Re: [css-compositing]new Editor's draft posted

On Tue, May 21, 2013 at 11:21 PM, Robert O'Callahan <robert@ocallahan.org>wrote:

> My most recent thought about compositing and blending is that a lot of the
> effects can be produced using CSS/SVG filters (not even requiring custom
> filters), which are already widely supported (at least the SVG side), and
> we at Mozilla are planning to invest more in our CSS/SVG filter support in
> the near future. At least, filters can be used to composite images and
> colors together with arbitrary modes.
>
> So, can you give us a list of use-cases for compositing and blending that
> can't be handled using CSS/SVG filters?
>

In order to do blending with other elements on the page, the most
convenient way is to use 'backgroundImage' as the input. Calculating this
image has the same problem as what we're trying to do for CSS blending.

If you don't want to use backgroundImage, you have to create the element
for the backdrop separately which is a huge pain in SVG. I'm unsure if this
is even be possible with HTML content.

Maybe we can revisit the issue about blending with non-isolated groups. If
the browser engines had support for those, we wouldn't have to care about
intermediate layers...