iOS实现高斯模糊效果(Swift版本)

给UIimage添加分类

 extension UIImage {
     /// 高斯模糊
     func gaussianBlur(var blurAmount:CGFloat) -> UIImage {
         //高斯模糊参数(0-1)之间，超出范围强行转成0.5
         if (blurAmount < 0.0 || blurAmount > 1.0) {
             blurAmount = 0.5
         }

         var boxSize = Int(blurAmount * )
         boxSize = boxSize - (boxSize % ) + 

         let img = self.CGImage

         var inBuffer = vImage_Buffer()
         var outBuffer = vImage_Buffer()

         let inProvider =  CGImageGetDataProvider(img)
         let inBitmapData =  CGDataProviderCopyData(inProvider)

         inBuffer.width = vImagePixelCount(CGImageGetWidth(img))
         inBuffer.height = vImagePixelCount(CGImageGetHeight(img))
         inBuffer.rowBytes = CGImageGetBytesPerRow(img)
         inBuffer.data = UnsafeMutablePointer<Void>(CFDataGetBytePtr(inBitmapData))

         //手动申请内存
         let pixelBuffer = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img))

         outBuffer.width = vImagePixelCount(CGImageGetWidth(img))
         outBuffer.height = vImagePixelCount(CGImageGetHeight(img))
         outBuffer.rowBytes = CGImageGetBytesPerRow(img)
         outBuffer.data = pixelBuffer

         var error = vImageBoxConvolve_ARGB8888(&inBuffer,
             &outBuffer, nil, vImagePixelCount(), vImagePixelCount(),
             UInt32(boxSize), UInt32(boxSize), nil, vImage_Flags(kvImageEdgeExtend))
         if (kvImageNoError != error)
         {
             error = vImageBoxConvolve_ARGB8888(&inBuffer,
                 &outBuffer, nil, vImagePixelCount(), vImagePixelCount(),
                 UInt32(boxSize), UInt32(boxSize), nil, vImage_Flags(kvImageEdgeExtend))
             if (kvImageNoError != error)
             {
                 error = vImageBoxConvolve_ARGB8888(&inBuffer,
                     &outBuffer, nil, vImagePixelCount(), vImagePixelCount(),
                     UInt32(boxSize), UInt32(boxSize), nil, vImage_Flags(kvImageEdgeExtend))
             }
         }

         let colorSpace =  CGColorSpaceCreateDeviceRGB()
         let ctx = CGBitmapContextCreate(outBuffer.data,
             Int(outBuffer.width),
             Int(outBuffer.height),
             ,
             outBuffer.rowBytes,
             colorSpace,
             CGImageAlphaInfo.PremultipliedLast.rawValue)

         let imageRef = CGBitmapContextCreateImage(ctx)

         //手动申请内存
         free(pixelBuffer)
         return UIImage(CGImage: imageRef!)
     }
 }