Cover Flow with Modern CSS: Scroll-Driven Animations in Action

Cover Flow – the iconic carousel of tilted album covers made famous by Apple in the late 2000s – remains a visually striking UI pattern. Originally seen in iTunes and Mac OS X Finder, Cover Flow let users flip through items as if browsing a tangible collection.

Today, we can recreate this effect on the web using only HTML and CSS, thanks to advancements like CSS scroll-driven animations.

In this article, we’ll briefly revisit the history of Cover Flow and traditional implementation methods, then dive into a modern CSS approach inspired by Bramus’ pure-CSS demo - I also have a React version available. We’ll explore how features like CSS Scroll Snap and the new Scroll-Driven Animations API (scroll timelines and the view() function) combine to deliver a smooth Cover Flow without heavy JavaScript. Along the way, we’ll look at code snippets, compare other recent techniques, and discuss performance and accessibility considerations.

A brief history of Cover Flow

Cover Flow began as a third-party idea by Andrew Coulter Enright before becoming synonymous with Apple’s design. In 2006, Apple acquired “CoverFlow” (originally spelled as one word) from a small software developer (Steel Skies) and integrated it into iTunes 7. The concept was simple but captivating: album covers (or file previews) are arranged in a horizontal line, with the centered item facing front and neighboring items angled away. Users could flip through their music library “just as they would CDs,” with the selected cover in focus. This 3D flipping UI (an “animated, three-dimensional graphical user interface element”) eventually appeared across Apple’s products – from iTunes to the iPod to the Mac’s Finder – as a novel way to visually browse content.

While Cover Flow was eye-catching, it was also resource-intensive on early devices. Over time, Apple retired the feature (it disappeared from iTunes and Finder in the early 2010s), but its legacy lives on. Developers have long sought to recreate Cover Flow on the web and in apps because it provides a visually rich, tactile browsing experience that plain grids or lists can’t match.

Traditional web implementations of Cover Flow

Before modern CSS capabilities, implementing Cover Flow on the web required clever workarounds. Early attempts often leaned on JavaScript and even Flash to mimic the 3D carousel effect:

• Flash-based galleries: In the late 2000s, before CSS3 was widely supported, Flash was used to render the 3D rotating carousel. Developers built Cover Flow-like components in ActionScript to achieve smooth animations and reflections that weren’t yet feasible with HTML/CSS.

• JavaScript + CSS Transforms: As browsers began to support CSS3 3D transforms (with vendor prefixes like -webkit-transform), JavaScript libraries sprang up to create Cover Flow. These scripts would handle the math and state: positioning each item in 3D space (using translate and rotateY for the angled look, plus scale for depth), and listening for arrow clicks or scroll events to advance the carousel. Libraries or plugins (e.g. jQuery CoverFlow plugins) and later React components encapsulated this logic. They essentially treated the Cover Flow as a specialized carousel: JavaScript would set the transform on each item based on an “active index,” and often use easing for the transition.

• WebGL or Canvas solutions: A few implementations even leveraged <canvas> or WebGL to render the covers in 3D space, especially before CSS 3D was consistent. This provided flexibility for lighting or smoother performance on some devices, at the cost of complexity. Below is a Three.js example of a Cover Flow-like effect I just published to GitHub. It’s relatively straight-forward to use and the demo should work in most modern browsers at 60fps.

• Heavy DOM updates: In older approaches, each frame of the animation might involve recalculating positions and updating many elements’ styles (e.g. via requestAnimationFrame). Without careful optimization, this could cause reflows or jank. Developers learned to offload work to the GPU by using CSS transform (which doesn’t trigger reflow of other elements) and opacity changes, rather than animating layout-affecting properties.

Traditional methods demonstrated that Cover Flow could be done, but often with significant JavaScript and performance tuning. There are a number of implementations I’ve liked including Coverflow.js by Shuding:

There are a number of others that are maintained, such as the Swiper.js Coverflow.

Older attempts at Cover Flow would attach handlers to arrow buttons or mouse scroll, then update classes or inline styles on dozens of list items to rotate the correct ones into view. Reflection effects under each cover (as seen in iTunes) were another challenge: some used duplicate flipped images or complex CSS tricks, and Flash implementations sometimes handled reflections via image processing. All of this made classic Cover Flow implementations relatively heavy.

