I am running emacs version GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.20, cairo version 1.16.0) of 2020-09-19, on Ubuntu 20.04 on a laptop with 4K display in 200% scaling mode (hiDPI).

Emacs does not adapt fully to scaling changes. On a large monitor I use 100% and everything renders ok. But when using the laptop screen only, the horizontal divider of the mode-line is incorrectly scaled. Can the size of the divider be customized?

I also have to change the Default font size every time I change between 100% and 200% scaling, is there a setting in Emacs where that can be automatically set based on screen resolution/scaling settings?


The mode line is not an issue any more, since I was informed that it was a scrollbar that concealed the text.

I still have a problem when changing from large monitor to laptop screen in 4K resolution. I have to manually change the default font size, and the cursor is too small.

Does Emacs have support for automatic adaptation to HiDPI screen sizes?

Icorrectly scaled horizontal divider

  • The question isn't very clear. Please provide a step-by-step recipe, starting from emacs -Q (no init file), showing what you've tried, and saying what you expected to see and what you saw instead.
    – Drew
    Feb 14, 2021 at 23:56
  • 2
    If you don't need it you could disable the horizontal scroll bar: (horizontal-scroll-bar-mode -1). Feb 15, 2021 at 9:17
  • You might file a bug report about the horizontal scroll bars (M-x report-emacs-bug). Regarding the issue with hidpi support, you should ask about it in a new question. Feb 16, 2021 at 10:32

1 Answer 1


A solution to the main problem is to hide the horizontal scroll-bar, either as suggested by Arch Stanton in a comment, or by disabling it in:

Options -> Show/Hide -> Scroll bar -> Horizontal

I did not understand that it was the scrollbar that was incorrectly rendered so that the text in the mode line was covered.

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