Re: HarfBuzz is available on MS-Windows

[Andy Moreton <andrewjmoreton@gmail.com>]

On Fri 07 Jun 2019, Eli Zaretskii wrote:

>> From: Andy Moreton <andrewjmoreton@gmail.com>
>> Date: Fri, 07 Jun 2019 18:05:23 +0100
>> 
>> I've tested this with an MSYS2 64bit build on Windows 10.
>
> Thanks, you can now just build the master branch.
>
>> It appears to work ok, but is noticeably slower compared to the
>> master branch.
>
> I didn't see any tangible slowdown with HarfBuzz on my system.  Can
> you post some benchmarks with timings?  (I assume both branches were
> built using the same optimization switches.)

My feeling was only subjective based on running from "emacs -Q", but
that may be problems with font lookup making everything slow.

I've now bootstrapped the master branch after you merged the harfbuzz
support, and everything appears to be working fine so far.

> In any case, the font backend has nothing whatsoever to do with how
> Emacs searches for a suitable font, at least on Windows.  What the
> above means is that Leelawadee somehow doesn't fit the criteria for
> the Lao script and/or the features bits these fonts exhibit don't
> announce that they cover the respective codepoint ranges.  The way to
> improve the font search is to customize the fontsets.

Agreed, but it would be nicer for the average Windows user if the
built-in fonts were used by default, and that configuring the fontset
would only be needed to override the default selection.

>> Perhaps the built in fonts should be added to the default mappings for
>> Windows 10.
>
> I think the policy is not to mention non-free fonts in our fontsets.

That's reasonable when recommending additional fonts to install, but it
is unhelpful to avoid using fonts that are installed by default.

    AndyM