Re: Entering emojis

[Eli Zaretskii]

> Date: Thu, 28 Oct 2021 06:50:57 +0000
> From: Gregory Heytings <gregory@heytings.org>
> cc: mattiase@acm.org, emacs-devel@gnu.org, schwab@linux-m68k.org, 
>     stefankangas@gmail.com, raman@google.com
> 
> > We don't know what software they used for layout, do we?
> 
> We do: the metadata of the PDF file indicate that this file has been 
> produced by LibreOffice 5.4.
> 
> But why does it matter?  The author of that font produced that PDF to 
> demonstrate what the font does.

Complex text layout needs two players: the font and the shaping
engine.  Each one must do its part of the job correctly; the font
alone is not enough.  The shaping engine is part of the editor that
produces the display, that's why I asked which one was that.

> > What does hb-view show for that text with those fonts?  If it shows 
> > correct display, the problem is somewhere in Emacs.
> 
> See attached.  The two vertical joiners are not rendered correctly, 
> perhaps they are misplaced/misused in the input?  But the rendering seems 
> better than that of Emacs.

Better in what sense?  The vertical arrangement is still wrong; it
looks like HarfBuzz understood incorrectly which glyph should be above
which, and the formatting controls were not removed from display.  Of
course, all of that could be due to my own mistakes, in how I decided
to type the codepoints for this display and/or in the
character-composition support for Egyptian hieroglyphs that I added.
Feel free to find what part(s) I did wrongly.

How does LibreOffice display the same text?