User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:92.0) Gecko/20100101 Firefox/92.0

Steps to reproduce:

Updated to Thunderbird 91.

Actual results:

After update to Thunderbird 91 all UI text is blurry and uncomfortable to read, which is something that gives me headache because my eyes tries to focus on something that can't be focused. So effectively it makes me feel like I have an abnormal disability.
See attached image, the text to the left is Thunderbird 91, text to the right is Thunderbird 78.

Expected results:

Any kind of font smoothing should be possible to switch off in the settings as this is an ease of access issue.

Does disabling hardware acceleration in the Thunderbird preferences help?

Disabling hardware acceleration does not change or improve the situation.

Does your issue match one of https://mzl.la/3mBLBdG ?

(In reply to Wayne Mery (:wsmwk) from comment #3)

Does your issue match one of https://mzl.la/3mBLBdG ?

It MIGHT be identical to bug 1729198, but I'm just reporting the effects I see, not sure about if this problem is anti-aliasing or generic font smoothing that's active.

In any case this is a quite annoying issue.

I have exactly the same problem as Nils Hammar. I wish this to be respected for the sake of accessibility.

Same issue for me as well after updating to 91, lost all my crisp fonts, everything is a mess now. Thunderbird used to be the last mohican.

Looks related to bug 1732583

(In reply to Kai Liu from comment #7)

Looks related to bug 1732583

No it isn't. That one is about wrong anti-aliasing. This one is about no anti-aliasing at all. Don't hijack the ticket.

(In reply to mdcclxv from comment #8)

(In reply to Kai Liu from comment #7)

Looks related to bug 1732583

No it isn't. That one is about wrong anti-aliasing. This one is about no anti-aliasing at all. Don't hijack the ticket.

Hence why I wrote "related", not "identical". Both issues appear to stem from a common cause, which is the switch to the new WebRender.

You can test this by disabling WebRender in Thunderbird and observing the results. To do so, access Preferences > General > Config Editor and search for and then toggle "gfx.webrender.force-disabled", and then restart Thunderbird after making the change.

(In reply to Kai Liu from comment #9)

(In reply to mdcclxv from comment #8)

(In reply to Kai Liu from comment #7)

Looks related to bug 1732583

No it isn't. That one is about wrong anti-aliasing. This one is about no anti-aliasing at all. Don't hijack the ticket.

Hence why I wrote "related", not "identical". Both issues appear to stem from a common cause, which is the switch to the new WebRender.

You can test this by disabling WebRender in Thunderbird and observing the results. To do so, access Preferences > General > Config Editor and search for and then toggle "gfx.webrender.force-disabled", and then restart Thunderbird after making the change.

You're right, my apologies.

I really hope that TB devs will not shove this down our throats like FF guys did with the Proton UI, without the possibility to disable it anymore. I already started tweaking SeaMonkey until you listed here the force-disable setting.

(In reply to Kai Liu from comment #9)

(In reply to mdcclxv from comment #8)

(In reply to Kai Liu from comment #7)

Looks related to bug 1732583

No it isn't. That one is about wrong anti-aliasing. This one is about no anti-aliasing at all. Don't hijack the ticket.

Hence why I wrote "related", not "identical". Both issues appear to stem from a common cause, which is the switch to the new WebRender.

You can test this by disabling WebRender in Thunderbird and observing the results. To do so, access Preferences > General > Config Editor and search for and then toggle "gfx.webrender.force-disabled", and then restart Thunderbird after making the change.

Thanks! The "gfx.webrender.force-disabled" resolved the issue for me for now and now the text is crisp and razor sharp, but I'm not alone and I still want these kinds of changes to be optional for the user in a way that's easy to access.

I wonder why this only affects some people?

I'd say GFX driver dependant.

This affects those that have anti-aliasing turned off system wide, which are increasing by the day. Anti-aliasing it's starting to take it's toll, especially on large full HD displays.

And, btw, this is not really a disability issue, anti-aliasing is perceived as blurred by those that have very good eye sight. I don't mean to brag, just to give you an image, my last eye check, a couple of months ago, turned out a 120% sight factor. I use a full HD 13" notebook, Windows scalling factor at 100%, and still find anti-aliasing an eye killer, it's like seeing letters through a steamy glass.

