Closed Bug 1242229 Opened 8 years ago Closed 8 years ago

fuzzy text rendering

Categories

(Firefox for Android Graveyard :: Toolbar, defect)

43 Branch
defect
Not set
normal

Tracking

(Not tracked)

RESOLVED FIXED
Firefox 48

People

(Reporter: bugzilla, Unassigned)

References

()

Details

Attachments

(3 files)

Hardware: Motorola Moto G (3rd gen), XT1540
Android version: 6.0

This problem (see attached screen shots) happens with various websites, usually after scrolling down, i.e. the bad rendering doesn't immediately happen. Sometimes the fuzzy rendering recovers after a delay, but eventually upon scrolling down more it will stick and never recover.

This problem has happened to me with Firefox of various versions over the past two years, on three different handsets, and Android 4, 5, and 6. So this is not a new problem, almost certainly is a duplicate, but this is reason #1 to just give up on Firefox. It needs to get fixed.

In every case, the problem is never reproducible on the same hardware, OS version, and web site, using Chrome.
Attached image screenshot Firefox
Attached image screenshot Chrome
Attached file android bugreport
This was taken shortly after going to the URL provided, scrolling around a bunch of times to reproduce the problem.
From the screenshot it looks like this is our low-precision painting codepath, which happens when you scroll too fast for the browser to keep up painting the content in high-res. The behaviour is expected while scrolling fast, but once you stop scrolling or slow down scrolling, it should starting painting normally again (not fuzzy). You say in comment 0 that sometimes it gets stuck in the fuzzy mode and doesn't recover - that's definitely a bug, and I don't think we have any duplicates for this issue that have not yet been fixed. (There have been a few in the past but they have all been fixed, as far as I'm aware).

In the logcat portion of the bugreport you attached I see the following line show up a lot, which is probably related to the issue:

01-23 20:28:33.004  8078  9991 D GeckoLayerClient: Aborting update due to viewport not in display-port

It seems like somehow the viewport gets out of sync with the displayport, resulting in the problem. I'm not entirely sure why this happens for you. Some questions to help narrow it down:

- You said that you've seen this issue on different handsets and android versions. Can you confirm that you've seen the "unrecoverable" version of the bug (as opposed to just "temporary" fuzziness) on different handset?
- Do you use Firefox Sync or Accounts to sync your settings across these handsets? If not I'm pretty surprised that you've experienced this issue on multiple handsets; I would have expected more reports if it were a widespread issue.
- If you go to about:config and type in "gfx.displayport" in the search field, do you see any items in the list which have a value other than -1?
- You said that you've seen this issue on different handsets and android versions. Can you confirm that you've seen the "unrecoverable" version of the bug (as opposed to just "temporary" fuzziness) on different handset?

Correct. LG e970 using its stock Android as well as various versions of Cyanogenmod. Same for the Google Galaxy Nexus (the very first one). So I've been seeing this problem for years in various forms. The manifestation on the e970 frequently was a pulsing between the fuzzy and legible, it'd just go back and forth, like it was animated.


- Do you use Firefox Sync or Accounts to sync your settings across these handsets? If not I'm pretty surprised that you've experienced this issue on multiple handsets; I would have expected more reports if it were a widespread issue.

The handsets were used in sequence, not at the same time. The current handset is the 2015 model Moto G, the e970 is retired. But yes I use Firefox Sync between desktop and this Moto G.


- If you go to about:config and type in "gfx.displayport" in the search field, do you see any items in the list which have a value other than -1?

gfx.displayport.strategy
1

All others are -1.
Thanks. The bad news is that your gfx.displayport prefs are all fine, so that's not the problem. This is bad news because it means it won't be easy to track down the problem. The good news is that we are moving to a new scrolling implementation which shouldn't have this problem, because the code in question isn't getting used any more.

The nightly builds (from nightly.mozilla.org) have the new scrolling implementation already enabled, so you should be able to take those for a spin and not have this problem. We're hoping to have that in the release channel as part of Firefox 47 or Firefox 48, but there's some bugs that need to be ironed out first.

Back to the bad news: because this bug is only in the old scrolling implementation (so I believe, anyway) we probably won't spend the time to fix it, because our efforts are better spent fixing bugs in the new implementation and getting that released. If it was a more widespread issue it might be worth the effort to track down and fix for Firefox 45/46 but at this point it doesn't seem that way.
(In reply to Kartikaya Gupta (email:kats@mozilla.com) from comment #4)
You say in comment 0 that sometimes it
> gets stuck in the fuzzy mode and doesn't recover - that's definitely a bug,
> and I don't think we have any duplicates for this issue that have not yet
> been fixed. 

we still have bug 1224970 open
Thanks, I hadn't seen that one. The screenshots on that bug don't look like low-res painting though, they look like the tiles are being stretched, which would be a different underlying root cause.
Sounds reasonable. I'll give a nightly a shot at some point, or 47/48 when available, and report back.

Coincidentally, the ghostery add-on may have resolved this problem. It's only been 48 hours but the problem hasn't happened so far. Maybe this is just because the browser isn't getting bogged down as much with ads and scripts and such.
Severity: blocker → normal
Closing as we shipped APZ in Fennec 48. Please reopen or file a new bug if you are still running into this issue (where the text remains permanently fuzzy) in 48 or up.
Status: NEW → RESOLVED
Closed: 8 years ago
Resolution: --- → FIXED
Target Milestone: --- → Firefox 48
Product: Firefox for Android → Firefox for Android Graveyard
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