Right, thanks for bringing this up. Indeed I plan to switch to the slightly-reordered CCC as mentioned in the FAQ. That is:
"And notice that the rendering engine could reorder the marks internally in a different order if it wanted to, as long as that order was canonically equivalent. In particular, any permutation of the non-zero CCC values can be used for a canonically equivalent internal ordering. So internally a rendering engine could permute weights <27, 28,..., 32, 33> to <33, 27, 28,..., 32>, getting SHADDA before all vowel signs, for example." And, done, and pushed to master. I tested it with Nazli and seems to be working. Cheers, behdad PS. Yes, I'm following a test-driven development model at this time! :) On 08/25/11 08:45, Khaled Hosny wrote: > After the introduction of canonical reordering of combining marks > (commit 34c22f8), I'm no longer able to do mark/mark substitution or > positioning for mark sequences that involve shadda as a first mark (or > most interesting sequences at least). > > After some digging, it turned out that shadda have a ccc=33 while most > Arabic marks that combine with it have a lower ccc value, which results > in the shadda being reordered after the other mark which, > unsurprisingly, breaks my contextual substitution and mkmk anchors. > > The issue seems to be quite known, there is even two FAQ entries for it: > http://unicode.org/faq/normalization.html#8 > > My font substitutes certain marks when following shadda by smaller > version, and uses mkmk anchors to properly position them. I could switch > to using ligatures and treat <shadda><mark> and <mark><shadda> the same, > but this is very inefficient since I want to support sequences up to > three marks after shadda at least (and in various combinations), also I > was trying to avoid ligatures at all in my font for several reasons, and > I suspect that my font is not the only affected font. > > Regards, > Khaled > _______________________________________________ HarfBuzz mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/harfbuzz
