Re: Issue 226753 in chromium: dithering in images/gradients causes flicker on MacBook Pro (1680x1050)

[chro...@googlecode.com]

Updates:
Summary: dithering in images/gradients causes flicker on MacBook Pro
(1680x1050)
Labels: -Cr-Blink-CSS Cr-Internals-Skia

Comment #41 on issue 226753 by mikelawt...@chromium.org: dithering in
images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

For those who can see the flickering, please visit
http://www.lagom.nl/lcd-test/inversion.php and look at the test images
there.

I see horrible flickering in 4a and 4b (depending on vertical scroll
position) on my late 2010 Macbook Air. It looks perfect on my Chromebook
Pixel.

This is not gradient specific, it is to do with the dithering that was
introduced as a fix to the complaint filed in
https://code.google.com/p/chromium/issues/detail?id=41756.

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[chro...@googlecode.com]

Comment #42 on issue 226753 by anonymous84327: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

@mikel...@chromium.org I don't see any problem with the link you posted.
It looks exactly the same on all browsers. There's no flickering.

The issue is with CSS gradients, not with images.
That can be confirmed by displaying the following image-based gradient:
http://www.lagom.nl/lcd-test/gradient.php#gradient-h.png
which looks OK also on Chrome.

Please read all the information we provided you with before replying with
non-related stuff. Thank you.

[chro...@googlecode.com]

Comment #43 on issue 226753 by mikelawt...@chromium.org: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

@anonymous84327 - there's no need to be rude. I did read everything, and
was agreeing with comment #28.

I actually do see some flickering on
http://www.lagom.nl/lcd-test/gradient.php#gradient-h.png on my 2010 Macbook
Air's LCD display. It flickers no matter what image display program I use.
Same (for me) with the pixel patterns I posted earlier.

Some pixel patterns tickle some graphics cards/displays to behave like
this. Searching for 'macbook flicker' or even 'lcd flicker' turns up
countless examples of this.

[chro...@googlecode.com]

Comment #45 on issue 226753 by neilqu...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

I'm still seeing this problem on a 2011 macbook pro 13" running 10.6.8 and
the latest version of chrome.

I've seen this across multiple websites, and switching to safari has always
fixed the issue for those sites.

[chro...@googlecode.com]

Comment #46 on issue 226753 by neilqu...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

The grey header on this site, in particular, is an example of the problem:

http://www.pcworld.com/article/2045885/email-security-strongest-from-social-media-report-reveals.html

[chro...@googlecode.com]

Comment #47 on issue 226753 by renat...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

Same happens here (Macbook Pro Mid June 2012). Only when using Chrome.
Safari is ok.

Another site example that shows that problem: http://bitbucket.org (the
blue background)

[chro...@googlecode.com]

Comment #48 on issue 226753 by dakinsl...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

Experiencing the same issue.

[chro...@googlecode.com]

Comment #49 on issue 226753 by acerfe...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

Same here. I'm on a Macbook Pro mid june 2012 model running 10.8.4. I'm
using Chrome 28.0.1500.95 and the problem is still there...

As others have said the problem is on Chrome only, sites with gradients on
other browsers like Safari and Firefox works as they should.

[chro...@googlecode.com]

Comment #50 on issue 226753 by ahmadA...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

I have the same problem with Ghrome, another example is
http://www.apple.com/ and http://codepen.io/juliangarnier/pen/hzDAF code
editor

[chro...@googlecode.com]

Comment #51 on issue 226753 by maciekp....@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

Same problem with Chrome 29.0.1547.57 / OSX 10.7.5 / 13" late 2011 MBP. The
flickering is visible only on the laptop's screen, not on an external
Cinema Display.

[chro...@googlecode.com]

Comment #52 on issue 226753 by marijn.v...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

Same happens for me on Chrome 31.0.1622.0 dev / OS X 10.8.4 / 15" MBP early
2011. The problem shows up a lot more when only using a single display, and
the built-in Intel HD Graphics 3000 is active. The AMD Radeon 5750M shows
the effect less.

