Every Frame Perfect

1 day ago (tonsky.me)

I agree that some of the examples the author provided are instances of bad animation. But I don't agree with the premise of the article.

Computer graphics is all about exploiting features of the human visual system. We perceive things differently when they're moving vs. when they're standing still. It's very possible that a "wrong" frame in isolation is the best looking one in a real-time context. We can also pick apart screenshots but these don't capture everything about how the user perceives a display in real-world lighting conditions.

I would draw an analogy to film. A fast tracking shot might look bad on individual frames because of motion blur. A wide-angle shot might make some objects look "wrong" because of optical distortion. But these are still the right choice if they have the intended artistic effect in the theater.

  • I initially thought "Every Frame Perfect" meant a strict avoidance of any jank or stutter in motion, which I'm fully on-board for but as a film, video and 3D technologist, you're spot on calling out motion blur and similar temporal artifacts. In motion, they not only look 'most correct' to the human visual system, they are the most interpretable.

    Adding the correct blur to motion makes it appear clearer but seen as a still, it's obviously not clearer. The nuance is correct motion blur appears clearer while guaranteeing it's as clear as the human visual system can perceive moving details at that speed, so no perceptual detail is actually lost. It's a method that objectively improves perception which only works in motion. If frozen, the method breaks. Thus, evaluating motion blurred stills for clarity or interpretability is incorrect.

    The rest of the article focuses on details of proper implementation while missing the opportunity to question whether some of these animations should exist at all. IMHO, motion can be a valuable affordance in limited doses but it's reached a point of overuse and, in some cases, outright abuse of the user's visual field and cognitive load. Designers (and their PMs) see it as a badge of 'Refined Modern UX' but it's devolved into a trendy gimmick aping good design without being good design.

    • Regarding your last point, I think it's almost always wrong to move something discontinuously, but I do think designers should think a lot more about getting out of the way of the user. A 50-100 ms animation is more than enough for most motions and keeps the UI feeling snappy. Also, animation should be decoupled from input wherever possible. I hate it when I have to sit there waiting for an animation to complete before the app will start acknowledging my keystrokes.

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  • I think you are taking it a step too far. First of all, unlike film, we are not recording reality in any way, every pixel that appears on screen is there because we put it there. I'd argue a closer parallel is a cartoon. And something like cartoon inbetweening is not an example of imperfect frames. These are in fact, perfect and even carefully crafted frames.

    It's one thing if the frame halfway through an animation looks a bit "funny", but is still completely logically correct. It is another if the intermediate state of the animation legitimately doesn't make any sense and is just the result of not really caring about what actually goes on during the animation. In that case I'd almost rather just not have the animation at all, or just have a simpler one.

  • The final "zoom animation from Preview app" also illustrates the inverse. Every frame looks perfect in isolation, just like the author wants. It's only when you see it in motion that you notice the issue.

  • I think it’s pretty telling that with the YouTube example, I legitimately couldn’t figure out what he could have a problem with until he slowed it down. The overall effect worked and gave the impression that it was aiming for. The fact that you can get out your calipers and find flaws in a paused animation is not compelling in the least to me. I don’t think looking at your animations in slow motion is a bad exercise — it may reveal unintentional things — but I don’t buy that animations need to “make sense” when paused in the middle any more than a 250ms snippet of audio clipped out of the middle of a word needs to make sense.

    • True that, but imho the jankiness of the video is clearly visible. It just jumps into place halfway.

    • It's crazy for me to think that people cannot see how wrong it is from the normal speed video. For me it's obvious and infuriating, it physically feels like it's punching my retina

  • I like this comment. The idea that animations should be able to be picked apart frame by frame and always be coherent doesn't make much sense, because the user will never actually do that.

    I do like the point the article makes about using ui fidelity as a proxy for software quality, and agree that they pointed out some bad animations. But, I think you hit the nail on the head .. frame by frame coherence isn't the best yardstick for measuring animation "goodness".

    • Exactly, you should optimize for quality and have a high bar forbit but I'm not sure sacrificing framerate for pixel perfect rendering or perfect subpixel antialiasing and compositing a perfect glass chroma aberration when wheezing a superfast animation is more important than it being solid 144Hz or audio synced.

  • This article would do better to show good use cases to draw strengths to their premise but I agree with your take that frames matter less than the total feel of the transition. Some of them definitely could be improved of what he outlined.

    I find AI to feel real nice for pushing delight like this further than I used to have time for as it was never a priority.

  • > the premise of the article

    I wouldn't mind it, if he had supplied suggested mitigations.

    I think every one of those animations are system-supplied ones. Some are likely SwiftUI ones, which heavily abstract you from the iron, and, if other frameworks are supplied, the abstraction goes even farther.

    It can be a major engineering effort, to improve a half-second animation.

    That said, this is how designers work. I have worked with some of the top designers in the world, and it can be tempting to want to strangle them, as they choose a half-pixel alias as the hill to die on.

    But if we try to work with them, it can make an enormous difference in how users react to our software.

    • > I think every one of those animations are system-supplied ones. Some are likely SwiftUI ones

      Yes, this is a major factor for the regression in overall UI quality and consistency on Apple platforms. SwiftUI aims to make all those fancy animations transitions a single line view modifier rather than 30 lines of manually specified CoreAnimation easing curves and manual animation blocks, but it results in a lot of things just feeling janky, because one-size-fits-all rule and precise polish are fundamentally at odds.

