Font Sizes

The Problem

In 2019 I blogged about getting a 4K monitor because of my vision being inadequate for a 2560*1440 monitor [1]. Now I’m using a 40″ 5120*2160 monitor [2] and still trying to find the correct balance between how much I want to see on the screen and what I am physically capable of seeing on screen.

Currently Kitty is my terminal emulator of choice [3]. What I most like about it is the feature of having multiple terminal windows in a single OS window, so instead of having 9 or 16 different xterm instances running all with possible alignment issues I have a single window for all terminals which can be brought to the foreground. The impending 6.7 release of KDE (my favourite Linux desktop environment) [4] includes the feature of per-screen virtual desktops which might be the feature I need to make multiple monitors usable for me. One of the factors stopping me from using multiple monitors in the past was the issue of not getting the alignment of dozens of xterms right if a monitor goes to sleep mode and is regarded as disconnected, moving a few Kitty windows is much easier than moving dozens of xterms (also a tiling window manager isn’t my style).

I’ve just decided that the Terminus font (my favourite out of the monospaced fonts in Debian) is too small for me at 9.0 point. But then I tried 10.0 which looked really ugly and an experiment showed that 10.5 looked good.

What I’ve Learned

This is the best explanation I’ve seen of how ridiculous the whole font point thing is [5]. It doesn’t and won’t ever correlate to pixels. So what we ideally want to do is set the size on screen to match the actual pixel size of the font. I can’t find any software to interrogate a font file and find out what sizes it supports. The web page for the Terminus font says that it supports 6×12, 8×14, 8×16, 10×18, 10×20, 11×22, 12×24, 14×28 and 16×32 [6]. So the question is how to get a terminal program that uses one of those.

Kitty doesn’t and won’t support specifying font size by pixel. I tried some other terminal programs, I started with the Debian Wiki page TerminalEmulator [7] which wasn’t very helpful, I added some new entries to that page. There doesn’t seem to be another option for a terminal emulator with multiple terminals in one OS window that can arrange them automatically. I didn’t even get to the stage of checking whether other terminal emulators supported font size in pixels.

The lcdf-typetools package contains the program otfinfo which gives some interesting information on fonts but nothing about the font sizes in pixels.

Sites like Coding Font to compare fonts [8] can never work properly as the fonts will always be slightly different sizes as the same point size doesn’t mean the same display size.

The Current Situation

On my 5120*2160 monitor with 9 Kitty terminal sessions with 9.0 point font they each have 277*50 characters. With 10 point it’s 237*46 but fuzzy and unpleasant to read. With 10.5 point it’s 208*43 which isn’t as good as I’m used to but is still almost 4.5* as many characters as the original 80*25 standard for terminals.

Some time before 2019 I had a 4*4 array of terminal windows that were 100*25 or 120*25. That left some space at the right and bottom so I could open another 8 or 9 terminals that were partially obscured if I needed to. By 2019 before getting a 4K monitor I had a 3*3 array of terminal windows as my standard desktop and a larger monitor that did 4K resolution allowed me to have 16+ terminals again. Now with Kitty I routinely have 9 terminals in a 3*3 array and I can easily open more if I need them and have them resize appropriately.

This situation works reasonably well, but the element of just trying different sizes in 0.5 point increments until I find something that looks good is unpleasant. I should be able to specify the next largest increment of the bitmaps in the font and just have it look good.

Conclusion

It would be good if more people tested the terminal emulators in Debian and added information to the wiki page about them. The current page is useful but needs more information to support the variety of features that people find important.

We need some tools to provide information on fonts in Debian, such as the sizes of bitmapped fonts.

The whole point size thing is just wrong and would ideally go away. The vast majority of font use nowadays is for things that will probably never end up on a printed page so trying to map it to a physical size in fractions of an inch makes no sense. But that’s just one of many horrible things used for backwards compatibility that aren’t going to go away any time soon. Really everything involving inches should go away.

• [1] https://etbe.coker.com.au/2019/11/18/4k-monitors/
• [2] https://etbe.coker.com.au/2024/07/23/more-5120×2160-monitor/
• [3] https://etbe.coker.com.au/2023/10/29/hello-kitty/
• [4] https://kde.org/announcements/plasma/6/6.7.0/
• [5] https://tonsky.me/blog/font-size/
• [6] https://terminus-font.sourceforge.net/
• [7] https://wiki.debian.org/TerminalEmulator
• [8] https://www.codingfont.com/