iOS实现背景高斯模糊效果

  UIView *bgview= [[UIViewalloc]initWithFrame:self.view.frame];//  bgview.backgroundColor = [UIColor blackColor];//  bgview.alpha = 0.9;  bgview.tag =10086;  [self.viewaddSubview:bgview];  UIBlurEffect *blur = [UIBlurEffecteffectWithStyle:UIBlurEffectStyleLight];  UIVisualEffectView *effectview = [[UIVisualEffectViewalloc] initWithEffect:blur];  effectview.frame =self.view.frame;  [bgview addSubview:effectview];

CIContext *context = [CIContext contextWithOptions:nil];   CIImage *inputImage = [[CIImage alloc] initWithImage:[UIImage imageNamed:@"1.png"]];   // create gaussian blur filter   CIFilter *filter = [CIFilter filterWithName:@"CIGaussianBlur"];   [filter setValue:inputImage forKey:kCIInputImageKey];   [filter setValue:[NSNumber numberWithFloat:10.0] forKey:@"inputRadius"];   // blur image   CIImage *result = [filter valueForKey:kCIOutputImageKey];   CGImageRef cgImage = [context createCGImage:result fromRect:[result extent]];   UIImage *image = [UIImage imageWithCGImage:cgImage];   CGImageRelease(cgImage);   self.mainImageView.image = image;