  • agree.

    I hacked a Panasonic GH1 to use 24fps in 2014. My newer camera, the GX85 includes this frame rate by default. Movies look more dreamlike in 24fps, due to the magic number of resetting some cycle every 5 seconds (24 frames in 5 seconds is 120 frames). Seinfeld was also filmed in 24fps. Maybe the jokes sounded funnier becaue of that? I don't know, but I enjoy playing games at 20- 30fps more than 60fps for the cinematic effect.

    • The difference with games is that they generally don't have motion blur, every frame is sharp like a photo, so at low framerates like 30 you can see a distracting judder from the series of low fps sharp frames which you don't see in movies. At high framerates your eyes will naturally see blur in the same way your eyes see your hand waving as blurry even though there is theoretically infinite frames.

      Some of this is also just learned and cultural. 24fps looks like movies because movies are 24fps and you have learned to make that association. In the same way certain color grades and aspect ratios look cinematic, just because that's a reinforced association rather than an inherent fact.

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  • > It's very possible that a "wrong" frame in isolation is the best looking one in a real-time context.

    For example?

  • > It's very possible that a "wrong" frame in isolation is the best looking one in a real-time context.

    Maybe that’s sometimes true. But, more often, the intermediate states will contribute in a predictable way to the overall look of the animation and if the intermediate states don’t look coherent, then the animation as a whole will be hard to understand.

    The examples in the article make this clear. For example, the search box where the initial text animates from the middle while the cursor starts on the left. That disconnects the text from the cursor. There’s no reason for that. It’s just shitty animation work.

  • What do you think the premise of the article is? The article is pretty narrowly speaking of "app" UI and your comment is a "well actually" that some videos intentionally introduce noise or temporary discomfort for an emotional or artistic effect. On the same basis, comments like yours would defend screen shake if it was added to desktop and mobile apps on every user input.

    • The premise of the article is that every frame of an animation should look good if captured and analyzed statically, in isolation. There's no reason provided for this other than "it feels right." I'm saying that this ignores how the human visual system works and how we perceive displays in real-world lighting conditions. I used film as an analogy to illustrate the point.

      The idea that I would defend screen shake is a complete straw man. How do you get from my comment to that conclusion?

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I still have Sonoma on some of my devices. All I can say is: wow, steady regress.

The save dialog, albeit a little shakey, is nowhere as chaotic as in your example. The buttons in Notes move between panes in a perfect seamless manner. Albeit the animation occasionally glitches out when you repeatedly focus and deselect the Safari bar, the cursor is perfectly timed with the text, only fading in after the text is done moving to the left. The Preview bug must be something recent too, I can't reproduce this.

https://streamable.com/kx7op6

I miss it when companies like Apple, Sony, and IBM paid attention to the smallest details. Apple in particular earned its current valuation with the iPhone, an all-touch device that did nothing extraordinary compared to Windows Mobile and Symbian PDAs of the time (and was in fact functionally lagging behind compared, failing to even match the then-contemporary feature phones in some areas) BUT one that you didn't actually want to smash against a wall after a few minutes of use. Now these animations are bringing back exactly the Windows Mobile and Symbian vibes.

Remember how happy Steve used to be with OS X animations? He would replay them on stage multiple times, in slow motion. These though, these would have the people behind them face the fate of the iPhone 4 antenna man.

  • The animations in your short video do in fact look more orderly and less chaotic. Could it be that Apple was using AppKit in Sonoma and switched to SwiftUI now?

I'm sure a UI that had none of these imperfect frames would feel better, but now I really want someone to edit each of these clips to show what it would actually look like.

At the same time, why does everything need motion? My understanding is that motion should be used if an action subtly changes the UI in a region that's different from where the action was triggered (e.g. toasts)

I think many of these transitions are unnecessary and would feel just as good if they snapped immediately with instantaneous reflow.

  • I think the “imperfect frames” on the Safari search bar are, practically, just fine and doing it in the way that looks better in screenshots would be worse.

    The cursor appears on the left because that’s where the user will actually start writing. I assume that’s where people look, if they know the UI. Having it appear in the middle of the screen and then move over would be unnecessary and distracting.

    The stand-in text slides over to the left, to draw the attention of the unfamiliar user.

    • To add to this, experienced users will often start typing without looking based on what they trust the eventual state of the UI will be. Moving the cursor immediately makes it explicit that this should work.

      This is following a more important rule which is "Never make keyboard input timing dependent!" I'm looking at you new Windows start menu and VS Code quick open.

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  • Play any game with good UI and you will see animations used everywhere. Instant transitions are only good in theory.

    • Games are entertainment products, not tools. It's acceptable for a game UI to draw attention to itself for artistic effect, but I don't want to have to put up with this when I'm trying to get work done. Instant state transitions become imperceptible as you learn how they work. An instant UI effectively functions as part of your body, just like hand tools do. Animations make this impossible.

      Compare an ordinary pencil (no animations, movement is directly tied to your hand) to a pencil with a pompom on a spring attached to the end. Which is most fun for brief use? Which would you rather write a whole page of text with?

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    • Maybe you dislike them, but that does not make for a fact.

      Instant transitions are something I strongly prefer and use in practice. There's no question, I don't want my operating system slowing itself down to a factor (literally) of 1000x, pointlessly fading and jiggling and sliding and bouncing and wiggling. And, as this article points out, animations in operating systems often make a visually illegible mess in the meanwhile.

