case: if this ScrollTrigger gets re-initted, a from() tween with a stagger could get initted initially and then reverted on the re-init which means it'll need to get rendered again here to properly display things. Otherwise, See https://gsap.com/forums/topic/36777-scrollsmoother-splittext-nextjs/ and https://codepen.io/GreenSock/pen/eYPyPpd?editors=0010
			self.animation = animation.pause();
			animation.scrollTrigger = self;
			self.scrubDuration(scrub);
			snap1 = 0;
			id || (id = animation.vars.id);
		}

		if (snap) {
			// TODO: potential idea: use legitimate CSS scroll snapping by pushing invisible elements into the DOM that serve as snap positions, and toggle the document.scrollingElement.style.scrollSnapType onToggle. See https://codepen.io/GreenSock/pen/JjLrgWM for a quick proof of concept.
			if (!_isObject(snap) || snap.push) {
				snap = {snapTo: snap};
			}
			("scrollBehavior" in _body.style) && gsap.set(isViewport ? [_body, _docEl] : scroller, {scrollBehavior: "auto"}); // smooth scrolling doesn't work with snap.
			_scrollers.forEach(o => _isFunction(o) && o.target === (isViewport ? _doc.scrollingElement || _docEl : scroller) && (o.smooth = false)); // note: set smooth to false on both the vertical and horizontal scroll getters/setters
			snapFunc = _isFunction(snap.snapTo) ? snap.snapTo : snap.snapTo === "labels" ? _getClosestLabel(animation) : snap.snapTo === "labelsDirectional" ? _getLabelAtDirection(animation) : snap.directional !== false ? (value, st) => _snapDirectional(snap.snapTo)(value, _getTime() - lastRefresh < 500 ? 0 : st.direction) : gsap.utils.snap(snap.snapTo);
			snapDurClamp = snap.duration || {min: 0.1, max: 2};
			snapDurClamp = _isObject(snapDurClamp) ? _clamp(snapDurClamp.min, snapDurClamp.max) : _clamp(snapDurClamp, snapDurClamp);
			snapDelayedCall = gsap.delayedCall(snap.delay || (scrubSmooth / 2) || 0.1, () => {
				let scroll = scrollFunc(),
					refreshedRecently = _getTime() - lastRefresh < 500,
					tween = tweenTo.tween;
				if ((refreshedRecently || Math.abs(self.getVelocity()) < 10) && !tween && !_pointerIsDown && lastSnap !== scroll) {
					let progress = (scroll - start) / change, // don't use self.progress because this might run between the refresh() and when the scroll position updates and self.progress is set properly in the update() method.
						totalProgress = animation && !isToggle ? animation.totalProgress() : progress,
						velocity = refreshedRecently ? 0 : ((totalProgress - snap2) / (_getTime() - _time2) * 1000) || 0,
						change1 = gsap.utils.clamp(-progress, 1 - progress, _abs(velocity / 2) * velocity / 0.185),
						naturalEnd = progress + (snap.inertia === false ? 0 : change1),
						endValue, endScroll,
						{ onStart, onInterrupt, onComplete } = snap;
					endValue = snapFunc(naturalEnd, self);
					_isNumber(endValue) || (endValue = naturalEnd); // in case the function didn't return a number, fall back to using the naturalEnd
					endScroll = Math.max(0, Math.round(start + endValue * change));
					if (scroll <= end && scroll >= start && endScroll !== scroll) {
						if (tween && !tween._initted && tween.data <= _abs(endScroll - scroll)) { // there's an overlapping snap! So we must figure out which one is closer and let that tween live.
							return;
						}
						if (snap.inertia === false) {
							change1 = endValue - progress;
						}
						tweenTo(endScroll, {
							duration: snapDurClamp(_abs( (Math.max(_abs(naturalEnd - totalProgress), _abs(endValue - totalProgress)) * 0.185 / velocity / 0.05) || 0)),
							ease: snap.ease || "power3",
							data: _abs(endScroll - scroll), // record the distance so that if another snap tween occurs (conflict) we can prioritize the closest snap.
							onInterrupt: () => snapDelayedCall.restart(true) && onInterrupt && onInterrupt(self),
							onComplete() {
								self.update();
								lastSnap = scrollFunc();
								if (animation && !isToggle) { // the resolution of the scrollbar is limited, so we should correct the scrubbed animation's playhead at the end to match EXACTLY where it was supposed to snap
									scrubTween ? scrubTween.resetTo("totalProgress", endValue, animation._tTime / animation._tDur) : animation.progress(endValue);
								}
								snap1 = snap2 = animation && !isToggle ? animation.totalProgress() : self.progress;
								onSnapComplete && onSnapComplete(self);
								onComplete && onComplete(self);
							}
						}, scroll, change1 * change, endScroll - scroll - change1 * change);
						onStart && onStart(self, tweenTo.tween);
					}
				} else if (self.isActive && lastSnap !== scroll) {
					snapDelayedCall.restart(true);
				}
			}).pause();
		}
		id && (_ids[id] = self);
		trigger = self.trigger = _getTarget(trigger || (pin !== true && pin));

