//
//  UIImage+Extension.swift
//  ChatBubbleProject
//
//  Created by 周辉 on 2017/5/16.
//  Copyright © 2017年 周辉. All rights reserved.
//

import Foundation
import UIKit
import QuartzCore
import Accelerate

extension UIImage {
  func blurredImage(radius: CGFloat, iterations: Int, tintColor: UIColor) -> UIImage {
    if floor(size.width) * floor(size.height) <= 0.0 {
      return self
    }
    
    var boxSize = UInt32(radius * scale)
    if boxSize % 2 == 0 {
      boxSize += 1
    }
    
    var imageRef = cgImage
    
    if imageRef?.bitsPerPixel != 32 ||
      imageRef?.bitsPerComponent != 8 ||
      !(imageRef?.bitmapInfo.contains(CGBitmapInfo.alphaInfoMask))!  {
      UIGraphicsBeginImageContextWithOptions(size, false, scale)
      draw(at: .zero)
      imageRef = UIGraphicsGetImageFromCurrentImageContext()?.cgImage
      UIGraphicsEndImageContext()
    }
    
    var buffer1 = vImage_Buffer()
    var buffer2 = vImage_Buffer()
    
    buffer1.width = UInt((imageRef?.width)!)
    buffer2.width = UInt((imageRef?.width)!)
    
    buffer1.height = UInt((imageRef?.height)!)
    buffer2.height = UInt((imageRef?.height)!)
    
    buffer1.rowBytes = (imageRef?.bytesPerRow)!
    buffer2.rowBytes = (imageRef?.bytesPerRow)!
    
    let bytes = buffer1.rowBytes * Int(buffer1.height)
    buffer1.data = malloc(bytes)
    buffer2.data = malloc(bytes)
    
    if buffer1.data == nil || buffer2.data == nil {
      free(buffer1.data)
      free(buffer2.data)
      return self
    }
    
    let tempBuffer = malloc(vImageBoxConvolve_ARGB8888(&buffer1,
                                                       &buffer2,
                                                       nil, 0, 0,
                                                       boxSize, boxSize, nil,
                                                       vImage_Flags(kvImageEdgeExtend+kvImageGetTempBufferSize)))
    let provider = imageRef?.dataProvider
    let dataSource = provider?.data
    if dataSource == nil {
      return self
    }
    
    let dataSourceData = CFDataGetBytePtr(dataSource)
    let dataSourceLength = CFDataGetLength(dataSource)
    memcpy(buffer1.data, dataSourceData, min(bytes, dataSourceLength))
//    CFRelease(dataSource) // CF 现在也在 ARC 的管辖范围之内，见http://swifter.tips/
    
    for _ in 0..<iterations {
      vImageBoxConvolve_ARGB8888(&buffer1,
                                 &buffer2,
                                 tempBuffer,
                                 0, 0, boxSize, boxSize,
                                 nil, vImage_Flags(kvImageEdgeExtend))
      swap(&buffer1.data, &buffer2.data)
    }
    
    free(buffer2.data)
    free(tempBuffer)
    
    let ctx = CGContext.init(data: buffer1.data,
                             width: Int(buffer1.width),
                             height: Int(buffer1.height),
                             bitsPerComponent: 8,
                             bytesPerRow: buffer1.rowBytes,
                             space: (imageRef?.colorSpace)!,
                             bitmapInfo: (imageRef?.bitmapInfo.rawValue)!)
    if tintColor.cgColor.alpha > 0.0 {
      ctx?.setFillColor(tintColor.withAlphaComponent(0.25).cgColor)
      ctx?.setBlendMode(.plusLighter)
      ctx?.fill(CGRect(x: 0, y: 0, width: Int(buffer1.width), height: Int(buffer1.height)))
    }
    imageRef = ctx?.makeImage()
    let image = UIImage(cgImage: imageRef!, scale: scale, orientation: imageOrientation)
    free(buffer1.data)
    return image
  }
}

🍜食用

class ViewController: UIViewController {
  let blurImageView: UIImageView = {
    let iv = UIImageView()
    iv.image = UIImage(named: "twg")?.blurredImage(radius: 0, iterations: 0, tintColor: UIColor.white)
    return iv
  }()  
}

🐶效果

QQ20170516-112318.png

QQ20170516-121755.png