[HarfBuzz] Question regarding hb-view categorization of runs of text

[Ed Trager]

Hi, everyone,

If I run hb-view (v. 0.9.25) to compose a line of text that consists solely
of Tai Tham, I get expected shaping results. However, if I add some Latin
text at the beginning of a line of Tai Tham text, then I get incorrect
shaping: specifically, Tai Tham prefixed vowels U+1A6E through U+1A72 and
consonant sign U+1A55 MEDIAL RA are not re-ordered.

(sample image attached)

I'm wondering if this is just an artifact of hb-view?:  Does hb-view always
take a single line of text as being a single run of text, based on the
first non-neutral character encountered?

To me it looks like this is what happens.  That is to say, it looks like
hb-view does not break single lines of text into separate runs of text even
when that is required.  Since hb-view is a tool for testing, this may be
acceptable behavior. I would just like to know if this is in fact the case,
or whether I am seeing some sort of bug?

Thanks!  -- Ed
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.freedesktop.org/archives/harfbuzz/attachments/20140118/7d77b457/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 2014.01.18.HarfBuzzQuestion.png
Type: image/png
Size: 75321 bytes
Desc: not available
URL: <http://lists.freedesktop.org/archives/harfbuzz/attachments/20140118/7d77b457/attachment-0001.png>