Stack to Content Layout Transition

/**
 * Class representing a Content Item
 */
 export class ContentItem {
    // DOM elements
	DOM = {
		// main element (.content__item)
		el: null,
        // title (.content__item-title)
        title: null,
        // description (.content__item-description)
        description: null,
        // all .oh__inner text spans that will animate in/out
        texts: null
	}
    
    /**
	 * Constructor.
	 * @param {NodeList} DOM_el - main element (.content__item)
	 */
	constructor(DOM_el) {
		this.DOM.el = DOM_el;
        this.DOM.title = this.DOM.el.querySelector('.content__item-title');
        this.DOM.description = this.DOM.el.querySelector('.content__item-description');

        this.DOM.texts = [...this.DOM.el.querySelectorAll('.oh > .oh__inner')];
	}
}

import { preloadImages } from './utils';
import { Slideshow } from './slideshow';

const slideshow = new Slideshow(document.querySelector('.stack'));

// Preload images
preloadImages('.stack__item').then( _ => document.body.classList.remove('loading'));

import { ContentItem } from './contentItem';
import { gsap } from 'gsap';
import { Flip } from 'gsap/Flip';
gsap.registerPlugin(Flip);
import { Observer } from 'gsap/Observer';
gsap.registerPlugin(Observer);

const body = document.body;

let winsize = {width: window.innerWidth, height: window.innerHeight};
window.addEventListener('resize', () => {
	winsize = {width: window.innerWidth, height: window.innerHeight};
});

/**
 * Class representing the Slideshow
 */
export class Slideshow {
	// DOM elements
	DOM = {
		// main element (.stack)
		el: null,
		// stack items (.stack__item)
		items: null,

		// the DOM location of the .stacks element when the slideshow is closed
		stackWrap: document.querySelector('.stack-wrap'),
		// the DOM location of the .stacks element when the slideshow is open
		slides: document.querySelector('.slides'),
		
		// .content element
		content: document.querySelector('.content'),
		// the content items (.content__item)
		contentItems: [...document.querySelectorAll('.content__item')],
		
		// the main title ("Photography")
		mainTitleTexts: [...document.querySelectorAll('.title > .oh > .oh__inner')],

		// back control (.content__back)
		backCtrl: document.querySelector('.content__back'),
		// navigation (.content__nav-wrap)
		nav: document.querySelector('.content__nav-wrap'),
		// navigation arrows
		navArrows: {
			prev: document.querySelector('.content__nav--prev'),
			next: document.querySelector('.content__nav--next'),
		}
	}
	// Content instances
	contentItems = [];
	// Check is Slishow is in open mode or closed mode
	isOpen = false;
	// Current item's position
	current = -1;
	// Total items
	totalItems = 0;
	// items gap (CSS variable)
	gap = getComputedStyle(document.documentElement).getPropertyValue('--slide-gap');

	/**
	 * Constructor.
	 * @param {NodeList} DOM_el - main element (.stack)
	 */
	constructor(DOM_el) {
		this.DOM.el = DOM_el;
		
		this.DOM.items = [...this.DOM.el.querySelectorAll('.stack__item:not(.stack__item--empty)')];
		this.totalItems = this.DOM.items.length;
		this.DOM.contentItems.forEach(item => this.contentItems.push(new ContentItem(item)));

		this.initEvents();
	}
	/**
	 * Event binding.
	 */
	initEvents() {
		
		this.DOM.items.forEach((item, position) => {
			// Clicking on a stack item reveals the slideshow navigation and the item's content
			item.addEventListener('click', () => {
				// Show the item's content
				this.open(item);
			});
		});

		this.DOM.backCtrl.addEventListener('click', () => {
			this.close();
		});

		this.DOM.navArrows.next.addEventListener('click', () => {
			this.navigate('next');
		});
		this.DOM.navArrows.prev.addEventListener('click', () => {
			this.navigate('prev');
		});

