[HarfBuzz] glyph advance difference between coretext and ot backend

[Rolf Langenhuijzen]

I did a similar test with 2 fonts and it was different between the two.. could it be some internal font thing that is causing this?

OSX:
hb-shape --shapers=coretext "/dev/fonts/MaiolaPro-Regular.otf" ABC
[A=0+670|B=1+565|C=2+640]

hb-shape --shapers=ot "/dev/fonts/MaiolaPro-Regular.otf" ABC
[A=0+660|B=1+555|C=2+630]

hb-shape --shapers=ot "/dev/Whitney-Book-Pro.otf" ABC
[A=0+691|B=1+547|C=2+638]

hb-shape --shapers=coretext "/dev/Whitney-Book-Pro.otf" ABC
[A=0+691|B=1+547|C=2+638]

I tried on Ubuntu: 
hb-shape --shapers=ot "MaiolaPro-Regular.otf" ABC
[A=0+660|B=1+555|C=2+630]

So the same as on OSX, not the same as with coretext as you are getting…

Regards,
Rolf

On Jul 31, 2012, at 12:42 PM, Dohyun Kim wrote:

> Hi,
> 
> I have compiled harfbuzz-ng on Mac OS X Lion.
> While testing some fonts, I encounterd a strange mismatch between
> coretext and ot backends:
> 
> $ ./hb-shape --shapers=coretext /System/Library/Fonts/AppleGothic.ttf ABC
> [gid41=0+726|gid42=1+644|gid43=2+685]
> 
> $ ./hb-shape --shapers=ot /System/Library/Fonts/AppleGothic.ttf ABC
> [gid41=0+743|gid42=1+659|gid43=2+701]
> 
> The Units Per Em of AppleGothic is 1000.
> However, ot backend under Mac seems to consider upem as 1024 and
> increase glyph widths in proportion, resulting in incorrect glyph positions.
> 
> BTW, ot backend on ubuntu machine gives the same result as coretext under Mac.
> 
> Best,
> -- 
> Dohyun Kim
> College of Law, Dongguk University
> Seoul, Republic of Korea
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