1157758 - in vertical writing mode with upright glyph orientation, Arabic-script shaping should not be applied

Status: RESOLVED FIXED

(Core :: Layout: Text and Fonts, defect)

Description

[Jonathan Kew [:jfkthame]]

Testcase:

data:text/html;charset=utf-8,
  <div style="writing-mode:vertical-rl;text-orientation:upright">الخط العربي

Should render the Arabic letters in their isolated ("unshaped") form.[1]

(This is a harfbuzz issue; PR submitted upstream.[2] Once it is fixed there, we'll resolve the Gecko bug by taking a new harfbuzz version.)

[1] http://dev.w3.org/csswg/css-writing-modes/#typeset-upright
[2] https://github.com/behdad/harfbuzz/pull/100

Comment 1

[Jonathan Kew [:jfkthame]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=b13cdf89efc2

Comment 2

[Jonathan Kew [:jfkthame]]

Attachment: Update harfbuzz to pick up fix for vertical-upright Arabic script (non-)shaping behavior; now at upstream commit f724cc351640ee075a9867ef42df32cf5e0ef3b7

Comment 3

[John Daggett (:jtd)]

It would be nice to have a reftest for this since no actual user is ever going to care about this codepath... :P

Comment 4

[Jonathan Kew [:jfkthame]]

https://treeherder.mozilla.org/#/jobs?repo=try&revision=e735e4040d7e

Comment 5

[Jonathan Kew [:jfkthame]]

Attachment: Reftest for Arabic text in vertical-upright mode

Here's a reftest that seems to work locally; if tryserver doesn't like it on some platforms, we might need to add a specific Arabic font to ensure consistent behavior, but let's see.

Comment 6

[Jonathan Kew [:jfkthame]]

https://hg.mozilla.org/integration/mozilla-inbound/rev/e2aabff6bd77
https://hg.mozilla.org/integration/mozilla-inbound/rev/876a0813cdc5

Comment 7

[Carsten Book [:Tomcat]]

https://hg.mozilla.org/mozilla-central/rev/e2aabff6bd77
https://hg.mozilla.org/mozilla-central/rev/876a0813cdc5