Another site which shows the issue: https://panic.com/~wade/picker/

[chro...@googlecode.com]

Comment #53 on issue 226753 by marijn.v...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

Same happens for me on Chrome 31.0.1622.0 dev / OS X 10.8.4 / 15" MBP early
2011. The problem shows up a lot more when only using a single display, and

the built-in Intel HD Graphics 3000 is active. The AMD Radeon 6750M shows

[chro...@googlecode.com]

Comment #54 on issue 226753 by tuomas.s...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

Here's what the test page
http://phaseone.me/internets/chromium_issue_226753/ looks like on (my)
different browsers on OSX 10.8.4:

- Chrome 29: "symmetric" dithering
- Safari 6: no dithering at all (visible bands)
- Firefox 23: (quite) random-looking dithering

I attached a 4x zoomed screenshot of a part of the page on different
browsers, with enhanced contrast. Note how Chrome's dithering patterns
closely resembles some of the lagom.nl tests.

At least on my 2010 MBA display, Firefox is clearly the winner here: no
flickering, smooth gradient.



Attachments:
chrome-firefox-safari.png 15.0 KB

[chro...@googlecode.com]

Comment #55 on issue 226753 by federico...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

I can confirm this problem is still present on MacBook Pro early 2011
1680x1050.
Is there any way we can ask google/apple to fix this?
Today many web sites are using gradients and all of them cause boring
flickering.

[chro...@googlecode.com]

Comment #56 on issue 226753 by jlaw...@sidekick.com.au: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

Still happening. Chrome 31.0.1650.63

[chro...@googlecode.com]

Comment #57 on issue 226753 by dougie.r...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

I'm seeing this issue on a Mid 2012 MacBook Pro. My graphics configuration
from System Profile follows:

Intel HD Graphics 4000:

Chipset Model: Intel HD Graphics 4000
Type: GPU
Bus: Built-In
VRAM (Total): 1024 MB
Vendor: Intel (0x8086)
Device ID: 0x0166
Revision ID: 0x0009
gMux Version: 1.9.23
Displays:
Color LCD:
Display Type: LCD
Resolution: 1680 x 1050
Pixel Depth: 32-Bit Color (ARGB8888)
Main Display: Yes
Mirror: Off
Online: Yes
Built-In: Yes

[chro...@googlecode.com]

Comment #59 on issue 226753 by nowhid...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

Just updated chrome to Version 33.0.1750.149 (disabled all plugins) can see
it happening on the bootstrap gradient on my Macbook Pro 10.9.2 Late 2011

AMD Radeon HD 6750M:

Chipset Model: AMD Radeon HD 6750M
Type: GPU
Bus: PCIe
PCIe Lane Width: x8
VRAM (Total): 1024 MB
Vendor: ATI (0x1002)
Device ID: 0x6741
Revision ID: 0x0000
ROM Revision: 113-C0170L-573
gMux Version: 1.9.23
EFI Driver Version: 01.00.573

Intel HD Graphics 3000:

Chipset Model: Intel HD Graphics 3000
Type: GPU
Bus: Built-In
VRAM (Total): 512 MB
Vendor: Intel (0x8086)
Device ID: 0x0126

[chro...@googlecode.com]

Comment #60 on issue 226753 by dieterbl...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

I have this issue too.
MBP mavericks with chrome latest version (stable channel)

[chro...@googlecode.com]

Comment #61 on issue 226753 by quydhn...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

It's same here on my Mac 10.9.2 with chrome Version 33.0.1750.152.
it happen with any web page use css to render background gradient.
it's only on chrome. safari or firefox, opera work fine!

[chro...@googlecode.com]

Comment #62 on issue 226753 by thomas.l...@produktmacher.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

I found out that the severity of the dithering depends on wether the
discrete (AMD) or the integrated (intel) graphics chip is used. being
slightly less severe running on the former.
rregards, thomas

[chro...@googlecode.com]

Comment #64 on issue 226753 by federico...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

For me it seems like this has been finally fixed. Today I see no flickering
on gradients for the first time.
Macbook pro early2011 15inch

[chro...@googlecode.com]

Comment #65 on issue 226753 by thomas.l...@produktmacher.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

@federico: I guess you are running on the discrete graphics chip (nvida or
amd) where the issue is not that prominently visible.

[chro...@googlecode.com]

Comment #66 on issue 226753 by caslivk...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

The original css I provided still exhibits the behavior.

https://casl-d02.andrew.cmu.edu/test/test.html

Indeed, it it much more prominent when the Intel integrated graphics are
in-use.

Chrome: 33.0.1750.152
OS X: 10.9.2

[chro...@googlecode.com]

Comment #67 on issue 226753 by federico...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

@thomas unfortunately you're right, I was using the nvidia card.
Sorry for giving you false hopes, my mac automatically switches between the
two graphics and I wasn't aware which card i was using

[chro...@googlecode.com]

Comment #68 on issue 226753 by quydhnni: dithering in images/gradients

causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

it happen on HDxxx intel graphic.

