2010 02 27Core Image black fringes
[CIImage imageByApplyingTransform:t], you'll see incorrect blending between the image and its background. In this case, a black and grey image on a red background shows darker interpolated pixels than exist in both image and background.
Core Image is by default assuming a black border when blending the image.
CIAffineClamp mentions black fringes when using a Gaussian Blur — when blurring, Core Image will blend border pixels with black. Adding
CIAffineClamp will extend the image infinitely to blur border pixels with a copy of themselves.
CIAffineClamp — this will remove black borders in
CIPointillize, … and all the blur filters.