Marcel Fabian Krüger
tex at 2krueger.de
Tue Oct 15 14:15:19 CEST 2019
On Tue, Oct 15, 2019 at 05:32:49PM +0900, Norbert Preining wrote:
> Hi Ulrike,
> thanks for your email, it would be great if we could work that out, I am
> helping a friend settting Tibetan/Sanskrit texts and this is a real
> I attach four files
> for ENGINE in luatex, xetex, luahbtex, harftex
> * First of all, the text you send does not show up correctly with
> luatex, only with xetex, there is considerable overlap in glyphs
> and the wrong compound is selected in the luatex and luahbtex case.
> * Then look at the first row of big characters
> - xetex got it correct with all fonts
> - lua(hb)tex use a strange glyph with a dotted circle set below,
> in the Noto case
I tried this with the current development branch for the HarfBuzz
support in luaotfload and got the same output as with XeTeX, so
luahbtex will be able to solve this issue.
> * The last line shows the biggest problem: In Tibetan there are
> "standard" combinations of characters, that are used in normal
> Tibetan, and then there are non-standard ones, that are often
> used to transcribe religious text, Devenagari etc etc. If the font
> does not provide a proper pre-composed glyph, the font/layout
> engine needs to do this manually.
> Back in Omega times I wrote code for this in OTPs (analyzing
> the stacks, and emitting TeX code creating the proper stacks),
> but with xetex and luatex the layout is completely broken.
> In the xetex case we even get the dotted circle variants set
> aside ..
These look like problems with the fonts, do they work better in other
programs? Especially the dotted circles in Noto Tibetan was a known bug
which is fixed in current versions. Related to this: The font
"Noto Sans Tibetan" has been renamed to "Noto Serif Tibetan" so the
"Sans" file hasn't been updated in recent years.
If I try your example with "Serif", I get a glyph which looks quite
similiar to your picture. (I attached the PDF file)
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