CIGaussianBlur图像大小 [英] CIGaussianBlur image size

问题描述

嘿想模糊我的观点，我使用这段代码：

Hey want to blur my view, and i use this code:

//Get a UIImage from the UIView
NSLog(@"blur capture");
UIGraphicsBeginImageContext(BlurContrainerView.frame.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: 5] forKey: @"inputRadius"]; //change number to increase/decrease blur
CIImage *resultImage = [gaussianBlurFilter valueForKey: @"outputImage"];

//create UIImage from filtered image
blurredImage = [[UIImage alloc] initWithCIImage:resultImage];

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

NSLog(@"%f,%f",newView.frame.size.width,newView.frame.size.height);
//insert blur UIImageView below transparent view inside the blur image container
[BlurContrainerView insertSubview:newView belowSubview:transparentView];

它使视图模糊，但不是全部。我如何模糊所有视图？

And it blurs the view, but not all of it. How can i blur all of the View?

推荐答案

问题不在于它不会模糊所有图像，而是相反，模糊是扩展图像的边界，使图像更大，并且因此没有正确排列。

The issue isn't that it's not blurring all of the image, but rather that the blur is extending the boundary of the image, making the image larger, and it's not lining up properly as a result.

为了使图像保持相同的大小，行之后：

To keep the image the same size, after the line:

CIImage *resultImage    = [gaussianBlurFilter valueForKey: @"outputImage"];

您可以获取矩形的 CGRect 此 resultImage 中心的原始图像大小：

You can grab the CGRect for a rectangle the size of the original image in the center of this resultImage:

// note, adjust rect because blur changed size of image

CGRect rect             = [resultImage extent];
rect.origin.x          += (rect.size.width  - viewImage.size.width ) / 2;
rect.origin.y          += (rect.size.height - viewImage.size.height) / 2;
rect.size               = viewImage.size;

然后使用 CIContext 来获取该部分图像：

And then use CIContext to grab that portion of the image:

CIContext *context      = [CIContext contextWithOptions:nil];
CGImageRef cgimg        = [context createCGImage:resultImage fromRect:rect];
UIImage   *blurredImage = [UIImage imageWithCGImage:cgimg];
CGImageRelease(cgimg);

---

或者，对于iOS 7，如果你去iOS UIImageEffects示例代码并下载 iOS_UIImageEffects.zip ，然后你可以获取 UIImage + ImageEffects 类别。无论如何，这提供了一些新的方法：

---

Alternatively, for iOS 7, if you go to the iOS UIImageEffects sample code and download iOS_UIImageEffects.zip, you can then grab the UIImage+ImageEffects category. Anyway, that provides a few new methods:

- (UIImage *)applyLightEffect;
- (UIImage *)applyExtraLightEffect;
- (UIImage *)applyDarkEffect;
- (UIImage *)applyTintEffectWithColor:(UIColor *)tintColor;
- (UIImage *)applyBlurWithRadius:(CGFloat)blurRadius tintColor:(UIColor *)tintColor saturationDeltaFactor:(CGFloat)saturationDeltaFactor maskImage:(UIImage *)maskImage;

因此，为了模糊和成像并使其变亮（赋予磨砂玻璃效果），您可以执行：

So, to blur and image and lightening it (giving that "frosted glass" effect) you can then do:

UIImage *newImage = [image applyLightEffect];

有趣的是，Apple的代码不使用 CIFilter ，而是致电 vImageBoxConvolve_ARGB8888 / doc / uid / TP30001001rel =noreferrer> vImage高性能图像处理框架。 WWDC 2013视频在iOS上实施Engaging UI 中说明了此技术。

Interestingly, Apple's code does not employ CIFilter, but rather calls vImageBoxConvolve_ARGB8888 of the vImage high-performance image processing framework. This technique is illustrated in WWDC 2013 video Implementing Engaging UI on iOS.

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