Question

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

当我下载已启动的项目并构建时，我收到了一些错误：

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：

'CIFeature'类型的值没有成员'hasLeftEyePosition'

那么如何解决这个问题。

任何帮助将不胜感激。感谢。

Answer 1

我刚刚下载了您提到的项目，它正在为我工作（在将其更新为最新的Swift版本之后）。

您缺少的重要内容是在您设置features的第9行：

let features = detector.featuresInImage(newImage)

这一定是

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

我强烈反对强制投射，但由于这不是一个制作应用程序，我可以使用它。如果你想确保永远不会崩溃（如果有人将CIDetectorType从“脸部”更改为其他内容）你可以保护它并返回输入图像：

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

CIFeature没有成员hasLeftEyePosition

1 个答案: