since the move seems to be going from force font dpi to display scaling, i got to report it makes fonts and various components blurry as of currently on plasma 5.27 beta. this is with forcing font dpi to 144 https://i.imgur.com/0ZaR2WG.png , and this is with scaling 150% which makes them roughly the same size. https://i.imgur.com/p6U5CoT.png SUMMARY with fractional scaling instead of forcing font dpi you get blurry text all over, most noticeably on the desktop icons on the screenshots. STEPS TO REPRODUCE 1. Change the scaling and compare text with force font dpi. OBSERVED RESULT blurry text EXPECTED RESULT crisp fonts. SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 5.26.90 KDE Frameworks Version: 5.102.0 Qt Version: 5.15.8 Kernel Version: 6.1.8-arch1-1 (64-bit) Graphics Platform: Wayland Processors: 16 × AMD Ryzen 7 5800H with Radeon Graphics Memory: 30,7 GiB of RAM Graphics Processor: AMD Radeon Graphics Manufacturer: Acer Product Name: Nitro AN515-45
We implemented fractional scaling protocol in 5.27, BUT the client side also needs to support it. Support for fractional scaling is missing in Qt 5 (kwin ceil()s the scale factor and downscales client buffers so the fonts don't look crisp anymore). Reopen this bug report if you see issues in apps using Qt 6.5 or newer, which should support fractional scaling.