ios - 如何在实时面部上映射面部轮廓点，我们从 Firebase MLKit for iOS 获得

Question

从 faceDetector 获取视觉点后如何映射 2D 视觉点数组以创建人脸图？

faceDetector.process(visionImage) { features, error in

    guard error == nil, let features = features, !features.isEmpty else {
        return
    }
    for face in faces {
        let frame = face.frame
        if let leftEyeContour = face.contour(ofType: .leftEye) {
            // 2D vision Points array
            let leftEyePoints = leftEyeContour.points
        }
        if let upperLipBottomContour = face.contour(ofType: .upperLipBottom) {
            let upperLipBottomPoints = upperLipBottomContour.points
        }
    }
}