Modern CSS to the Rescue: Scroll Snap & Scroll-Driven Animations

Fast-forward to today: modern CSS has evolved to handle interactive animation patterns that previously required JavaScript. Two CSS features in particular make a pure-CSS Cover Flow possible: CSS Scroll Snap and CSS Scroll-Driven Animations.

• CSS Scroll Snap: The allows us to create scrollable carousels that snap to discrete positions. For Cover Flow, we can lay out all the “covers” in a row inside a scroll container and use scroll snapping so that one item is always centered. This gives us the basic interactive behavior (scrolling through covers one by one) without any JavaScript. The user can flick or drag the carousel, and it will neatly snap so that a cover is centered.

• CSS Scroll-Driven Animations: This is an exciting new addition to CSS that lets us tie animations to the scroll position using only CSS. In essence, we can define an animation timeline that progresses as the user scrolls, rather than over a timed duration. Specifically, CSS can track an element’s position in a scroll container (using a view timeline), and drive keyframe animations based on that. This means as a cover moves into the center of the viewport, we can animate its properties (like rotation or z-index) accordingly. All of this is done in CSS without JavaScript observers.

Scroll-Driven Animations 101 (Scroll vs. View Timelines)

To understand the technique, let’s briefly recap how scroll-driven animations work in CSS. There are two types of scroll-driven timelines: scroll progress and view progress timelines. A scroll progress timeline links an animation to the scroll position of a container (e.g., scrolling a page drives an animation progress). A view progress timeline (also known as a view timeline) tracks the position of a particular element within a scroll viewport – essentially when the element enters, centers, and exits the container. This latter type is exactly what we need for Cover Flow: we want to animate each cover based on where it is relative to the center of the carousel.

CSS provides a convenient function view() for simple cases: for example, one line of CSS can make an image fade in as it scrolls into view by tying its opacity animation to a view timeline. Under the hood, animation-timeline: view(); creates a timeline that goes from 0% to 100% as the element goes from out-of-view to fully in-view. For finer control or multiple animations, we can also define named view timelines. This involves assigning a custom timeline to an element (e.g. via view-timeline-name) and then referencing that name in animation-timeline for any animations we want to drive.

Pure CSS Cover Flow: Bramus’ implementation

Frontend developer Bramus Van Damme (@bramus) showcased a Cover Flow demo built entirely with HTML + CSS, using scroll snapping and scroll-driven animations. Let’s break down how it works:

• HTML structure: The covers are simply an unordered list of images. For example:

<ul class="cards">
    <li>
        <img draggable="false" 
            src="album-cover-1.jpg" 
            width="1200" height="1200" 
            alt="Album cover" />
    </li>
    <li>
        <img draggable="false" 
            src="album-cover-2.jpg" 
            width="1200" height="1200" 
            alt="Album cover" />
    </li>
    <!-- More list items with album covers -->
</ul>

There are no special elements per item, just an <img> inside each <li>. This simplicity is possible because all the behavior (snapping and animating) will be handled by CSS.

• Base CSS layout and Scroll Snap: The list is styled as a horizontal strip of covers. We ensure the <ul> scrolls horizontally and that exactly one cover is centered at a time:

.cards {
  list-style: none;
  white-space: nowrap;
  overflow-x: auto;
  scroll-snap-type: x mandatory;   /* Snap scrolling on horizontal axis */
}
.cards li {
  display: inline-block;
  width: var(--cover-size);
  aspect-ratio: 1;
  scroll-snap-align: center;      /* Each item snaps to center */
}

In the above snippet, white-space: nowrap and inline-block <li> elements place all covers in one line that can scroll. We use scroll-snap-type: x mandatory on the container and scroll-snap-align: center on items so that as you scroll, the nearest cover will lock into the center position. The CSS variable --cover-size can be used to set a consistent size for the cover images (for example, 300px or similar). The container’s overflow is set to auto (scrollable); in a real design you might hide the scrollbar for a cleaner look.

