import Foundation
import UIKit

extension UIImage {
    
    /* 压缩图片 */
    func imageCompress(toScale: CGFloat) -> UIImage {
        
        let targetHeight = toScale * self.size.height
        let targetWidth = toScale * self.size.width

        let size = CGSize(width: targetWidth, height: targetHeight)
        //创建一个基于位图的上下文
        UIGraphicsBeginImageContext(size)
        
        self.draw(in: CGRect(x: 0, y: 0, width: targetWidth, height: targetHeight))
        //根据size 返回图形大小
        let newImg : UIImage = UIGraphicsGetImageFromCurrentImageContext()!
        //关闭上下文
        UIGraphicsEndImageContext()
        
        return newImg
    }
    /* 图片模糊 */
    func blurImage(value:NSNumber) -> UIImage {
        
        // CoreImage
        let context = CIContext(options: [kCIContextUseSoftwareRenderer: true])
        //根据UIImage 创建 CIImage类型，进行操作，然后再返回 UIImage类型
        let ciImg = CIImage(image: self)
        //滤镜
        let blurFilter = CIFilter(name: "CIGaussianBlur")
        
        blurFilter?.setValue(ciImg, forKey: kCIInputImageKey)
        //设置模糊程度
        blurFilter?.setValue(value, forKey: "inputRadius")
        let imageRef = context.createCGImage((blurFilter?.outputImage)!, from: (ciImg?.extent)!)
        
        let newImg = UIImage(cgImage: imageRef!)
        
        return newImg
        
        
    }
    
    /*
     出现问题：因为在模糊的时候，边缘会变成半透明的状态，所以理想状况是可以对原图像进行适当放大，选择使用CIAffineClamp在模糊之前对图像进行处理。
     */
    
    func blurImageAnother(value:NSNumber) -> UIImage {
        
        // CoreImage
        let context = CIContext(options: [kCIContextUseSoftwareRenderer: true])
        //根据UIImage 创建 CIImage类型，进行操作，然后再返回 UIImage类型
        let inputImage = CIImage(image: self)
        //滤镜
        let affineClampFilter = CIFilter(name: "CIAffineClamp")
        
        let xform = CGAffineTransform(scaleX: 1.0, y: 1.0)
        
        affineClampFilter?.setValue(inputImage, forKey: kCIInputImageKey)
        
        affineClampFilter?.setValue(NSValue.init(cgAffineTransform: xform), forKey: "inputTransform")
        
        let outinputImg = affineClampFilter?.outputImage!
        
        let blurFilter = CIFilter(name: "CIGaussianBlur")
        
        blurFilter?.setValue(outinputImg, forKey: kCIInputImageKey)
        //设置模糊程度
        blurFilter?.setValue(value, forKey: "inputRadius")
        
        let imageRef = context.createCGImage((blurFilter?.outputImage)!, from: (inputImage?.extent)!)
        
        let newImg = UIImage(cgImage: imageRef!)
        
        return newImg
        
        
    }
}