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New Oriya overline character is not positioned correctly #754

Open devosb opened 3 years ago

devosb commented 3 years ago

I created a font, Japa Sans Oriya (based on Noto Sans Oriya) to support the new overline character, U+0B55 ORIYA SIGN OVERLINE, new in Unicode 13. You can get a copy of the font from the HarfBuzz issue I filed about this character.

The shaping of this character with DirectWrite is good for the most part, except for the overline above a left vowel. DirectWrite (in Notepad and Word 2016 on a Dev version of Windows 10 with the Windows Insider program (updated yesterday)

Edition Windows 10 Pro Insider Preview
Version Dev
Installed on    ‎2021-‎03-‎30
OS build    21343.1000
Experience  Windows 10 Feature Experience Pack 321.7401.0.3

DirectWrite shows dw while HarfBuzz shows hb

There is OpenType code in the font to re-order the overline so that it can be placed over a left vowel.

The codepoints for this sample are

0B2E 0B47 0B55 0B23 0B4D 0B24

which is the word sheep that you can see in the proposal.

PeterCon commented 3 years ago

@devosb: thanks for reporting. Note that you should not need to add lookups that effect a re-ordering of glyphs (to get the overline glyph before the base glyph) or have a positioning lookup that ignores base glyphs for letters. Rather the shaping engine should re-order the overline glyph together with the vowel sign. A bug was filed on DWrite with those details.

devosb commented 3 years ago

@PeterCon Thanks for catching that the added lookups to re-order (as you mention) are not needed (both with the fix in HB and the coming fix in DWrite. They were needed before HB was fixed, and since Adobe InDesign (tested with 16.2.1) has (apparently) not updated HB since the fix, the Noto project (which has a request for the overline character) would need to make sure their testing environment had the needed fixes.