Konsole font rendering with HiDPI display scaling: glyphs cut off vertically

[Horst Schirmeier]

Depending on the text-cursor position (e.g., in vim), glyphs in a complete text line in Konsole are cut off vertically. These characters need not be fancy Unicode ones, plain ASCII suffices.

Konsole font is the default one here (Oxygen Mono, 9.0), but due to my Hi-DPI display (14" with 2560x1440px) I set "Force fonts DPI" to 192 in KDE's Settings->Appearance->Font->Fonts.

This seems to have already been reported and fixed upstream, it may suffice to back-port the patch.
https://bugs.kde.org/show_bug.cgi?id=371687 -- which has a duplicate here https://bugs.kde.org/show_bug.cgi?id=336832 showing this screenshot: https://bugsfiles.kde.org/attachment.cgi?id=87451

ProblemType: Bug
DistroRelease: Ubuntu 16.10
Package: konsole 4:16.04.3-0ubuntu1
ProcVersionSignature: Ubuntu 4.8.0-32.34-generic 4.8.11
Uname: Linux 4.8.0-32-generic x86_64
NonfreeKernelModules: nvidia
ApportVersion: 2.20.3-0ubuntu8.2
Architecture: amd64
CurrentDesktop: KDE
Date: Sun Jan 8 18:32:08 2017
InstallationDate: Installed on 2016-11-26 (43 days ago)
InstallationMedia: Kubuntu 16.10 "Yakkety Yak" - Release amd64 (20161012.1)
SourcePackage: konsole
UpgradeStatus: No upgrade log present (probably fresh install)

[Horst Schirmeier (horst)]

Also reproducible with the "Hack" font instead of "Oxygen Mono", and/or disabling the fonts setting "Force fonts DPI".

[Horst Schirmeier (horst)]

How I created the screenshot: Create text file with sufficient number of lines; open with vim; move cursor down until I'm at the terminal's last line and beyond; move back up until cursor is about in the vertical middle of the terminal.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Horst Schirmeier (horst)]

... did I mention this bug makes Konsole unusable for anything like programming or text editing? This is so annoying I really wonder why something like this can make into an Ubuntu release, actually.

[Horst Schirmeier (horst)]

Update: This seems to be triggered by a fractional (> 1, but < 2, 1.4 in my case) Displays -> Scale -> Scale Factor setting (which is meant for HiDPI displays, and probably for people with sight issues), not "Force fonts DPI".

This upstream bug report seems to be related: https://bugs.kde.org/show_bug.cgi?id=373232

[Bruno Randolf (br1-l)]

A possible workaround is to create a sddm.conf (with sddm --example-config > /etc/sddm.conf) and add "-dpi 144" to ServerArguments. Then set Scale to 1 in System Settings and reboot.