Bidi paragraph direction in terminal emulators

[Eli Zaretskii via Unicode]

> Date: Sat, 9 Feb 2019 18:42:52 +0100
> Cc: unicode Unicode Discussion <unicode at unicode.org>
> From: Egmont Koblinger via Unicode <unicode at unicode.org>
> 
> What if harfbuzz tells us that the overall width for rendering a
> particular grapheme cluster is significantly different from its
> designated area (the number of character cells [wcswidth()]
> multiplied by the width of each)?

You need to use what HarfBuzz tells you _instead_ of wcswidth.  It is
in general wrong to use wcswidth or anything similar when you use a
shaping engine and support complex script shaping.