Open Bug 1473501 Opened 2 years ago Updated 3 months ago

Improve the way Gecko selects images based on srcset values (don't just round up, when rounding up is a huge jump)

Categories

(Core :: Layout: Images, Video, and HTML Frames, enhancement, P3)

63 Branch
Unspecified
Android
enhancement

Tracking

()

Webcompat Priority revisit
Tracking Status
firefox63 --- affected

People

(Reporter: karlcow, Unassigned)

References

()

Details

(Whiteboard: [webcompat])

I'm opening this issue because in a couple of cases, we get an image which is slightly blurry in Firefox while Chrome seems to get a higher resolution image.


1. Load URL on a phone.
2. Scroll down to image.
3. Compare to mobile Chrome.


We have at least two issues already with this behavior.

https://webcompat.com/issues/12774 
https://webcompat.com/issues/16836


There's a good discussion and analysis in 
https://webcompat.com/issues/12774#issuecomment-339094641

comparing what chrome and firefox do.
(In reply to Karl Dubost :karlcow (away from 2018-07-10 to 2018-07-25) from comment #0)
> I'm opening this issue because in a couple of cases, we get an image which
> is slightly blurry in Firefox while Chrome seems to get a higher resolution
> image.

That's an accurate description of the latter NatGeo webcompat issue that you linked.

However: I think the former webcompat issue ( https://webcompat.com/issues/12774 ) is substantially different -- there, Firefox was getting a *higher-res* (i.e. larger/wider) image as compared to Chrome.

(Also, a big part of the main issue there was that the website was lying about the image resolutions. I don't think that's the case with this NatGeo scenario.)

So there may be different problems... Unfortunately I can't investigate the NatGeo issue because I'm getting just-fine image resolutions on my (Google Pixel 2) mobile device -- no blurriness/low-qualitiness visible.
Correction: per updates on the NatGeo webcompat issue, it's hitting the same sort of issue as in https://webcompat.com/issues/12774 after all.

The general webcompat issue here is that *Firefox* is picking a higher-resolution image than Chrome is. We round up when deciding between sources, whereas Chrome rounds to the nearest (possibly picking an image whose "###w" specifier is lower than the screen resolution). Or something like that.

And this is particularly problematic (for us) when rounding up is a large jump whereas rounding down would be a small jump.
Component: Layout → Layout: Images
Summary: Improve the way Gecko selects images based on srcset values → Improve the way Gecko selects images based on srcset values (don't just round up, when rounding up is a huge jump)
Product: Core → Core Graveyard
Product: Core Graveyard → Core

Migrating Webcompat whiteboard priorities to project flags. See bug 1547409.

Webcompat Priority: --- → ?

See bug 1547409. Migrating whiteboard priority tags to program flags.

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