On Mon, May 18, 2020 at 01:05:53PM -0400, Stefan Monnier wrote:
> [ I know nothing about the underlying APIs and such, so speaking here
>   only as a random user.  ]

[...]

> So, maybe we don't need very much info: all we need is a boolean which
> tells us whether the glyph should be treated atomically or not.
> When not treating it atomically, we would (somewhat arbitrarily) divide
> the glyph horizontally into N equal sized "subglyphs" and draw the
> cursor on the corresponding subglyph.

I'm somewhat out of my depth here, but I have the hunch that some
"ligatures" aren't "just stacked horizontally".

> If Harfbuzz could tell us more precisely how to divide the glyph into
> subglyphs, we could do a better job, of course.

On a very superficial glance it seems they can [1]

Cheers
[1] https://github.com/harfbuzz/harfbuzz/blob/master/docs/usermanual-clusters.xml
-- tomás