CIFilter blur issues

[mikevann]

Thanks a lot for the clamping tip, this seems to solve my issue.


On Dec 18, 2007, at 1:33 AM, Paul Sargent wrote:

> On 18 Dec 2007, at 08:18, mikevann wrote:
>
>> I'm doing a gaussian blur using Core Image (CIGaussianBlur).  The  
>> problem I'm having is the edges are not being extended during the  
>> blur so all four edges fade into transparency.  Is there a way to  
>> control how the CIGaussianBlur treats edges, such as  
>> kvImageEdgeExtend does for vImage convolves, or at least set the  
>> background color used for the blur?
>
> I don't think so, as the edge behaviour is a property of the  
> sampler. The code to create the sampler is inside the CIFilter,  
> hence it is only modifiable if you write a custom filter. (That  
> doesn't stop Quartz Composer doing it, so there's a method  
> somewhere, but I don't think it's public)
>
> The only solution I've come up with (in theory) is to have another  
> filter add a clamped edge to the image prior to blurring.