Core Image是一个强大的滤镜处理框架。它除了可以直接给图片添加各种内置滤镜，还能精确地修改鲜艳程度, 色泽, 曝光等，下面通过两个样例演示如何给UIImage添加滤镜。

1，棕褐色滤镜  - CISepiaTone

这个有点复古老照片发黄的效果（上面一张是原图）。

扩展UIImage类，添加棕褐色滤镜：

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import UIKit   //--- UIImageFilterExtension.swift --- extension UIImage {      //棕褐色复古滤镜（老照片效果）      func sepiaTone() -> UIImage ?      {          let imageData = UIImagePNGRepresentation ( self )          let inputImage = CoreImage . CIImage (data: imageData!)          let context = CIContext (options: nil )          let filter = CIFilter (name: "CISepiaTone" )          filter !.setValue(inputImage, forKey: kCIInputImageKey)          filter !.setValue(0.8, forKey: "inputIntensity" )          if let outputImage = filter !.outputImage {              let outImage = context.createCGImage(outputImage, fromRect: outputImage.extent)              return UIImage ( CGImage : outImage)          }          return nil      } }

使用样例：

1	imageView1.image = UIImage (named: "img2.jpg" )?.sepiaTone()

2，黑白滤镜 - CIPhotoEffectNoir

 

扩展UIImage类，添加黑白滤镜：

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import UIKit   //--- UIImageFilterExtension.swift --- extension UIImage {      //黑白效果滤镜      func noir() -> UIImage ?      {          let imageData = UIImagePNGRepresentation ( self )          let inputImage = CoreImage . CIImage (data: imageData!)          let context = CIContext (options: nil )          let filter = CIFilter (name: "CIPhotoEffectNoir" )          filter !.setValue(inputImage, forKey: kCIInputImageKey)          if let outputImage = filter !.outputImage {              let outImage = context.createCGImage(outputImage, fromRect: outputImage.extent)              return UIImage ( CGImage : outImage)          }          return nil      } }

使用样例：

1	imageView1.image = UIImage (named: "img2.jpg" )?.noir()

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