Indic request: Reph reordering

[ArchivePoster]

Posted by: SpaceyT-17
         

For Indic scripts, Uniscribe of Windows Vista does a neat job of reordering pre-base vowel signs around half-form glyphs. Some similar reordering logic should be applied for Reph.

 

Say I enter the Bengali characters < Ra Halant C1 Halant C2 Ikaar >, where C2 is not Ba, Ra or Ya (i.e. it has no below-base or post-base form). As a result, C2 is the base consonant for this syllable. Also, there is no conjunct glyph for < C1 Halant C2 > defined in the cjct feature.

 

As Vrinda has half-form glyphs for almost all consonants (including C1), the following happens:

reorder1: C1 Halant C2 (Ra Halant)rphf Ikaar
cmap:     gC1 gHalant gC2 (gRa gHalant)rphf gIkaar
rphf:     gC1 gHalant gC2 gReph gIkaar
half:     gC1.half gC2 gReph gIkaar       // gC1.half is a half-form glyph
reorder2: gIkaar gC1.half gC2 gReph       // gIkaar reorders to the left of gC1.half

rendering of Vrinda, which contains a half-form glyph of C1

 However, a font without a half-form glyph of C1 would cause the following:

reorder1: C1 Halant C2 (Ra Halant)rphf Ikaar
cmap:     gC1 gHalant gC2 (gRa gHalant)rphf gIkaar
rphf:     gC1 gHalant gC2 gReph gIkaar
half:     gC1 gHalant gC2 gReph gIkaar    // no change
reorder2: gC1 gHalant gIkaar gC2 gReph    // gIkaar reorders to the left of gC2 only
haln:     gC1.haln gIkaar gC2 gReph

[ArchivePoster]

Posted by: OldKnip
         

Hi Spacey,

To increase the confusion you could type the sequence < ra + halant + khanda ta + sa >. In this case reph will not even be formed!

Regards

Elmar

[ArchivePoster]

Posted by: SpaceyT-17
         

< Ra Halant KhandaTa Sa > works fine for me (both with Vrinda and my fonts). The Reph gets formed okay. I'm running Windows Vista SP1.

[ArchivePoster]

Posted by: SpaceyT-17
         

Any comments from Microsoft on whether this rule will be implemented in Uniscribe?

[ArchivePoster]

Posted by: SpaceyT-17
         
Is Microsoft considering implementing the requested logic to Uniscribe?

[ArchivePoster]

Posted by: Star Gazer
         

The behaviour you desire is actually how I expected Uniscribe in Vista would behave. I know I tested that with Devanagari fonts, but I don't recall trying it for Bengali. But I can't think of a reason why it wouldn't work. (Of course, that doesn't mean there isn't an issue preventing it.) I'll have to give it a try and get back.

[ArchivePoster]

Posted by: pgcon
         

I tested this on Vista and it works, as I expected: I modified the Vrinda font by removing the rule to form half TTA in the lookup for the 'half' feature. Then I tried displaying the r.tt.si sequence you gave as an example using this modied font. The result was that the Ikaar displays after r.tt and before s; and the reph displays on the tt. (See the attached file.)

 

 

[ArchivePoster]

Posted by: pgcon
         

Well, I can't figure out how to get an image up here. At any rate, my results using my modified Vrinda on Vista SP1 looked the same as the last image in the original message -- the behaviour that was requested. All it took was to make sure there was no ligature substitution

 

    gTta gHalant -> gTta.half

 

that happens when the 'half' feature is processed.

 

 

Peter

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Posted by: 
         
This message has been deleted by the author.

[ArchivePoster]

Posted by: pgcon
         

OK, I figured it out:

 

 

 

 

 

Peter

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Posted by: SpaceyT-17
         

Thanks for trying it out, Peter. So it appears it is because of a problem in my fonts.

[ArchivePoster]

Posted by: SpaceyT-17
         

Solved the problem. I had mistakenly set Aa-kaar, I-kaar, Ii-kaar, E-kaar, Ai-kaar, and Au-mark glyphs as mark glyphs instead of simple glyphs in Glyph Editor. Now it works correctly.

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