Bug 468465

My distribution upgraded konsole from v22.08.3 to v22.12.3 recently and this introduced some regressions in font handling.

I use the Liberation Mono 9pt font but when displaying japanese characters it falls back to Arial Unicode MS 1.01 for those characters. This looked correct in v22.08.3 but when I try to select any japanese text in v22.12.3 only half the character is selected. This also impacts the new "select mode" (ctrl+shift+d). The cursor can be placed inside of japanese characters and you have to press the directional keys twice to move between those characters.

https://i.imgur.com/4ldFigD.png <- v22.08.3 showing the full 二 character selected
https://i.imgur.com/PoYtSCr.png <- v22.12.3 showing only half of the 二 character selected

The japanese characters are twice as wide as Liberation Mono characters on screen so if the screen is divided into a strict monospace grid the japanese characters gets chopped in half but v22.08.3 seem to handle that fine.

There is also a slight change in visual appearance. If konsole is displaying a mix of Liberation Mono and japanese text on different lines some of the pixels from the japanese text remains after the screen is cleared.

https://i.imgur.com/DD6CM3I.png <- displaying some mixed text on v22.12.3
https://i.imgur.com/v1tqx6R.png <- after running nano, which clears the screen, the top row of pixels from the japanese text remains

I've bisected both problems to the following commit:
76f879cd70fb494ab2334d2660b34679546f3d9d is the first bad commit
commit 76f879cd70fb494ab2334d2660b34679546f3d9d
Author: Matan Ziv-Av <matan@svgalib.org>
Date:   Sat Aug 6 19:15:42 2022 +0300

Draw characters in exact positions

The latest git version is also affected.