解决问题:将图像模糊
前提:添加 CoreGraphics.framework
源码:
- (UIImage*) blur:(UIImage*)theImage { // create our blurred image CIContext *context = [CIContext contextWithOptions:nil]; CIImage *inputImage = [CIImage imageWithCGImage:theImage.CGImage]; // setting up Gaussian Blur (could use one of many filters offered by Core Image) CIFilter *blurFilter = [CIFilter filterWithName:@"CIGaussianBlur"]; [blurFilter setValue:inputImage forKey:kCIInputImageKey]; [blurFilter setValue:[NSNumber numberWithFloat:10.0f] forKey:@"inputRadius"]; CIImage *result = [blurFilter valueForKey:kCIOutputImageKey]; // CIGaussianBlur has a tendency to shrink the image a little, // this ensures it matches up exactly to the bounds of our original image CGImageRef cgImage = [context createCGImage:result fromRect:[inputImage extent]]; UIImage *returnImage = [UIImage imageWithCGImage:cgImage]; //create a UIImage for this function to "return" so that ARC can manage the memory of the blur... //ARC can't manage CGImageRefs so we need to release it before this function "returns" and ends. CGImageRelease(cgImage);//release CGImageRef because ARC doesn't manage this on its own. return returnImage; }出现问题:因为在模糊的时候,边缘会变成半透明的状态,所以理想状况是可以对原图像进行适当放大,选择使用CIAffineClamp在模糊之前对图像进行处理。
源码:
- (UIImage*) blur:(UIImage*)theImage { // create our blurred image CIContext *context = [CIContext contextWithOptions:nil]; CIImage *inputImage = [CIImage imageWithCGImage:theImage.CGImage]; CIFilter *affineClampFilter = [CIFilter filterWithName:@"CIAffineClamp"]; CGAffineTransform xform = CGAffineTransformMakeScale(1.0, 1.0); [affineClampFilter setValue:inputImage forKey:kCIInputImageKey]; [affineClampFilter setValue:[NSValue valueWithBytes:&xform objCType:@encode(CGAffineTransform)] forKey:@"inputTransform"]; CIImage *extendedImage = [affineClampFilter valueForKey:kCIOutputImageKey]; // setting up Gaussian Blur (could use one of many filters offered by Core Image) CIFilter *blurFilter = [CIFilter filterWithName:@"CIGaussianBlur"]; [blurFilter setValue:extendedImage forKey:kCIInputImageKey]; [blurFilter setValue:[NSNumber numberWithFloat:10.0f] forKey:@"inputRadius"]; CIImage *result = [blurFilter valueForKey:kCIOutputImageKey]; // CIGaussianBlur has a tendency to shrink the image a little, // this ensures it matches up exactly to the bounds of our original image CGImageRef cgImage = [context createCGImage:result fromRect:[inputImage extent]]; UIImage *returnImage = [UIImage imageWithCGImage:cgImage]; //create a UIImage for this function to "return" so that ARC can manage the memory of the blur... //ARC can't manage CGImageRefs so we need to release it before this function "returns" and ends. CGImageRelease(cgImage);//release CGImageRef because ARC doesn't manage this on its own. return returnImage; }
http://stackoverflow.com/questions/12839729/correct-crop-of-cigaussianblur
iOS 图像处理 - 模糊图像,布布扣,bubuko.com
原文:http://blog.csdn.net/willyang519/article/details/38716019