1230456 - central baseline-alignment of mixed text (fullwidth glyph with latin sideways-ed text)

Status: NEW

(Core :: Layout: Block and Inline, defect)

Description

[Gérard Talbot]

Precondition
------------

You must have the "Droid Sans Fallback" font installed on your system.


Vendor-prefixed test
--------------------

http://www.gtalbot.org/BrowserBugsSection/CSS3WritingModes/text-orientation-mixed-002-GT.xht


Expected results
----------------

The "Ｔ" in the middle box (orange color) should be exactly in the center of the line box.


Actual results
--------------

The "Ｔ" in the middle box (orange color) is 8-10px farther to the left of the center of the line box.


Explanations
------------

Since text-orientation is mixed and since the dominant baseline is central, then the FULLWIDTH LATIN CAPITAL LETTER T in the middle rectangle (color orange) is expected to be exactly in the center of the line box. The sideways-ed "ext" chunk is expected to be a bit (say, 10px) farther to the left of the horizontal middle of the line box.


Notes
-----

- First of all, when you load the test, the 3 "T"s may not be painted... you need to highlight, drag-to-select the area: that's another bug which I will report in a few minutes
- I get expected result if I use TakaoPGothic font or if I use the mplus-1p-regular.woff file as the font resource
- I get actual result with Firefox 42.0 buildID=20151030084315
- Chrome 48.0.2564.22 passes the test
- I am using Firefox 45.0a1 buildID=20151203062327 
- I use Linux 3.16.0-71-generic x86_64, Qt: 4.8.6, KDE 4.14.3; Kubuntu (trusty) 14.04.03 LTS
- I can upload a screenshot if requested
- I've searched for duplicates and did not find any.

Comment 1

[Gérard Talbot]

> you need to highlight, drag-to-select the area: that's another bug which I will
> report in a few minutes

That's bug 1230464

Comment 2

[Gérard Talbot]

> You must have the "Droid Sans Fallback" font installed on your system.

I use DroidSansFallbackFull.ttf (4.3 Megabytes) coming from the fonts-droid (1:4.3-3ubuntu1.2) package:
http://packages.ubuntu.com/trusty-updates/fonts-droid

> Actual results
> --------------
> 
> The "Ｔ" in the middle box (orange color) is 8-10px farther to the left of
> the center of the line box.

It actually seems to be 14-16px farther to the left of the center of the line box when "Droid Sans Fallback" is used.

I do get expected result if I replace "Droid Sans Fallback" with TakaoPGothic in both Firefox 42 and Firefox 45. 

package fonts-takao-pgothic (003.02.01-9ubuntu2)
http://packages.ubuntu.com/trusty/fonts-takao-pgothic
file installed on my system: /usr/share/fonts/truetype/takao-gothic/TakaoPGothic.ttf

If I replace "Droid Sans Fallback" with "DejaVu Serif" in both Firefox 42 and 45, then the orange "Ｔ" seems 8-10px farther to the left of the center of the line box.

Comment 3

[Gérard Talbot]

I do not know if this could be related (I don't think it is related):

"
  * 65-fonts-takao-gothic.conf, 65-fonts-takao-pgothic.conf:
    Added 'binding="strong"' for sans-serif and monospace. This makes
    Takao fonts be used for Japanese despite of the new
    65-droid-sans-fallback.conf, which is included in the seeded
    fonts-droid package (LP: #1227034).

 -- Gunnar Hjalmarsson <[e-mail]>  Tue, 08 Apr 2014 21:06:00 +0200
"

https://bugs.launchpad.net/ubuntukylin/+bug/1227034 

comment 29 mentions both fonts and non-japanese characters ... but anyway, I do not see how this relates to this bug report here.

Comment 4

[Gérard Talbot]

> - I get expected result if I use the mplus-1p-regular.woff file as the font resource

http://www.gtalbot.org/BrowserBugsSection/CSS3WritingModes/text-orientation-mixed-002-GT-mplus-1p.xht

Comment 5

[Gérard Talbot]

Attachment: Expected result versus Actual result screenshot of text-orientation-mixed-002-GT.xht test

Self-explanatory describing screenshot of the orange "T" in text-orientation-mixed-002-GT.xht test