[HarfBuzz] Accent positioning with greek smallcaps

[Behdad Esfahbod]

Figured it out:

If you check with ttx for example, indeed Lookup 34, MarkBasePos subtable 1
covers that mark and base sequence but has no anchor for it.  However,
subtable 2 has.  Just fixed HarfBuzz to keep looking if an anchor is missing.
 Renders fine now.

Thanks,

behdad

On 13-01-08 01:14 AM, Georg Duffner wrote:
> Hi Behdad,
> 
> which tool did you use for debugging? With Fontforge I can’t find the null
> anchor you found. The source featurefile as well as the featurefile extracted
> from the font both show correct values for the anchors and inn Fontforge’s
> metrics view, the results look as expected. What’s more, XeTeX and LuaTeX
> position the accents correctly (they fail at other places though).
> 
> Georg
> 
> Am 2013-01-07 10:25, schrieb Behdad Esfahbod:
>> Hi Georg,
>>
>> I debugged the font.  It does look like a font issue to me.  The MarkBase
>> table for those accents and those bases has a null anchor for the base.
>> That's all I know.
>>
>> behdad
>>
>> On 13-01-07 02:06 AM, Georg Duffner wrote:
>>> Hello,
>>>
>>> There seems to be something wrong with accent positioning in greek smallcaps
>>> with a ccmp feature enabled. In EB Garamond I’ve put together a feature (as
>>> stylistic set ss20) that decomposes all composed characters and mark and mkmk
>>> anchors are in place where needed. This all works nicely with Harfbuzz except
>>> for greek smallcaps as you can see at
>>> http://georgduffner.at/ebgaramond/greektests.html (with Firefox of course).
>>> Accents are placed in front of the letters at the bottom instead of atop of
>>> the letters. The last row of “Smallcaps” shows that latin smallcaps are fine,
>>> simple ones as well as stacked ones. I got the same results with hb-view
>>> (harfbuzz 0.9.9 on Arch Linux).
>>>
>>> Results from hb-shape are:
>>>
>>> 1: (ἂἅἇ)
>>> 1: <U+1F02,U+1F05,U+1F07>
>>> 1:
>>> [alpha.sc=0+549|uni0313.grksc=0 at -751,-630+0|gravecomb.grkstacksc=0 at -626,-630+0|alpha.sc=1+549|uni0314.grksc=1 at -751,-630+0|acutecomb.grkstacksc=1 at -626,-630+0|alpha.sc=2+549|uni0314.grkstacksc=2 at -684,-665+0|uni0342.sc=2 at -771,-489+0]
>>>
>>>
>>>
>>> and
>>>
>>> 1: (áäấÄÖÜ)
>>> 1: <U+00E1,U+00E4,U+1EA5,U+00C4,U+00D6,U+00DC>
>>> 1:
>>> [a.sc=0+549|acutecomb.sc=0 at -319,65+0|a.sc=1+549|uni0308.sc=1 at -421,84+0|a.sc=2+549|uni0302.stacksc=2 at -389,65+0|acutecomb.stacksc=2 at -197,167+0|Adieresis.deu=3+684|Odieresis.deu=4+763|Udieresis.deu=5+738]
>>>
>>>
>>>
>>> I attach the results from hb-view.
>>> The options used are:
>>> --features="ss20","smcp"
>>>
>>> You can find the font used in the tests at
>>> http://georgduffner.at/ebgaramond/tests/EBGaramond12-Regular.otf (it is too
>>> big for the limit of this list, even when compressed).
>>>
>>> Please note that the testpage on the web uses a version of the font where the
>>> decomposition table is included in ccmp which I don’t want to because this
>>> should only be enabled when really necessary. But it doesn’t make a
>>> difference.
>>>
>>> Best regards,
>>> Georg
>>>
>>>
>>> _______________________________________________
>>> HarfBuzz mailing list
>>> HarfBuzz at lists.freedesktop.org
>>> http://lists.freedesktop.org/mailman/listinfo/harfbuzz
>>>
>>
> 
> 

-- 
behdad
http://behdad.org/