Bangla font rendering problem with letter ড় ঢ় in LibreOffice 6.0 with some bengali fonts

[kuntalkundu]

I reported this issue on https://bugs.documentfoundation.org/show_bug.cgi?id=115421 on 3rd Feb, 2018. (Bug Id- 115421). In reply of this bug report, Mr. Khaled Hosny told me to report this bug here, so I did so. The problem as I told early is problem with Nukta sign. Libre Office use this character to create few bengali alphabet like ড় ঢ় where the round dots of those letters become slightly displaced with some bengali fonts. But I test those fonts in alternative office packages like OpenOffice, MS Office where the Nukta character doesn't use to form those alphabets. My request is please fix this problem of LibreOffice in next update. I attaced few screenshots and few font which are used

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[KrasnayaPloshchad]

Behdad, you can get the font from here for test.

[KrasnayaPloshchad]

OK, I tested with hb-shape, there are different behaviors between HarfBuzz and Uniscribe.

harfbuzz-1.7.5-win32\hb-shape.exe "Bangla Akademi.ttf" --unicodes="09DC 0020 09DD 0020 09A1 09BC 0020 09A2 09BC"  --shapers=ot
[glyph521=0+1011|space=1+582|glyph522=2+756|space=3+582|glyph521=4+1011|space=6+582|glyph522=7+756]

harfbuzz-1.7.5-win32\hb-shape.exe "Bangla Akademi.ttf" --unicodes="09DC 0020 09DD 0020 09A1 09BC 0020 09A2 09BC"  --shapers=uniscribe
[bn_rha=0+976|space=1+582|bn_yya=2+763|space=3+582|glyph521=4+1011|space=6+582|glyph522=7+756]

So I think this is probably HarfBuzz bug.

[KrasnayaPloshchad]

I made another test for this.
harfbuzz-1.7.5-win32\hb-view "Bangla Akademi.ttf" --unicodes="09DC 0020 09DD 0020 09A1 09BC 0020 09A2 09BC" --shapers=ot --output-format=png --output-file=test1.png

harfbuzz-1.7.5-win32\hb-view "Bangla Akademi.ttf" --unicodes="09DC 0020 09DD 0020 09A1 09BC 0020 09A2 09BC" --shapers=uniscribe --output-format=png --output-file=test2.png

On Windows, LibreOffice switched to HarfBuzz since 2016 when LO 5.3 is under heavy development, but AOO still relying on Uniscribe, thus your screenshots are in fact showing how does HarfBuzz and Uniscribe behavoired in this case. BTW it’s so weird that dda + nukta ≠ rra in this font.

[KrasnayaPloshchad]

CC @khaledhosny

[kuntalkundu]

I am really thankfull to team Harfbuzz for this concern. Your team took this font issue seriously. You can test this font in fontforge by reshaping the size, width of nukta dot. Then you can realize the issue. Thanks on advance. Get Outlook for Android<https://aka.ms/ghei36>

…

________________________________ From: Krasnaya Ploshchad’ <notifications@github.com> Sent: Monday, March 12, 2018 10:27:50 PM To: harfbuzz/harfbuzz Cc: Kuntal Kundu; Author Subject: Re: [harfbuzz/harfbuzz] Bangla font rendering problem with letter ড় ঢ় in LibreOffice 6.0 with some bengali fonts (#779) CC @khaledhosny<https://github.com/khaledhosny> — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<#779 (comment)>, or mute the thread<https://github.com/notifications/unsubscribe-auth/AbCm_TQhJdbJuGTcoBDtJtYeeeWEDUN4ks5tdqkOgaJpZM4SBXOR>.

[KrasnayaPloshchad]

CC @ebraminio

[ebraminio]

Confirmed the issue using your test case,

$ WINEDLLOVERRIDES="usp10=n" wine winbuild/util/hb-shape.exe "Bangla Akademi.ttf" --unicodes="09DC 0020 09DD 0020 09A1 09BC 0020 09A2 09BC"  --shapers=uniscribe

[bn_rha=0+976|space=1+582|bn_yya=2+763|space=3+582|glyph521=4+1011|space=6+582|glyph522=7+756]

$ wine winbuild/util/hb-shape.exe "Bangla Akademi.ttf" --unicodes="09DC 0020 09DD 0020 09A1 09BC 0020 09A2 09BC" --shapers=ot

[glyph521=0+1011|space=1+582|glyph522=2+756|space=3+582|glyph521=4+1011|space=6+582|glyph522=7+756]

@KrasnayaPloshchad I like to help on Indic shaping but to be honest I just don't know what is going on :P Anyone interested on these and have free time, feel free to contact me privately, using an instant messenger to talk about these is the best option for me.

[ebraminio]

I guess I've found a fix on #977 But it would be super useful if you can find a free font with the issue.