Re: [css-images][css-compositing] Blurring an element’s backdrop

On Thu, Dec 5, 2013 at 10:26 PM, Dirk Schulze <dschulze@adobe.com> wrote:

>
> On Dec 6, 2013, at 5:42 AM, Rik Cabanier <cabanier@gmail.com> wrote:
>
> > In going with Lea's comment that authors equate backdrop with blending,
> I propose the following new property:
> > backdrop-blur: none | <length>
> > Length would be the parameter passed into the blur() filter [1].
>
> This is extremely specific for exactly one use case. At least color matrix
> filters are common as well.
>

Do you have an example where this was used?
Michael's use case of dropping off the alpha and overlaying with a solid
color, could be accomplish with a CSS gradient + mix-blend-mode of
'soft-light' or 'screen'


>
> >
> > Specifying this parameter in combination with mix-blend-mode[2], would
> blur the backdrop that is available during the blending step. Compositing
> would happen as usual.
> > An alternate would be to extend mix-blend-mode so you can write the
> following:
> > mix-blend-mode: screen blur(10px);
>
> I would be more in favor for that. Although, it should have all filter
> functions as a list of filter functions.
>
> > This can still be made compatible with future additions that target
> parts of an element.
> >
> > I'm in the process of creating an experimental windows-only build of
> firefox that implements.
> >
> > Thoughts?
> >
> > 1: http://www.w3.org/TR/filter-effects/#funcdef-blur
> > 2: http://dev.w3.org/fxtf/compositing-1/#mix-blend-mode
>
> Greetings,
> Dirk
>
>
> >
> >
> > On Fri, Nov 29, 2013 at 7:51 PM, Rik Cabanier <cabanier@gmail.com>
> wrote:
> >
> >
> >
> > On Thu, Nov 28, 2013 at 10:35 PM, Lea Verou <lea@verou.me> wrote:
> > On Nov 29, 2013, at 12:45, Rik Cabanier <cabanier@gmail.com> wrote:
> > > This might work.
> > > My main concern is that it would overload mix-blend-mode too much
> since we're also hoping to repurpose it to blend different areas of an
> element. I'm unsure how we would reconcile that.
> > > Do you have a suggestion?
> >
> > If the syntax for that is what was discussed in the FXTF a while ago, I
> don’t see what the conflict would be. Care to elaborate? :)
> >
> > Looking 18 months (!) back on this thread, I proposed the following:
> > mix-blend-mode: color-burn(blur(5px))
> >
> > Doing it this way will be confusing if we want to blend different
> elements, ie
> > mix-blend-mode: background screen, border multiply, content overlay,
> element hue
> > Now, each of those *could* theoretically blur the backdrop but that is
> not a strong use case.
> > This syntax also gives the impression that your content/border/element
> has the effect applied as opposed to the backdrop.
> >
> > Also, as Michael mentioned, simply blurring will not give you the
> desired effect. You often want to soften the backdrop with a white color
> that's blended with soft light or screen.
> > He also mentions:
> >  we need finer control of the blur opacity/falloff
> >
> > I'd prefer if we could create a new property that has nice defaults and
> if we can avoid writing filter chains in CSS.
> >
> >
> >
>
>