[chro...@googlecode.com]

Comment #69 on issue 226753 by k.barbi...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

Having the same problem in Chrome. Flickering appears when the gradient's
surface is large (width:960px; height:300px;). Safari doesn't flicker but
displays a banded gradient. Firefox works fine.

[chro...@googlecode.com]

Comment #70 on issue 226753 by ntfo...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

I can confirm that this issue only occurs on the Intel HD graphics card. If
your mac is running 2 graphics cards inside it, you can go into the energy
saver preferences and disable automatic graphics switching to resolve this
issue. It seems like it's more of an issue with the card than it is with
Chrome, as I've seen other apps exhibit similar behavior.

[chro...@googlecode.com]

Comment #71 on issue 226753 by anonymous84327: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

@70 ntf...@gmail.com:

> "It seems like it's more of an issue with the card than it is with Chrome"

Shut the fuck up, wherever Chrome fails to render a proper gradient,
Firefox/IE/Safari succeed.

Sincerely,
Anne

[chro...@googlecode.com]

Comment #72 on issue 226753 by ntfo...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

As far as I'm concerned, Safari isn't rendering the gradient properly at
all. Safari's "fix" is to reduce the gradient to color bands, which doesn't
accurately reproduce the gradient and looks extremely ugly, so that's a
fail in my book.


As for IE, this issue is prevalent to Mac OSX, which IE doesn't run on, so
there's no argument there.




In addition, as I said, Chrome isn't the only Mac app that has this issue
rendering gradients, and by switching to a different card, the problem
fixes itself system-wide. Not only that, but I've tested the issue on other
Macs running the same version of Chrome, and they don't have this problem.
So yeah, Firefox is the only browser that doesn't fail at rendering
gradients. Thanks for your kind words, though. 

[chro...@googlecode.com]

Comment #73 on issue 226753 by anonymous84327: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

@72 ntf...@gmail.com

> "As for IE, this issue is prevalent to Mac OSX, which IE doesn't run on,
> so there's no argument there."

I'm having this issue on Windows 7. As I said, shut the fuck up with your
misinformation. This is a Chrome issue. Safari-Windows renders gradients as
good as Firefox and as good as IE.

[chro...@googlecode.com]

Comment #74 on issue 226753 by ntfo...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

That's great, and I apologize for my mistake. However, we're talking about
2 different operating systems, which means there'll be 2 different fixes.
There's no need to get upset over one issue; I'm chalking it up to the fact
that there may be more than one factor contributing to the problem
depending on what system you're running on, and what your setup looks
like. --
Noel Forté
Designer

(339)-227-2699
ntf...@gmail.com
http://noelforte.com

[chro...@googlecode.com]

Comment #76 on issue 226753 by sankalps...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

Yes, I happened to search the net for the issue on why it was happening on
my MacBook Pro 13' and then found this post. So I guess I am not the only
one and seems like a Chrome issue. I am not able to see this problem in
Firefox or Safari.

I hope this gets fixed soon. I do intensive Web Designing and this is a
major hinderance.

[chro...@googlecode.com]

Comment #77 on issue 226753 by mar...@wave.ee: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

Having same issue on Macbook pro 13'. In Safari can't reproduce. Good that
my screen is not broken as I was afraid. :)

[chro...@googlecode.com]

Comment #78 on issue 226753 by jimm...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

I first started having this problem about 3 weeks ago. Since then I've had
my macbook pro 13" mid 2011 screen replaced in an attempt to fix it. It of
course didn't solve the problem and I was about to have the macbook pro's
logic board replaced, luckily I found this bug report first!

I've just come from the apple store and explained that other people are
having this issue, so it appears to be an issue with all the macbook pro
13" none-retina displays that chrome is exposing via it's gradient
rendering. The apple guy agreed and said there is nothing they can do.

Here are some screen shots I've collected which I've been showing to the
Apple store

Attachments:
flickering site.png 10.8 KB
flickering greys.png 53.3 KB
flickering greys 2.png 65.9 KB
Screen Shot 2014-07-30 at 18.10.30.png 25.7 KB
flickering grey.png 34.6 KB
revealjs.png 263 KB
bg.png 10.8 KB

[chro...@googlecode.com]

Comment #79 on issue 226753 by e...@bovie.me: dithering in images/gradients

causes flicker on MacBook Pro (1680x1050)
http://code.google.com/p/chromium/issues/detail?id=226753

We're aware of the problem and its symptoms. This issue won't be fixed
until the other blocking issues in the Skia core are resolved. Basically
the whole gradient rendering system has to be rebased. Nobody wants to take
on these issues, and it's been 4, yes 4, years since the underlying bug has
been active.


