iOS：毛玻璃效果

使用core image

//生成一张毛玻璃图片

- (UIImage *)blur:(UIImage
*)theImage

{

CIContext *context = [CIContext
contextWithOptions:nil];

CIImage *inputImage = [CIImage
imageWithCGImage:theImage.CGImage];

CIFilter *filter = [CIFilter
filterWithName:@"CIGaussianBlur"];

[filter setValue:inputImage
forKey:kCIInputImageKey];

[filter setValue:[NSNumber
numberWithFloat:15.0]
forKey:@"inputRadius"];

CIImage *result = [filter
valueForKey:kCIOutputImageKey];

CGImageRef cgImage = [context
createCGImage:result
fromRect:[inputImage
extent]];

UIImage *returnImage = [UIImage
imageWithCGImage:cgImage];

CGImageRelease(cgImage);

return returnImage;

}

系统方法，iOS8以上

//方法一：系统方法，iOS8及以上可用

if (!UIAccessibilityIsReduceTransparencyEnabled())
{

UIBlurEffect *blurEffect = [UIBlurEffect
effectWithStyle:UIBlurEffectStyleDark];

UIVisualEffectView *blurEffectView = [[UIVisualEffectView
alloc]initWithEffect:blurEffect];

blurEffectView.frame = _imageView.bounds;

[_imageView addSubview:blurEffectView];

}