On 16 Sep 2010, at 15:29, Ed wrote: > On Thu, Sep 16, 2010 at 3:42 AM, Jonathan Kew <jonat...@jfkew.plus.com> wrote: >> >> On 16 Sep 2010, at 02:33, Ed wrote: >> >>> Hi, Behdad and everyone, >>> >>> Just want to confirm something: >>> >>> I thought Harfbuzz-ng did not yet have "complex text shaper" support. >>> But in Firefox 4 beta with gfx.font_rendering.harfbuzz.level set to 1, >>> Devanagari and Arabic looks correct. So shapers are present then? >> >> No. Firefox is using harfbuzz only for certain "simple" scripts such as >> Latin; it falls back to platform code (CoreText on OS X, Uniscribe on >> Windows) for complex scripts. > > And old Pango-harfbuzz-whatever on Linux?
On Linux, we're not yet using harfbuzz-ng at all (work is in progress to move in that direction, but it's not in current betas). So *all* text there is going through Pango at present. > > Also, if I am trying to test Tai Tham Unicode fonts which utilize > OpenType features such as mark-to-base (mark), mark-to-mark (mkmk), > and contextual ligatures (clig) --but doing so using Latin "dflt" > since there is no tag for Tai Tham-- is Firefox 4x really using > Harfbuzz-ng or not? > > It seems possible --even likely given the kinds of results I am seeing > so far-- that Firefox is perhaps marking the runs of text as being Tai > Tham and so would not be using the new Harfbuzz-ng That's what I would expect, yes. Firefox divides the text according to scripts (based on the Unicode character codes), and then chooses whether to use harfbuzz-ng or platform text layout libraries for each script run. It currently uses HB *only* for the major "simple" scripts, not for those requiring complex shaping. > > And is there any possible way to know what renderer FF is really using > for any given run of text. I guess the answer is probably not ... Not really, short of reading the source to determine how it will behave. :) JK _______________________________________________ HarfBuzz mailing list HarfBuzz@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/harfbuzz