      Animations might be a good idea in theory, but it doesn't seem like anyone has figured out how to do them right.

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    • No they are not used everywhere. Some games with good UI use animations everywhere that an animation is appropriate. But plenty of good UI exist without animations. The point above is that no animation is better than an inappropriate animation.

    • Instant transitions are wonderful for efficiency, and you do see that mirrored in games as well. And you hope to see it in utility-oriented software.

    • You will also see plenty of cases where a screenshot captures incoherent frames.

      Squash and stretch is a whole art style that relies on unrealistic frames.

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    • > Instant transitions are only good in theory.

      For a professional tool, animations are anathema. They interfere with muscle memory.

      Someone who uses a program continuously can be clicking or typing before a dialog box or button is even in the right position.

      My wife drives me MAD with this. She has already clicked the cancel button on a popup before I can even read the first word in the dialog box. This is fine when she is working as the dialog box is just a dumbass notification from some idiot UI designer. This is NOT fine when she has asked me to help debug a problem. I have to force her hand off the mouse so that I can read the damn error message before she clicks it away.

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    • Games are for fun. Wasting time in a game is fine, that's what it is for. (edit: not saying that pejoratively)

      Other applications are to do things. They should do the thing and get out of the way as fast as possible. Animation-induced delays are fundamentally contradictory with that; they waste the user's time instead of doing the thing.

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    • Games are games, work is work. I disabled every animated transitions in my desktop UI. Elements appear instantly at full size in the place they rest and disappear instantly.

      Reasons:

      1) I'm doing that thousands of times per week, I know what's going to happen

      2) It's my desktop, there is no one else who might be puzzled by a non standard behavior

      3) It's faster.

      By the way, it is a GNOME desktop on Debian 13.

      Oops, I lied. I was about to click on Reply and I realized that the bottom panel (which on a standard GNOME is at the top) is on autohide with a short transition. Maybe because it's the only transition that I activate with the mouse pointer: I hit the bottom of the screen and while it's traveling the last pixels the bar starts sliding in. It's very fast.

  • > At the same time, why does everything need motion?

    They don't. Most things don't. This kind of nonsense keeps an extra half-dozen people employed, and gives license to a half-dozen other people to smugly proclaim $BRAND's design language is superior to alternatives.

    In most of the cases shown, it would probably feel better if the animations weren't there. I clicked the button, show me the thing. Don't do a dance and then show me the thing, just show it!

  • Slot machines has to have something always going on, overly dynamic Apple animations help with that. For regular UI animations, it helps normal users who struggle with sudden changes in screen contents, as well as helping to smooth out framerate and hide delays caused by API calls or backend processing.

  • I think exactly that. When you add motion, do it right, but when you don't put time in to do it right, it's clearly the better option to leave it out completely. Without animations, much things feel snappier because you don't have to wait on a shitty animation thats running through.

  • Motion is critical for reorientation after transition.

    Often with out it your brain has to rescan the entire page on each refresh.

    • Do you have some concrete examples?

      "Back-in-the-days" you'd click and stuff would instantly happen, and I don't remember anything being more difficult to visually interpret.

      On my Kubuntu desktop if I disable all animations (the whole compositor) I don't feel there is an increased cognitive load of rescaning things - but maybe it's my preexisting memory of the UIs and certain baked in UI expectations. Maybe this animated stuff helps people that are computer illiterate? (software made for the lowest common denominator)

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    • Outside of dedicated notification areas, a GUI should only change state in response to user action. Because the user requested the state change, they naturally know how it changed. This means any animation is a redundant waste of time.

      The notification area doesn't need animations either, because a GUI is only appropriate for displaying non-urgent notifications. If something really needs urgent attention, you need alarms and flashing lights, not an animated "toast".

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    • This isn't true generally. I am personally far more comfortable with disabling smooth scroll. It has more to do with your mind's expectations. Which can vary between people. Some people expect smooth and others don't. Motion itself isn't necessary.

      The only time I have to "rescan" is if I input a scroll and anticipate a scroll and it doesn't scroll. It has nothing to do with motion. In fact, in that case, I "rescan" even though the page hasn't changed, but because it doesn't match my expectation that it would change.

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    • The OS shouldn't be making many big changes that force me to reorient. When I'm moving between different UIs I often want to compare them; animations make it harder to compare state A to state B. I can detect very fine differences between two images by switching between them within a second, if there's a 1-second animation it not only means it's going to add a second, it adds a bunch of visual noise which might make it impossible to be able to distinguish what's an actual difference and what's just noise introduced by the animation.

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    • >Motion is critical for reorientation after transition.

      The only case I can think of where this is true is on scroll, and that barely counts as animation. Anything else is an irritating waste of time.

      The absolute worst offence is animating page content on scroll. Great job making me wait on pointless nonsense while scanning your website for the bit I'm looking for. People who do this should be sent to reeducation camps. Both for the animation, and for disregarding 'prefers-reduced-motion'.

I have a lot of thoughts about this:

I think this is a weakly presented argument. The article doesn’t actually present stronger alternatives or even why anything shown is negative to the user. It might be negative but otherwise this is the same vacant critique that is levied by pointing at smear frame or transitional points in media to critique it.

