JEP Proposal update, and JavaOne

[Steven R. Loomis]

On 09/30/2014 09:19 AM, Doug Felt wrote:
> For the JEP, I'd just like to state that
>
> 1) even when both engines support a language, the GlyphVectors output by
> ICU LayoutEngine and HarfBuzz will not always be the same.  In particular,
> ICU uses 'filler glyphs' and tries to arrange the glyph to char mapping to
> be as exact as possible.  HarfBuzz does not natively use filler glyphs or
> generate a close mapping, so the icu-le-hb compatibility shim generates an
> emulation of this.  Anyone who depends in detail on the placement of filler
> glyphs or the glyph-to-char mapping will see changes. We expect there to be
> very few such clients, but they should be aware of this possibility.

Yes, we should note that the compatibility is not bit for bit.

>
> 2) Given that we expect few such clients, and some of them will possibly
> break anyway, another option is to not generate the filler glyphs at all,
> but instead generate HarfBuzz's native output and adjust the layers inside
> the JDK (not API) that consume them to use the HarfBuzz native output
> instead.
I will add that to the JEP.   Would you be able to file a ticket on
this? (tag it 'harfbuzz')
>
> 3) Third party clients are unable to effectively use the current
> glyphvector data (all that is exposed in the API) to determine the
> boundaries of glyph clusters, which is necessary for client layout of text
> on a path. If we change the GlyphVector data, we might consider reworking
> it so that it is useful for this purpose.

I will probably put something in like "address limitations in the
GlyphVector API"

Can you file a ticket on this one as well?

>
> On Mon, Sep 29, 2014 at 10:30 PM, Steven R. Loomis <steven.loomis at oracle.com
>> wrote:
>> On 08/01/2014 10:44 PM, Steven R. Loomis wrote:
>>> Forgot to mention!
>>> We'll be talking about HarfBuzz at this session - if you are at JavaOne
>>> come by!
>>>
>>>
>>>
>> https://oracleus.activeevents.com/2014/connect/sessionDetail.ww?SESSION_ID=2890
>> Hello.
>> I've updated the JEP here: http://goo.gl/n5SSMV
>>
>> See some of you at 9pm tomorrow in SF hopefully!
>>
>> Steven
>>
>>
>


-- 

IBMer but all opinions are mine.
https://www.ohloh.net/accounts/srl295 // fingerprint @ https://ssl.icu-project.org/trac/wiki/Srl