CI Filter to create Black & White image?

Question

I have a CIImage I need to convert from color to Black and White within my Cocoa / objective C program. Peter H. previously pointed me to this link http://www.codingadventu

Answer 1

Took some time to figure out the code for CIColorMap so i wanted to post this. Joshua has the answer above. This is just an example of implementation...

CIImage *beginImage = [CIImage imageWithContentsOfURL:[NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"wedding" ofType:@"jpg"]]];
CIImage *inputGradientImage = [CIImage imageWithContentsOfURL:[NSURL fileURLWithPath:[[NSBundle mainBundle] pathForResource:@"grad" ofType:@"png"]]];
CIContext *context = [CIContext contextWithOptions:nil];
CIFilter *filter = [CIFilter filterWithName:@"CIColorMap" keysAndValues:kCIInputImageKey, beginImage, @"inputGradientImage",inputGradientImage, nil];
CIImage *outputImage = [filter outputImage];
CGImageRef cgimg = [context createCGImage:outputImage fromRect:[outputImage extent]];
UIImage *newImage = [UIImage imageWithCGImage:cgimg];
self.imageView.image = newImage;
CGImageRelease(cgimg);