iOS Swift Flood填充algorithm

我为触点的“桶填充”（填充）创build了这个扩展：

extension UIImageView { func bucketFill(startPoint: CGPoint, newColor: UIColor) { var newRed, newGreen, newBlue, newAlpha: CUnsignedChar let pixelsWide = CGImageGetWidth(self.image!.CGImage) let pixelsHigh = CGImageGetHeight(self.image!.CGImage) let rect = CGRect(x:0, y:0, width:Int(pixelsWide), height:Int(pixelsHigh)) let bitmapBytesPerRow = Int(pixelsWide) * 4 var context = self.image!.createARGBBitmapContext() //Clear the context CGContextClearRect(context, rect) // Draw the image to the bitmap context. Once we draw, the memory // allocated for the context for rendering will then contain the // raw image data in the specified color space. CGContextDrawImage(context, rect, self.image!.CGImage) var data = CGBitmapContextGetData(context) var dataType = UnsafeMutablePointer<UInt8>(data) let newColorRef = CGColorGetComponents(newColor.CGColor) if(CGColorGetNumberOfComponents(newColor.CGColor) == 2) { newRed = CUnsignedChar(newColorRef[0] * 255) // CUnsignedChar newGreen = CUnsignedChar(newColorRef[0] * 255) newBlue = CUnsignedChar(newColorRef[0] * 255) newAlpha = CUnsignedChar(newColorRef[1]) } else { newRed = CUnsignedChar(newColorRef[0] * 255) newGreen = CUnsignedChar(newColorRef[1] * 255) newBlue = CUnsignedChar(newColorRef[2] * 255) newAlpha = CUnsignedChar(newColorRef[3]) } let newColorStr = ColorRGB(red: newRed, green: newGreen, blue: newBlue) var stack = Stack() let offset = 4*((Int(pixelsWide) * Int(startPoint.y)) + Int(startPoint.x)) //let alpha = dataType[offset] let startRed: UInt8 = dataType[offset+1] let startGreen: UInt8 = dataType[offset+2] let startBlue: UInt8 = dataType[offset+3] stack.push(startPoint) while(!stack.isEmpty()) { let point: CGPoint = stack.pop() as! CGPoint let offset = 4*((Int(pixelsWide) * Int(point.y)) + Int(point.x)) let alpha = dataType[offset] let red: UInt8 = dataType[offset+1] let green: UInt8 = dataType[offset+2] let blue: UInt8 = dataType[offset+3] if (red == newRed && green == newGreen && blue == newBlue) { continue } if (red.absoluteDifference(startRed) < 4 && green.absoluteDifference(startGreen) < 4 && blue.absoluteDifference(startBlue) < 4) { dataType[offset] = 255 dataType[offset + 1] = newRed dataType[offset + 2] = newGreen dataType[offset + 3] = newBlue if (point.x > 0) { stack.push(CGPoint(x: point.x - 1, y: point.y)) } if (point.x < CGFloat(pixelsWide)) { stack.push(CGPoint(x: point.x + 1, y: point.y)) } if (point.y > 0) { stack.push(CGPoint(x: point.x, y: point.y - 1)) } if (point.y < CGFloat(pixelsHigh)) { stack.push(CGPoint(x: point.x, y: point.y + 1)) } } else { } } let colorSpace = CGColorSpaceCreateDeviceRGB() let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.PremultipliedFirst.rawValue) let finalContext = CGBitmapContextCreate(data, pixelsWide, pixelsHigh, CLong(8), CLong(bitmapBytesPerRow), colorSpace, bitmapInfo) let imageRef = CGBitmapContextCreateImage(finalContext) self.image = UIImage(CGImage: imageRef, scale: self.image!.scale,orientation: self.image!.imageOrientation) } } 

现在我想提高性能。 我怎样才能使这个algorithm工作更快？ UInt8.absoluteDifference扩展是我的尝试，包括几乎相同的颜色填补洪水，它的工作，但这可能是真的改善，我知道它，但我不知道如何。

 extension UInt8 { func absoluteDifference(subtrahend: UInt8) -> UInt8 { if (self > subtrahend) { return self - subtrahend; } else { return subtrahend - self; } } } 

我的堆栈类：

 class Stack { var count: Int = 0 var head: Node = Node() init() { } func isEmpty() -> Bool { return self.count == 0 } func push(value: Any) { if isEmpty() { self.head = Node() } var node = Node(value: value) node.next = self.head self.head = node self.count++ } func pop() -> Any? { if isEmpty() { return nil } var node = self.head self.head = node.next! self.count-- return node.value } } 

感谢帮助