waydabber
commented
2 years ago This is expected. The native resolution is only available as LoDPI, this is a macOS limitation. But using HiDPI for the native resolution would only result in a supersampling/antialiasing effect (some do like this). If you really want this effect, you still need to use dummy mirroring. I think most of the benefits of HiDPI come only if you use a resolution that is lower than the native resolution (the more you lower the HiDPI resolution, the more details emerge as more physical pixel belongs to a logical pixel (which contains 4 framebuffer pixels).
This is my setup:
I've correctly configured the new native smooth scaling feature for hardware displays without using any dummy, which is a feature I was really waiting for months. However when I was changing the Low Resolution "2560x1440, 75Hz, Default, Native" to the HiDPI equivalent, the max I can get is "2544x1431, 75Hz", which is strange.
If I go to Settings > App Menu > Show additional resolution options, I do get the expected HiDPI 2560x1440 option, but it is flagged as Invalid, and when I click it, nothing happens, and the resolutions remains the previous selected one.
Is this a bug or is it expected? I fear that missing those horizontal and vertical pixels may have an effect on image quality although it's definitely better than the low resolution one.