Bug 119764 – srcset: Respect updates to display density

• Status: UNCONFIRMED
• Component: Images

[Ricky Romero]

There are situations in which a browser window may encounter a display density change:

1.) Opening a webpage on a @2x laptop, closing the laptop, then later connecting a @1x display.
2.) Dragging the browser window from a @1x display to a @2x display.
3.) Enabling the developer-only HiDPI mode in OS X.

Webkit does not appear to detect these changes and load in the correct images from srcset when they are available.  This is a bug.

[Dean Jackson]

Yeah, -image-set suffers equally.

[Radar WebKit Bug Importer]

<rdar://problem/14734254>

[Beth Dakin]

(In reply to comment #1)
> Yeah, -image-set suffers equally.

Are you sure?  All of these things worked at some point. Can either of you please provide a concrete set of steps to reproduce this bug?

[Beth Dakin]

(In reply to comment #3)
> (In reply to comment #1)
> > Yeah, -image-set suffers equally.
> 
> Are you sure?  All of these things worked at some point. Can either of you please provide a concrete set of steps to reproduce this bug?

I should clarify. -image-set worked at some point. But of course srcset is new, so that has never worked.

[Sam Weinig]

(In reply to comment #4)
> (In reply to comment #3)
> > (In reply to comment #1)
> > > Yeah, -image-set suffers equally.
> > 
> > Are you sure?  All of these things worked at some point. Can either of you please provide a concrete set of steps to reproduce this bug?
>  
> I should clarify. -image-set worked at some point. But of course srcset is new, so that has never worked.

This works for image-set because on device scale factor changes we force a style recalc in all frames in the page (see Page::setDeviceScaleFactor).  Page::setDeviceScaleFactor is getting a bit intense, it may (or may not) make sense to generalize things a bit and add some DeviceScaleFactorListener generalization that HTMLImageElement could register for.