Is my vision that bad? No, it's just a bug in Apple's Calculator

macOS on a low dpi screen is mostly full of those kind of issues. I wouldn't recommend using a low dpi screen.

The problem appeared in the screenshots that the article shows, I don't think it has anything to do with the screen.

It's a screenshot of macOS running in low-dpi mode.

I’ve used fullhd imac/osx for many years until around 2018 and never noticed anything like that. Easier to call it “low dpi issues” now that they destroyed it, I guess ;)

2018 was about when they stopped selling the last Mac with a non-Retina display, so that would make sense for when they stopped testing for it.

6 years is a long time ;)

It's not only about stopping testing: they dropped subpixel rendering altogether.

Though this seems more like a hinting issue.

They removed subpixel hinting after Mojave IIRC. Now it's unusable on anything less than a 27inch 4K display, and it's been like that since years...

It’s crazy that I had to buy BetterDisplay (great tool btw) just to get fonts from incomprehensible to merely ugly on a 25x16 monitor via a fake 2x scaled one. Windows renders razor sharp even without gfx drivers.

There’s a great article with explanations on the net. But the gist is that macOS renders like a giant image with no care for pixels and small details. It works fine when using native resolution (low dpi) or have enough pixels for their “retina” approved resolution. Anything else and it looks blurry.

Linux and Windows use actual pixels for their rendering, and even with anti-aliasing, it looks sharp. If you’re stuck with macOS, aim for 4k at least.

The issue persisted when I disconnected the external screen, but I probably should have taken additional screenshots from the built-in laptop screen.

You don't stop testing when you stop selling X. You stop testing when you stop supporting X.

Ideally, you want a screen that natively runs at a resolution that’s a perfect 2x multiplier of a mainstream 1x resolution that has the right amount of screen real estate for the screen size.

So for example, a 20”-24” screen should be 4K so it can run at 1920x1080 @ 2x. Similarly for 27”, you want 5K which is 2560x1440 @ 2x.

This is a really good post describing how it all works:

https://bjango.com/articles/macexternaldisplays2/

That’s the article. I got hit with this issue after purchasing a 27” QHD monitor. Native resolution made everything too small, and everything else was blurry. I gave up after trying pretty much everything and bought a 24” 4K monitor for the mac.