[HarfBuzz] Change in HarfBuzz after version 0.90 ?

[Ed Trager]

Oh, wait, you did push Jonathan's patch, thanks so much!  Sorry I missed
that first time around!


On Thu, Jan 2, 2014 at 3:38 PM, Ed Trager <ed.trager at gmail.com> wrote:

> Happy New Year, Behdad!
>
> Hey just wondering what do you think about Jonathan's patch (attached
> below)?
>
> Best - Ed
>
>
> ---------- Forwarded message ----------
> From: Jonathan Kew <jfkthame at googlemail.com>
> Date: Fri, Dec 27, 2013 at 12:09 PM
> Subject: Re: [HarfBuzz] Change in HarfBuzz after version 0.90 ?
> To: Ed Trager <ed.trager at gmail.com>, Danh Hong <danhhong at gmail.com>,
> Behdad Esfahbod <behdad at behdad.org>
> Cc: Martin Hosken <mhosken at gmail.com>, Richard Wordingham <
> richard.wordingham at ntlworld.com>, Theppitak Karoonboonyanan <
> theppitak at gmail.com>, Harfbuzz <harfbuzz at lists.freedesktop.org>
>
>
> On 27/12/13 16:21, Ed Trager wrote:
>
>>
>> Hi, Martin, Richard, and Danh Hong,
>>
>> With regard to forcing the re-ordering of the
>> UCD-enforced-but-totally-broken normalisation of TAI THAM TONE MARK plus
>> U+1A60, does the following approach in the OpenType feature file make
>> sense as the quickest and cleanest way to do it or not?:
>>
>> Basically the idea is to compose the out-of-order pair of characters
>> into a ligature; and then take that ligature and decompose it back to a
>> pair of characters that are in the correct order:
>>
>> If there is a better way to do this in OpenType, please enlighten me!
>> :-)  I was trying to get this to work last night, so far without success:
>>
>>
> The trouble with this idea (or at least one trouble with it!) is that by
> the time your lookups have a chance to do anything, harfbuzz has already
> inserted dotted-circle glyphs because it treated the (normalized) sequence
> as being a "broken" cluster. The pattern for a "consonant syllable" in the
> SEAsian shaper allows for a <sakot, consonant> pair (i.e. a subjoined
> consonant) among the various possible syllable-tail items, but it does not
> allow for the <sakot> and <cons> to be separated by other marks, which is
> what the normalization does.
>
> You -might- be able to work around this by explicitly including the dotted
> circles in your ligature-composition rules, though that will make them all
> more cumbersome. The better way forward is for us to fix harfbuzz, as
> previously suggested.
>
> Possible patch attached; Behdad, wdyt?
>
>
>
>
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