[HarfBuzz] Change in HarfBuzz after version 0.90 ?
jfkthame at googlemail.com
Fri Dec 27 09:09:35 PST 2013
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?
-------------- next part --------------
A non-text attachment was scrubbed...
Size: 718 bytes
Desc: not available
More information about the HarfBuzz