获取UIImage的Pixel颜色

// 将UIImage对象转换为CGImage对象
let cgImage = image.cgImage

// 获取CGImage的宽度和高度
let width = cgImage.width
let height = cgImage.height

// 创建位图上下文
let colorSpace = CGColorSpaceCreateDeviceRGB()
let bytesPerPixel = 4
let bytesPerRow = bytesPerPixel * width
let bitsPerComponent = 8
let bitmapInfo = CGImageAlphaInfo.premultipliedLast.rawValue | CGBitmapInfo.byteOrder32Big.rawValue
let context = CGContext(data: nil, width: width, height: height, bitsPerComponent: bitsPerComponent, bytesPerRow: bytesPerRow, space: colorSpace, bitmapInfo: bitmapInfo)!

// 将CGImage绘制到位图上下文中
context.draw(cgImage, in: CGRect(x: 0, y: 0, width: width, height: height))

// 获取位图上下文的数据指针
let data = context.data!.assumingMemoryBound(to: UInt8.self)

// 计算指定像素位置的内存地址
let pixelIndex = (y * width + x) * bytesPerPixel
let pixelAddress = data + pixelIndex

// 解析颜色值
let red = pixelAddress[0]
let green = pixelAddress[1]
let blue = pixelAddress[2]
let alpha = pixelAddress[3]

// 创建UIColor对象
let color = UIColor(red: CGFloat(red) / 255.0, green: CGFloat(green) / 255.0, blue: CGFloat(blue) / 255.0, alpha: CGFloat(alpha) / 255.0)