The user also has an untenable maxim. Every frame must make sense? I would posit this is impossible, or I’d ask the author how they’d handle window resizing while keeping every frame perfect.

I also think the author themself finds it easier to point out flawed frames (again without actually explaining why they’re issues) than doing as they say. Tap the header links on their blog and see the animations play after the click is complete. Or go see their own UI projects and see how text and objects don’t stay within their containers. Surely someone saying that this is a tenet that should be followed could demonstrate it themselves.

I think this is just a very hollow critique on their end.

A more competently written article would have focused on why anything shown is bad for the end user, and how they might handle it instead. A good critique should actually include some substance and point to more than just the what, but the why and how.

  • I think your critique is actually the hollowest thing here.

    The article is presenting an idea, not a solution. You've failed to see this and have constructed several strawman arguments in order to critique it.

    Most importantly the article does not present itself in a definite sense - it is written with care to say "I think", "Next thought:", "Probably", "So yeah.". This article is a person sharing what they are thinking, and unlike many of my thoughts - it is a fairly complete thought which is clearly sparking many other reasonable people to think along similar lines.

    The author doesn't present the solution - but there is no reason they should have to. What an odd and unreasonable bar you set.

    I also don't find your attacks on the authors site particularly endearing. The taste gap is well known, and punishing someone for their conceptual contribution outstripping their practical skill is quite... distasteful.

    A more competently written critique would have been more charitable and in the spirit of this community.

    • There’s an irony in you claiming my comment is uncharitable and claiming the article is a discussion point when you haven’t even taken up the question I posited and framed them as a strawman.

      Can it be possible to make everything during a user interaction perfect looking? What does that mean?

      That was part of my original comment that you skimmed past rather than engaging with. So if you truly believe this should be a starting point of a discussion, then why not even bother taking that point to build a discussion point off of?

      I’d also argue that this is not presented as just an idea. That is disingenuous. The author clearly writes “I call these situations “The technology has outsmarted the programmer” “

      That is more than just a discussion point but a levied criticism at the skill of the people making things. In turn therefore they’ve set the framing of skill as part of the discussion and I don’t think it’s unfair to point out their own lack of ability to execute to their high standard.

      But let’s go by your standard of saying that we shouldn’t take the authors own execution or their own words into consideration but only focus on the core idea they present.

      Then that still leaves defining what they consider every frame being perfect. What are the bounds of that statement?

    • >> The article is presenting an idea, not a solution.

      The article establishes an arbitrary standard, provides examples and criticizes them on the basis that they don't meet that arbitrary standard, and then... nothing.

      It is easy to criticize something from the outside. Much harder to dig deep, learn the material and understand why it produces the status quo, and then propose workable solutions. That's where the actual value lies.

I'd rather have an imperfect frame now than a perfect frame later. Latency should be the top priority for any UI, because when latency is low enough it feels like a part of your own body, which minimizes cognitive load. Animation is especially bad for this, because animations add hundreds of milliseconds of latency.

  • I think that's a false dichotomy. The examples the author gives would not be slower in any way if done correctly.

    • Old computers, before double-buffering and compositing, were fast. Single-digit millisecond latency from input to output was common.

      Now it’s 30-ish years later and computers have not recovered the latency increase from compositing, double-buffering, and other attempts to make every frame perfect. If you are showing a frame on the screen that has failed to react to input that already occurred, especially more than about 20ms later, that frame is not perfect. It’s extra imperfect if the user cannot easily do what they’re trying to do while waiting for the computer to catch up with them.

      But yes, most of the examples in the article are surely both imperfect in the sense the author meant and pointlessly slow, so there is no dichotomy :-/

    • However, the author makes these assertions:

      - No partially loaded content. - No relayout while content loads.

      Holding those as hard rules leads to delay or rejection. Instead, while I agree it's better to have everything up front, gracefully handling cases when we don't is important, and some degree of responsiveness, even with partially loaded content, often makes for a better experience for the user than a delay.

      Just be up front about it and find ways to keep continuity of relationship and smoothness. Diffeomorphic mappings are your friend...

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  • You might have thought the title was about Wayland and you're right. But this isn't about Wayland.

I've seen a few comments along the lines of wishing that the author had included examples of solutions. I wrote a very similar post recently that details both the issues with the animations, very similar to this article, as well as how I improved them.

For anyone curious, https://www.thisischris.dev/projects/project-6/

  • Ty but the animations don't seem to animate on mobile chrome on Android.

    • Appreciate heads-up! I just checked Chrome on my Android device and it's all working fine for me. I don't know if I set the page up weirdly but I have to refresh the page sometimes for the videos to show up.

I think it's not uncommon for good animations to cheat a bit while in motion, rather than look perfect on every frame. Like how cartoons can use smear frames that look bizarre when paused at the wrong time but when viewed as part of a larger animation help sell the motion visually.

  • Yeah the difference is that the blur frames are deliberate and purposeful for the overall effect. The animations showcased here are accidental jank that reveal a clobbered together unpolished app.

  • I don't think this analogy works because the blur frames look good in motion, and the frames in the blog post look terrible in motion. The animation in the first example is so bad that the first time I watched it I thought there was going to be three buttons at the top at the end, and it was weird and disorienting to realize there was only two.

  • Smear frames are not something often applicable in this kind of animation. Smear frames are just about specific to frame-by-frame animation. No smear frames are demonstrated in this article.

  • Agreed!