		// if a trigger has some kind of scroll-related effect applied that could contaminate the "y" or "x" position (like a ScrollSmoother effect), we needed a way to temporarily revert it, so we use the stRevert property of the gsCache. It can return another function that we'll call at the end so it can return to its normal state.
		customRevertReturn = trigger && trigger._gsap && trigger._gsap.stRevert;
		customRevertReturn && (customRevertReturn = customRevertReturn(self));

		pin = pin === true ? trigger : _getTarget(pin);
		_isString(toggleClass) && (toggleClass = {targets: trigger, className: toggleClass});
		if (pin) {
			(pinSpacing === false || pinSpacing === _margin) || (pinSpacing = !pinSpacing && pin.parentNode && pin.parentNode.style && _getComputedStyle(pin.parentNode).display === "flex" ? false : _padding); // if the parent is display: flex, don't apply pinSpacing by default. We should check that pin.parentNode is an element (not shadow dom window)
			self.pin = pin;
			pinCache = gsap.core.getCache(pin);
			if (!pinCache.spacer) { // record the spacer and pinOriginalState on the cache in case someone tries pinning the same element with MULTIPLE ScrollTriggers - we don't want to have multiple spacers or record the "original" pin state after it has already been affected by another ScrollTrigger.
				if (pinSpacer) {
					pinSpacer = _getTarget(pinSpacer);
					pinSpacer && !pinSpacer.nodeType && (pinSpacer = pinSpacer.current || pinSpacer.nativeElement); // for React & Angular
					pinCache.spacerIsNative = !!pinSpacer;
					pinSpacer && (pinCache.spacerState = _getState(pinSpacer));
				}
				pinCache.spacer = spacer = pinSpacer || _doc.createElement("div");
				spacer.classList.add("pin-spacer");
				id && spacer.classList.add("pin-spacer-" + id);
				pinCache.pinState = pinOriginalState = _getState(pin);
			} else {
				pinOriginalState = pinCache.pinState;
			}
			vars.force3D !== false && gsap.set(pin, {force3D: true});
			self.spacer = spacer = pinCache.spacer;
			cs = _getComputedStyle(pin);
			spacingStart = cs[pinSpacing + direction.os2];
			pinGetter = gsap.getProperty(pin);
			pinSetter = gsap.quickSetter(pin, direction.a, _px);
			// pin.firstChild && !_maxScroll(pin, direction) && (pin.style.overflow = "hidden"); // protects from collapsing margins, but can have unintended consequences as demonstrated here: https://codepen.io/GreenSock/pen/1e42c7a73bfa409d2cf1e184e7a4248d so it was removed in favor of just telling people to set up their CSS to avoid the collapsing margins (overflow: hidden | auto is just one option. Another is border-top: 1px solid transparent).
			_swapPinIn(pin, spacer, cs);
			pinState = _getState(pin);
		}
		if (markers) {
			markerVars = _isObject(markers) ? _setDefaults(markers, _markerDefaults) : _markerDefaults;
			markerStartTrigger = _createMarker("scroller-start", id, scroller, direction, markerVars, 0);
			markerEndTrigger = _createMarker("scroller-end", id, scroller, direction, markerVars, 0, markerStartTrigger);
			offset = markerStartTrigger["offset" + direction.op.d2];
			let content = _getTarget(_getProxyProp(scroller, "content") || scroller);
			markerStart = this.markerStart = _createMarker("start", id, content, direction, markerVars, offset, 0, containerAnimation);
			markerEnd = this.markerEnd = _createMarker("end", id, content, direction, markerVars, offset, 0, containerAnimation);
			containerAnimation && (caMarkerSetter = gsap.quickSetter([markerStart, markerEnd], direction.a, _px));
			if ((!useFixedPosition && !(_proxies.length && _getProxyProp(scroller, "fixedMarkers") === true))) {
				_makePositionable(isViewport ? _body : scroller);
				gsap.set([markerStartTrigger, markerEndTrigger], {force3D: true});
				markerStartSetter = gsap.quickSetter(markerStartTrigger, direction.a, _px);
				markerEndSetter = gsap.quickSetter(markerEndTrigger, direction.a, _px);
			}
		}

