LibreOffice got support for optional OpenType feature since 5.3, but if a font have intergrated both OT and Graphite features, some of OpenType features failed to work.
Steps to Reproduce:
Test with Duolos SIL
1. New Writer document
2. Enter some text, e.g. "ff, ffi, ff"
3. Change font for paragraph to "Duolos SIL"
4. Select text and add the ":liga=0" OT switch to the font list entry
Test with Ponomar Unicode TT (http://sci.ponomar.net/fonts.html)
1. Enter some text, e.g. "У, Є"
2. Change font for paragraph to "Ponomar Unicode TT"
3. Select text and add the ":salt=1" OT switch to the font list entry
4. Enter text "The quick brown fox."
5. Select text and add the ":ss02=1" OT switch to the font list entry
Standard ligature failed to work when I use Duolos SIL, also, stylistic alternates and stylistic set #2 failed to work with Ponomar Unoicode TT.
If a intergrated both OT and Graphite features, both of them should works proper.
User Profile Reset: No
Version: 220.127.116.11 (x64)
Build ID: 5ad7b2889021c491af62f7930a4b1cb631392f16
CPU Threads: 4; OS Version: Windows 6.19; UI Render: default; 布局引擎：新;
Locale: zh-CN (zh_CN); Calc: group
Documentation for Ponomar Unicode TT is available here: http://www.ponomar.net/files/fonts-churchslavonic.pdf
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:51.0) Gecko/20100101 Firefox/51.0
When a font has Graphite or AAT layout tables, they will take precedence and OpenType layout tables will be ignored. In both cases here the Graphite layout is used and it is not reasonable to expect OpenType layout to work at the same time. If you don’t want Graphite layout, don’t use graphite fonts.