swift - CIFeature 没有成员 hasLeftEyePosition

Question

我正在阅读此 https://www.raywenderlich.com/79149/grand-central-dispatch-tutorial-swift-part-1 中的 GCD 教程.

当我下载启动的项目并构建时，出现一些错误:

private extension PhotoDetailViewController {
  func faceOverlayImageFromImage(image: UIImage) -> UIImage {
    let detector = CIDetector(ofType: CIDetectorTypeFace,
                     context: nil,
                     options: [CIDetectorAccuracy: CIDetectorAccuracyHigh])

    // Get features from the image
    let newImage = CIImage(CGImage: image.CGImage!)
    let features = detector.featuresInImage(newImage)

    UIGraphicsBeginImageContext(image.size)
    let imageRect = CGRect(x: 0, y: 0, width: image.size.width, height: image.size.height)

    // Draws this in the upper left coordinate system
    image.drawInRect(imageRect, blendMode: CGBlendMode.Normal, alpha: 1.0)

    let context = UIGraphicsGetCurrentContext()
    for faceFeature in features {
      let faceRect = faceFeature.bounds
      CGContextSaveGState(context)

      // CI and CG work in different coordinate systems, we should translate to
      // the correct one so we don't get mixed up when calculating the face position.
      CGContextTranslateCTM(context, 0.0, imageRect.size.height)
      CGContextScaleCTM(context, 1.0, -1.0)

      if faceFeature.hasLeftEyePosition {
        let leftEyePosition = faceFeature.leftEyePosition
        let eyeWidth = faceRect.size.width / FaceBoundsToEyeScaleFactor
        let eyeHeight = faceRect.size.height / FaceBoundsToEyeScaleFactor
        let eyeRect = CGRect(x: leftEyePosition.x - eyeWidth / 2.0,
          y: leftEyePosition.y - eyeHeight / 2.0,
          width: eyeWidth,
          height: eyeHeight)
        drawEyeBallForFrame(eyeRect)
      }

      if faceFeature.hasRightEyePosition {
        let leftEyePosition = faceFeature.rightEyePosition
        let eyeWidth = faceRect.size.width / FaceBoundsToEyeScaleFactor
        let eyeHeight = faceRect.size.height / FaceBoundsToEyeScaleFactor
        let eyeRect = CGRect(x: leftEyePosition.x - eyeWidth / 2.0,
          y: leftEyePosition.y - eyeHeight / 2.0,
          width: eyeWidth,
          height: eyeHeight)
        drawEyeBallForFrame(eyeRect)
      }

      CGContextRestoreGState(context);
    }

    let overlayImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    return overlayImage
  }

在这一行faceFeature.hasLeftEyePosition，它说:

Value of type 'CIFeature' has no member 'hasLeftEyePosition'

那么如何解决这个问题。

任何帮助将不胜感激。谢谢。

Answer 1

我刚刚下载了您提到的项目，它对我有用(将其更新到最新的 Swift 版本后)。

您缺少的重要部分位于您设置features的第9行:

let features = detector.featuresInImage(newImage)

这一定是

let features = detector.featuresInImage(newImage) as! [CIFaceFeature]

我强烈反对强制转换，但由于这不是一个生产应用程序，我对此表示同意。如果您想确保永远不会崩溃(以防有人将 CIDetectorType 从“face”更改为其他内容)，您可以保护它并返回输入图像:

guard let features = detector.featuresInImage(newImage) as? [CIFaceFeature] else { return image }