    With MacOS I felt there was a major quality change for visual quality & animations when SwiftUI was used BY Apple for the OS and applications.

    I'm not a developer, but it felt there were areas where an icon or window just didn't visually work the way it used to or SHOULD in placement or animation.

    The hackish-ness hasn't changed over time: there are so many examples throughout the OS/Applications that I want to say "it was always like that", except it wasn't: Apple set the bar and it was high, the quality was exceptional.

    I feel there are a lot of hacks going on with SwiftUI to achieve the same UI placement or animation.

    Last quick note I think about often: a lot of analog creation was really hard. It still is. When it comes to digital we've been thinking we'll come back to things later, but never do... we build more bad on top of bad... sadly.

Would be nice if there were some _positive_ examples to go along with all of the negative ones. All I’m really getting from this is that I should avoid animations, which I don’t think is what the author is actually trying to say.

  • > All I’m really getting from this is that I should avoid animations

    Wouldn't be the worst takeaway from the article. You should avoid animation for animation's sake in general. Imagine if we animated letters flying up from your phone's keyboard into the text field as you type them for example.

    • Most of the animation examples in the article are there to communicate transitions in the UI (eg the movement of a UI element). Functional animations are genuinely a good practice from an accessibility standpoint and not just flourish. It’s just hard to do well.

    • As a user of software I find myself disabling most transition animations when the OS or application supports it, desktop, mobile and web. Very rarely I find myself turning something back on - either it's actually useful in the situation, or it's done so well that it's pleasant even to an old like me.

    • I think it would be hilarious if you'd combine that with the clacking sound of a typewriter.

An app with no animations at all is going to feel terrible. You can test this out yourself, if you have an Android you can set animation speed to 0x in the developer settings. It is jarring to see instant changes and it actually takes your brain a second to process what happened, and that process is probably slower than having the animation in the first place.

I have mine at 0.5x and that feels sufficient, still fast but I can see apps opening and closing etc.

  • I'm a happy user of android with animations turned off. It's the only mean to make it somewhat "snappy". IMHO lag is always worse than lack of fancy transient state in input -> UI change context.

  • Not for me, I always turn off animations. It feels fine for me, and I can operate the phone a lot quicker without having to wait for animations to complete.

    • I don't turn them off entirely, I kind of enjoy the feeling of momentum animated elements can provide, but I definitely do go in and speed them up massively. I find that when a phone is feeling unresponsive or sluggish, it's usually because I'm moving two steps ahead of the animation and it has to catch up. Feels like tripping on your own feet.

  • I have mine at 0.5x.

    The problem with 0x is that it seems to only affect like 90% of the UI. Certain things still animate, and the cadence feels awful as a result.

    At 0.5x the stuff that's mysteriously unaffected by the animation speed setting isn't as jarring.

    I would use 0x if it worked properly.

  • After using Android for like a decade, I eventually succumbed and got a iPhone 12 Mini (back when it was new). I still miss the ability of turning off animations as I could do on Android, and I'm 110% my current phone would feel 200% faster if I could just turn off every damn animation that just exists to exists. I'd much rather have a second to process if that's needed (which I don't think it is), than being slowed down by one second every time an app changes the page, everything feels like molasses when you navigate around.

    • Try "reduce motion"? It's not quite the same thing (prefers cross-fades in many cases), but it might help. Anecdotally some things are noticeably faster, and not having them swing around before settling lets me get a read on their location faster.

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  • All animations are just wasted time while you can't properly interact with the UI, it's much better to just turn every one of them off.

  • Give it one day and you won't come back to those sluggish animations slowing your intent down.

    • I have it at 0.5x. 0x is just not smooth enough, plus sometimes apps actually don't load fast enough so you're stuck waiting for them anyway.

  • It's jarring to see instant changes that don't make sense. Animations are primarily a way to paper over UI that sucks to begin with.

    Many transitions in Android are perfectly fine at 0x animation speed. The majority of transitions that suck without animation suck because the pre-/post-transition layout sucks and the transition between the two states doesn't make sense as a result.

    It's the same with several of the transitions in TFA. For example, the address bar placeholder text[1] should just be left-aligned all the time. The save dialog[2] should leave all the basic controls in their original location[3] when switching from the basic mode to the advanced mode. That means the "Where:" label should also remain in the advanced mode, and the controls[4] that pop up to replace it should either be moved to the right or below. The search bar should also be moved down.

    These are some really basic details and it is my understanding Apple used to not screw them up nearly as badly.

    [1]https://tonsky.me/blog/every-frame-perfect/safari@2x.mp4?t=1...

    [2]https://tonsky.me/blog/every-frame-perfect/save@1x.mp4?t=178...

    [3]https://imgur.com/ZpHLCsv Artist's rendition. Please excuse the minor jank and criminal amount of empty space; I couldn't be arsed to fiddle with the screenshots to get pixel-perfect positioning and shrink the advanced dialog horizontally. Bikeshedding over where exactly the new controls belong is welcomed but irrelevant to the point I'm making.

    [4]Is it just me, or are their icons uselessly, impenetrably, unhelpful?

  • An app with no animations feels awesome. It's great and it doesn't take my brain any time to process what happened since I already knew what was going to happen when I press the button that makes things happen on purpose.

This resonated with me, but I would have loved to see some positive examples as well. The tone did not read as a rant, but as someone that doesn't know too much about good UI construction, I did not feel like I walked away any closer to understanding what a North Star should be.

