[austinl]

This is also likely a performance nightmare. Funny that they mention that "new hardware has enabled us to..." which means that this will perform poorly on old devices.

At a previous company, we were forbidden from using translucency (with a few exceptions) because of the performance cost of blending. There are debugging tools we'd use fairly often to confirm that all layers were opaque.

[ricardobeat]

Unlikely. Frosted glass blur was introduced almost twelve years ago in iOS 7, and was supported all the way down to the iPhone 4. Many apps like control center have used a full screen blur without any performance issues for a long time.

Apple at the time created their own 'approximate gaussian blur' algorithm specifically to enable this, and it ran crazy fast on devices where a simple gaussian blur would barely achieve double digit FPS. Even if this 'liquid glass' effect is heavier to compute, on the hardware we have today it will be a negligible performance concern.

[miffy900]

> Unlikely. Frosted glass blur was introduced almost twelve years ago in iOS 7, and was supported all the way down to the iPhone 4. Many apps like control center have used a full screen blur without any performance issues for a long time.

"Without any performance issues"? Entirely false - reviews at the time noted iOS 7 dramatically reduced battery life - all across the board for Apple devices, even for the then latest iPhone 5S and 5c (https://arstechnica.com/gadgets/2013/09/ios-7-thoroughly-rev...).

The abuse of transparency/translucency in the UI was the primary reason - you could go to Accessibility settings and disable animations + transparency/translucency and get notable increases in both runtime speed of the OS UI and battery life.

[mholt]

This isn't just a gaussian blur though, there's raytracing and refractions happening. The OS is becoming a low-key high-fidelity video game.

[p_l]

Early iPhone hardware was barely keeping with rendering the UI with a total ban on transparency. Even on iPhone 4 which improved the hardware a lot had the issue that it also increased amount of pixels to be pushed around.

And yes, later iOS on early hardware was huge PITA and slowdown.

[andrewmcwatters]

Yes! And it was frustratingly patented! https://patents.google.com/patent/US7397964B2/en

I made a comment about this a couple of years ago, but I fudged the explanation of it. https://news.ycombinator.com/item?id=34937618

I suspect that their new technique implements the existing fast gaussian blur, and since the patent is about to expire, it was a good time to spice it up.

I suspect as others have mentioned here, they use a "Liquid Glass" shader which samples the backing layer of the UI composition below the target element and applies a lens distortion based on the target element's border radius, all heavily parameterized so as to be used with the rest of the system's Liquid Glass applications like the new icon system.

[DecentShoes]

iOS 7 made the iPhone 4 practically unusable.

[loloquwowndueo]

“Supported” and “works well” ain’t the same. Do you remember how your iPhone 4 crawled when that effect was enabled?

[rjmunro]

Surely it's a performance nightmare because whatever is behind the frosting has to be rendered in full. Without this it can see that it's occluded and not have to render. Or does MacOS not do that?

[kevingadd]

Anyone who's ever written a blur shader knows that blurs aren't cheap.

[nikeee]

> Wirth's law is an adage on computer performance which states that software is getting slower more rapidly than hardware is becoming faster.

https://en.wikipedia.org/wiki/Wirth%27s_law

[raydev]

> this will perform poorly on old devices

I don't know how long you've been following Apple but with previous "high cost on old hardware" features they just disabled them for old hardware.

Apple loves their battery life numbers, they won't purposefully ship a UI feature that meaningfully reduces them. Now bugs that drop framerates and cause hangs, they love shipping those.

[lxgr]

> Apple loves their battery life numbers

For devices currently being sold, primarily.

[Cthulhu_]

> Apple loves their battery life numbers

...under pressure of consumer protection and e-waste laws. As it should be, I hope the other phone manufacturers are experiencing the same pressure.

[WhyNotHugo]

Windows Vista introduced this same concept. Performance was awful unless you had compatible graphics acceleration. 20 years later, I think most devices should be fine, especially Apple devices.

