Re: [filter-effects] resolution dependent filter primitives

On Wed, Aug 28, 2013 at 1:02 AM, Paul LeBeau <paul.lebeau@gmail.com> wrote:

> On 28 August 2013 16:38, Dirk Schulze <dschulze@adobe.com> wrote:
>
> > Is the blurring following the rotation or does it stay in the horizontal
> position?
>
> The latter.  The blur is applied to the transformed object, so even if
> stdDevation.Y is 0, you still get blurring in the "Y" direction.
>
> Paul
>

Surely this is because they apply the blur to the frame-buffer target in
hardware (not to a render target that is subsequently applied as texture to
a transformed quad).

Stephen.


> On 28 August 2013 16:38, Dirk Schulze <dschulze@adobe.com> wrote:
>
>>
>> On Aug 28, 2013, at 6:11 AM, Paul LeBeau <paul.lebeau@gmail.com> wrote:
>>
>> >
>> > On 27 August 2013 20:42, Dirk Schulze <dschulze@adobe.com> 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?
>>
>> Greetings,
>> Dirk
>>
>> >
>> > Paul
>> >
>>
>>
>