On Mon, Apr 22, 2013 at 09:06:53PM -0400, Behdad Esfahbod wrote: > On 13-04-22 08:20 PM, Khaled Hosny wrote: > > On Sat, Apr 20, 2013 at 10:49:26AM +0100, Jonathan Kew wrote: > >> On 19/4/13 22:13, Behdad Esfahbod wrote: > >> > >>> - What should HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES do to variation > >>> selectors? Right now they do not become visible no matter what. Is it > >>> relevant whether the variation selector was actually used during glyph > >>> lookup > >>> or not? > >> > >> Yes, I think it's relevant. A variation selector that was used > >> during glyph lookup has (in a sense) become "visible", manifested as > >> a particular choice of glyph. I don't think it should -also- appear > >> as a separate glyph, even in a "show invisibles" mode. In effect, > >> the <base, VS> pair has been ligated - it's just a "ligation" that's > >> handled by the cmap instead of GSUB. > > > > But this can be said about many other control characters, ZWJ or ZWNJ > > for example, they have a visual effect. > > > > IMO PRESERVE_DEFAULT_IGNORABLES should simply show any default ignorable > > character that is being removed from the output not as a result of > > OpenType glyph substitution. One use of such feature (the only use?) is > > to make visible all characters that has mysterious effects on the output > > so they can be easily checked/edited, and I can see variation selectors > > benefiting from this just like any other default ignorable. > > > Note that if the font has a lookup ligating with ZWJ / ZWNJ (or any other > default-ignorable) those won't be display even with > PRESERVE_DEFAULT_IGNORABLES either.
Which is fine since it can happen to any other usually visible glyph and one can switch fonts to make them visible. Regards, Khaled _______________________________________________ HarfBuzz mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/harfbuzz
