829943 - Firefox font "blurry" rendering issues

Status: RESOLVED DUPLICATE of bug 828206

(Core :: Layout, defect)

Description

[neovatar]

Attachment: fontbug.png

User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:21.0) Gecko/20130111 Firefox/21.0
Build ID: 20130111190743

Steps to reproduce:

I am using Ubuntu 12.04 with the standard Ubuntu packages for Firefox. After the upgrade from FF 16 to 18 the font rendering has changed. Subpixel rendering causes a "greenish" shadow and blurry fonts.

The following was used in testing:
- Ubuntu 12.04
- Completely new and empty FF user profile
- I did try the different standard font workaounds for each try (disable HW acceleration, un/setting specific font rendering values in about:config), but they did not help

Firefox 16 (standard Ubuntu repo):
- Font rendering ok

Firefox 18 (standard Ubuntu repo):
- Font rendering issues

Firefox 21.0~a1~hg20130110r118352-0ubuntu1~umd1~precise (ppa:ubuntu-mozilla-daily/ppa, ):
- Font rendering is again like it was back in FF 16


Actual results:

I attached some screen shots taken with the xmag tool. Note the rendering differences: In FF 16 there is a green "shadow" with pixel below the rendered chars, while in FF 16/21 there are no antialias pixel below the chars.

There is also a thread in the mozilla forums about this bug, including quite a few screenshots to illustrate the rendering issue:
http://forums.mozillazine.org/viewtopic.php?f=9&p=12593861

Comment 1

[neovatar]

Attachment: screen shot forums.mozillazine.org thread

Comment 2

[neovatar]

Repeated the tests with FF 17.0.1 (17.0.1+build1-0ubuntu0.12.04.1) from the official Ubuntu ppa:
- Font rendering ok

Comment 3

[Alice0775 White]

I can reproduce the problem attachment 701462 [details] in Firefox18.0 and Firefox 19beta, but not in Aurora20.0a2 and Nightly21.0a1.

Regression window(aurora cannel)
Good:
http://hg.mozilla.org/releases/mozilla-aurora/rev/fe20163490ec
Mozilla/5.0 (X11; Linux i686; rv:19.0) Gecko/20121207 Firefox/19.0a2 ID:20121207042017
Bad:
http://hg.mozilla.org/releases/mozilla-aurora/rev/e8c2cb8c583f
Mozilla/5.0 (X11; Linux i686; rv:19.0) Gecko/20121208 Firefox/19.0a2 ID:20121208042017
Pshlog:
http://hg.mozilla.org/releases/mozilla-aurora/pushloghtml?fromchange=fe20163490ec&tochange=e8c2cb8c583f


Regression window(beta cannel)
Good:
http://hg.mozilla.org/releases/mozilla-beta/rev/b5fab1c304d2
Mozilla/5.0 (X11; Linux i686; rv:18.0) Gecko/20121207 Firefox/18.0 ID:20121207003552
Bad:
http://hg.mozilla.org/releases/mozilla-beta/rev/4e486ec47f47
Mozilla/5.0 (X11; Linux i686; rv:18.0) Gecko/20121208 Firefox/18.0 ID:20121208005051
Pshlog:
http://hg.mozilla.org/releases/mozilla-beta/pushloghtml?fromchange=b5fab1c304d2&tochange=4e486ec47f47

Suspected : Bug 810302

However I could not find regression window in mozilla-central.


Graphics

        Adapter Description
        VMware, Inc. -- Gallium 0.4 on SVGA3D; build: RELEASE;

        Device ID
        Gallium 0.4 on SVGA3D; build: RELEASE;

        Driver Version
        2.1 Mesa 8.0.4

        GPU Accelerated Windows
        0/1 Basic

        Vendor ID
        VMware, Inc.

        WebGL Renderer
        VMware, Inc. -- Gallium 0.4 on SVGA3D; build: RELEASE;

        AzureCanvasBackend
        cairo

        AzureContentBackend
        none

        AzureFallbackCanvasBackend
        none

Comment 4

[Alice0775 White]

in local build
Last Good: 735426e182ac
First Bad: b64693f63118
Triggered by:
b64693f63118	Matt Woodrow — Bug 810302 - When flattening layers together to avoid component alpha, attempt to pick the 'best' active scrolled root to minimize invalidation during scrolling. r=roc, a=lsblakk

Comment 5

[James]

Bug 828206 is a dupe.

Can you confirm the mozilla-central regression range I posted in that bug Alice? Possibly fixed by Bug 806099 in FF20/21.