[p_l]

Vista was dogged by issues caused by migrating display drivers from NTDDM to WDDM 1.0, something that was only finished by 7 (which dropped NTDDM fully and introduced WDDM 1.1) and 8 (which afaik had mandated WDDM 1.1 only).

Unlike previous GDI acceleration, DWM.EXE could composite alpha channel quickly with the GPU, and generally achieved much higher fill rates on the same hw - if the drivers worked properly.

[krferriter]

Yeah one of the easiest ways to make windows vista+7 perform better was to simply disable all the fancy UI graphics that add nothing. I don't care if my window title bars have a gradient and animated transparency. It's actually a bit distracting and makes the system perform worse, so I just turned it off.

Even on modern devices though which have more computation and graphics power to the point that they aren't going to actually lag or anything while rendering it, why waste cycles and battery animating these useless and distracting things? There's no good justification.

[chasil]

https://en.m.wikipedia.org/wiki/Windows_Aero

[Cthulhu_]

20 years later and they're building the start menu in React Native.

[slt2021]

these performance hungry "improvements" are forcefully introduced to legitimately slow down older devices and force the device refresh across the user base.

I have been using 8 year old iPhone just fine, but features like these over time will make the experience slower and slower and slower, until I am forced to refresh my iphone

[cosmic_cheese]

I think probably a much bigger problem is app bloat. Devs are usually using very recent if not brand new top end devices to test and develop against which naturally makes several types of performance degradation invisible to them (“works on my machine”). Users on old and/or low end devices on the other hand feel all of those degradations.

If we want to take increasing device lifetimes seriously we need to normalize testing and development against slow/old models. Even if such testing is automated, it’d do wonders for keeping bloat at bay.

[dkarl]

More likely it's a result of pressure to ship highly visible "improvements," combined with a lack of ideas that could improve the experience in a meaningful way. What do you do in that situation? Ship an obvious UI update that wouldn't have performed on the last gen hardware.

[mikestew]

And you base your first sentence on…? Surely not the ol’ “my phone slows down when my battery is failing so that I’ll buy a new phone” canard?

To be clear, these are new features that will likely have a setting to turn off. There’s no conspiracy, nothing “forcefully” added for the purpose of driving upgrades. (Ah, ninja edit): There’s not even a guarantee these features will be supported on an eight year old phone. EDIT: wait a minute...your eight year old phone won't even be supported.

(EDIT: reworded first paragraph to account for the ninja edit.)

[dmix]

No matter what happens in the world someone will blame it on a top down conspiracy decided in some smoke filled back room.

[sanswork]

In the late 90s/early 2000s desktop computing was moving at such a pace that an 8 year old PC was near unusable. Overtime progress slowed and its not unusual to have a decade old desktop now. The problem is thinking that mobile has slowed that much too. Mobile is still progressing quite rapidly so yeah an almost decade old device is going to feel slow.

You have what an iPhone 6? 1GB of RAM vs 8GB for modern devices, the first A chip came out 2 generations after yours as has 2% of the power of a current chip so modern chips are likely close to 100x as powerful as your phone.

Why should we hold back software to support extreme outliers like you?

[RollingRo11]

Currently replying from my iPhone 16 pro (granted, not old by any means) on the iOS 26 dev beta. MOST things actually feel smoother/snappier than iOS 18. Safari is a joy to use from a performance perspective.

It’s in beta so ofc I’m getting a ton of frame hitches, overheating, etc. but my summarized initial thoughts are “it’ll take some getting used to, but it feels pretty fast”

[mminer237]

How can you get overheating and better performance? Is it just using the big cores for basic OS functions now?

[dmix]

> MOST things actually feel smoother/snappier than iOS 18

I have a feeling the whole smooth animations thing contributes to this a lot. Obsessing about the reaction time and feeling of how stuff comes on the screen. But yeah iPhone 16 pro is probably a bad performance test case

[andrekandre]

  > It’s in beta so ofc I’m getting a ton of frame hitches, overheating

how is battery-life?

[c-hendricks]

These transparency effects have been in macOS, ipadOS, iOS, and tvOS for years though?