• Reflection effect (optional): In Apple’s Cover Flow, each cover had a reflection below it. This can be achieved in modern CSS using the non-standard -webkit-box-reflect property (WebKit/Blink only):

.cards li img {
  /* ... normal image styles ... */
  -webkit-box-reflect: below 0.5em 
      linear-gradient(transparent, rgba(0,0,0,0.25));
}

This reflects the image below itself with a gradient fade-out. It’s a nice visual touch, though not essential to the core effect (and not supported in Firefox at the time of writing).

• Establishing a View Timeline: Here’s the magic that powers the animation. We want CSS to know how far each cover <li> is along its journey through the carousel (from off-screen left to center to off-screen right). Using the Scroll-Driven Animations API, we create a view timeline for each item:

.cards li {
  /* Track this element as it enters/exits the scroll container */
  view-timeline-name: --li-in-and-out-of-view;
  view-timeline-axis: inline;
}

This declares a timeline named --li-in-and-out-of-view on each <li> element, tracking along the “inline” axis (horizontal, in this case). Now, as each <li> scrolls through the viewport of its parent, CSS will calculate a progress value for that timeline: 0% when the item just starts to appear on the left, 50% when it’s perfectly centered, and 100% when it’s about to disappear on the right. Essentially, we’ve set up something analogous to an IntersectionObserver in CSS – each cover knows where it is relative to the center of the carousel.

• Keyframe animations for the Cover Flow effect: We have two separate animations to apply: one to adjust the stacking order of the item (so the centered cover appears on top of the others), and one to handle the 3D rotation/position of the cover image itself.

  1. Z-index bump (stacking): The centered item should overlap the others. We animate the <li>’s z-index such that it’s low (e.g. 1) normally, but high when at the 50% mark (center):

      @keyframes adjust-z-index {
        0%   { z-index: 1; }
        50%  { z-index: 100; /* when centered, bring to front */ }
        100% { z-index: 1; }
      }
     

     At the scroll timeline’s midpoint (when the item is centered), z-index becomes 100, ensuring the focused cover renders above its neighbors. Before and after center, z-index goes back to 1.

  2. 3D rotation (the cover angle): Each cover image needs to rotate and slide as it moves. When off to the side, it should be angled (~45 degrees) and partially out of view; when centered, it faces forward and appears larger/closer:

      @keyframes rotate-cover {
        0%   { transform: translateX(-100%) rotateY(-45deg); }
        35%  { transform: translateX(0) rotateY(-45deg); }
        50%  { transform: rotateY(0deg) translateZ(1em) scale(1.5); }
        65%  { transform: translateX(0) rotateY(45deg); }
        100% { transform: translateX(100%) rotateY(45deg); }
      }
     

     Let’s unpack these values:

     • At 0%, when the item is just entering from the left, it’s positioned slightly to the left (translateX(-100%)) and rotated -45° around the Y-axis (tilted away).
     • By 35%, it has moved into the frame (translateX(0)) but is still rotated at -45°, meaning as it approaches center it’s fully visible but angled.
     • At 50% (centered), the image is facing forward (rotateY(0)), and we also pop it out a bit (translateZ(1em)) and scale it up 1.5x – this gives a nice emphasis to the center cover, as if it’s closer to the viewer.
     • After that, symmetrically, by 65% the image has started rotating the other direction (45°) and by 100% (exiting right) it’s fully rotated 45° and moved out to the right (translateX(100%)).

     The combination of translation and rotation creates the smooth swinging-in/out effect on each side. These specific keyframe percentages (35% and 65%) provide a bit of easing around the center; effectively the cover stays flat from 50% (center) until about 65%, then starts rotating out.

     The result: as you scroll, whichever cover is near the center will gradually straighten up and enlarge, and as it leaves center it turns and recedes.

