[tor-qa] Font debugging page (TBB 5.0a4)

Arthur D. Edelstein arthuredelstein at gmail.com
Thu Aug 6 18:09:16 UTC 2015

On Thu, Aug 6, 2015 at 9:41 AM, David Fifield <david at bamsoftware.com> wrote:
> On Thu, Aug 06, 2015 at 01:36:57PM +0200, Moritz Bartl wrote:
>> On 08/06/2015 11:43 AM, David Fifield wrote:
>> > Oh, very interesting. It seems the difference is only in one code point,
>> > in the "cursive" and "fantasy" styles (last two columns): [...]
>> > Could you make screenshots of the two renderings?
>> Attached. I don't see any difference between default and cursive.
> That's very interesting. In just that one code point, your computer
> chooses a sans-serif font for the "fantasy" and "cursive" styles, while
> mine chooses a serif font. Probably we would find more examples if we
> tested more of Unicode.
> I would not have expected a difference like this. It does not come down
> to small rendering differences; the browser is simply choosing a
> different font. Perhaps there is something non-deterministic about how
> Firefox (or Fontconfig) loads its font files. Like, maybe it iterates a
> directory in inode order and takes the first match when there is a tie.

If you add "Noto Serif Armenian" or "Noto Sans Armenian" to the lists
in the prefs "font.name-list.fantasy.x-unicode" and
"font.name-list.cursive.x-unicode" (these can be edited in
about:config) does that determine the font chosen for that code point
and allow you to get a checksum match? If so, it seems we should
include as many fonts as possible in each "name-list" to ensure the
font priority is consistent across platforms.

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