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'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.

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.

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 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.

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.

> 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.

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

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.

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.

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.

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".

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

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.

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.

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.

This explains why I feel compelled to turn off any animation whenever there is a toggle to do so

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.

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?

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.

What a rare creature, an article without AI mentioned in it! Thanks for sharing

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

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.

This blog makes me appreciate my browser's reading mode

Now I have to get Ubuntu/Wayland/winit/wgpu/rend3/egui/wine to work.

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.

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