Scroll animation issue

[Dmytro Ivanovich]

I made an animation of horizontal scrolling, it works fine on a computer, it works poorly on mobile phones, when scrolling, it scrolls in one direction to the end, after which it stops animating.

    let galleryScene = gsap.timeline();
    let item = gsap.utils.toArray(".gallery__item");

const galleryTriger =  new ScrollTrigger.create({
        animation: galleryScene,
        trigger: ".photo-gallery",
        start: "top top",
        end: "+=" + 600,
        // markers: true,
        scrub: 1,
        snap: 1 / (item.length - 1),
        pin: true,
        ease: "none",
    });

function getMoveDistance(){
        let move = document.querySelector('.gallery').scrollWidth;
        let block = document.querySelector('.gallery').offsetWidth ;

        move = (move - block)  * -1;
        galleryScene.clear();
        galleryScene.to(".gallery", 25, {x: move})
    }

    getMoveDistance();

    window.addEventListener('resize', getMoveDistance, true);

 

[GSAP Helper]

It's pretty tough to troubleshoot without a minimal demo - the issue could be caused by CSS, markup, a third party library, your browser, an external script that's totally unrelated to GSAP, etc. Would you please provide a very simple CodePen or CodeSandbox that demonstrates the issue? 

 

Please don't include your whole project. Just some colored <div> elements and the GSAP code is best (avoid frameworks if possible). See if you can recreate the issue with as few dependancies as possible. If not, incrementally add code bit by bit until it breaks. Usually people solve their own issues during this process! If not, then at least we have a reduced test case which greatly increases your chances of getting a relevant answer.

 

Here's a starter CodePen that loads all the plugins. Just click "fork" at the bottom right and make your minimal demo: 

See the Pen aYYOdN by GreenSock (@GreenSock) on CodePen

 

If you're using something like React/Next/Vue/Nuxt or some other framework, you may find StackBlitz easier to use. We have a series of collections with different templates for you to get started on these different frameworks: React/Next/Vue/Nuxt.

 

Once we see an isolated demo, we'll do our best to jump in and help with your GSAP-specific questions. 

[GreenSock]

Mobile devices often show/hide the address bar which causes it to dispatch a bunch of "resize" events. You're re-populating the timeline on every resize event which is overkill. ScrollTrigger automatically throttles those and does a refresh() after 0.2 seconds elapses without a refresh event.

 

You don't need to create a timeline, plus a separate ScrollTrigger, plus a resize event handler. I think your code could be simplified to:

let item = gsap.utils.toArray(".gallery__item"),
    galleryScene = gsap.to(".gallery", {
		x: (i, target) => target.offsetWidth - target.scrollWidth,
		ease: "none",
		scrollTrigger: {
			trigger: ".photo-gallery",
			start: "top top",
			end: "+=" + 600,
			// markers: true,
			scrub: 1,
			snap: 1 / (item.length - 1),
			pin: true,
			invalidateOnRefresh: true
		}
    });

Also, if you don't want ScrollTrigger to do a refresh on mobile devices when the address bar shows/hides, you can just do this: 

ScrollTrigger.config({ignoreMobileResize: true});

My guess is that'll resolve the issue you were seeing. 

 

Good luck!