“unrecognized selector” when attempting to access CIFilter's outputImage

Question

I\'m experimenting with Core Image (on OS X, 10.7.3) for the first time and am running into a brick wall. I\'m certain this is something silly I\'m doing and just need some

Answer 1

I believe your extents are the culprit (however strange it is). When I change the extents to be a CIVector* it works.

NSURL *imageURL = [NSURL fileURLWithPath:@"/Users/david/Desktop/video.png"];
CIImage *inputImage = [CIImage imageWithContentsOfURL:imageURL];
CIFilter *filter = [CIFilter filterWithName:@"CIAreaAverage"];
[filter setValue:inputImage forKey:kCIInputImageKey];
CGRect inputExtent = [inputImage extent];
CIVector *extent = [CIVector vectorWithX:inputExtent.origin.x
                                       Y:inputExtent.origin.y
                                       Z:inputExtent.size.width
                                       W:inputExtent.size.height];
[filter setValue:extent forKey:kCIInputExtentKey];
CIImage *outputImage = [filter valueForKey:@"outputImage"];

[inputImage extent] returns an CGRect, but apparently a CIVector* works better.