[landl0rd]

There's a difference between something like a transparent background (you can run i3/picom on a potato) and having to composite many little UI elements to render a frame.

[blinding-streak]

The reality distortion field is back, it seems.

[david-gpu]

> At a previous company, we were forbidden from using translucency (with a few exceptions) because of the performance cost of blending.

I imagine this was on mobile devices.

Blending was relatively expensive on GPUs from Imagination Technologies and their derivatives, including all Apple GPUs. This is because these GPUs had relatively weak shader processors and relied instead on dedicated hardware to sort geometry so that the shader processor had to do less work than on a traditional GPU.

Other GPUs vendors rely more on beefier shader processors and less on sorting geometry (e.g. Hierarchical-Z). This turned out to be a better approach in the long term, especially once game engines started relying on deferred shading anyway, which is in essence a software-based approach that sorts geometry first before computing the final pixel colors.

[Synaesthesia]

Modern iOS and Mac devices have plenty of GPU power for a shader effect. They already do one with the translucent blue.

[illiac786]

Interestingly, in iOS 18, suppressing transparency (there’s a setting for it) makes performance worse, not better. The UI lags significantly more with transparency disabled. I expect it will be the same with iOS 26: there will be setting to reduce the transparency (which I find highly distracting) but it will make performance actually worse…

[citrin_ru]

Thanks for this insight. It's very counter intuitive. Normally transparency is additional work for a GPU.

I had "Reduce Transparency" check-box in settings turned on because I distaste semit-transparent interfaces. Was not noticing performance problems except one application - Ogranics Maps which were unusably slow after switching to another app and returning to maps so I had to restart it freqently (swipe up). I was thinking that the problem is with Ogranics Maps code.

After seeing this comment re-enabled transparency (iOS default) and Ogranics Maps working fast even if I switch between Organic Maps and other apps!

[krferriter]

Did suppressing transparency also turn on processor throttling or something too? Like putting the device in a power saver mode?

[arvinsim]

> This is also likely a performance nightmare. Funny that they mention that "new hardware has enabled us to..." which means that this will perform poorly on old devices.

Not sure if it is planned obsolescence but it certainly is an upsell to upgrade.

[jmrm]

I think brand most recent iPhones are ridiculously powerful for their average use, so I don't think this would be an issue.

For older models, on the other hand, it would be an issue, and will put pressure to people to buy a new one.

[skhr0680]

Translucency being a main feature of Mac OS X is decades old at this point. I remember a magazine article touting it as an advantage over the upcoming release of Windows XP!

[cryptonector]

> Funny that they mention that "new hardware has enabled us to..." which means that this will perform poorly on old devices.

They're going to backport this? I seriously doubt it.

[abhinavk]

It runs on iPhone 11 and later.

[nyarlathotep_]

> At a previous company, we were forbidden from using translucency (with a few exceptions) because of the performance cost of blending. There are debugging tools we'd use fairly often to confirm that all layers were opaque.

I feel like a few years back when I still used an Intel macbook i noticed an increase in battery life and less frames dropping (like during 'Expose' animations) by disabling transparency in Accessibility settings.

I think this was after the BIg Sur update.

[drob518]

These modern chips have so much graphics processing capability, I think they just throw the problem at the hardware and let it do its thing.

[solfox]

It may not be overt, but it also seems they are working to justify the hardware with the software.

[hombre_fatal]

This reminds me of disabling the Windows Vista translucent UI to claw back performance on my crappy Gateway laptop in uni.

[Macha]

Meh, Vista laptops could run lots of translucency fine (well as long as they were actualy Vista era laptops and not just XP era laptops with Vista installed)

[slt2021]

you just proved that MSFT released slow OS to force people refresh hardware.

Plus, vista was released in 2007, XP SP2 (the most popular version) was in 2004. so its like ~3 years diff. So its not like hardware has progressed in 3 years, its more like new software got significantly slower

[dylan604]

It's almost like they said the same thing: Funny that they mention that "new hardware has enabled us to..."

oh wait. it's not like they did. they did say it.