When using the Minecraft launcher on Linux, the launcher does not scale its content according to the system's display scaling factor. According to user reports, this affects multiple Linux distributions, desktop environments, and windowing systems.

Impact

Users with HiDPI displays have extreme difficulty viewing and navigating the Minecraft launcher. Since the launcher does not scale properly according to the display scaling factor, the size of content is very small. For example, text with a 12px font size would be 4px on a typical 4k 13.3" laptop with 300% scaling (equivalent size as 150% scaling on a 1080p 13.3" display).

How to reproduce

1. Set a display scaling factor on your Linux distribution that is not 100%. For example, on Linux distributions with the GNOME desktop environment, go to Settings > Displays > Scale and set it to 200%.
2. Open the Minecraft Launcher.
   → The scale of the launcher content does not match that of the system. On HiDPI displays, the text size is unreadable and the interface is difficult to navigate.

Notes

• If I remember correctly, this is an upstream issue with CEF. However, I can't seem to find a relevant issue report. This does appear to be an upstream issue. When using the latest beta build of the CEF sample application (94.2.2+g0c2cc26+chromium-94.0.4606.50), the scaling of the content is not correct on a HiDPI display.
• In launcher versions prior to 2.2.2159, the content was scaled correctly. However, the resolution of the window was not changed, causing it to appear blurry. See MCL-16405.
• Since launcher version 2.2.2159, the size and resolution of the window are set properly, but the content scale is not. Try running the launcher with GDK_SCALE=1, GDK_SCALE=2, and GDK_SCALE=3. Notice how the window size grows, but the content size does not.