GNOME Bugzilla – Bug 132378
Problem with Arabic Orphan Marks
Last modified: 2004-12-22 21:47:04 UTC
We were working on Fall-Back rendering for Arabic language, but there are some problems for Arabic Orphan Marks: 1- Pango doesn't find any valid shape engine for Orpahn marks, because, the script specified for Arabic marks in "pango_script_table" is "PANGO_SCRIPT_INHERITED" not "PANGO_SCRIPT_ARABIC". 2- FriBIDI gives an Odd level number for Arabic Orphan marks, so, even if Pango shape them with Arabic shape engine, positioning rules can not be applied to them, because in OpenType lookup and rules (OTL), Arabic runs are assumed to be RTL. Best Regards
From what I see in the code, Pango renders all marks on the previous character in the visual stream. So never assumes that a mark is used in an RTL context. Moreover, I really doubt that FriBidi assigns an odd level to an orphan mark. Marks simply get the level of their base characters. Moreover, ASAIK Arabic module in Pango does nothing about marks, so I cannot see what the bug is.
I don't think trying to make sure that "orphan" Arabic fonts always go to the Arabic shaper makes sense, so this just duplicates bug 103938 or bug 127176; whatever engine gets the orphan mark needs to handle it the best it can. *** This bug has been marked as a duplicate of 103938 ***