2052019 - openmhz.com dropdowns blurry with layout.disable-pixel-alignment=true

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect)

Description

[Sam Johnson]

When visiting https://openmhz.com/system/chi_cta a modal appears with a dropdown menu inside of it. With layout.disable-pixel-alignment=true, this dropdown is blurry. Other dropdowns within this webpage are also all blurry, such as within the "Filter" modal.

If I set layout.disable-pixel-alignment=false, the dropdowns become clear again.

Comment 1

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 2048146

:hiro, since you are the author of the regressor, bug 2048146, could you take a look? Also, could you set the severity field?

For more information, please visit BugBot documentation.

Comment 2

[Hiroyuki Ikezoe (:hiro)]

Thanks for reporting. Would you mind trying mozregression with layout.disable-pixel-alignment=true? Thanks!

Comment 3

[Hiroyuki Ikezoe (:hiro)]

This is also an identity transform related problem. There's transfrom: rotate(0) style on div.ui.selection.dropdown element which is an ancestor of blurry texts.

CCing Glenn.

Note that I am able to see the issue on the latest nightly so it's including bug 2050692 fix.

Comment 4

[Sam Johnson]

(In reply to Hiroyuki Ikezoe (:hiro) from comment #2)

Thanks for reporting. Would you mind trying mozregression with layout.disable-pixel-alignment=true? Thanks!

Sure thing, mozregression points to bug 2001524.

Comment 5

[Hiroyuki Ikezoe (:hiro)]

Thanks! Moving to the same component of bug 2001524.

Comment 6

[Glenn Watson [:gw]]

This is caused by the perspective element present on the drop-down, followed by an off-screen filter (opacity). WR conservatively assumes if perspective is present it shouldn't try snapping. However in this case the content is all at z=0 with no preserve-3d, so we should be able to allow snapping here.

Comment 7

[Glenn Watson [:gw]]

Attachment: Bug 2052019 - Keep text device-snapped under a flat perspective

A perspective ancestor put an m34 term in the text transform, so
has_perspective_component() forced glyphs onto the local-raster path and blurred
them at fractional device offsets. For coplanar z=0 content that perspective is
affine, so add has_2d_plane_perspective() (m14/m24 only) and use it instead:
flat perspectives stay device-snapped, real 3D still use local raster.

Comment 8

[Pulsebot]

Pushed by [e-mail]:
https://github.com/mozilla-firefox/firefox/commit/c1f8b689c9bb
https://hg.mozilla.org/integration/autoland/rev/3e6e3f4a1f86
Keep text device-snapped under a flat perspective r=gfx-reviewers,lsalzman

Comment 9

[pstanciu]

https://hg.mozilla.org/mozilla-central/rev/3e6e3f4a1f86

Comment 10

[BMO Github Automation]

Authored by Glenn Watson
https://github.com/mozilla/enterprise-firefox/commit/c1f8b689c9bb4bb94505dc33e0e549c57e3dd274
[enterprise-main] Bug 2052019 - Keep text device-snapped under a flat perspective r=gfx-reviewers,lsalzman