So, please please, don't make this WebRender mandatory, leave us an option to turn it off. Or, better yet, fix this rendering bug, fonts like Verdana or MS Reference Sans Serif should render at sizes of 8-14 px in one pixel lines, no duplicate pixels, especially on inflection points.

(In reply to mdcclxv from comment #15)

And, btw, this is not really a disability issue, anti-aliasing is perceived as blurred by those that have very good eye sight. I don't mean to brag, just to give you an image, my last eye check, a couple of months ago, turned out a 120% sight factor. I use a full HD 13" notebook, Windows scalling factor at 100%, and still find anti-aliasing an eye killer, it's like seeing letters through a steamy glass.

It may have different reasons why one cannot stand some versions of font smoothing. Astigmatism. Hyperfocusing (neurodivergency) Perfect sight as you mentioned. I daresay, even people with some or other sight impairment could have trouble as well. There are so incredibly many variants.

I used to have perfect vision, but not so anymore. Though I have astigmatism, and I also hyperfocus on the blurriness as it is extremely distracting. I hate the subpixel antialiasing the most, I can actually SEE the color fringing clearly. This is why I cannot use Windows 10. I have tried to use it, and hack it in many ways, but I could not iron away everything, so I gave up and reverted back to 7. And I have tried 2-3 times.

This is a major issue, but sadly many developers don't want to acknowledge that this is accessibility issue. They just... ignore us.

Ok, sorry for the rant. But maybe wanted to share that it is a major and important concern overall.

I also had to turn off the rendering in Firefox as well. (about:config gfx.e10s.font-list.shared to false)

Thanks. Disabling the gfx force option referenced above solved the issue.

(In reply to Magnus Melin [:mkmelin] from comment #12)

I wonder why this only affects some people?

My guess is that these text rendering issues affect everyone. But when it's just grayscale vs. subpixel anti-aliasing, which was the problem that I ran into, the differences are subtle. Things looked fuzzier, but it was subtle and I couldn't identify what specifically was wrong until went pixel-peeping. I imagine that for users with higher DPI scaling, it would be an even more subtle difference.

Anti-aliased vs. non-anti-aliased, which is the problem the reporter ran into, is a far more noticeable problem, but I suspect that users who disable anti-aliasing outright represent a very small minority.

In short, people who disable anti-aliasing are few in number. And people who don't disable it have lost subpixel anti-aliasing, but either haven't noticed it or just shrugged it off.

(In reply to Kai Liu from comment #18)

(In reply to Magnus Melin [:mkmelin] from comment #12)

I wonder why this only affects some people?

Anti-aliased vs. non-anti-aliased, which is the problem the reporter ran into, is a far more noticeable problem, but I suspect that users who disable anti-aliasing outright represent a very small minority.
In short, people who disable anti-aliasing are few in number.

I can't believe what I'm reading. So screw'em, right?! Because that's definitely what you are implying! Let's do that to the wheelchair folks. Let's do the Alzheimer people. Majority rules, minority ... who cares?! First time when you find yourself in a minority just remember what you said here.

(In reply to mdcclxv from comment #19)

(In reply to Kai Liu from comment #18)

(In reply to Magnus Melin [:mkmelin] from comment #12)

I wonder why this only affects some people?
Anti-aliased vs. non-anti-aliased, which is the problem the reporter ran into, is a far more noticeable problem, but I suspect that users who disable anti-aliasing outright represent a very small minority.
In short, people who disable anti-aliasing are few in number.

I can't believe what I'm reading. So screw'em, right?! Because that's definitely what you are implying! Let's do that to the wheelchair folks. Let's do the Alzheimer people. Majority rules, minority ... who cares?! First time when you find yourself in a minority just remember what you said here.

I was answering the question of why "this only affects some people", which is an important question, since it's useful to clarify that the low reporting rate of this issue isn't because the WebRender only has problems under certain circumstances, but rather that those problems are always there, but are not as noticeable for most people.

I should also note that this is the second time that you've failed to read the context before adding a nonconstructive reply.

(In reply to mdcclxv from comment #19)

...
I can't believe what I'm reading. So screw'em, right?! Because that's definitely what you are implying! Let's do that to the wheelchair folks. Let's do the Alzheimer people. Majority rules, minority ... who cares?! First time when you find yourself in a minority just remember what you said here.

