[HarfBuzz] Wrong GDEF class in timesi.ttf on Win7

[Behdad Esfahbod]

Thanks Jonathan.  Somehow that Mozilla bug escaped my attention for five
years!

I'll add code to reject GDEF table based on its length and glyph class of
doublequote.  Do you have any more blacklisted tables like that in Firefox?

behdad
On Feb 24, 2016 11:17 PM, "Jonathan Kew" <jfkthame at gmail.com> wrote:

> On 24/2/16 02:25, Behdad Esfahbod wrote:
>
>> Hi Jonathan,
>>
>> As you probably know, I changed mark zeroing from BY_UNICODE_LATE to
>> BY_GDEF_LATE in HarfBuzz.  So far I only got a bug report about Cantarell
>> breaking, which was fixed in the font's GDEF table.
>>
>> Today, Dominik and I noticed that Times New Roman Italic on Windows 7 has
>> wrong GDEF class for ASCII double-quote, and as such, we now zero its
>> advance
>> width.  The bug is not present in Windows XP or Windows 8 on.  It also
>> happens
>> to be present on the OpenType Times New Roman Italic on OS X, but that is
>> superseded by a non-OpenType version of the font.
>>
>> Even with the broken font, CoreText does not show the bad rendering,
>> whereas,
>> in my testing, Uniscribe from Windows 7 does.
>>
>> Given that Windows 7 still has the largest market share across PCs, I feel
>> like we cannot ignore this.  I assume IE probably does not expose this bug
>> because they don't process OpenType features for Latin?  Can someone test
>> on
>> Windows 7?
>>
>
> I don't have a test system handy just now, but I believe you're correct.
>
>
>> I'm not sure how to proceed forward.  IIRC we have had also observed one
>> Latin
>> glyph with wrong GDEF back a few years ago, in Georgia or some other font
>> on
>> Windows.  That should be in mozilla bug tracker somewhere.
>>
>
> See https://bugzilla.mozilla.org/show_bug.cgi?id=589682 for the Times New
> Roman Italic GDEF bug. (We added a hack in Gecko to ignore the GDEF for
> that particular font.)
>
> JK
>
>
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