456578 - Font rendering regression (hinting)

Status: RESOLVED WORKSFORME

(Core :: Graphics, defect)

Description

[Thomas Jones]

User-Agent:       Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1b1pre) Gecko/20080922020401 Minefield/3.1b1pre
Build Identifier: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1b1pre) Gecko/20080922020401 Minefield/3.1b1pre

Font hinting seems to be wrong.

With subpixel hinting on there are colour fringes, this only occurs in Firefox (and only in the nightly, Firefox 3 has correct rendering.

Also even without subpixel hinting fonts do not seem to show correct shape/hinting.

The rendering has the appearance of having been scaled AFTER being rendered to pixels. (I don't know that that is what is happening, but that's what it looks like to me)

Reproducible: Always

Steps to Reproduce:
1. visit webpage
2. look at fonts
3.
Actual Results:  
Ugly fonts

Expected Results:  
Nice Fonts

Comment 1

[Thomas Jones]

Attachment: Example of the ugly rendering in Minefeild

Comment 2

[Thomas Jones]

Attachment: Nice fonts in Firefox 3.0.1

Comment 3

[Thomas Jones]

Oh and additionally fonts seem to be ugly regardless of the anti-ailiasing/hinting mode, all that seems to change is the kind of ugly you get.

I have not tested it with anti-aliasing off totally though.

Also some fonts seem to be better than others.

Comment 4

[Thomas Jones]

also this is new sometime in the last week or so

Comment 5

[philippe (part-time)]

I see that as well (Ubuntu 8.04 running in a virtual machine), but only/mostly with serif fonts.
It started somewhere between 20080905 and 20080913. That day (0913) I upgraded my copy of VirtualBox *and* there where a truckload of Ubuntu updates waiting in the wings - not sure if that has anything to do with the issue. I don't have time to check for more details/regression range though.

Hmm, there was a Cairo upgrade during that period: bug 453765. Adding Vlad to the CC.

Comment 6

[Thomas Jones]

Just a note, I took both screenshots on the same machine (the bad one first), so whatever it is causing it, it is Firefox...

I don't think I had a Cairo update the same time this started...

Comment 7

[Matthew Turnbull [Bluefang]]

I'm also seeing the same thing, however it didn't show up until the 09-27 or 09-28 build.

I don't know about you seeing it earlier, but there was a font related check-in during 26-28 build range, so I think what I'm seeing might be fallout from Bug 385263

Comment 8

[Matthew Turnbull [Bluefang]]

Attachment: Fonts from the 09-26 build

Comment 9

[Matthew Turnbull [Bluefang]]

Attachment: Fonts from the 09-28 build

Comment 10

[Michael Ventnor]

I'm not seeing this, because my global font settings are set to subpixel hinting for LCD's. Have you tried changing the font settings in the GNOME Appearance dialog?

Comment 11

[philippe (part-time)]

(In reply to comment #10)

Yeah, I should've mentioned this. I changed my settings here to something else (from subpixel smoothing, LCD), restarted the VM, then changed it back to what it was and now most text displays fine. Small serifs still looks slightly more blurred though.

Comment 12

[Matthew Turnbull [Bluefang]]

(In reply to comment #10)
> I'm not seeing this, because my global font settings are set to subpixel
> hinting for LCD's. Have you tried changing the font settings in the GNOME
> Appearance dialog?

Yes, though I've always used subpixel smoothing and full hinting, I tried changing them around and restarting Firefox. Subpixel looks the best in all cases, and fonts display "correctly" in GNOME and other GTK+ apps EXCEPT the trunk versions of Firefox and Thunderbird (post 09-26).

Comment 13

[Thomas Jones]

The problem (visually) is that the sub-pixel stuff is spreading too much so instead of seeing something that looks higher-res than your screen is it just looks blurry and colour fringed.

I have also seen the same problem on two separate machines, running different distros on each. (one Gentoo one Ubuntu), the fonts are also still ugly when sub-pixel hinting is off, the ugly is just different.

Comment 14

[Rémi Cardona]

Just noticed this bug with Shredder alpha3. Any news on this bug?

Thanks

Comment 15

[Matthew Turnbull [Bluefang]]

Recent builds seem to be rendering correctly. It think this may have been resolved thanks to Bug 462938.

Comment 16

[Thomas Jones]

(In reply to comment #15)
> Recent builds seem to be rendering correctly. It think this may have been
> resolved thanks to Bug 462938.

yup seems to be fixed

Comment 17

[Karl Tomlinson (:karlt)]

WFM based on comments 15 and 16

Comment 18

[Sohail Mirza]

Attachment: Font hinting - Firefox 3.0.4 vs. Minefield 11-24

Comment 19

[Sohail Mirza]

Attachment: Font hinting - Firefox 3.0.4 vs. Minefield 11-24 (Zoomed)

Comment 20

[Sohail Mirza]

I'm finding that this issue is actually not resolved for me in the trunk build from 11/24/2008.  Attachment 350431 [details] and attachment 350432 [details] demonstrate the difference in font rendering between Firefox 3.0.4 and Minefield 11/24.

The version strings from both browsers:

Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.0.4) Gecko/2008111319 Ubuntu/8.10 (intrepid) Firefox/3.0.4

Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1b2pre) Gecko/20081124 Minefield/3.1b2pre

Comment 21

[Karl Tomlinson (:karlt)]

Sohail, the issue that the reporter of this bug noticed has been fixed, so I think you are seeing a different issue.

It looks like a simple difference in font rendering preferences.
Ubuntu have changed their system fontconfig settings, which is covered in bug 458612, and I'm guessing that is what you are seeing.

If adjusting fontconfig settings doesn't restore the behavior you like, and the following two commands produce the same output, then please file a new bug (and CC me).

pango-view -t "Mozilla Foundation" --font="Verdana,sans-serif 13px" --backend=cairo

pango-view -t "Mozilla Foundation" --font="Verdana,sans-serif 13px" --backend=xft

Note also that if "Ubuntu/8.10 (intrepid) Firefox/3.0.4" is built with system-cairo (check about:buildconfig) then it will be using some Ubuntu-specific patches that affect lcd subpixel antialiasing, in which case it won't necessarily be possible to see exactly the same aliasing in a Mozilla build of Firefox (bug 404637).