在swift 5中删除UIImage中的白色背景

let image = UIImage(named: "your_image_name")
guard let cgImage = image?.cgImage else {
    // 处理转换失败的情况
    return
}

let colorSpace = CGColorSpaceCreateDeviceRGB()
let bitmapInfo = CGBitmapInfo(rawValue: CGImageAlphaInfo.premultipliedLast.rawValue)
guard let context = CGContext(data: nil, width: cgImage.width, height: cgImage.height, bitsPerComponent: 8, bytesPerRow: 0, space: colorSpace, bitmapInfo: bitmapInfo.rawValue) else {
    // 处理创建图形上下文失败的情况
    return
}

let rect = CGRect(x: 0, y: 0, width: cgImage.width, height: cgImage.height)
context.draw(cgImage, in: rect)

let data = context.data
let buffer = data?.assumingMemoryBound(to: UInt8.self)

for i in 0..<(cgImage.width * cgImage.height * 4) {
    let alpha = buffer?[i + 3]
    let red = buffer?[i]
    let green = buffer?[i + 1]
    let blue = buffer?[i + 2]

    if red == 255 && green == 255 && blue == 255 {
        buffer?[i] = 0
        buffer?[i + 1] = 0
        buffer?[i + 2] = 0
        buffer?[i + 3] = 0
    }
}

guard let newCGImage = context.makeImage() else {
    // 处理创建新CGImage对象失败的情况
    return
}

let newImage = UIImage(cgImage: newCGImage)