On Sat, 15 Mar 2014, Dirk Schulze wrote:
>
> I would suggest a filter attribute that takes a list of filter
> operations similar to the CSS Image filter function. Similar to
> shadows[2], each drawing operation would be filtered. The API looks like
> this:
>
> partial interface CanvasRenderingContext2D {
>     attribute DOMString filter;
> }
>
> A filter DOMString could looks like: “contrast(50%) blur(3px)”
>
> With the combination of grouping in canvas it would be possible to
> group drawing operations and filter them together.
>
> Filter functions include a reference to a <filter> element and a
> specification of SVG filters. I am unsure if a reference do an element
> within a document can cause problems. If it does, we would just not
> support SVG filter references.