OverStrike control character

Sławomir Osipiuk sosipiuk at gmail.com
Wed Jun 10 09:39:08 CDT 2020

On Tue, Jun 9, 2020 at 10:55 PM abrahamgross--- via Unicode
<unicode at unicode.org> wrote:
> It should just simply overlay the pixels of the two characters, with a thin character going in the center of a wider character.
> Even if doesn't come out perfect, I'd take almost-exact-representation over no-represtation any day.

To be sure, it would be a cool feature to have. However, as Raymond
Chen (a Windows developer) succinctly put it, "every feature starts
out at minus 100 points". It's not just a matter of having some value;
that value must outweigh the effort it would take to fully implement
it, and it must compete with other features that that effort could go
to instead. The proposal here is to add a completely new feature to
Unicode, that in turn demands an updated font rendering process, and
to convince vendors to support it. It's not just a new character which
can be added to a font. It's new behaviour for characters. That's big;
that's a lot of effort. The idea of just overlaying pixels is a
tunnel-view of what's involved. Character combination (as it's
currently done) doesn't occur at that level. It's done earlier. Pixels
are at the final level of display. You'd need a new set of routines to
enable combination there. And it's not trivial then, either. What
about anti-aliasing, sub-pixel rendering?

Who will want to do all that? You'd need not just font support but an
OS-level change in the rendering process, in all major OSes. All for a
feature that's a bit of fun but isn't guaranteed to produce elegant

There is also the question of backward-compatibility. Even if this
change is included in new releases, there will be plenty of old
systems out there that won't have any idea of what an overstrike
character is. You won't just get an "unknown character" glyph, you'll
get an "unknown character" glyph between the two characters you're
trying to combine.

I'm not saying it can't be done, or that it wouldn't be a
nice-to-have. Where there's a will, there's a way. Realistically,
though, I don't predict a lot of will to get something like this done.

Sławomir Osipiuk

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