1529260 - Text snapping more noticeable after animation on https://git.news/

Status: RESOLVED FIXED

(Core :: Graphics: WebRender, defect, P3)

Description

[Jeff Muizelaar [:jrmuizel]]

Also notice a small amount of snapping in Safari but it's less noticeable than in Firefox.

Comment 1

[Jeff Muizelaar [:jrmuizel]]

Lee, do you see what I'm talking about here? Can we do better?

Comment 2

[Lee Salzman [:lsalzman]]

Andrew, do your recent snapping changes help this any?

Comment 3

[Andrew Osmond [:aosmond] (he/him)]

Attachment: Bug 1529260 - Match shader and CPU glyph rasterization logic for glyphs in local space.

This patch makes the CPU side incorporate the raster scale when
calculating the subpixel position of a glyph. It also makes the shader
side not include the glyph scale factor when recalculating the glyph
position (since it was not known/used when determining the subpixel
position in the first place). This makes the subpixel position stable
when we transition between Screen and Local(raster_scale) spaces.

Comment 4

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/9bd4120bc977
Match shader and CPU glyph rasterization logic for glyphs in local space. r=lsalzman

Comment 5

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/9bd4120bc977

Comment 7

[Andrew Osmond [:aosmond] (he/him)]

Comment on attachment 9126544 [details]
Bug 1529260 - Match shader and CPU glyph rasterization logic for glyphs in local space.

Beta/Release Uplift Approval Request

• User impact if declined: Glyphs may wiggle / be placed on the wrong subpixel position during animations
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): It is a minor change to how to we place glyphs when animated with WebRender. It is already drawn at the wrong position, so it is unlikely to get worse.
• String changes made/needed:

Comment 8

[Ryan VanderMeulen [:RyanVM]]

Comment on attachment 9126544 [details]
Bug 1529260 - Match shader and CPU glyph rasterization logic for glyphs in local space.

Fixes visual glitches related to glyph positioning with WebRender. Approved for 74.0b4.

Comment 9

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/releases/mozilla-beta/rev/33e592c555fe