		// Trigger the close() on scroll by using the gsap observer plugin
		const scrollFn = () => {
			if ( this.isOpen && !this.isAnimating ) {
				this.close();
				this.scrollObserver.disable();
			}
		}
		this.scrollObserver = Observer.create({
			type: 'wheel,touch,pointer',
			wheelSpeed: -1,
			onDown: scrollFn,
			onUp: scrollFn,
			tolerance: 10,
			preventDefault: true,
		})
		this.scrollObserver.disable();

	}
	/**
	 * Opens the slideshow navigation and reveals the item's content.
	 * @param {NodeList} stackItem - the clicked item
	 */
	open(stackItem) {

		if ( this.isAnimating || this.isOpen ) {
			return;
		}
		this.isAnimating = true;
		
		// Update the current value
		this.current = this.DOM.items.indexOf(stackItem);

		// enable the observer (closes teh slideshow on scroll/touch)
		this.scrollObserver.enable();

		const scrollY = window.scrollY;
		
		body.classList.add('oh');
		this.DOM.content.classList.add('content--open');
		
		// set CSS current classes to both content and stack item elements
		this.contentItems[this.current].DOM.el.classList.add('content__item--current');
		this.DOM.items[this.current].classList.add('stack__item--current');

		const state = Flip.getState(this.DOM.items, {props: 'opacity'});
		this.DOM.slides.appendChild(this.DOM.el);

		const itemCenter = stackItem.offsetTop + stackItem.offsetHeight/2;
		
		// seems to solve a bug in firefox
		document.documentElement.scrollTop = document.body.scrollTop = 0;

		gsap.set(this.DOM.el, {
			y: winsize.height/2 - itemCenter + scrollY
		});		
		
		// seems to solve a bug in firefox
		document.documentElement.scrollTop = document.body.scrollTop = 0;

		// Flip
		Flip.from(state, {
			duration: 1,
			ease: 'expo',
			onComplete: () => {
				this.isOpen = true;
				this.isAnimating = false;
			},
			// seems to solve a bug in firefox
			onStart: () => document.documentElement.scrollTop = document.body.scrollTop = scrollY,
			absoluteOnLeave: true,
		})
		.to(this.DOM.mainTitleTexts, {
			duration: .9,
			ease: 'expo',
			yPercent: -101
		}, 0)
		.to(this.contentItems[this.current].DOM.texts, {
			duration: 1,
			ease: 'expo',
			startAt: {yPercent: 101},
			yPercent: 0
		}, 0)
		.to(this.DOM.backCtrl, {
			duration: 1,
			ease: 'expo',
			startAt: {opacity: 0},
			opacity: 1
		}, 0)
		.to([this.DOM.navArrows.prev, this.DOM.navArrows.next], {
			duration: 1,
			ease: 'expo',
			startAt: {
				opacity: 0,
				y: pos => pos ? -150 : 150
			},
			y: 0,
			opacity: pos => this.current === 0 && !pos || this.current === this.totalItems-1 && pos ? 0 : 1
		}, 0);

	}
	/**
	 * Closes the slideshow navigation and hides the content
	 */
	close() {

		if ( this.isAnimating || !this.isOpen ) {
			return;
		}
		this.isAnimating = true;

		this.scrollObserver.disable();

		this.DOM.items[this.current].classList.remove('stack__item--current');

		body.classList.remove('oh');
		
		const state = Flip.getState(this.DOM.items, {props: 'opacity'});
		this.DOM.stackWrap.appendChild(this.DOM.el);

		gsap.set(this.DOM.el, {
			y: 0
		});

		// Flip
		Flip.from(state, {
			duration: 1,
			ease: 'expo',
			onComplete: () => {
				this.DOM.content.classList.remove('content--open');
				this.contentItems[this.current].DOM.el.classList.remove('content__item--current');