Please avoid "me too" responses unless you are asked for some more examples
at this point, as messages get blasted to everyone that starred this issue.
--
Sent from Mailbox

[chro...@googlecode.com]

Comment #80 on issue 226753 by hannu.p...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)

https://code.google.com/p/chromium/issues/detail?id=226753

Just to mix this soup a bit to take in consideration

I have been trying to fight with Apple last half an year to fix my laptop.
It's having flickering issues when gradients are involved. I first thought
that it is problem with Chrome as many here seem to think. But, after
taking screenshot of the webpage having this issue and accidentally
watching it later in fullscreen mode... I recognized that it was flickering
too. After spending some time investigating, it wasn't related to any
specific application. Just the colors and their contrast and via them to
gradients.

After four months Apple said that they have got "some" reports about
flickering and it's so slight that it is in specifications. I just don't
approve that answer as it isn't just slight flickering. They asked me to
send screenshots (again) and make video of it. Video is having noise and
other distortion as almost always when recording screens.. but flickering
is still highly recognizable and Apple admitted that they can see it from
video. Links below for some screenshots that have in 1:1 ratio flickering
issues with 2011, 2012 and 2013 Macbook Pro 13" models without retina
display. Also with Macbook Air 2012 have some issues. It depends on model
how strong flickering is. Not sure about other MBP models, like 15" but at
least iMac has similar issues with current and older ones, but not as heavy
one as I do have.


Download screenshot, see it on 1:1 ratio in Preview or in another
application (with MBP). Video should be clear enough to see in any
computer: vertical lines moving and flickering around green gradient.

Screenshot 1:
https://www.dropbox.com/s/ok9x8fr5q89so4b/Screenshot%202014-06-17%2023.23.43.png?dl=0
Screenshot 2:
https://www.dropbox.com/s/c4uqao8kp98678h/Screenshot%202014-04-13%2017.15.42.png?dl=0
Screenshot 3:
https://www.dropbox.com/s/i2gpm0t4xq5vzsf/Screenshot%202014-05-05%2018.59.55.png?dl=0
Video: https://www.dropbox.com/s/g3px4wx1r6dclii/3_SLR_olympus.AVI?dl=0


I will continue arguing with Apple, but they are keeping saying that this
issue is "expected" and there are nothing wrong with screens as engineers
are saying it is inside specifications... "hurray". Even my reseller thinks
that it is crappy piece of screen, but they are not going to give money
back because Apple says to them that it has nothing wrong with it. First
repair service provided was convinced that it must be repaired. Second one
where AppleCare asked me to send laptop said same, until Apple stated that
it's "expected" as same issue occurs with all new computers in same MBP 13"
product line.



Regards,
Hannu Piki

[chro...@googlecode.com]

Comment #82 on issue 226753 by wanz...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

Also have this problem with my macbook pro 13" 2012 @ 1280x800 tested
multiple websites - all gradients that are "big" are flickering. codepen.io
background, getbootstrap.com background... and some more.

Chrome 37.0.2062.124
Mac OS X 10.9.5

Also in Chrome 39.0.2171.2 canary (64-bit)

Firefox, Safari and Opera the gradient works great.

[chro...@googlecode.com]

Comment #83 on issue 226753 by wanz...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

Also have this problem with my macbook pro 13" 2012 @ 1280x800 tested
multiple websites - all gradients that are "big" are flickering. codepen.io
background, getbootstrap.com background... and some more.

Chrome 37.0.2062.124
Mac OS X 10.9.5

Also in Chrome 39.0.2171.2 canary (64-bit)

Firefox, Safari and Opera the gradient works great.

Video here: http://youtu.be/hFg1usHdktU (Chrome/Safari comparison + system
info +date)

[chro...@googlecode.com]

Comment #84 on issue 226753 by tomasz.n...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

HI there,
so i have this issue, and dunno what is going on, i have MB PRO mid 2012 -
on external monitor Chrome show gradient pages nicely, on builtin MB screen
everything flickering.

On my colleague retina MB everything works like a charm ! :(

So the question is, where is issue - at the side of MB screen, or chrome
browser ?

