[Silgraphite-devel] Different result under Graphite1 vs. Graphite2

[Johan W. <joh...@te...>]

Hi!

I got a bug report today from a user of my Graphite font, pointing out
that the font behaved differently in LibreOffice 3.4 compared to previous
versions. To demonstrate this, I have managed to construct a minimal (or
at least small) testcase:

---- GDL file begins ----

table(glyph)
     a=codepoint("a")
     A=codepoint("A")
     b=codepoint("b")
     B=codepoint("B")
endtable;

table(substitution)
     pass(1)
       b b > B B / _ ^ a a _ ; // Rule 1
       a > A / B A ^ _ ;       // Rule 2
       a > A / B ^ _ ;         // Rule 3
     endpass;
endtable;

---- EOF ----

A Graphite font compiled with this GDL file is attached.

If I understand the GDL language correctly, these rules (slightly
contrived as they are) should handle the string "baaba" as follows
(^ shows scan position):

^baaba  (Initial string)
B^aaBa  (By rule 1)
B^AaBa  (By rule 3)
BA^aBa  (No match)
BA^ABa  (By rule 2)
BAA^Ba  (No match)
BAAB^a  (No match)
BAAB^A  (By rule 3)
BAABA^  (No match)

This ("BAABA") is the result I get in applications using pango-graphite
under Ubuntu, but in LibreOffice 3.4 the result is "BAABa", with a final
lower case "a". Is Graphite2 in error here?

Regards,
Johan Winge