Show HN: CSS generator for a high-def glass effect

This suffers from the problem of only blurring using the pixels immediately behind the surface, as demonstrated well in https://www.joshwcomeau.com/css/backdrop-filter/#the-issue. That and the discussion in https://news.ycombinator.com/item?id=42302907 are good reading. If the backdrop is going to move underneath, this is fairly important; if it will be static, it’s not normally important.

kris-kay · 2 months ago

I did read Josh's great article and had a go at implementing the tutorials. Unfortunately, I ran into some issues with the border-radius via SVG mask bit. It worked great on a hardcoded element, but I still need to figure out how to make it work across a whole component library where the border-radius changes based on the user's branding and container-queries.

andrewmcwatters · 2 months ago

Josh’s solution also intuitively appears wrong to me because it seems to assume that nearby elements are emissive, and I can’t agree with that as a standard physical property of “materials” on the web.

I instead assume that materials are by default more similar to paper.

chrismorgan · 2 months ago

The backdrop blur is unrelated to the surface properties of the elements underneath: it’s about the frosted glass refracting light, and some of that light it refracts comes from beyond its bounding box, which a naive backdrop-blur won’t observe.

nothrabannosir · 2 months ago

That article covers a bug in implementations of blurring in browsers. It shows how when a 200px red circle is fully covered by a blur with radius 16px, today you will see a 232px sized blurred circle. But when the circle is shifted down from under the blur, so there is one pixel of space separating the two, you would still expect to see 15 px of blurred red circle. Instead it goes 18, 17, 16, 0, 0, for every successive frame. That’s a bug.

account42 · 2 months ago

I don't think either version is really more correct than the other. The default approximates an object that is directly behind the frosted glass while the tweaked version simulates an object that is much further away.

For me the tweaked version is much more distracting and looks more wrong due to conflicting depth signals.

Looks pretty good.

But missing out on the refractive aspect of glass takes away the strong visual separation of layers that IMO is Liquid Glass's biggest contribution.

Material has these wonderful designer resources showing how the app ought to be built of consistent moving layers, shown in 3D from the side. It's clear that there's these layers. But once you go 2d, put it all together, its incredibly hard for me to find all the features. The number of times that there's an action button in some corner that folks don't see massive. Motion sort of helps highlight the chrome vs content, but there's just so little thats visually defining.

Liquid Glass's biggest strength IMO is the edge distortion. That when the content moves, there's this non-linear motion that the human visual sense immediately picks up on. Static screenshots don't always look great, but in motion there's so much more distinction of elements than anything else I've seen.

And that key refractive element, that takes such huge advantage of human's motion sensing, is missing here.

I'd seen one other great web web demo, but am struggling to find it right now. I did find this one, which I don't think looks as good, and the performance is bad for me here on mobile. But it nicely breaks down steps and shows how complex a task this can be. Getting these edge distortions in is hard, and relying on SVG filters to do it is a brutal path to hack together. https://atlaspuplabs.com/blog/liquid-glass-but-in-css#breaki...

There is a collection of attempts (CodePen Spark) at Liquid Glass that I just found. Second link is one I thought did a pretty nice job, via very specifically pre defined / hard coded SVG. https://codepen.io/spark/453 https://codepen.io/lucasromerodb/pen/vEOWpYM

jasonthorsness · 2 months ago

I think this is a clever moat Apple created with Liquid Glass: they picked an effect that is easy to make a worse version of, but very hard to do the real/right way (and humans have an intuition for real/right because they see real glass every day). So any copycats will look worse in a way that's pretty obvious and Apple gets to keep the "premium-looking" product.

_benton · 2 months ago

I don't think it's that hard for someone with experience writing shaders to emulate. The moat is that it's almost impossible to replicate with browser technology, which hurts web-based ui systems and is still a big challenge with something like flutter or jetpack compose multiplatform.

