High DPI

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This article helps users to configure their system for High DPI display, like a 4K monitor or notebook with retina display.

What is my DPI?

DPI setting of a regular display is 96. If you have a 27 inch 4K display (resolution is 3840x2160), you want to display 2 pixel width for 1 actual pixel width, the scale factor is 2. Then the DPI setting should be 192.

Some recommended DPI settings:

Screen size (inch) Resolution (pixel) Scale factor DPI
28 3840x2160 1.5 144
17 3840x2160 2 192
13 2560x1600 2 192
13 1920x1080 1.5 144

Increasing scale factor could make fonts and user interface bigger and sharper. However it will make the available desktop space smaller. You should balance what you want: a larger space to show four windows at the same time, or a nice and beautiful desktop.

GRUB

By default, GRUB automatically detects the resolution of screen. In high DPI devices, texts of boot menu are too small. To change it, open YaST -> System -> Boot Loader, in Kernel Parameters tab, change console resolution to a specific value, NOT Autodetect by grub2. After that, boot menu will always scale up to resolution of your choice.

YaST Boot Loader kernel parameters screenshot.png

SDDM

SDDM is the default desktop manager in KDE 5. It provides the login screen. SDDM cannot detect your screen DPI so it won't scale to fit. Here is no option available on YaST or KDE System Settings, you need to modify /etc/sddm.conf and add the following option:

ServerArguments=-dpi 192

The full configuration file looks like:

...

[XDisplay]
DisplayCommand=/etc/X11/xdm/Xsetup
MinimumVT=7
ServerPath=/usr/bin/X
SessionCommand=/etc/X11/xdm/Xsession
ServerArguments=-dpi 192

KDE

In System Settings -> Display & Monitor module, scroll down and click the Scale display button at the bottom.

KDE System Settings Displays Screenshot.png

You can change scale factor in the opened dialog:

KDE System Settings Displays Scale factor Screenshot.png

Click OK button to save.

In System Settings -> Fonts module, check if Force font DPI was set to correct value. You should have 192 for high DPI screen.

KDE System Settings Fonts Screenshot.png

Click OK button to save.

Note: you must reboot system to make these settings take effects.

GNOME

TODO

Applications

Firefox

Perfect. No need to configure anything.

Chrome/Chromium

Perfect. No need to configure anything.

LibreOffice

Almost perfect. No need to configure anything.

  1. Toolbar icons are scaled bitmap picture so they are not clear and sharp.
  2. Radio button, checkbox and scroll bar are small in KDE. (GNOME not tested)

Thunderbird

Perfect. No need to configure anything.

VLC (Qt5)

Perfect. No need to configure anything.

GIMP

GIMP's high DPI support is still poor. Problems including:

  1. Icons are too small.
  2. Radio button, checkbox and scroll bar are small in KDE. (GNOME not tested)

Here are some community made high DPI icon theme for GIMP:

  1. https://github.com/jedireza/gimp-hidpi

After install this icon theme, toolbox icon in GIMP will become normal.

Inkscape

Inkscape looks poor on high DPI without configuration:

  1. Icons are too small. (can be configured)
  2. Radio button, checkbox and scroll bar are small in KDE. (GNOME not tested)
  3. Cursors and control box of shapes are small.
  4. Page size is scaled up. (can be configured)

However, you can do a little configuration to make it much better.

Open menu Edit -> Preferences, choose Interface in the dialog.

Inkscape Preferences Interface HiDPI.png

Choose Larger for all icon sizes. Set Zoom correction factor to 200% (depends on your scale factor).

Restart Inkscape to take effects. After configuration, tool bar icon size is big enough.

Inkscape on high DPI screen after configuration.png

Telegram Desktop

Perfect. No need to configure anything.

KDE5/Qt5 applications

Almost all KDE5/Qt5 applications work out of box in KDE.

However, here might be some graphics, like icons and images, are blur. This is caused by missing HiDPI support in source code. Gwenview's image viewer is a bad example.

Qt4 applications

Many KDE4/Qt4 applications have poor support to high DPI screen, including Amarok, Clementine.

GNOME3/GTK3 applications

All GNOME3 core applications are perfectly engineered for high DPI screen.

GTK2 applications

Many GTK2 applications have poor support to high DPI screen, like GIMP, Inkscape.

Electron applications

Electron applications, like Atom, Visual Studio Code, Slack, use Chromium as render engine. So they should work perfectly in high DPI display.

Steam

Steam game client in window mode has no support for high DPI display. However, you can try its Big Picture mode, which support screen of any size, any resolution. You can find the button on the top right corner near minimum, maximum and close buttons.

Steam big picture mode button.png

The big picture mode is designed for TV. So it will scale content to fit screen size. It is nor as sharp and clear as regular desktop applications.

Steam big picture mode home screen.png

See also

Related articles

External links