#884 BLOC Trial-2: Web activity has trouble with arabic and urdu fonts

[Zarro Boogs per Child]

#884: Web activity has trouble with arabic and urdu fonts
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  Reporter:  sj           |       Owner:  behdad 
      Type:  defect       |      Status:  new    
  Priority:  blocker      |   Milestone:  Trial-2
 Component:  web browser  |     Version:         
Resolution:               |    Keywords:  relnote
  Verified:  0            |  
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Comment (by behdad):

 Replying to [comment:32 jg]:
 > It is a symptom of a much more general problem, from perusing the
 mozilla bug reports, that goes beyond Arabic (which is widely used in many
 countries).  Even more fun: it is a regression.
 >
 > However, I'm disagree with the analysis in the mozilla bug reports, from
 a quick look there. Fontconfig should be selecting usable fonts for a
 given set of languages, which it is very good at indeed.
 >
 > There are two possibilities here:
 >   1) moz is providing the wrong languages to fontconfig for lookup
 >   2) a fontconfig bug; either in computing coverage or the orthography
 database for particular languages.
 >
 > Behdad, do you agree?

 From my understanding what ff3 is doing is to just pass the explicit
 language tags to fontconfig, get the first matching font and use it.  This
 is a far cry from what ff2 does with pango.

 When using pango like ff2 does, pango guesses languages for pieces of text
 and passes language tags to fontconfig that make a lot more sense, and if
 the first found font doesn't handle a character the next font is tried,
 etc.

 The end result is that for an untagged piece of Arabic text under an
 English locale, ff2+pango detects that Arabic script is doesn't make sense
 with English language, so tags the Arabic segment as Arabic language.
 This results in the right  font to be selected.  AFAIU ff3 is not doing
 this, and is not doing fallback fonts either.

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Ticket URL: <http://dev.laptop.org/ticket/884#comment:33>
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