Closed Bug 1408669 Opened 7 years ago Closed 7 years ago

strange font rendering issue

Categories

(Core :: Graphics: Layers, defect)

58 Branch
defect
Not set
normal

Tracking

()

RESOLVED DUPLICATE of bug 1408566

People

(Reporter: lukas.magi, Assigned: dvander)

References

Details

Attachments

(2 files)

Attached image Capture.JPG
User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:58.0) Gecko/20100101 Firefox/58.0
Build ID: 20171014100219

Steps to reproduce:

chatting via https://web.telegram.org


Actual results:

Rendering of the text got bold without being bold in certain areas of the screen. (see screenshot)


Expected results:

should not be bold
Please make sure you have the latest graphics driver: https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration
Component: Untriaged → Graphics: Text
Product: Firefox → Core
(In reply to Kohei Yoshino [:kohei] from comment #1)
> Please make sure you have the latest graphics driver:
> https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-
> acceleration

I have tested it under:
- Windows 10 1703 Build 15063.674 - Intel HD Graphics 620 - Driver Version 21.20.16.4550 - this is the latest supported driver from Lenovo
- Windows 10 1703 Insider Preview Build 17017 - VMware 3D Graphics Driver from VMware vsphere 6.5U1
- Archlinux (latest Build) with KDE 5.11 (latest Build) and the latest firefox-nightly build from aur (Build from 2017-10-05) - xf86-video-intel 1:2.99.917+794+ga384b462-1 (latest xorg intel graphics driver) - here it is a little bit less appearing but also noticeable

By deactivating graphics acceleration the problem disappears, but that can't be the solution.

One and only under macOS 10.13 (intel graphics) the problem doesn't exist with the acceleration activated.
I can verify this behavior on the latest Windows 10 on the latest nvidia drivers 387.92.

I only notice it on the Telegram web client when using Firefox versions 57b8 and latest Firefox nightly.  No font problem when using 56 stable.
The JPEG compression of the screenshot is a bit unfortunate, it makes it harder to tell exactly what is happening with the rendering. However, it looks to me like the difference between the "lighter" text in the upper part of the screenshot and the "bolder" text below is that the former is rendered with grayscale antialiasing, and the latter has subpixel (ClearType) AA, which tends to make many fonts look heavier.

(For future reference, PNG is a better choice for screenshots. If you could attach a fresh screenshot in PNG format -- not the already-JPEG-compressed one converted to PNG, which won't clean it up -- that would be helpful.)

Note that the "bold" effect begins at a particular level, part-way through a text line, which suggests perhaps we're seeing a boundary between rendering tiles, or perhaps an area that was repainted after invalidation, and the painting pipeline chose different rendering options for some reason.
Attached image Capture_2017-10_16.PNG
Ok thank you, I will post future pictures in png.

As it is visible in the 2nd picture the boldness of the text doesn't follow a direction, but always like a gradient in a picture modulation program.

Maybe the html/css settings for this area help:
font: 13px/18px Tahoma
font-feature-setting: normal
font-kerning: auto
Thanks for the added screenshot. OK, again the bad rendering is a specific rectangular area of the screen (rather than a specific run of text), implying that the problem is with the painting of a certain graphics tile or repaint region.

It appears from this image that both the "good" and "bad" text do have ClearType (subpixel) antialiasing; but in the bad region, it is much too intense, as though there is a serious error in the gamma used or something like that.
Further I have to mention that the site gets unstable and hangs when I try to select on one of the messages.
Then it is also not possible to mark the text anymore.

Maybe there is also an issue in the code of telegram's website.
It's interesting that the issue only occurs in version newer than the stable build.
See Also: → 1408796
disabling AL fixes the problem. dvander, could you please take a look.
Flags: needinfo?(dvander)
Component: Graphics: Text → Graphics: Layers
This is probably bug 1408566 - assigning in the meantime.
Assignee: nobody → dvander
Status: UNCONFIRMED → ASSIGNED
Ever confirmed: true
Flags: needinfo?(dvander)
(In reply to David Anderson [:dvander] from comment #11)
> Can someone try a Windows build from
> https://tools.taskcluster.net/index/artifacts/gecko.v2.try.revision.
> 57b3ba2d1c13b7ded8b9c2a9d9d8b6c415722075.firefox to see if it resolves this
> problem?

that build resolves the problem.
Thanks! Duping to bug 1408566 then.
Status: ASSIGNED → RESOLVED
Closed: 7 years ago
Resolution: --- → DUPLICATE
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