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Starred by 7 users

Issue metadata

Status: Available
Owner: ----
EstimatedDays: ----
NextAction: ----
OS: All
Pri: 2
Type: Bug

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Issue 408777: font-size measured in ex or ch scales quadratically with page zoom

Reported by, Aug 28 2014

Issue description

UserAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/37.0.2062.94 Safari/537.36

Example URL:

Steps to reproduce the problem:
1. Visit
2. At 100% page zoom, observe that all the lines are roughly the same size.
3. Zoom in.

What is the expected behavior?
All lines should get bigger by the same ratio.

What went wrong?
The lines where font-size is measured in ex or ch get bigger much faster than the other lines.  At 500% page zoom, they are shown at 25 times their original size.

Does it occur on multiple sites: Yes

Is it a problem with a plugin? No 

Did this work before? N/A 

Does this work in other browsers? Yes 

Chrome version: 37.0.2062.94  Channel: beta
OS Version: 
Flash Version: Shockwave Flash 14.0 r0

I’m using 200% default zoom as a workaround for missing high-DPI support on Linux, so this makes some pages look really odd.  I first noticed it on

Comment 1 by, Sep 1 2014

Labels: -Cr-Content Cr-Blink-Rendering Cr-Blink-PageZoom

Comment 2 by, Sep 3 2014

Labels: -OS-Linux OS-All M-39
Status: Untriaged
Able to reproduce the issue on Mac and Linux. This is a non-regression from M24 24.0.1312.57 (Official Build 178923)  chrome versions to latest canary 39.0.2144.2.

Comment 3 by, Oct 10 2014

Labels: -M-39 MovedFrom-39 M-40
Moving all non essential bugs to the next Milestone.

Comment 4 by, Nov 17 2014

Labels: -M-40 MovedFrom-40
This issue has already been moved once and is lower than Priority 1,therefore removing mstone.

Comment 5 by, Jan 9 2015

Labels: -Cr-Blink-Rendering Cr-Blink-Layout
Migrate from Cr-Blink-Rendering to Cr-Blink-Layout

Comment 6 by, Jan 4 2016

Labels: -Pri-2 Pri-3
Status: Available

Comment 7 by, May 23 2016

Components: -Blink>PageZoom
Deprecating Blink>PageZoom

Comment 8 by, Jul 11 2016

We recently ran into this bug in MathJax, cf.

Due to this bug, we have to resort to measuring the surrounding font (to match the x-height with a webfont) instead of just using a suitable ex-height.

It would be great if this was fixed. FWIW, FF and IE/Edge handle this fine.

Comment 9 by, Jul 11 2016


Comment 10 by, Apr 5 2017

Confirm that this bug exists even now, with Chrome's HiDPI support. (using --force-device-scale-factor=2). Happens with both the the test page and the Fedora project wiki page listed in the examples in Comment 1.

Comment 11 by, May 1 2018

Project Member
Labels: Hotlist-Recharge-Cold
Status: Untriaged (was: Available)
This issue has been Available for over a year. If it's no longer important or seems unlikely to be fixed, please consider closing it out. If it is important, please re-triage the issue.

Sorry for the inconvenience if the bug really should have been left as Available.

For more details visit - Your friendly Sheriffbot

Comment 12 by, May 1 2018

FWIW, the problem is still present (current Chrome 66).

Comment 13 by, May 2 2018

Status: Available (was: Untriaged)

Comment 14 by, Aug 20

Components: -Blink>Layout Blink>Fonts
Labels: -Pri-3 Pri-2

Comment 15 by, Feb 8

Labels: Hotlist-GoodFirstBug

Comment 16 by, Feb 11

 Issue 928036  has been merged into this issue.

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