The KDE Plasma desktop handles Retina resolutions almost flawlessly. Using a 200% scale to achieve 2x HiDPI on a capable monitor ensures crisp edges, and no shimmering interpolation when moving or resizing windows.

If you run a 4K or better display with the right drivers on FreeBSD or Linux, Plasma helpfully doubles some of the UI elements. To make 200% scaling universal, there are a few more tweaks to make.

Launch System Settings:

  1. Scroll down to Hardware in the sidebar, and choose Display and Monitor. It should select Display Configuration for you. Use the Global Scale slider to set the scale to 200%.

  2. Click the < (Go back) button in the top-left corner, then choose Appearance, then Cursors. From the Size dropdown at the bottom-left, choose 48.

If you’re like me and are still running xorg, you might still see tiny icons in menus and buttons. If so, you can set this environment variable to enforce scaling:

$ echo "export PLASMA_USE_QT_SCALING=1" >> ~/.profile

Log off and back on, and everything will look as it should :).