Tuesday, July 27, 2010

worked on Meera font today!! (waiting harfbuzz very eagarly)

finally resolved (at least with my testing) Meera Fonts bug https://bugzilla.redhat.com/show_bug.cgi?id=616324

ohh, what a day!!
was trying to resolve this problem
initially thought it will be easier one, just will increase kern for U+0d4d characters, and whenever it will followed by U+200C in will just make it kern to minus.
mine test cases are
1) ക്  (U0d15 U0d4d) should leave proper space, when it will be last character of word (presently chandrakala/virama is getting cut)
2) ക്‌ക (U0d15 U0d4d U200c U0d15) when virama/chadrakala will be followed by 200c it should use present kern to get form in word

so tried first dist feature first,
1) increased kern of U+0d4d and
2) added pair positioning for "U+0d4d  ZWNJ" with dist flag kerning
was working well when i was debugging in fonts but failed when was testing with pango :(

next try was
then added ligature and was trying to bring that ligature when someone type
Cons + 0d4d + 200C
but again it failed in pango :(
tested same in Open Office and it was working there fine, with some more trial understood that pango is not considering 200c for contextual comparison
so writing rule i.e when U+0d4c is preceded by ZWNJ will not work in pango

next try
since it was need to increase kern of virama only when it will be last character of word,
and luckily while trying contextual feature found {Everything Else} group, so used this one
and it worked perfectly in pango :)
but again problem, it was not working in oowriter

so added both 2nd and third solution in font for making it work with oowriter and gnome
link for
1) scratch build is available on http://koji.fedoraproject.org/koji/taskinfo?taskID=2353995
2) modified source file is @ http://pravins.fedorapeople.org/Meera.sfd
3) binary file for testing @ http://pravins.fedorapeople.org/Meera.ttf
4) patch: http://pravins.fedorapeople.org/bug-616324.patch   

dont know how dream of harfbuzz will come true, and will make font engineers life easy


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Pravin Satpute said...

yes, no props
go ahead