NotoSerifTibetan Some characters are not drawn correctly in MS-WORD (2010)

[KazunariTsuboi]

Font

NotoSerifTibetan-Regular.ttf

Where the font came from, and when

https://github.com/googlefonts/noto-fonts/blob/master/phaseIII_only/unhinted/ttf/NotoSerifTibetan/NotoSerifTibetan-Regular.ttf Date: 2019-06-13

Font Version

Sans: Version 2.001

OS name and version

Microsoft Windows [Version 10.0.17134.829]

Application name and version

Microsoft Word 2010 (Version 14.0.7232.5000)

Issue

The following string is not drawn correctly in MS-Word (2010). ཟཱ U+0F5F U+0F71 ངྨ U+0F44 U+0FA8 ངྨཱ U+0F44 U+0FA8 U+0F71 ངྨེ U+0F44 U+0FA8 U+0F7A ཆཱོ U+0F46 U+0F71 U+0F7C

The drawing results by HarfBuzz are as expected.

[marekjez86]

@KazunariTsuboi : my "gut feeling" is that Windows 10 doesn't know the language is Tibetan (is there a way to set this?) or if it knows doesn't know how to render it, but I could be wrong

[dscorbett]

Microsoft Word 2010 is rather old; is it possible that it is using the old Tibetan shaper instead of USE? The Tibetan shaper enables 'abvm' and 'blwm' but this font uses 'mark'.

[KazunariTsuboi]

I displayed NotoSerifTibetan on Word in another environment.

Windows 10 [10.0.17134.829] Word 2013 (Version 15.0.5127.1000)

In this environment it was drawn correctly.

It looks like NotoSerifTibetan using blws and abvs. Even if Word 2010 used the old Tibetan shaper, I thought that it would draw this font correctly.

[KazunariTsuboi]

I'm sorry, I was confusing GSUB and GPOS. Certainly, mark feature is used in NotoSerifTibetan GPOS. Word 2010 seems to use the old Tibetan shaper.

[punchcutter]

@KazunariTsuboi Yes, it's on the website at https://docs.microsoft.com/en-us/typography/script-development/tibetan where it says

Starting in Windows 10, Tibetan will be supported by the Universal Shaping Engine rather than a stand-alone shaping engine

[KazunariTsuboi]

I tried to make a simple prototype. It is NotoSerifTibetan which used 'abvm' and 'blwm' instead of 'mark'. The display on MS-WORD (2010) is now successful. I have attached a prototype.

The generation method is as follows. Added "Tibt" to indicScripts in MarkFeatureWriter Class of ufo2ft/featureWriters/markFeatureWriter.py Then I used 'fontmake' to generate from NotoSerifTibetan-MM.glyphs.

I tested Tibetan on noto-source using fontdiff. Attach the resulting PDF. Apparently, it looks like it is going well.

I do not know all the backgrounds that 'mark' is used for Tibetan but not 'abvm' and 'blwm'. I just report it because it was an interesting result. TibetanTEST.zip

[simoncozens]

I think this is do to with legacy software and shaping engines, so not a font problem. Let me know if not and we can reopen.