  • I did just this recently. I detailed the imperfections first, which were similar to this in concept, and then walked through the improvements I made.

    If you're curious, you can see it here: https://www.thisischris.dev/projects/project-6/

    • Thanks for highlighting the "one element cross fades into a totally different one" example. That particular type of animation really makes an app feel ungrounded and unreliable to me, it gives a sense that the UI elements aren't really tied closely to the data and are just barely existing. And somehow I see it all the time across tons of apps.

      The improved versions where the elements actually transform into each other, sharing the same visual real estate, is so much better.

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Excellent article. The examples from Mac OS Tahoe show how sloppy the work is. Just lazy shit done without attention and care. Steve Jobs would have fired a bunch of people. And this stuff matters:

> This creates a false feeling that something subtly changes when you switch between modes. And you know what? I don’t want my UI to give me false feelings.

The animations in iOS 26 and MacOS Tahoe feel wrong. Almost like an uncanny valley. It makes the UI unpleasant to use.

The root cause of this stuff, from experience, is that animations are hard to retro-fit after the fact. It's a lack of planning.

The UI code needs to be structured with animation in mind, with hooks in the right places. And to do that, you need to know what is likely to be animated together.

But what ends up happening is you encapsulated a few of the moving pieces in abstractions (e.g. "toolbar", "sidebar"), but you want to animate stuff within. You end up copy+pasting animation logic inside each (now leaky) abstraction and duct taping it all together. UI abstractions are hard!

(Yes, on apple platforms there are transition blocks which will capture changes to the entire view hierarchy, but then the battle becomes preventing animations on stuff that shouldn't change!)

I think a lot of these are because Apple has built animations into their products as first-class citizens, but that means that they need to somehow figure out how to compose them well. (Which obviously is a rather difficult problem to solve!) In my experience, you end up spending a lot more time trying to get all of the animations to work well together than you do on creating the actual UI, and that time is just not worth it if your start and end states are beautiful and intuitive. There's also the cross-UI-framework tax that has come up since Apple has allowed mixing SwiftUI and (App|UI)Kit, and animations are part of that.

  • I'd slightly rephrase that as "Apple has recently started building pointless animations into their product, instead of sticking to meaningful animations like they were doing since unmemorable times".

    Old Apple knew not to overdo things.

This is the kind of things that bother me when using software and unfortunately almost every software is affected.

I just look at the largest tech companies in the world that with their unlimited finances cannot produce software that isn't glitchy like this.

The KDE start menu has always annoyed me (well, since whenever they switched from the Windows 95 inspired one to the XP or Vista inspired one) for this reason. When you switch views, the view switches immediately (which is good) but the indicator animates slowly from one state to the other.

The result is that the indicator is not really indicating what it's supposed to (since it's out of sync with the view): It's indicating the old view when I'm already in the new one, and then it's indicating something between the old and new views, when clearly I'm not between views at all. So it's completely wrong for the entire animation until it finishes.

> The rule of thumb is: If I take a screenshot of your app at any moment, it must make sense

After reading this blog post, I think the rule of thumb should be "If I take a screenshot of your app at any moment (except during animations), it must make sense". I don’t think making sense during an animation should really be a goal, as long as it makes sense before and after.

  • Well, this is the exact opposite of his point. Of course it should make sense when not animating! That is given. The entire crux of his point is that it should also make during an animation.

    In an ideal world, it is hard to argue with. Yes, sure it should make sense. But also, please don't spend precious cycles on this unless all the other bugs are fixed, and this animation consistency is truly the most important remaining issue to address.

  • It's like you read until that point, but then didn't read the justification for why it makes sense to care about frames during the animation, the author does outline a bunch of reasons why it should make sense during the entire thing.

    Maybe I've just spent too many years as a pixel-perfect chasing frontend developer, but things can look very janky if they jump out of place during animations, compared to where they are before/after.

    • > It's like you read until that point, but then didn't read the justification

      My comment starts with "After reading this blog post"; of course I read it, but it left me totally unconvinced, especially because the author doesn’t bother showing good examples: he criticizes these and then leave you with a random raccoon animation and that’s all. For example, I don’t understand what’s wrong with the Youtube animation; it looks perfectly fine to me.

  • But the author tried to show exactly that, if screenshots during animation don't look sensible, it points to animation as a whole not making sense - it being either messy, overlapping, or confusing - and, in general, eroding the user's trust.

    • Yes and I disagree. Youtube doesn’t "erode the user’s trust" with an animation that the author of this post finds yanky just because if you take a screenshot in the middle of it you see a frame that no real user sees that doesn’t look good.

  • I first heard something similar taking motion design classes in art school: every frame should look good. Transitions and animations that have bad in-betweens look bad overall

This is begging for someone to spin up Mac OS X Tiger or Snow Leopard and compare! I recall their butter smooth rollout animations looking pixel perfect

  • I suspect the specific versions you call out were in that time period for a reason.

    Snow Leopard was the first to integrate iOS's CoreAnimation framework. Nearly all animations now are based on that. Before, the CPU manually updated the sizes and positions of things, frame by frame, in a loop. This is how you'd program a Game Engine.

