Re: [filter-effects] resolution dependent filter primitives

On Aug 28, 2013, at 6:11 AM, Paul LeBeau <> wrote:

> On 27 August 2013 20:42, Dirk Schulze <> wrote:
> Again, it is extremely hard to determine the right scale level for the horizontal and vertical axis...
> As someone who is implementing filter support in my renderer at the moment, I can concur with this :)
> It would be helpful if the spec gave some guidance on best practice for determining an appropriate size for the filter bitmap.  By "filter bitmap" I mean the intermediate bitmap used for SourceGraphic etc.  For axis aligned content it is easy, but if the element has a transform, it is not so straightforward.

I actually planned to discuss that in a different threat. I agree with you on that and invite implementers to give feedback on how they estimate the affected area in screen coordinates. I will do so for WebKit shortly.

>   In fact I notice that IE doesn't even try. It performs all filters on the transformed content and doesn't use user-coordinate-space.

I never really experimented with filters in IE so far. I wonder how that works with gaussian blur and a horizontal blur radius on a rotated object. Is the blurring following the rotation or does it stay in the horizontal position?


> Paul

Received on Wednesday, 28 August 2013 04:39:09 UTC