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Issue 610460 link

Starred by 6 users

Issue metadata

Status: Available
Owner: ----
Cc:
Components:
EstimatedDays: ----
NextAction: ----
OS: Chrome
Pri: 3
Type: Bug

Blocked on: View detail
issue 414283
issue 456622
issue 485650



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Fractional scroll offfset feature causes jitter during scroll on high-dpi

Project Member Reported by rbyers@chromium.org, May 9 2016

Issue description

Chrome Version       : 51.0.2704.37
OS Version: 8172.25.0
URLs (if applicable) : https://drafts.csswg.org/css-ui-4/

What steps will reproduce the problem?
1. On high-dpi (eg. pixel)
2. Load https://drafts.csswg.org/css-ui-4/
3. Scroll the main document
4. Watch the table of contents on the left

What is the expected result?
What happens instead of that?

Table of contents jitters up and down while scrolling - presumably by a single physical pixel.

Please provide any additional information below. Attach a screenshot if
possible.

UserAgentString: Mozilla/5.0 (X11; CrOS x86_64 8172.25.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.37 Safari/537.36



 

Comment 1 by bokan@chromium.org, May 11 2016

I can't reproduce this on any of Stable (M50), Beta (M51), ToT (M52) on Pixel. Rick, is it still occurring? 

Comment 2 by bokan@chromium.org, May 12 2016

Labels: Needs-Feedback

Comment 3 by rbyers@chromium.org, May 17 2016

Cc: skobes@chromium.org
Labels: -Pri-1 -Type-Bug-Regression Pri-2 Type-Bug
Ah, it's occurring only with --enable-experimental-web-platform-features
So next step is probably to figure out which feature is triggering this.  But that means it's not really a regression and probably not Pri-1.

Comment 4 by skobes@chromium.org, May 17 2016

My money's on FractionalScrollOffsets. :)
Project Member

Comment 5 by sheriffbot@chromium.org, May 18 2016

Labels: -Needs-Feedback Needs-Review
Owner: bokan@chromium.org
Thank you for providing more feedback. Adding requester "bokan@chromium.org" for another review and adding "Needs-Review" label for tracking.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot
Labels: -Pri-2 -Needs-Review Pri-3
Status: Assigned (was: Unconfirmed)
Assigning to bokan@ for now. Lowering priority since this is an experimental feature.

Comment 7 by rbyers@chromium.org, May 19 2016

Blockedon: 485650 414283 456622
Cc: aelias@chromium.org
Summary: Fractional scroll offfset feature causes jitter during scroll on high-dpi (was: Seeing fractional-px jitter during scroll )
Related to issue 414283 and issue 456622.

What we're doing with fractional scrolling isn't completely clear, but it looks like we'll get all the benefits from issue 485650.  So perhaps this blink FractionalScrollOffsets RuntimeEnabledFeature is now dead.  I'm going to demote the feature to 'test' or disabled status just to solve this jitter issue while we figure out what we want to do (there are a non-trivial number of people running with experimental web platform features enabled).

Comment 8 by e...@chromium.org, May 19 2016

Sounds like a good plan. Thanks Rick.
Project Member

Comment 9 by bugdroid1@chromium.org, May 27 2016

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/8591ae927ed0dfafd977121533265d5cbc88a9fe

commit 8591ae927ed0dfafd977121533265d5cbc88a9fe
Author: rbyers <rbyers@chromium.org>
Date: Fri May 27 15:54:36 2016

Disable fractional scroll feature by default

This feature is in a half-finished state and has regressed at some point.
The primary use case will soon be addressed by bug 485650, we need to
figure out what to do about the remaining use cases (eg. scroll while
pinch-zoomed).  In the interim, don't enable / test the partial code
we have for this in blink unless the feature is explicitly enabled.
I left support in the tests (though not the expected output files)
so that we can easily find the affected tests later when we either
resume work on the feature or remove it entirely.

BUG=610460, 456622

Review-Url: https://codereview.chromium.org/2005193005
Cr-Commit-Position: refs/heads/master@{#396476}

[modify] https://crrev.com/8591ae927ed0dfafd977121533265d5cbc88a9fe/third_party/WebKit/LayoutTests/fast/events/scale-and-scroll-div-expected.txt
[modify] https://crrev.com/8591ae927ed0dfafd977121533265d5cbc88a9fe/third_party/WebKit/LayoutTests/fast/events/scale-and-scroll-div.html
[modify] https://crrev.com/8591ae927ed0dfafd977121533265d5cbc88a9fe/third_party/WebKit/LayoutTests/fast/events/touch/gesture/touch-gesture-scroll-div-scaled-expected.txt
[modify] https://crrev.com/8591ae927ed0dfafd977121533265d5cbc88a9fe/third_party/WebKit/LayoutTests/fast/events/touch/gesture/touch-gesture-scroll-div-scaled.html
[modify] https://crrev.com/8591ae927ed0dfafd977121533265d5cbc88a9fe/third_party/WebKit/LayoutTests/fast/scrolling/fractional-scroll-offset-document-expected.txt
[modify] https://crrev.com/8591ae927ed0dfafd977121533265d5cbc88a9fe/third_party/WebKit/LayoutTests/fast/scrolling/fractional-scroll-offset-document.html
[modify] https://crrev.com/8591ae927ed0dfafd977121533265d5cbc88a9fe/third_party/WebKit/LayoutTests/fast/scrolling/scrolling-apis-subpixel-expected.txt
[modify] https://crrev.com/8591ae927ed0dfafd977121533265d5cbc88a9fe/third_party/WebKit/LayoutTests/fast/scrolling/scrolling-apis-subpixel.html
[modify] https://crrev.com/8591ae927ed0dfafd977121533265d5cbc88a9fe/third_party/WebKit/Source/platform/RuntimeEnabledFeatures.in
[modify] https://crrev.com/8591ae927ed0dfafd977121533265d5cbc88a9fe/third_party/WebKit/Source/web/tests/ScrollingCoordinatorTest.cpp
[modify] https://crrev.com/8591ae927ed0dfafd977121533265d5cbc88a9fe/third_party/WebKit/Source/web/tests/VisualViewportTest.cpp

Comment 10 by bokan@chromium.org, May 11 2017

Owner: petermayo@chromium.org
Cc: -aelias@chromium.org petermayo@chromium.org
Owner: ----
Status: Available (was: Assigned)

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