    After, with CA, state-change property models are sent to a different process entirely which does its own interpolation to animate the UI at a higher thread-priority than any other process in the operating system. This is fantastic if maintaining 60+ FPS at all times, even on an iPhone 1 or 3G with less power than you'd have in today's AirPod chips, was a central requirement. (And it was, the first iPhones dominated their competitors in terms of input latency and framerate)

    But programming CoreAnimation is much more complicated and easy to make mistakes in if you want "every frame perfect". Trust me, I made a lot of the animations that shipped in iOS 7 (the Calendar app is full of them, OS level transitions for the core chome elements of iOS). It took nearly a year of meticulousness to get things looking ok. In the years since I left the company, I've noticed these transitions get more and more janky and buggy and full of artifacts. Clearly, whoever replaced me doesn't have the same eye and sense of craft. Oh well.

There’s a similar principle of congruence in information visualization, stated in Animated Transitions in Statistical Data Graphics by Heer & Robertson as: “Maintain valid data graphics during transitions. To ensure viewers’ mental models are congruent with the semantics of the data, we suggest that, as much as possible, intermediate interpolation states remain valid data graphics.” https://idl.uw.edu/papers/animated-transitions

The entire premise of this article is wrong and derived from a misquote. Kristian Høgsberg, in Wayland stated his goal was a system in which "every frame is perfect, by which I mean that applications will be able to control the rendering enough that we'll never see tearing, lag, redrawing or flicker."

It had nothing to do with "if I take a screenshot of your app at any moment, it must make sense." As others here have pointed out - this entire article is very poorly conceived.

  • Misquote or not, the article is bang on and I think a better interpretation of that sequence of words anyway.

  • The entire premise of your comment is wrong and derived from not understanding this quote of the author:

    > Wayland is talking about the technical side of things (modern GPU stacks are very complex and Wayland is trying to take control back) but it could be applied to UI too.

These seem like low-priority bugs to spend time on? Most apps have bigger problems.

  • The issue is that we didn’t have these kinds of incongruent animations twenty years ago, and nowadays they are the norm, worsening user experience.

  • These aren’t bugs in the traditional sense. They built the animation system to work like this, and replaced the old system that didn’t produce these psychedelic transition states.

    • Is there more about what they did somewhere else? I don’t see any implementation details in the article.

I feel like OP brought up a good problem to solve, with no solution. I dream of the days where posts like these end with "5 ways to better execute on this today".

Instead, we get a zooming in/out raccoon (making fun of the reader, IMO) for recognizing this problem via the OP author.

Maybe it's just a really hard problem to solve across all devices & latencies... Perhaps more time needs spent on "problem solving" vs "problem description".

  • The expectations set for what turns out to be an article without solutions are also raised by the title the author chose. Show us these mythical perfect frames?

Feels like UI elements have a lot of abstractions that are not perfect for motions. With every hack you work around the layout engine that gives you this simplicity of defining layouts. Some libraries allow you to define keyframes for the motions in between, but it still isn't perfect, especially if you look at the youtube sample where one element overlaps the other and the animation would take up too much time or look odd if this wasn't the case. Even if you perfect all of this, would you really want to spend more processing power and script weight on these aspects? I feel like most UIs have severe latency issues out of the box, anything that doesn't address the elephant in the room adds insult to injury.

Never use animation just for the sake of it. This article would not have existed had software designers stuck to this rule. All examples in the article use completely unnecessary animation.

The application of "every frame perfect" to the mouse pointer ranges from neutral to actively harmful. It causes roughly 1 frame of delay, which can be enough to bump the display-eye-hand-mouse loop out of whack (this seems to be different from person to person). It also causes pointer stutter when the system is under load side the pointer can't be independently updated.

  • +1... every frame perfect is less important than lag (ie something should happen at next frame after user action).

    Pointer should be async with the rest of desktop anyway, unless the system is broken.

I don't want animation in my UI at all. I'd much rather have hard cuts between states, as it used to be.

Wasting processing cycles making things look pretty yet it almost always results in a worse situation for the user.

New Principle and I love it, however its hard to do on move dynamic and populated sites like youtube. Gonna follow this from my next project.

  • Re: YouTube example, the issue (as I understand it, and I'm what you could describe as the opposite of an expert in that) is that the video and the playlist blend with transparency over one another. Had the playlist appeared sliding from the right side of the screen, it would have worked (I guess).

    • yes what you described is how it is right now on youtube, the main reason is to make it look more fluid and natural, apple examples shown mostly work because the overall structure is very static and have a lot of negative spacing. More animations tend to negate the principle described if not done with extreme care.

Curious is there most efficient&precise(SOTA?) way to create animations/transitions(like theorem), I've written some of these and really hard to figure and fix out(e.g like the zoom animation from last section of page).

We do not perceive the world as a series of still frames. Any UI forcing that upon us is unnatural and will break immersion in subtle and unexpected ways. Apple and macOS may have their faults but the UI design is head and shoulders above anything the Wayland team has produced to date.

I couldn't understand author's point, because they haven't provided the right way to do each thing, their opinion.

It's easy to criticize.

Dragning downwards on the iPhone Home Screen to search is a perfect example, the gradual blur animation is never auto playing once activated. Instead, it responds to your drag and you are always in control.

The title reminds me of The Simpsons, watch an episode and pause it. Unlike live action, every frame of The Simpsons is art. It is almost unbearable to internalize the sheer volume of purposely constructed images that The Simpsons is sending at you. Gluttonous in scale.