[chro...@googlecode.com]

Comment #85 on issue 226753 by mikewein...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

I have a MacBook Pro (15-inch, Early 2011) running Yosemite (Mac OS X:
10.10.0) and Chrome 39.0.2171.62 beta.

I get flickering with some backgrounds, but only when the integrated
graphics card is in use. If I use gfxCardStatus to switch to discrete
graphics, it works fine.

[chro...@googlecode.com]

Comment #86 on issue 226753 by ddehg...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

I have this issues as well. I can clearly see screen flickering in Chrome
38 but not is Safari.

here is an example page:

http://lab.hakim.se/reveal-js/#/


Mac Book Pro 17'' Early 2011
Intel HD Graphics 3000 512 MB
OSX 10.10.1 (14B25)

[chro...@googlecode.com]

Comment #87 on issue 226753 by pedro.sa...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

I'm also experiencing heavy flickering on the URL provided by the OP:
https://casl-d02.andrew.cmu.edu/test/test.html.

As for the reveal.js page (http://lab.hakim.se/reveal-js) I'm not
experience any heavy or visible flickering.

I have Chrome 39.0.2171.95 and I'm on a MacBook Pro (13-inch, Mid 2012)
with Intel HD Graphics 4000 1024 MB graphics.

[chro...@googlecode.com]

Comment #88 on issue 226753 by pedro.santa: dithering in images/gradients

causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

Also I'm on Mac OS Yosemite 10.10.1 (14B25).

[chro...@googlecode.com]

Comment #89 on issue 226753 by wanz...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

So this issue exists nearly 2 Years. When could it be fixed? It is really
annoying while surfing on Websites with big gradients.
The issue still exists on my MacBook Pro 13" Mod 2012 with chrome 40 and
yosemite

[chro...@googlecode.com]

Comment #90 on issue 226753 by wanz...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

So this bug is getting old. 14 versions later and still no news about it.
Or is there a fix or solution for this?! It is very annoying on the daily
usage.

[chro...@googlecode.com]

Comment #91 on issue 226753 by caslivk...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

I don't expect a fix. As I understand it. The issue deals with the
implementation of the Intel driver.

[chro...@googlecode.com]

Comment #92 on issue 226753 by luka.rad...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

can we do something about this to get them fix it? and who is them to blame
on? Apple, Google, Intel?

[chro...@googlecode.com]

Comment #94 on issue 226753 by srinivas...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

chrome 39 version images are working fine but 41 version directly not
displaying at that time we press backspace button images are displaying in
classic asp.
chrome 39 version images are working fine

[chro...@googlecode.com]

Comment #95 on issue 226753 by thola...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

I noticed if you use the "IE Tab Helper" extension to force pages to
display as if in IE, images look fine.

[chro...@googlecode.com]

Comment #96 on issue 226753 by luka.rad...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

i actually changed the resolution for my macbook pro late 2012 13" to first
lower value and the flickering is gone. i read something about refresh rate
bug on LCD monitors and i tried changing the resolution and it worked,
flickering issue is gone. now, obviously, this is a crappy monitor made for
my macbook and i think apple is responsible for this. any suggestions what
to do next? i dont think i want to keep this resolution, so please advise
what can be done.

[chro...@googlecode.com]

Comment #99 on issue 226753 by mikelawt...@chromium.org: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

My comment back in #41 is still my understanding of this issue. Skia
dithers gradients, while other browsers use solid colors. We dither to
avoid the banding effect you can get with solid colors, but ditheriing can
lead to flickering on some LCD screens. My MacBook Air (13-inch, Early
2014) still has the flickering effect on the example URL from the original
report (https://casl-d02.andrew.cmu.edu/test/test.html).

What needs to happen is we need to decide whether we will continue to
dither gradients or not.

[chro...@googlecode.com]

Updates:
Status: Assigned
Owner: fma...@chromium.org

Comment #100 on issue 226753 by chri...@chromium.org: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

Florin, can you consult with Skia as necessary and make a call on this?

[chro...@googlecode.com]

Comment #101 on issue 226753 by luka.rad...@gmail.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

Im so happy, i think im gonna cry

[chro...@googlecode.com]

Updates:
Cc: bsalo...@chromium.org robertph...@chromium.org

Comment #102 on issue 226753 by r...@google.com: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

(No comment was entered for this change.)

[chro...@googlecode.com]

Updates:
Labels: -M-46 M-47

Comment #103 on issue 226753 by p...@chromium.org: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

This is the most-starred paint bug, would be great to have it fixed in 47.

