[CSS3 Values] ch unit with text-orientation and vertical writing modes

[Gérard Talbot]

{
ch unit
    Equal to the used advance measure of the "0" (ZERO, U+0030) glyph found in the font used to render it. (The advance measure of a glyph is its advance width or height, whichever is in the inline axis of the element.)

    Note: The advance measure of a glyph depends on writing-mode and text-orientation (...)
}
CSS3 Values and Units, section 5.1.1 Font-relative lengths: the em, ex, ch, rem units
https://www.w3.org/TR/css-values-3/#ch


Tests
-----

In 'vertical-rl' writing mode with 'text-orientation: upright', the ch unit is equal to the used vertical advance measure of the 0 (ZERO, U+0030) glyph
http://w3c-test.org/css/css-values/ch-unit-002.html

In 'vertical-rl' writing mode with 'text-orientation: mixed', the ch unit is equal to the used horizontal advance measure of the 0 (ZERO, U+0030) glyph
http://w3c-test.org/css/css-values/ch-unit-003.html

In 'vertical-rl' writing mode with 'text-orientation: sideways', the ch unit is equal to the used horizontal advance measure of the 0 (ZERO, U+0030) glyph
http://w3c-test.org/css/css-values/ch-unit-004.html

In 'vertical-rl' writing mode with 'text-orientation: mixed', the ch unit is the advance width measure of the 0 (ZERO, U+0030) glyph
http://w3c-test.org/css/css-values/ch-unit-010.html

In 'vertical-rl' writing mode with 'text-orientation: upright', the ch unit is the advance height measure of the 0 (ZERO, U+0030) glyph
http://w3c-test.org/css/css-values/ch-unit-011.html

In 'vertical-rl' writing mode with 'text-orientation: sideways', the ch unit is the advance width measure of the 0 (ZERO, U+0030) glyph
http://w3c-test.org/css/css-values/ch-unit-012.html

These 6 tests fail in latest stable Safari 12 and in latest Safari Technology Preview. 

Firefox 68 and Epiphany Technological Preview 3.31.90-8061c1929 (WebKitGTK 2.24.0) pass these 6 tests. 

I searched for duplicates and did not find any. This is not a duplicate of bug 85755.

Unfortunately, I do not have and do not use and do not have access to Mac OS X or to latest stable Safari 12 or to latest Safari Technological Preview; I was informed by Florian Rivoal about these test results.

[Radar WebKit Bug Importer]

<rdar://problem/49222649>

[Ahmad Saleem]

It seems these are now on WPT, adding WPTImpact tag:

WPT Tests - https://wpt.fyi/results/css/css-values?label=master&label=experimental&aligned&view=subtest&q=css-values%2Fch-

[Tim Nguyen (:ntim)]

*** This bug has been marked as a duplicate of bug 266937 ***