Re: Filters spec: CSS vs SVG

Hi Chris,

these were just the changes that have been discussed on the FX mailing
list.
In the start of this thread, I said that I wasn't aware that this was
intended to be a replacement for SVG filters.

I personally don't think that this should be the case and I'm fairly sure
that Dean didn't intend this either. The CSS filter spec just took the
general approach of the SVG filter specfor simplicity. If possible, we
should not change behavior of overlapping functionality but it should be OK
to remove or add keywords.

For now, the filter spec is supposed to be as simple as possible both for
implementors and web designers.
This means:
- easy syntax for basic filters. More complicated filters can be done using
a subset of SVG filter. The reason for their use is that they were already
well defined.
- no access to the background or blending for ease of implementation
- no enable-background. This concept does not exist in the HTML.
- no section support. HTML generally is not a fixed layout so 'sections'
don't make much sense.

I agree that IF this is a replacemet spec, we need to thread more lightly...

Rik

On Thu, May 5, 2011 at 5:01 AM, Chris Lilley <chris@w3.org> wrote:

> On Wednesday, May 4, 2011, 11:29:45 PM, Rik wrote:
>
> RC> Thank Erik!I didn't know that this was a replacement for the current
> spec.
>
> RC> So far, I think these are the following proposed changes:
> RC> - remove section 6, the filter effects region
> RC>  - remove backgound-image and background-alpha
> RC> - remove section on the enable-background keyword
> RC> - change default behavior of an unknown filter to 'ignore' instead of
> the 'null filter'
> RC>  - remove filters that create an image and move them to the
> RC> image-values spec (ie feTurbulence)
> RC> - remove the feComposite filter and replace with the CSS/SVG
> compositing spec
>
> Given that your first sentence quoted above makes clear that you understand
> that this is a replacement spec that covers both HTML/CSS as well as SVG
> (and SVG/CSS) usage - please provide an analysis of the impact of such
> *radical* changes to existing on existing uses of SVG filters.
>
>