仅在 xCode 中的触摸区域应用高斯模糊滤镜

Question

这里是所有图像的高斯滤波器

//Get a UIImage from the UIView
UIGraphicsBeginImageContext(self.view.bounds.size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

//Blur the UIImage
CIImage *imageToBlur = [CIImage imageWithCGImage:viewImage.CGImage];
CIFilter *gaussianBlurFilter = [CIFilter filterWithName:@"CIGaussianBlur"];
[gaussianBlurFilter setValue:imageToBlur forKey:@"inputImage"];
[gaussianBlurFilter setValue:[NSNumber numberWithFloat:2] forKey:@"inputRadius"];
CIImage *resultImage = [gaussianBlurFilter valueForKey:@"outputImage"];
UIImage *endImage = [[UIImage alloc] initWithCIImage:resultImage];

//Place the UIImage in a UIImageView
newView = [[UIImageView alloc] initWithFrame:self.view.bounds];
newView.image = endImage;
[self.view addSubview:newView];

我正在寻找仅对图像中的触摸区域应用模糊过滤器但只为整个图像创建此过滤器的类。我的问题是关于如何使 CIFilter 仅适用于：

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{ ... }
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{ ... }
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{ ... }

Answer 1

像这样它应该可以工作：

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{ 
    //Get a UIImage from the UIView
    UIGraphicsBeginImageContext(self.view.bounds.size);
    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    //Blur the UIImage
    CIImage *imageToBlur = [CIImage imageWithCGImage:viewImage.CGImage];
    CIFilter *gaussianBlurFilter = [CIFilter filterWithName:@"CIGaussianBlur"];
    [gaussianBlurFilter setValue:imageToBlur forKey:@"inputImage"];
    [gaussianBlurFilter setValue:[NSNumber numberWithFloat:2] forKey:@"inputRadius"];
    CIImage *resultImage = [gaussianBlurFilter valueForKey:@"outputImage"];
    UIImage *endImage = [[UIImage alloc] initWithCIImage:resultImage];

    //Place the UIImage in a UIImageView
    newView = [[UIImageView alloc] initWithFrame:self.view.bounds];
    newView.image = endImage;
    [self.view addSubview:newView]; 
}

其他方法也一样:)