Stuff like React Native get it basically for free because their ui is still technically "native".

But apps that rely on web views are screwed and I'm sure Apple will be happy to push devs away from those solutions as they're inferior for users.

Now they just need to figure out a way to push RN apps towards true native.

gumby271 · 2 months ago

I think the same is true for when they started using blurs everywhere. They knew Android OEMs would copy it in a worse way and shoot themselves in the foot. That's also why material design doesn't rely on blur effects, it needs to run well on much worse hardware.

It's fun seeing the attempts to mimic Liquid Glass though, the most impressive so far is this Flutter package: https://pub.dev/packages/liquid_glass_renderer

dotancohen · 2 months ago

I recently saw a large gold (plated) surface - larger than a hand. The effect the light played off of that metal was amazing, I've never seen the effect in small gold jewelry. Photographs and video just don't capture it. If Apple ever turns their attention to gold and manages to nail that effect, I would consider one of their devices just for that aspect.

kris-kay · 2 months ago

The moat is real! I haven't tried recreating Liquid Glass in the browser yet. From what I've seen, it's possible, but not in a practical, cross-browser, "can be applied to an arbitrary component" kind of way.

Of course, as soon as we figure out how to get it done, Apple will move on to the next thing. I'm okay with that though. It was a bold move, and I can't imagine how much time and money Apple spent making Liquid Glass look that good.

9dev · 2 months ago

That is one way things could turn out. On the other hand, when Apple started to introduce the iOS-7-style frosted glass effects, we got backdrop-blur in CSS, which handles the hard parts of achieving a similar effect on the web.

If this whole liquid glass effect catches on big time (which isn't out of the question right now), we might see something in the web platform that gives developers access to the platform primitives required to render it.

Why shouldn't there be an effort to make more OS UI elements available via HTML? There's no technical reason against it. So I'm not saying that is what's going to happen, but I don't think this is a kind of moat they created with the explicit intention to make web apps worse.

silvestrov · 2 months ago

I think you overestimate how much most users are able to detect such differences and will care about it.

Somewhat like the blind tasting tests of Coca Cola versus Pepsi versus supermarket brands.

kevincox · 2 months ago

They literally said this is the reason in their marketing.

> features an entirely new material called Liquid Glass. It combines the optical qualities of glass with a fluidity only Apple can achieve

https://www.apple.com/ca/newsroom/2025/06/apple-introduces-a...

But yeah, it is a pretty clever way to make most cross-platform toolkits stand out and create a desire to create true native apps which increases their moat and means that some apps will have only an Apple version (or a worse app on other platforms) rather than releasing the same app on all platforms.

altairprime · 2 months ago

I think the other component of the moat is that their OS/GPU stack is power-optimized for this effect in hardware, which generic solutions for generic hardware will have trouble matching - even a lower fidelity replication’s power drain could be an order of magnitude higher as a result.

kris-kay · 2 months ago

I agree that Liquid Glass's edge distortion looks great, and I will try my hand at recreating it eventually. For the current project, I aimed to create a material that looked polished, worked consistently across browsers, and didn't use real 3D. And you're right about the effect being more visible when moving over a fixed background. The demo site I'm working on for the library does this, it's just not ready yet.

Thanks for sharing the resources!

incrudible · 2 months ago

> But missing out on the refractive aspect of glass takes away the strong visual separation of layers that IMO is Liquid Glass's biggest contribution

Good. I was already on the fence about frosted glass, but I absolutely hate the refraction effect, it is super distracting and will always look ugly in certain scenarios. Yes, it is how real glass behaves, but I do not care for that. It is like someone took the worst part of skeumorphism and doubled down on it, and I say that as someone who liked iOS better before version 7.

jauntywundrkind · 2 months ago

magic_hamster · 2 months ago

It's a nice effect, but to me this doesn't really feel like glass.

I think the most immediate difference is how light has no interaction with the bevels. I also expect some light to shine back into the glass and affect the lighting and coloring. It's not enough to just throw a blur in there.