• Linking animations to the scroll timeline: Now we tie it all together. We want each <li> to use our custom timeline to run the adjust-z-index animation, and each <img> to use the same timeline to run the rotate-cover animation:

.cards li {
  /* Use the view timeline to drive z-index animation */
  animation: adjust-z-index linear both;
  animation-timeline: --li-in-and-out-of-view;
  perspective: 40em;
}
.cards li > img {
  /* Use the same timeline (of parent <li>) to drive rotation */
  animation: rotate-cover linear both;
  animation-timeline: --li-in-and-out-of-view;
}

We set animation-duration: auto implicitly by using a scroll timeline – meaning the duration is controlled by the scroll progress rather than a fixed time. The linear timing function is used so the animation follows the scroll exactly (no easing, since the scroll position itself is the ease). Also, both (equivalent to fill-mode: both) ensures the animation’s end-state is retained when out of range. We add a perspective: 40em on the parent <li> to give a sense of 3D depth for the child image’s 3D transforms (this is like setting up a camera perspective for the 3D scene).

Because we didn’t specify an explicit animation-range, the animation automatically runs for the element’s entire time in view (entry to exit) – this default “cover” range is exactly what we want. Now, as the user scrolls the carousel, the CSS engine adjusts each element’s timeline progress and applies the corresponding keyframe state. The center item gets z-index:100 and a face-forward transform, neighbors are partway, and distant ones are angled.

• Why animate the <img> and not the <li>: One subtle but important trick in Bramus’ implementation is that the 3D transform (rotate/translate) is applied to the <img> inside the <li>, not on the <li> itself. This is to avoid affecting the document flow. If we rotated or scaled the <li> container, it would actually change its bounding box and could alter the scroll width (since a rotated element might take more space), causing janky scroll behavior. By keeping the <li> dimensions constant (and only changing its child), the scroll snapping and positioning remain stable. As Bramus notes: if the <li> itself were transformed, the total scroll distance would change, leading to flicker; by rotating the inner <img>, the <li>’s layout is untouched and no flicker occurs. This is a great performance tip for any scroll-linked animation: avoid transformations that affect layout, stick to transforms on inner elements or absolutely positioned children.

Here’s the complete CSS for the core Cover Flow effect:

/* Animation that rotates the cover */
@keyframes rotate-cover {
  0% {
    transform: translateX(-100%) rotateY(-45deg);
  }
  35% {
    transform: translateX(0) rotateY(-45deg);
  }
  50% {
    transform: rotateY(0deg) translateZ(1em) scale(1.5);
  }
  65% {
    transform: translateX(0) rotateY(45deg);
  }
  100% {
    transform: translateX(100%) rotateY(45deg);
  }
}

/* Animation that adjusts z-index */
@keyframes adjust-z-index {
  0% { z-index: 1; }
  50% { z-index: 100; /* When at the center, be on top */ }
  100% { z-index: 1; }
}

/* Container setup */
.cards-wrapper {
  perspective: 40em;
}
.cards {
  transform-style: preserve-3d;
  list-style: none;
  white-space: nowrap;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
}

/* List item setup */
.cards li {
  transform-style: preserve-3d;
  display: inline-block;
  width: var(--cover-size);
  aspect-ratio: 1;
  scroll-snap-align: center;
  
  /* Create the named view timeline */
  view-timeline-name: --li-in-and-out-of-view;
  view-timeline-axis: inline;
  
  /* Apply the z-index animation */
  animation: adjust-z-index linear both;
  animation-timeline: --li-in-and-out-of-view;
  perspective: 40em;
}

/* Image styling and animation */
.cards li img {
  width: 100%;
  height: auto;
  
  /* Optional reflection */
  -webkit-box-reflect: below 0.5em linear-gradient(transparent, rgba(0,0,0,0.25));
  
  /* Apply the rotation animation */
  animation: rotate-cover linear both;
  animation-timeline: --li-in-and-out-of-view;
  
  /* Prevent FOUC with polyfill */
  transform: translateX(-100%) rotateY(-45deg);
  transform-style: preserve-3d;
  will-change: transform;
  
  position: relative;
  user-select: none;
}

At this point, we have a fully functional Cover Flow purely in CSS! As you scroll the .cards list, each item animates according to its scroll position. The center one pops out, others angle away, and the snapping ensures you land exactly with one centered. The experience is silky smooth because the animations are handled by the browser’s compositor and are tied to scrolling (no JavaScript running on scroll).