		if (containerAnimation) {
			let oldOnUpdate = containerAnimation.vars.onUpdate,
				oldParams = containerAnimation.vars.onUpdateParams;
			containerAnimation.eventCallback("onUpdate", () => {
				self.update(0, 0, 1);
				oldOnUpdate && oldOnUpdate.apply(containerAnimation, oldParams || []);
			});
		}

		self.previous = () => _triggers[_triggers.indexOf(self) - 1];
		self.next = () => _triggers[_triggers.indexOf(self) + 1];

		self.revert = (revert, temp) => {
			if (!temp) { return self.kill(true); } // for compatibility with gsap.context() and gsap.matchMedia() which call revert()
			let r = revert !== false || !self.enabled,
				prevRefreshing = _refreshing;
			if (r !== self.isReverted) {
				if (r) {
					prevScroll = Math.max(scrollFunc(), self.scroll.rec || 0); // record the scroll so we can revert later (repositioning/pinning things can affect scroll position). In the static refresh() method, we first record all the scroll positions as a reference.
					prevProgress = self.progress;
					prevAnimProgress = animation && animation.progress();
				}
				markerStart && [markerStart, markerEnd, markerStartTrigger, markerEndTrigger].forEach(m => m.style.display = r ? "none" : "block");
				if (r) {
					_refreshing = self;
					self.update(r); // make sure the pin is back in its original position so that all the measurements are correct. do this BEFORE swapping the pin out
				}
				if (pin && (!pinReparent || !self.isActive)) {
					if (r) {
						_swapPinOut(pin, spacer, pinOriginalState);
					} else {
						_swapPinIn(pin, spacer, _getComputedStyle(pin), spacerState);
					}
				}
				r || self.update(r); // when we're restoring, the update should run AFTER swapping the pin into its pin-spacer.
				_refreshing = prevRefreshing; // restore. We set it to true during the update() so that things fire properly in there.
				self.isReverted = r;
			}
		}

		self.refresh = (soft, force, position, pinOffset) => { // position is typically only defined if it's coming from setPositions() - it's a way to skip the normal parsing. pinOffset is also only from setPositions() and is mostly related to fancy stuff we need to do in ScrollSmoother with effects
			if ((_refreshing || !self.enabled) && !force) {
				return;
			}
			if (pin && soft && _lastScrollTime) {
				_addListener(ScrollTrigger, "scrollEnd", _softRefresh);
				return;
			}
			!_refreshingAll && onRefreshInit && onRefreshInit(self);
			_refreshing = self;
			if (tweenTo.tween && !position) { // we skip this if a position is passed in because typically that's from .setPositions() and it's best to allow in-progress snapping to continue.
				tweenTo.tween.kill();
				tweenTo.tween = 0;
			}
			scrubTween && scrubTween.pause();