Also, glass can have its own shadow with some interesting caustics (not sure even Apple does this). I see the shadow here, and it feels like a simple drop shadow. It makes the box feel like a flat card more than a 3d physical object which I think is part of the new trend.

Either way, This will not be easy to emulate with just css, it's probably more suitable to be a shader running in a gpu.

Deleted Comment

ivape · 2 months ago

If it can't be done with CSS, then how can it be done? How can you apply GPU shader effects to a common div? If we can't apply GPU effects to basic HTML and need to do so on custom things like an arbitrary Canvas concoction, then we may as well rebuild a brand-new rendering engine that can apply GPU effects.

HTML is dead. I see no reason to care about it because we only need <p> tags to get some text across, as just about everything else is used to make a webpage an ad-bomb. So let's just start again with the <p> tag and better gpu integration, and leave everything else out.

madeofpalk · 2 months ago

> we may as well rebuild a brand-new rendering engine that can apply GPU effects.

They've been trying, with various degrees of success, over the past 10 years with Houdini.

https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_propert...

explosion-s · 2 months ago

I've made a JavaScript version that actually refracts elements on the page, check it out: https://real-glass.vercel.app/

savy91 · 2 months ago

FYI frosting does not work in Safari

cududa · 2 months ago

This is sick yo

swyx · 2 months ago

i collect these! https://github.com/swyxio/spark-joy

others

- https://ui.glass/generator/ Get started with this free CSS generator based on the glassmorphism design specifications to quickly design and customize the style properties.

- frosted glass sticky header https://www.joshwcomeau.com/css/backdrop-filter/

- glassy glassmorphism [codepen](https://codepen.io/a-trost/pen/dypQzwq), [in context](https://codepen.io/TurkAysenur/pen/ZEpxeYm)

  ```css
  .blur-and-rotate {
    border-radius: 20px;
    backdrop-filter: blur(20px) hue-rotate(120deg);
    -webkit-backdrop-filter: hue-rotate(120deg);
  }
  ```

leptons · 2 months ago

Searched for an ASCII Font generator, but didn't see one. Here's one tool I use:

https://patorjk.com/software/taag/#p=testall&f=Graffiti&t=He...

added!

Just saw that you added this project to the spark-joy list. Thanks so much!

Nice! Spark Joy looks like an awesome resource.

mbforbes · 2 months ago

Really nicely done! It's always surprising to me how often computer graphics isn't "one weird trick" and more like "5 layered tricks." Doing it with cross-browser compat is an additional challenge.

Do you have a sense of which aspects are the most resource-intensive? Naively I would guess it's the backdrop-filter.

Yes, same! I didn't expect it to need so many tricks to implement. Your intuition is correct, the most resource-intensive part is the blur bit of the backdrop-filter. The higher the blur value, the more neighbouring pixels need to be "consulted" before rendering. Another resource-intensive aspect is continuous repaint as you scroll or as a video background changes the look of the glass.

whycome · 2 months ago

And sometimes it's 5 layered tricks just to "center" something.

Not anymore! We live in the golden age of display: grid; + place-items: center;

tyleo · 2 months ago

This looks like it uses similar techniques to my own glass implementation: https://news.ycombinator.com/item?id=42225481

Especially with respect to the abuse of box shadow.

Your project looks awesome! I'm glad not to be the only one going 5+ layers deep into the shadows. The addition of Light Rays is particularly impressive!

armchairhacker · 2 months ago

Small issue: the shadow between the top and the scrollable area with the toggles and code fades out when you scroll down (presumably it should be initially hidden and fade in).

Good catch! It's not a fading-in issue; the shadow is just scrolling out of view. I designed those "overhang" box-shadows to be applied to the inside of an element rather than cast down from one. I see now that I need to apply the latter kind in this case. Thanks for letting me know!