我想模糊我的iOS应用程序的整个屏幕,我不能使用UIBlurEffect,因为我希望能够控制模糊.所以我正在尝试使用CIGaussianBlur,但是我遇到了屏幕边缘的问题.
我正在截取屏幕截图,然后通过带有CIGaussianBlur的CIFilter运行它,将CIImage转换回UIImage,并在屏幕顶部添加新的模糊图像.
这是我的代码：
let layer = UIApplication.sharedApplication().keyWindow?.layer
UIGraphicsBeginImageContext(view.frame.size)
layer!.renderInContext(UIGraphicsGetCurrentContext()!)
let screenshot = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
let blurRadius = 5
var ciimage: CIImage = CIImage(image: screenshot)!
var filter: CIFilter = CIFilter(name:"CIGaussianBlur")!
filter.setDefaults()
filter.setValue(ciimage,forKey: kCIInputImageKey)
filter.setValue(blurRadius,forKey: kCIInputRadiusKey)
let ciContext = CIContext(options: nil)
let result = filter.valueForKey(kCIoUtputImageKey) as! CIImage!
let cgImage = ciContext.createCGImage(result,fromRect: view.frame)
let finalImage = UIImage(CGImage: cgImage)
let blurImageView = UIImageView(frame: view.frame)
blurImageView.image = finalImage
blurImageView.sizeToFit()
blurImageView.contentMode = .ScaleAspectFit
blurImageView.center = view.center
view.addSubview(blurImageView)
这是我看到的：
除边缘外,它看起来几乎是正确的.似乎模糊度从模糊半径到边缘起飞.我尝试使用上下文大小,但似乎无法使其工作.
如何让模糊一直到边缘？
解决方法
之所以发生这种情况,是因为高斯模糊滤镜会对图像边缘外的像素进行采样.但是因为没有像素,你会得到这个奇怪的人工制品.您可以使用“CIAffineClamp”滤镜在所有方向上无限地“扩展”您的图像.
请看这个答案https://stackoverflow.com/a/18138742/762779
我尝试用链式’CIAffineClamp->运行你的代码CIGaussianBlur’过滤并获得了良好的效果.
let layer = UIApplication.sharedApplication().keyWindow?.layer UIGraphicsBeginImageContext(view.frame.size) layer!.renderInContext(UIGraphicsGetCurrentContext()!) let screenshot = UIGraphicsGetImageFromCurrentImageContext() UIGraphicsEndImageContext() let blurRadius = 5 let ciimage: CIImage = CIImage(image: screenshot)! // Added "CIAffineClamp" filter let affineClampFilter = CIFilter(name: "CIAffineClamp")! affineClampFilter.setDefaults() affineClampFilter.setValue(ciimage,forKey: kCIInputImageKey) let resultClamp = affineClampFilter.valueForKey(kCIoUtputImageKey) // resultClamp is used as input for "CIGaussianBlur" filter let filter: CIFilter = CIFilter(name:"CIGaussianBlur")! filter.setDefaults() filter.setValue(resultClamp,forKey: kCIInputImageKey) filter.setValue(blurRadius,forKey: kCIInputRadiusKey) let ciContext = CIContext(options: nil) let result = filter.valueForKey(kCIoUtputImageKey) as! CIImage! let cgImage = ciContext.createCGImage(result,fromRect: ciimage.extent) // changed to ciiimage.extend let finalImage = UIImage(CGImage: cgImage) let blurImageView = UIImageView(frame: view.frame) blurImageView.image = finalImage blurImageView.sizeToFit() blurImageView.contentMode = .ScaleAspectFit blurImageView.center = view.center view.addSubview(blurImageView)