			if (invalidateOnRefresh && animation) {
				animation.revert({kill: false}).invalidate();
				animation.getChildren && animation.getChildren(true, true, false).forEach(t => t.vars.immediateRender && t.render(0, true, true)); // any from() or fromTo() tweens inside a timeline should render immediately (well, unless they have immediateRender: false)
			}

			self.isReverted || self.revert(true, true);
			self._subPinOffset = false; // we'll set this to true in the sub-pins if we find any
			let size = getScrollerSize(),
				scrollerBounds = getScrollerOffsets(),
				max = containerAnimation ? containerAnimation.duration() : _maxScroll(scroller, direction),
				isFirstRefresh = change <= 0.01 || !change,
				offset = 0,
				otherPinOffset = pinOffset || 0,
				parsedEnd = _isObject(position) ? position.end : vars.end,
				parsedEndTrigger = vars.endTrigger || trigger,
				parsedStart = _isObject(position) ? position.start : (vars.start || (vars.start === 0 || !trigger ? 0 : (pin ? "0 0" : "0 100%"))),
				pinnedContainer = self.pinnedContainer = vars.pinnedContainer && _getTarget(vars.pinnedContainer, self),
				triggerIndex = (trigger && Math.max(0, _triggers.indexOf(self))) || 0,
				i = triggerIndex,
				cs, bounds, scroll, isVertical, override, curTrigger, curPin, oppositeScroll, initted, revertedPins, forcedOverflow, markerStartOffset, markerEndOffset;
			if (markers && _isObject(position)) { // if we alter the start/end positions with .setPositions(), it generally feeds in absolute NUMBERS which don't convey information about where to line up the markers, so to keep it intuitive, we record how far the trigger positions shift after applying the new numbers and then offset by that much in the opposite direction. We do the same to the associated trigger markers too of course.
				markerStartOffset = gsap.getProperty(markerStartTrigger, direction.p);
				markerEndOffset = gsap.getProperty(markerEndTrigger, direction.p);
			}
			while (i-- > 0) { // user might try to pin the same element more than once, so we must find any prior triggers with the same pin, revert them, and determine how long they're pinning so that we can offset things appropriately. Make sure we revert from last to first so that things "rewind" properly.
				curTrigger = _triggers[i];
				curTrigger.end || curTrigger.refresh(0, 1) || (_refreshing = self); // if it's a timeline-based trigger that hasn't been fully initialized yet because it's waiting for 1 tick, just force the refresh() here, otherwise if it contains a pin that's supposed to affect other ScrollTriggers further down the page, they won't be adjusted properly.
				curPin = curTrigger.pin;
				if (curPin && (curPin === trigger || curPin === pin || curPin === pinnedContainer) && !curTrigger.isReverted) {
					revertedPins || (revertedPins = []);
					revertedPins.unshift(curTrigger); // we'll revert from first to last to make sure things reach their end state properly
					curTrigger.revert(true, true);
				}
				if (curTrigger !== _triggers[i]) { // in case it got removed.
					triggerIndex--;
					i--;
				}
			}
			_isFunction(parsedStart) && (parsedStart = parsedStart(self));
			parsedStart = _parseClamp(parsedStart, "start", self);
			start = _parsePosition(parsedStart, trigger, size, direction, scrollFunc(), markerStart, markerStartTrigger, self, scrollerBounds, borderWidth, useFixedPosition, max, containerAnimation, self._startClamp && "_startClamp") || (pin ? -0.001 : 0);
			_isFunction(parsedEnd) && (parsedEnd = parsedEnd(self));
			if (_isString(parsedEnd) && !parsedEnd.indexOf("+=")) {
				if (~parsedEnd.indexOf(" ")) {
					parsedEnd = (_isString(parsedStart) ? parsedStart.split(" ")[0] : "") + parsedEnd;
				} else {
					offset = _offsetToPx(parsedEnd.substr(2), si