Comparing other modern approaches

The CSS method above is cutting-edge, but it’s worth noting other approaches from the past few years that developers have used to achieve Cover Flow or similar “cover carousel” effects:

• React Coverflow components: Several React libraries implement Cover Flow as a ready-made component. For example, react-coverflow provides a <Coverflow> component that handles the layout and animation via React state and CSS transforms. These typically still rely on JavaScript under the hood (managing which item is active, responding to user input), but abstract away the details. With scroll-driven CSS, one could build a similar carousel with far less JS, possibly making these libraries less necessary going forward.

import React from 'react';
import ReactDOM from 'react-dom';
import Coverflow from 'react-coverflow';

const fn = function () {
  /* do your action */
}

ReactDOM.render(
  <Coverflow width="960" height="500" classes= className=''
    displayQuantityOfSide={2}
    navigation={false}
    enableScroll={true}
    clickable={true}
    active={0}
  >
    <div
      onClick={() => fn()}
      onKeyDown={() => fn()}
      role="menuitem"
      tabIndex="0"
    >
      <img
        src='image/01.jpg'
        alt='title or description'
        style=
      />
    </div>
    <img src='image/02.jpg' alt='title or description' data-action="..."/>
    <img src='image/03.jpg' alt='title or description' data-action="..."/>
  </Coverflow>,

  document.querySelector('.content')
);

• CSS Scroll Snap + :target or :focus tricks: Before the scroll-linked animations API, creative developers used pure CSS hacks to animate the focused item. One approach was using the :target pseudo-class or radio inputs: for example, each cover is linked to an anchor, and CSS :target selectors adjust transforms so the targeted item is large and centered while others are angled. Navigating between items can be done by updating the URL hash or using hidden radio inputs (a known pure CSS carousel technique). However, these approaches can be clunky and lack the smooth interpolated motion that true animations provide.

• IntersectionObserver + CSS Variables: A more script-driven (but light) approach used in recent years is to leverage the IntersectionObserver API to watch when an item is in the center of the carousel. The script can then add a class like .active to the centered item and maybe .prev/.next to its neighbors. CSS can then apply different transform styles to those classes. This is simpler than managing a full animation via JS, but it only gives you discrete states (center vs not) rather than a continuously interpolating animation. Now that the browser can handle that linking natively, it’s easier and more performant to let CSS do it.

• Popular CodePen demos: The web dev community has produced many Cover Flow-inspired pens. Some use pure CSS (like one by Chris Coyier that used scroll-snap and :focus-within to enlarge the centered card), others use a touch of JS. A recent example by Jhey Tompkins showcased an “Infinite Cover Flow” using scroll-driven animations and clever CSS, creating a looping illusion. The general trend is clear: less JavaScript, more CSS. What once might have been done with GSAP or jQuery UI is now often achieved with a few lines of CSS keyframes and the browser’s native scroll abilities.

Performance considerations

One of the biggest advantages of using modern CSS for Cover Flow is performance. Scroll-driven animations run off the main thread, meaning they don’t bog down JavaScript execution. The heavy lifting is done by the browser’s rendering engine, often on the compositor thread, which is optimized for animations. In fact, these CSS animations are GPU-accelerated, since properties like transform and opacity are being animated. The result is typically very smooth at 60fps (or more), even with many elements, because the browser can rasterize the layers and just adjust them with the scroll.

By contrast, a JavaScript approach that listens to scroll events and updates styles might struggle to keep up at high frame rates, and could cause jank if not carefully debounced or optimized. IntersectionObservers help by not firing events each pixel, but they still can’t interpolate between states – you’d need to manually calculate interpolation on scroll, which is essentially reimplementing what CSS does natively.

That said, there are still a few things to watch out for:

• Use will-change for heavy transforms: In Bramus’ CSS, you might notice will-change: transform on elements. This is a hint to the browser that those properties will change, allowing it to optimize rendering (e.g., by promoting elements to their own layer). It’s generally good practice when doing complex transforms or animations, though one must not overuse it (too many layers can hurt performance).

• Limit reflection effects: The reflection using -webkit-box-reflect is convenient but under the hood it’s doing extra drawing work. If performance is a concern (e.g., on mobile), consider turning off reflections or using a static image for reflection to reduce GPU load.

