by kragen | 2025-12-15 19:33:03+00:00
Seems related to the discussion the other day of Unifont, which is an 8×16/16×16 Unicode bitmap font: https://news.ycombinator.com/item?id=46248859

A great deficiency of Unifont mentioned several times in the other thread was its lack of combining-character support, and the absence of alternative glyphs for the code points in scripts like Arabic (well, and Engsvanyáli) whose form is affected by joiner or non-joiner context. Does anyone know if Unscii does better at this?

From opening it in Fontforge, Unscii seems to have pretty broad coverage, including things like Bengali, Ethiopic, and even runic, plus pretty full CJK(V) coverage. It seems to have some of the CSUR https://www.evertype.com/standards/csur/ assignments, such as the Tengwar of Feanor in the range U+E000 to U+E07F, but has conflicting assignments for some other ranges, like the Cirth range U+E080 to U+E0FF (present in Unifont but arguably duplicative with the runic block), which is assigned to Teletext/Videotex block mosaics. I note that my system has different conflicting assignments for this range, with Tux at U+E000 followed by a bunch of dingbats, while the Cirth range is a bunch of math symbols.

Given that astral-plane support is virtually universal in Unicode implementations these days (thanks largely to emoji) it might be better for future such efforts to use SPUA and SPUB to reduce the frequency of such codepoint clashes. SPUA and SPUB are each the size of the entire BMP: https://en.wikipedia.org/wiki/Private_Use_Areas

For day-to-day use of semigraphic characters, I ran into the problem two hours ago in https://news.ycombinator.com/item?id=46277275 that the "BOX DRAWING" vertical lines don't connect, consequently failing to draw proper boxes. I had the same problem in Dercuano, where I fixed it by reducing the line-height for <pre> elements. The reason seems to be that Firefox defaults line-height to "normal", which is apparently equivalent to "1.41em", which doesn't sound very normal to me (isn't an "em" defined as the normal line height?), and, although the line-drawing characters in my font (which seems to be Noto Sans Mono) are taller than 1em, they still don't reliably join up if the line-height is taller than 1.21em.

Chromium does the same thing, except its abnormal definition of "normal" is evidently more like 1.35em.

It's probably too late to make a change to the standard HN stylesheet so major as

pre { line-height: 1.2em }

since it would change the rendering of the previous decades of comments. It would be a significant improvement for things like what I was doing there, and I don't think it would be worse for normal code samples. However, given the lengths to which the HN codebase goes to limit formatting (replacing characters like U+2009 THIN SPACE with regular spaces, stripping out not just emojis but most non-alphanumeric Unicode such as U+263A WHITE SMILING FACE, etc.) maybe discouraging the use of these semigraphics is intentional?

If not, though, perhaps the fact that the line-height is already different between Chromium and Firefox represents a certain amount of possible flexibility...

Obviously the line-height would be a much more serious problem for the kinds of diagonal semigraphic characters that viznut is largely focusing on here; those would strictly require a line-height of exactly 1em, which I think would substantially impair the readability of code samples.