				this.current = -1;
				this.isOpen = false;
				this.isAnimating = false;
			},
			absoluteOnLeave: true
		})
		.to(this.DOM.mainTitleTexts, {
			duration: .9,
			ease: 'expo',
			startAt: {yPercent: 101},
			yPercent: 0
		}, 0)
		.to(this.contentItems[this.current].DOM.texts, {
			duration: 1,
			ease: 'expo',
			yPercent: -101
		}, 0)
		.to(this.DOM.backCtrl, {
			duration: 1,
			ease: 'expo',
			opacity: 0
		}, 0)
		.to([this.DOM.navArrows.prev, this.DOM.navArrows.next], {
			duration: 1,
			ease: 'expo',
			y: pos => pos ? 100 : -100,
			opacity: 0
		}, 0);
	}
	/**
	 * Navigation
	 * @param {String} direction 'prev' || 'next'
	 */
	navigate(direction) {
		
		if ( this.isAnimating || (direction === 'next' && this.current === this.totalItems-1) || (direction === 'prev' && this.current === 0) ) return;
		this.isAnimating = true;

		const previousCurrent = this.current;
		const currentItem = this.DOM.items[previousCurrent];
		this.current = direction === 'next' ? this.current+1 : this.current-1
		const upcomingItem = this.DOM.items[this.current];
		
		currentItem.classList.remove('stack__item--current');
		upcomingItem.classList.add('stack__item--current');

		// show/hide arrows
		gsap.set(this.DOM.navArrows.prev, {opacity: this.current > 0 ? 1 : 0});
		gsap.set(this.DOM.navArrows.next, {opacity: this.current < this.totalItems-1 ? 1 : 0});
		
		gsap.timeline()
		.to(this.DOM.el, {
			duration: 1,
			ease: 'expo',
			y: direction === 'next' ? `-=${winsize.height/2 + winsize.height*.02}` : `+=${winsize.height/2 + winsize.height*.02}`,
			onComplete: () => {
				this.isAnimating = false;
			}
		})
		.to(this.contentItems[previousCurrent].DOM.texts, {
			duration: .2,
			ease: 'power1',
			yPercent: direction === 'next' ? 101 : -101,
			onComplete: () => this.contentItems[previousCurrent].DOM.el.classList.remove('content__item--current')
		}, 0)
		.to(this.contentItems[this.current].DOM.texts, {
			duration: .9,
			ease: 'expo',
			startAt: {yPercent: direction === 'next' ? -101 : 101},
			onStart: () => this.contentItems[this.current].DOM.el.classList.add('content__item--current'),
			yPercent: 0
		}, .2)
	}
}

const imagesLoaded = require('imagesloaded');

/**
 * Preload images
 * @param {String} selector - Selector/scope from where images need to be preloaded. Default is 'img'
 */
const preloadImages = (selector = 'img') => {
    return new Promise((resolve) => {
        imagesLoaded(document.querySelectorAll(selector), {background: true}, resolve);
    });
};

export {
    preloadImages
};

README.md
## Credits

- Images from [Unsplash](https://unsplash.com/)


## License
[MIT](LICENSE)

Made with :blue_heart:  by [Codrops](http://www.codrops.com)

MIT License

Copyright (c) 2009 - 2021 [Codrops](https://tympanus.net/codrops)

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.

GSAP standard license snapshot
Source: https://gsap.com/community/standard-license/
Retrieved: 2026-09-22T04:22:49.089Z
Original distribution copyright and version headers remain in the runtime code.

Standard "No Charge" GSAP License

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 FAQ

 Is it acceptable for AI tools like ChatGPT, Cursor, Lovable, Webstudio, etc. to generate GSAP code?
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 Yes, really! Commercial usage is covered under the standard license. All of GSAP including the plugins that were formerly "members-only" like SplitText (https://gsap.com/docs/v3/Plugins/SplitText/) and MorphSVG (https://gsap.com/docs/v3/Plugins/MorphSVGPlugin) can be used in commercial projects at no charge. Enjoy! 💚

 Effective date: April 30, 2025

 Last modified date: May 30, 2025

 Copyright (©) 2025, Webflow


ev-emitter@2.1.2 — LICENSE.md
Copyright (c) 2016-2021 [David DeSandro](https://desandro.com)

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.


imagesloaded@5.0.0 — LICENSE.md
Copyright (c) 2011-2022 [David DeSandro](https://desandro.com) and [contributors](https://github.com/desandro/imagesloaded/graphs/contributors)

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.