He said nothing of the sort. Please be respectful in bugzilla.

Sometimes graphics issues affecting Thunderbird don't get detected until late in a development cycle, or in this case even after release, sometimes because we exercise core code that is less used or more obsolete for Firefox. I'm not sure that's the case here, but it's nothing new.

Regardless, the key to progress is without a lot of drama to identify the issue, see if it's been reported before, and get it before the right people. I've started a quick examination of core graphics and the good news is so far I don't see any wontfixed bug reports. After we have that assessment we look to see if anything can be done about it.

If someone knows of an already confirmed, relevant unfixed bug report please cite it. Else, have a look at this list of 32 core graphics bug reports going back 5 years https://mzl.la/3voXNSZ

My previous query is useful, but not quite as expansive as I intended.

https://mzl.la/3vqJ5en is 87 graphics bugs casting a wider net but includes only open, invalid and wontfixed bugs

https://mzl.la/3BTubji is the same query, showing 6 bugs in the Thunderbird product

I found another error in the query, which I have corrected in an EDIT of comment 23. The count is now 87 and 6 (vs 42 and 3).

18 more https://mzl.la/2YY2vuU - searching on "aa"

(In reply to Kai Liu from comment #18)

In short, people who disable anti-aliasing are few in number. And people who don't disable it have lost subpixel anti-aliasing, but either haven't noticed it or just shrugged it off.

People that disables it are few in numbers because it's very hard to understand what the issue is when it's seen. That means that people not understanding how to resolve the issue because they don't even know what anti-aliasing is will just try to locate another product.

The whole concept of anti-aliasing is from my perspective a name that don't say anything useful and it tries to fix something that isn't broken except in the mind of the font creators.

As this is a readability issue I saw this as "Disability Access", and even if it impacts a minority (I have seen figures elsewhere that 20 to 30% of the population have issues with fuzzy fonts) it's still significant enough that I'd like to see it fixed.

Thanks for the "gfx.webrender.force-disabled" option, this at least allowed for the blurriness to go away. I too, am very sensitive to the blurriness effects, so much that I took the time to write an entire article on the subject: https://www.obones.com/en/more/blog/astigmatism-part-2

Migrating to Windows 10 was a pain for me as well, but at least the registry trick to force substituting Segoe UI with MS Sans Serif still works in most parts of the operating system.

Now, on to figure out why the font size in the message list and tree feels so much smaller since Thunderbird 91.

(In reply to Kai Liu from comment #9)

(In reply to mdcclxv from comment #8)

(In reply to Kai Liu from comment #7)

Looks related to bug 1732583

No it isn't. That one is about wrong anti-aliasing. This one is about no anti-aliasing at all. Don't hijack the ticket.

Hence why I wrote "related", not "identical". Both issues appear to stem from a common cause, which is the switch to the new WebRender.

You can test this by disabling WebRender in Thunderbird and observing the results. To do so, access Preferences > General > Config Editor and search for and then toggle "gfx.webrender.force-disabled", and then restart Thunderbird after making the change.

This worked like magic! Thank you a million times.

Julia

Just wanted to chime in and say that this isn't specific to those switching off anti-aliasing and it is affecting font rendering on Linux as well. I have font anti-aliasing enabled, Subpixel rendering: RGB, Hinting: Full on a Fedora 33.

But toggling "gfx.webrender.force-disabled" fixed my issue as well. Thanks @Kai Liu

(In reply to philbyjohn from comment #29)

Just wanted to chime in and say that this isn't specific to those switching off anti-aliasing and it is affecting font rendering on Linux as well. I have font anti-aliasing enabled, Subpixel rendering: RGB, Hinting: Full on a Fedora 33.

But toggling "gfx.webrender.force-disabled" fixed my issue as well. Thanks @Kai Liu

After updating to Thunderbird 102.0, the antialiasing on the folder-pane and in the message-list is turned on again.

To switch "gfx.webrender.force-disabled" to "true" doesn't work with version 102.0

Is there already a solution to turn antialiasing off again?

When upgrading from 91.11.0 to 102.0 this bug is definitely back so this is definitely now an issue for Thunderbird 102.

For me the blurry fonts is like staring into a welding arc.