I scrolled the article and there were frames during the scroll where half a line of text was clipped by the start and bottom of the viewport.

It would have been compelling to describe / show what it should have looked like. Because the only alternative for some of these would just be sharp jumps instead of any animation - animating simultaneous appearance and transition of information will inherently result in frames that look imperfect.

i actually like that the crop snaps after the fact, it reminds me that the crop is in fact active, same with rubber-banding type stuff.

Negative examples are cool. Time consuming to put together. I did appreciate that. What are some positive examples?

  • Positive examples are all other animations that do work well, or are just animated in After Effects, for which there are plenty of examples online already, like on Twitter.

Great article, the worst offender is compact tab mode in the current Safari. The animations they implemented make that unusable, sometimes it’ll move tabs away from where the tab was when clicking, the animation always look clunky and the entire experience feels utterly untested. Doesn’t just look poor, but violates quite a lot of HIG rules Apple recommends for third party devs. Maybe something to focus on in a part two of this article.

Bah, each time someone say this they "forgot" that one side effect of 'every frame is perfect' is that it can increase latency.. Perfection or latency? That should be the user's choice not the developer's..

All I can think seeing those examples is how macOS went from beautiful to utterly jank in the last 10 years.

Animation should convey meaning, not achieve pixel-perfect morphs between states.

When iOS first launched, some of the brilliance was in how UI elements transformed into one another—a title in the title bar becoming a "back" button on the left, for instance. There were no intricate morphs, just a simple cross-dissolve between two elements shown briefly at the same time. It read as meaningful without being literal.

The Crop/Adjust example doesn't hold up here, because the two modes don't share a focus. The crop animation is deliberately different: it emphasizes the cropping controls at the edges of the image that you might otherwise miss, prepping you visually for the task and tying the controls into the image workspace. Adjust mode has no direct controls on the image itself, so the transition out should differ. The mismatch is the point, not a flaw.

For most UI, you don't need pixel-perfect morphs between small elements. The real job of animation and behavior is to convey meaning and context. Make your transitions pixel-perfect and most people would never notice the difference.

A really infuriating example of this is the Windows Photos app (or whatever it is called this month) where scrolling through a photo album will show every image jumping around as it first shows them at some arbitrary scale, and then fits them to the window.

Lazy, lazy development.

"Job done, boss! Ready to ship to... checks notes... 3 billion users!"

"Did you test it?"

"Test? I thought we had a QA department!"

"Nah, we fired all of them a decade ago. You're the QA now."

This silly pretentiousness goes a long way to explain why it took so long for Wayland to even be usable.

I get that this is the way of the world, but I still think we'd have been be better off with, you know, real attention paid to classic free/open source ideas (like not breaking backward compatibility.)

Bold words for the site which makes my eyes bleed.

  • Articles from this site pop up occasionally. Something about the background color causes me to see a medium-sized bright spot in my vision after a few minutes. Due to this, I have to remind myself not to click when I see the URL.

The thing about UI animation is that even if no tween frame was ever hinky I'd still turn it off because it's an anti-pattern. It's there to look good on a retail shelf, not to improve day to day usage.

I would love to understand these people, really!

On a personal level, if thing works - I say, cool, lets focus on something else now.

But I have worked with people who are similar to the author and we will get into the conversation:

    - they: wait, but the bundle size is 2.4Mb, it can be improved a lot
    - me: by how much? and we have 10k users/day and we have cache policy setup
    - they: we can reduce it to 1Mb, imagine saving 10k*1.4Mb every day
    - me: yeah, but its not costing us much, if you focus on making it perfect your salary will cost us 2 years of outbound traffic cost.
    - they: no, but its not perfect

I admire those people, because they're valuable asset in some companies (e.g. Google scale, saving 1.4Mb for 1 Billion people every day is a lot), but my mind doesn't even want to think about what's perfect.

How do I get there? What are the resources I can read and learn from to look at things to make them perfect?

  • Broken windows theory

    The issue with “premature optimization is bad” is that some see it as a permission to not optimize at all. Hence you eventually end up with a system where everything is bad.

    Although for some of us being obsessive-compulsive weirdos this is the only way of life: an itch that keeps on physically scratching until resolved.

    “Be guided by beauty. I really mean that. Pretty much everything I’ve done has had an aesthetic component, at least to me. Now you might think ‘well, building a company that’s trading bonds, what’s so aesthetic about that?’ But, what’s aesthetic about it is doing it right. Getting the right kind of people, and approaching the problem, and doing it right […] it’s a beautiful thing to do something right.”

    • > Broken windows theory

      Absolutely, but on the other hand businesses operate with lots of broken windows as well, and they are fine with it.

      Dilemma I am having is, on one side, business needs my best judgement for today and short term, because this is how most businesses survive, on the other hand, on a personal level I feel like I am stuck making non-perfect decisions, hence I can't even think about perfect world, because I am not training that part of my brain.

  • Starting from a literal bandwidth costs perspective definitely won't get you there. I'd start by trying to feel personally annoyed by things like that. Then maybe try to feel more annoyed, since you know it'll touch every customer forever.

    In that bandwidth case I'd be annoyed by the waste which kind of pervades software already, and it'd feel great to know at least we countered it a little bit.

  • > but my mind doesn't even want to think about what's perfect.

    That's the barrier to understanding right there! This also makes it easy to make up 2x cost estimates to justify not improving anything