高斯模糊濾鏡逆轉：iOS

Question

我有一個高斯模糊，我正在做一個應用程序。

//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]; 

它工作的很好，但我希望能夠扭轉它，並返回到正常的視圖。

我該怎麼做，因爲試圖從模板的視圖中刪除模糊的視圖不起作用。我也嘗試將各種屬性設置爲零，但沒有運氣。

Answer 1

保持一個指向viewImage在屬性

@property (nonatomic, strong) UIImage* originalImage; 

再經過

UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext(); 

添加

self.originalImage = viewImage; 

要恢復你的形象：

newView.image = self.originalImage; 

當您應用模糊時，它不會改變viewImage ..您創建了一個單獨的CIImage，它會變得模糊，並且您會從模糊的CIImage創建一個新的UIImage。

Answer 2

就像我在之前的評論中所說的那樣，您可以創建一個屬性/ iVar，在應用效果之前保存圖像，並在需要撤消時恢復。

if(!_originalImage) 
    _originalImage = [[UIImage alloc] init]; 

_originalImage = viewImage; //(Creates a copy, not a C-Type pass-by-reference) 

// Do your Blur Stuff 

// Now somewhere down the line in your program, if you don't like the blur and the user would like to undo: 

viewImage = _originalImage; 

根據您對@ HeWas的回答的評論，您不應該完全模糊視圖。如果視圖變得模糊，那麼在程序的其他地方還有其他問題。

Answer 3

• 我在代碼中看到的第一件事是，您不在異步任務中應用過濾器。模糊圖像需要時間，所以如果你不想凍結你應該使用主線程：

---

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ 
    //blur the image in a second thread 
    dispatch_async(dispatch_get_main_queue(), ^{ 
     //set the blurred image to your imageView in the main thread 
    }); 
}); 

---

• 爲了能夠逆轉原始圖像，你只需把在原始圖像上出現的其他圖像模糊副本。在我的情況下，原始圖像不是imageView，而是視圖本身。所以我只在我的視圖中添加一個imageView來設置模糊的圖像，並且當我想要反轉時將其設置爲零。

---

• 最後，如果你想避免閃爍，當你設置的模糊圖像，你可以用α的動畫製作軟過渡玩：

---

[self.blurredImageView setAlpha: 0.0]; //make the imageView invisible 
[self.blurredImageView setImage:blurredImage]; 
//and after set the image, make it visible slowly. 
[UIView animateWithDuration:0.5 delay:0.1 
          options:UIViewAnimationOptionCurveEaseInOut 
         animations:^{ 
          [self.blurredImageView setAlpha: 1.0]; 
         } 
         completion:nil]; 

---

• 這是我的com plete方式：

---

- (void)makeBlurredScreenShot{ 
    UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, self.view.opaque, 0.0); 
    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()]; 
    UIImage *imageView = UIGraphicsGetImageFromCurrentImageContext(); 
    UIGraphicsEndImageContext(); 

    CIContext *context = [CIContext contextWithOptions:nil]; 
    CIImage *sourceImage = [CIImage imageWithCGImage:imageView.CGImage]; 

    // Apply clamp filter: 
    // this is needed because the CIGaussianBlur when applied makes 
    // a trasparent border around the image 
    NSString *clampFilterName = @"CIAffineClamp"; 
    CIFilter *clamp = [CIFilter filterWithName:clampFilterName]; 
    if (!clamp) 
     return; 

    [clamp setValue:sourceImage forKey:kCIInputImageKey]; 
    CIImage *clampResult = [clamp valueForKey:kCIOutputImageKey]; 

    // Apply Gaussian Blur filter 
    NSString *gaussianBlurFilterName = @"CIGaussianBlur"; 
    CIFilter *gaussianBlur   = [CIFilter filterWithName:gaussianBlurFilterName]; 
    if (!gaussianBlur) 
     return; 

    [gaussianBlur setValue:clampResult forKey:kCIInputImageKey]; 
    [gaussianBlur setValue:[NSNumber numberWithFloat:8.0] forKey:@"inputRadius"]; 

    CIImage *gaussianBlurResult = [gaussianBlur valueForKey:kCIOutputImageKey]; 
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{ 

     CGImageRef cgImage = [context createCGImage:gaussianBlurResult fromRect:[sourceImage extent]]; 

     UIImage *blurredImage = [UIImage imageWithCGImage:cgImage]; 
     CGImageRelease(cgImage); 

     dispatch_async(dispatch_get_main_queue(), ^{ 
      [self.blurredImageView setAlpha: 0.0]; 
      [self.blurredImageView setImage:blurredImage]; 
      [UIView animateWithDuration:0.5 delay:0.1 
           options:UIViewAnimationOptionCurveEaseInOut 
          animations:^{ 
           [self.blurredImageView setAlpha: 1.0]; 
          } 
          completion:nil]; 
     }); 
    }); 
} 

---

- (void)removeBlurredScreenShot{ 
    [UIView animateWithDuration:0.5 delay:0.1 
         options:UIViewAnimationOptionCurveEaseInOut 
        animations:^{ 
          [self.blurredImageView setAlpha: 0.0]; 
          } 
        completion:^(BOOL finished) { 
          [self.blurredImageView setImage:nil]; 
        }]; 
}