Blurry font in Thunderbird 102 that causes readability issues.

I think I have found a solution. But I'm not sure if this parameter is meant for that, or if that's just a side effect:

Setting "gfx.webrender.blob-images" to false switch the antialias off.

Greetings Andreas

From a look at the parameters it seems like gfx.webrender.force-disabled is now no longer an active parameter since all you can do is to remove it (Trashcan icon) instead of reverting it (curved arrow).

And gfx.webrender.blob-images definitely fixes the blurry font issue. Not sure if that will cause any other side effects in Thunderbird. Thanks Andreas!

All I want is a checkbox where it's possible to turn off whatever makes the font rendering blurry.

This seems to be the same cause as Bug 1734343 regarding WebRender + Tree View.

(In reply to Andreas Fecht from comment #30)

(In reply to philbyjohn from comment #29)

Just wanted to chime in and say that this isn't specific to those switching off anti-aliasing and it is affecting font rendering on Linux as well. I have font anti-aliasing enabled, Subpixel rendering: RGB, Hinting: Full on a Fedora 33.

But toggling "gfx.webrender.force-disabled" fixed my issue as well. Thanks @Kai Liu

After updating to Thunderbird 102.0, the antialiasing on the folder-pane and in the message-list is turned on again.

To switch "gfx.webrender.force-disabled" to "true" doesn't work with version 102.0

Is there already a solution to turn antialiasing off again?

Someone in this string suggested gfx.webrender.blob-images and this worked for me.

Hi,

• First, this is not necessary a "disability access" problem. I like crisp rendering.

• Second, yes, Thunderbird font for "treechildren" is too small, although it matchs the System Font. The possibility to change it should be promoted to a GUI setting IMO. Parsing a list of emails is not the same thing that reading a top menu.

Increasing the size through useChrome.css is possible. Up to TB 102 I've been satisfied with that.
Perhaps it's just me aging, but the thing is that I now see it blurry when increased. The reason maybe the "monochrome" vs "polychrome" nature of that font ? (see picture)

Comment on attachment 9290652 [details]
TB102.png

"Correspondents" appears to be polychrome when magnified. "Celine" is monochrome. This is perhaps where the blurriness lies.

(In reply to duparchy from comment #39)

Comment on attachment 9290652 [details]
TB102.png

"Correspondents" appears to be polychrome when magnified. "Celine" is monochrome. This is perhaps where the blurriness lies.

Unfortunately not - I perceive BOTH as blurry.

It's only if there's only black and white in the font and no grey/color-scale that I perceive the fonts as sharp, crisp and easy to read. The blurriness caused by the softening gives me headache so therefore it's an accessibility issue. This fashion of blurry fonts has forced me to block downloadable fonts for many web sites as well to avoid headache and lock to fonts that not blur.

Just updated to version 102.1.2 and the font rendering issue is back.

Setting the below config options doesn't work either
gfx.webrender.force-disabled - true
gfx.webrender.blob-images - false

Fedora 35 (64 bit):
anti-aliasing : enabled
Subpixel rendering: RGB
Hinting: Full

Great job guys!

Just corrected this issue on 3 machines, 2 running Windows 10 and 1 running Linux Mint 21:
On Windows: Thunderbird-->Settings-->General-->Config Editor search for "gfx.text.disable-aa" and toggle it to "true" Restart Thunderbird.

Additionally on Linux Mint:

System settings-->Appearance-->Font Selection

Hinting: full
Antialiasing: None
RGBA Order: RGB

Then go to /etc/fonts/conf.d and delete the files that start with a 10. Open the terminal and type "sudo dpkg-reconfigure fontconfig". Restart Thunderbird. Fonts will look crisp now in both Firefox and Thunderbird.
(Source: https://forums.linuxmint.com/viewtopic.php?t=102666)

Win10x64, TB 102.4.1x64
Issues: blurry text in titles and mailboxes
fixed: Setting "gfx.webrender.blob-images" to false
Thanks.

Using Win 10, 64. Noticed when I updated TB to the latest version (102.5.1) that the blurry text problem returned. I looked in TB Settings->General and Hardware Acceleration was enabled. I disabled this option, restarted TB, and the blurry text problem went away again. Not sure why enabling Hardware Acceleration is suddenly an issue in this update.