On 09/24/2014 06:26 PM, Ehsan Akhgari wrote:
> Hmm, doesn't that basically allow non-interoperable implementations? :(
> I think Jonas' idea on having separate properties for the upscale vs.
> downscale cases is much better.
I'm unconvinced about the usefulness of exposing that much control. This
is something that could be added to CSS Images level 4, though, if you
really thing it merits doing. I suspect CSS Images level 3 is too late
in the game for that sort of change.
> So, what's Chrome's position with regards to this spec churn?
As of this morning, their "intent to ship" thread had a few posts
sounding like they'd take out the smart-downscaling eventually, to align
with the ED as-it-stood-this-morning.
But now that prettier downscaling is allowed, I assume they'll stick
with what they've already implemented (which includes the default
> Is what
> they're going to ship in Chrome 38 going to be interoperable with our
It depends on what you mean by "interoperable". If you're asking if
they'll produce the exact same result, pixel-for-pixel, when downscaling
an image, then no. But that's likely already the case, with the default
scaling behavior; I'd be surprised if we matched them 100% on
Also, stepping back a bit w.r.t. the interoperability of the
"image-rendering" property -- this property is explicitly a _hint_, to
express author intent. Its description in the spec starts like this:
# "The image-rendering property provides a hint
# to the user-agent about what aspects of an
# image are most important to preserve when the
# image is scaled, to aid the user-agent in the
# choice of an appropriate scaling algorithm.
So, it's not required to behave exactly the same everywhere; it simply
codifies an author's intent. (OK, I suppose it *is* required to behave
exactly the same everywhere in the case of "pixelated" & upscaling,
since that requires a particular algorithm, to achieve a particular
effect. But other than that, it's purely a hint.)
So, I don't think pixel-for-pixel-identical is a level of
interoperability that's required or expected for this property, in general.
Also, note that once followup-bug-1072703 is fixed, we'll be as
interoperable with Chrome as our default downscaling behavior is with
theirs. (which is probably pretty close, though I suspect not