[chro...@googlecode.com]

Updates:
Owner: r...@google.com
Cc: fma...@chromium.org

Comment #104 on issue 226753 by fma...@chromium.org: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

Disabling gradient dithering unconditionally would result in significant
quality degradation across the board, for what sounds like an MBP
driver/chipset bug. See attached screenshots with the gradient from
https://casl-d02.andrew.cmu.edu/test/test.html rendered in Chrome vs.
Safari.

A couple of alternatives

1) surface a user setting for disabling dithering manually (Mac-only?)

2) try to detect vulnerable configurations (???) and disable dithering
automatically


These are all policy changes which don't belong in Skia, but they do
require a Skia mechanism for disabling gradient dithering. We have
SkPaint::kDither_Flag, although I don't think we observe it for gradients.

Attachments:
gradient_dithering.png 8.0 KB
gradient_no_dithering.png 5.7 KB

[chro...@googlecode.com]

Updates:
Owner: chri...@chromium.org

Comment #105 on issue 226753 by chri...@chromium.org: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

(No comment was entered for this change.)

[chro...@googlecode.com]

Comment #107 on issue 226753 by p...@chromium.org: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

Issue 547305 has been merged into this issue.

[chro...@googlecode.com]

Updates:
Owner: ccam...@chromium.org

Comment #110 on issue 226753 by chri...@chromium.org: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

Chris C., see comment 108. When you are in MTV next could you grab the
machine manoranjanr@ reproed on and check its hardware? Or check out
chrome://gpu in comment 108 and see if there is anything that seems
actionable to you?

[chro...@googlecode.com]

Comment #111 on issue 226753 by ccam...@chromium.org: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

I got the laptop and I'll bring it to the other office. It's definitely a
problem with the LCD not being able to handle regular dithering problems --
the issue occurs even outside of Chrome.

Interestingly, Safari seems to know that it is "not safe" to dither on that
monitor, and creates banding artifacts, but knows that it is "safe" on my
retina Macbook Pro, and allows dithering.

I'm going to try some external monitors to see if how it behaves there. A
few ideas
- it would be great if there is some "LCD doesn't support regular
dithering" flag that we can read from the system
- we could disable dithering only on non-retina non-external LCDs (seems
heavy-handed)
- we could investigate implementing a non-regular dithering scheme

[chro...@googlecode.com]

Comment #112 on issue 226753 by ccam...@chromium.org: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

Sorry, #111 was a lie -- Safari still bands on the retina Macbook pro. So
they don't know which monitors are safe and which aren't.

[chro...@googlecode.com]

Updates:
Owner: r...@chromium.org

Comment #113 on issue 226753 by ccam...@chromium.org: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

The problem here is that some displays flicker when you display a dithered
gradient on them, if that dithering is computed using ordered dithering,
with a very regular threshold matrix.

In particular, in SkLinearGradient::LinearGradientContext::shade4_clamp, we
use the use the 2x2 dithering matrix
const float ditherCell[] = {
1/8.0f, 5/8.0f,
7/8.0f, 3/8.0f,
};

The solution is to use a larger and less regular dithering matrix. You can
see the sort of results for halftoning on the Wikipeda page on dithering at
https://en.wikipedia.org/wiki/Dither#Algorithms
We're currently doing something very similar to the Bayer matrix, and we
can probably get away with doing a Random matrix, or some larger and less
regular matrix.

Sending over to reed@ to have someone in Skia take a look. This shouldn't
be very hard to fix (it's not as easy as just changing the matrix above,
but not too much more involved).

[chro...@googlecode.com]

Comment #117 on issue 226753 by chri...@chromium.org: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

Ok. Chris Cameron has one MacBook here in SFO...one option could be for you
to give us a sample SKia patch which tries to match whatever Firefox may be
doing? Then one of us could try it on the MacBook in question.

[chro...@googlecode.com]

Comment #118 on issue 226753 by fma...@chromium.org: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

Some good info I found on LCD inversion (which I think is behind this
issue): http://www.techmind.org/lcd/

My takeaway is that all LCD panels are vulnerable to inversion patterns, so
I'm also concerned about the generality of our fix. Maybe we can use
existing info to choose an unlikely cell configuration.

[chro...@googlecode.com]

Comment #121 on issue 226753 by ccam...@chromium.org: dithering in

images/gradients causes flicker on MacBook Pro (1680x1050)
https://code.google.com/p/chromium/issues/detail?id=226753

(Getting shipping details offline).