Bug 182042 – 'vert' font feature is not enabled in vertical text

• Component: Text
• Status: NEW

[Myles C. Maxfield]

We should enable it when rendering vertical text.

[Radar WebKit Bug Importer]

<rdar://problem/36817474>

[Chris Lilley]

Steps to reproduce the problem:
1. Go to https://test.csswg.org/harness/test/css-fonts-3_dev/single/font-kerning-03/format/html5/
2. Compare test result to reference page (linked from the above url)

Firefox passes the test correctly. WebKit, Edge and Chrome do not


Spec text:
" When rendering with OpenType fonts, the [OPENTYPE] specification suggests that kerning be enabled by default. When kerning is enabled, the OpenType kern feature is enabled (for vertical text runs the vkrn feature is enabled instead)."
https://drafts.csswg.org/css-fonts-3/#font-kerning-prop

WebKit passes the equivalent test for horizontal text (with the `kern` feature; the bug is just in vertical text. This looks like a simple oversight.


The test case is in web platform tests, in CSS/css-fonts/font-kerning-03.html and the reference is font-kerning-03-ref.html

https://github.com/w3c/web-platform-tests/blob/master/css/css-fonts/font-kerning-03.html
https://github.com/w3c/web-platform-tests/blob/master/css/css-fonts/font-kerning-03.html

Just another reminder, WPT test https://github.com/web-platform-tests/wpt/blob/master/css/css-writing-modes/text-orientation-mixed-vrl-100-ref.html
also fails due to this issue.

[Myles C. Maxfield]

*** Bug 198638 has been marked as a duplicate of this bug. ***

[Ahmad Saleem]

https://wpt.fyi/results/css/css-fonts?label=master&label=experimental&product=chrome&product=firefox&product=safari&aligned=&view=interop&q=font-kerning

^ font-kerning* tests.