Re: [filter-effects-2] Split functionality of 'filter' and 'backdrop-filter' into several properties

> On Feb 8, 2016, at 6:18 pm, Robert O'Callahan <robert@ocallahan.org> wrote:
> 
> On Sun, Feb 7, 2016 at 12:14 AM, Sebastian Zartner <sebastianzartner@gmail.com <mailto:sebastianzartner@gmail.com>> wrote:
> On 6 February 2016 at 09:28, Robert O'Callahan <robert@ocallahan.org <mailto:robert@ocallahan.org>> wrote:
> Implementing ::backdrop for every element would be pretty hard for us and not something I'd want to do.
> 
> 
> Can you elaborate on this?
> 
> ::backdrop only applies to "top layer" elements so there's some special-casing we can do to simplify the layout and rendering of ::backdrop. If you allow ::backdrop on non-top-layer elements then it can appear anywhere.
>  
> And would it generally be hard to implement or only for Mozilla?
> 
> I don't know.
>  
> And if it's generally hard to implement, let's discuss another solution. And what about the other parts of the suggested approach?
> 
> I guess I don't understand why we need backdrop-filter at all. Why can't authors use BackgroundImage with the 'filter' property to get the same effects? Is it because they'd have to use SVG filters and a standalone CSS property is easier to use?

I’m trying to find out where this “BackgroundImage” thing is specified and failing. I assume it’s different to CSS background-image, give your statement that it could be used for backdrop filters?

Simon