• Continuous vs snap scrolling: The scroll-driven approach inherently ties animation to scroll position. On touch devices, this feels natural. On desktop with a trackpad or mousewheel, users can “fling” the scroll and the animation will follow at whatever speed – this can actually be more taxing than the discrete step-by-step animation a JS carousel might do. Fortunately, browsers handle scroll-linked animations efficiently, but ensure your keyframes don’t have extremely expensive steps in between. Our keyframes are straightforward transforms, which are cheap to interpolate. Avoid animating layout or paint-heavy properties.

In summary, the modern CSS Cover Flow should be as performant as it gets: no JavaScript on scroll, mostly transform animations, and leveraging the browser’s optimized engine. These scroll-linked animations deliver “smooth, high-performance, GPU-accelerated experiences”.

Accessibility considerations

A fancy carousel means nothing if some users can’t use it. Here are important accessibility points for a Cover Flow interface:

• Keyboard navigation: Users should be able to navigate the carousel with the keyboard. With a scroll-snap list, one approach is to allow the container itself to receive focus (e.g., add tabindex="0" to the .cards container). Once focused, arrow keys can be used: the browser’s native scroll behavior will scroll the container left or right. Because we have snap points, arrow scrolling should snap to the next item. We might also add an enhancement: listening for left/right arrow key presses on the container and calling el.scrollBy() or using the new Scroll Snap API to advance one snap point. This can ensure consistent behavior across browsers.

• Role and Labels: The Cover Flow is essentially a carousel of items. It should be communicated to assistive tech as such. One could use a <ul> as in our example (which is appropriate for a list of items) and perhaps add aria-roledescription="carousel" to give a hint. Alternatively, a <div role="listbox"> with children as role="option" could be used if we consider it a picker of one item.

• Visible Focus Indicator: When navigating by keyboard, the focused element (be it the scroll container or an item) should have a visible outline or indicator. We can style .cards:focus { outline: 2px solid ... } or similar to ensure users can see when the carousel has focus.

• Alt text: Each image needs meaningful alt text. In a music library, the album name is important information. Ensure the alt text or an adjacent caption conveys what each item is.

• Handling reduce motion: Some users enable “prefers-reduced-motion” to request minimal animations. Our scroll-driven animations are directly tied to user scrolling, so they may not be as problematic as auto-advancing carousels. But it’s still kind to check for @media (prefers-reduced-motion) and perhaps simplify the animation (maybe reduce the scale change or speed).

In implementing Cover Flow, we should test with screen readers and keyboard-only use. For instance, does a screen reader user know they can arrow through the covers? Perhaps adding instructions or using ARIA live regions when the center item changes (e.g., announce the title of the new centered item) could help. These details ensure the flashy UI doesn’t exclude anyone.

Conclusion

Cover Flow’s journey – from a 2004 concept to an Apple UI staple, and now to a pure-CSS web demo – shows how far web technology has come. What once required proprietary plugins or complex JavaScript can now be done with a few dozen lines of CSS, running at native speed. By leveraging CSS scroll snapping for user interaction and scroll-driven animations for the 3D transitions, we get an elegant solution that is both performant and maintainable. Bramus’ Cover Flow demo is a testament to modern CSS capabilities: it uses the browser’s engine to do the heavy lifting, keeping our code concise.

As you experiment with this technique, remember that scroll-driven animations open up many possibilities beyond Cover Flow. They enable parallax effects, progress indicators, creative scroll storytelling, and more – all without a single line of JavaScript. Cover Flow is essentially a specific case of animating elements based on scroll position (a view timeline case study), and you can likely adapt the same pattern to other creative UI ideas.

Finally, when implementing such experiences in production, balance the gloss with usability. Ensure it works on different screen sizes (CSS’s responsiveness makes it easy to adjust cover sizes or the number of visible side items). Test that it doesn’t degrade the page’s performance, and provide fallbacks or polyfills for browsers that don’t support the latest features. With careful consideration, you can provide an engaging, accessible Cover Flow-style carousel that enhances your site’s UX.