1550710 - SVG containing downsized image displayed with img tag has pixel aliasing (flutter.dev logo)

Status: VERIFIED FIXED

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

Description

[Kestrel]

Attachment: Flutter logo showing pixel aliasing

Bug 1534188 improved raster image downsizing for SVGs (confirmed in Bug 1538180), however if the SVG is displayed with an img tag like the flutter.dev logo it still has pixel aliasing.

Comment 1

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

The priority flag is not set for this bug.
:aosmond, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 2

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

I'll take a look at this soon.

Comment 3

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

Sorry this took longer than I thought. When we rasterize the SVG image into its own buffer:

https://searchfox.org/mozilla-central/rev/23d4bffcad365e68d2d45776017056b76ca9a968/image/VectorImage.cpp#306

We actually forget the FLAG_HIGH_QUALITY_SCALING. We should probably pass that through as PaintFrameFlags::ToWindow to ensure the lower levels get the flag set as expected.

Comment 4

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

Attachment: Bug 1550710 - Make vector images enable high quality scaling for embedded raster images.

We did not pass FLAG_HIGH_QUALITY_SCALING down to the document used to
rasterize the SVG to a surface, resulting in embedded raster images to
not use high quality downscaling.

Comment 5

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

try: https://treeherder.mozilla.org/#/jobs?repo=try&revision=491eaff5918bc946ad29e99b1152389a4c4de9ca

Comment 6

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

new try after rewriting to use a dedicated flag in various places: https://treeherder.mozilla.org/#/jobs?repo=try&revision=9c5345ff57eaafede8ac1838ece04fd048e5390a

Comment 8

[Timothy Nikkel (:tnikkel)]

needinfo to make sure this doesn't drop off the radar

Comment 9

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

Just waiting for it to be picked up by autoland.

Comment 10

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/6bcb0cefd0b9
Make vector images enable high quality scaling for embedded raster images. r=tnikkel

Comment 11

[Dorel Luca [:dluca]]

https://hg.mozilla.org/mozilla-central/rev/6bcb0cefd0b9

Comment 12

[Gabi Cheta [:Gabi] Desktop QA]

Reproduced the issue with Firefox Nightly 68.0a (2019-05-10) on Windows 10x64.
Verified as fixed with Firefox 80.0a1 and Firefox 79.0b3 on Windows 10x64, Ubuntu 16.4 and macOS 10.13.