ataeb wrote:
Thank you very much for your response. Since I haven't used a Mac device before, I wasn't aware that screen size, resolution, and PPI values of the monitor I’ll purchase are important for proper scaling.
I assumed it would automatically adjust the scaling, just like Windows devices. However, after seeing warnings that I might experience blurry visuals, especially with fonts, if I don't choose the right monitor, I wanted to ask for advice.
I believe the high-PPI transition is a case where Apple put more effort into maintaining backwards compatibility.
I believe on Windows, you would set the Control Panel resolution for your display to match its native resolution. Then you would set a separate scale factor (e.g., "150%" for a 27" 4K display) to tell applications what to do in terms of sizing things. However, I'm not sure that there is anything in Windows to actually force applications to honor that setting, and in the early days, there were applications that didn't play well on high-PPI displays.
On Macs, Apple set up a system where you have a nominal ("UI looks like") resolution and a drawing canvas that has twice as many pixels in each direction. Retina-aware applications tell macOS that they are Retina-aware and, in return, get to fill in things like photo areas in higher detail. If an application is not Retina-aware, macOS lets it believe that the "UI looks like" "resolution" is the actual resolution. Behind the legacy application's back, macOS modifies drawing requests so that things will still have the "expected" size and placement on the screen – even if they lack the extra detail a Retina-aware application could have provided.
Although virtually all Mac applications today are Retina-aware, changing APIs when you have a huge code base that depends on existing APIs is something that can be very hard to do. I believe this is why Apple continues to use the Retina scaling approach. It works well enough in a practical sense (even if it can be difficult to explain), and the application compatibility pain of changing it would be enormous.