611205 - Some font glyphs are rendered too close to one another in Fx 4.0b7 (Win)

Status: RESOLVED DUPLICATE of bug 605043

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

Description

[amyspark]

User-Agent:       Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b7) Gecko/20100101 Firefox/4.0b7
Build Identifier: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0b7) Gecko/20100101 Firefox/4.0b7

(I'm filing this bug here because I don't know if it's related to Gecko or what else. Feel free to reassign it!)

On Fx 4.0b7, it seems that the font rendering engine has changed.
I've noticed that some glyphs are rendered too close, which makes some texts to look odd.
I've attached a screenshot of https://arantius.com/misc/gm-nightly/updates.rdf showing the issue on beta 7. I'll get a screenshot from Stable trunk after I file this bug. (I cannot get to run the two versions together in Sandboxie)

Reproducible: Always

Steps to Reproduce:
1. Load a page like https://arantius.com/misc/gm-nightly/updates.rdf or https://www.facebook.com
2. Pay special attention to the font rendering!
Actual Results:  
Look at the screenshot from Fx 4.0b7, the "S" and the "t" are too close, almost overlapped. I've ruled out any problem with font files, since they are _exactly_ the same.

Expected Results:  
Look at the screenshot from Fx 3.6.12, the "StartCom Ltd.". Each glyph is clearly separated.

Comment 1

[amyspark]

Attachment: Screenshot of a sample page in Fx 4.0b7

Comment 2

[amyspark]

Attachment: Screenshot of a sample page in Fx 3.6.12

Check the yellow circle in the first screenshot (3.6.12 stable), then compare the rendering to the second screenshot (4.0b7).

Comment 3

[amyspark]

Forgot to mention that I'm _not_using any form of hardware acceleration (DirectWrite disabled).

Comment 4

[(mostly gone) XtC4UaLL [:xtc4uall]]

Might be Bug 605043.
Does setting "Setting gfx.font_rendering.harfbuzz.level" to "0" help?

Comment 5

[amyspark]

Yes, it helps. No more weird typos in font rendering.