>I'm typing this on a MacBook with scaled display and legibility is just fine. Asian scripts look fine, too. iPhones also use a scaled output (most recent models all do, there's no match between physical pixel and GPU pixel at all anymore on OLED, and there's no match between GPU and logical pixel either). You'll never hear customers in Japan or China complain about poor legibility.

>That's the difference between theory and practice. If you try it, you realize there's no problem. Otherwise I'm sure we can keep writing about how bad it's in theory all day.

I do not appreciate the way you are treating me as if I clearly do not have any experience or knowledge on the subject matter. I in fact use an iPhone and have owned multiple Mac computers, including my M1 Mac Mini. I also studied Japanese in college and font rendering was always a kind of issue.

Comparing Linux and macOS is not too interesting since Linux actually is closer to macOS in many regards with font rendering. Instead, it would be instructive to first compare Windows 10 to macOS (Big Sur).

https://files.catbox.moe/cho5iw.png

This comparison shows the default fonts in macOS and Windows 10 rendering the word 「醤油」. macOS Text Edit is on the left, and Windows 10 Notepad is on the right. I set the font size to 10pt on Windows to help make it a more even comparison; Windows defaults to 12pt which makes 1x plenty legible. However, in a head-to-head comparison at a similar font size, 1x is not terribly legible here on either side. Still, at 1.5x you can see a clear difference in legibility already. This is with a common word that is mildly complex, but still not nearly the worst case scenario for typography. And yet, some of the features are quite difficult to distinguish. It's good enough, but it's not great. The Windows typography here is ugly, but practical.

What if macOS could scale 1.5x natively? Well, the comparison would look like this:

https://files.catbox.moe/hiyvr6.png

On the left is 12pt at 1x, and on the right is 18pt at 1x. At first glance it does look similar, and neither is ideal. However, this is still a noticeable improvement. The two strokes near the bottom of the left kanji are now distinguishable with the human eye, and it is generally less blurry. This is without the advantage of hinting or subpixel AA, which should make it even less blurry and increase the horizontal spatial resolution enough to make more features easily distinguishable. And this is still not a worst case example. It’s an example of something common.

By the way, regarding iPhones. I have an iPhone XS. The iPhone XS has a DPI of 458! That is insane. The monitor I'm currently using, by comparison, has a DPI of around 110. So yes, you can get away with quite a lot on an iPhone XS without any noticeable artifacts or blurriness. But that's not realistic. Laptops and phones are different devices with different hardware and different distances that we view them at. OLED displays on computers are still the exception.

> You're talking about an iBook that 1) isn't high DPI 2) using OSX which isn't scaled (fractionally or in any way at all).

> I'm sorry but your iBook is irrelevant to the discussion. We're not discussing here legacy text AA on legacy low DPI display. None of this matters.

I don't know what to tell you, I was trying to illustrate the pitfalls of Apple's early choice to not integrate techniques like hinting and subpixel anti-aliasing into their font rendering. It's not like the font rendering looks meaningfully different on an iBook G4 than it does today, it's that the screens have gotten higher resolution. They waited it out. If you want to talk about impractical decisions, the 10 year stretch when Apple laptops had blurry fonts and no HiDPI displays is certainly relevant to the discussion.

Also, Linux still needs to support 1x rendering well. It does not have the luxury of choosing the hardware it runs on.