PDFKit Ink Annotations

Question

我一直在使用iOS PDFKit框架处理PDF编辑器/注释器。当我使用默认选项创建注释时，它们最终会奇怪地呈现或者根本不呈现（我已经确定它们意味着它们只是在注释的边界之外进行渲染，因为设置注释边界说{0,0,4000,4000}有效） 。现在显而易见的是，我正在设置错误的边界，但是当我继承PDFAnnotation并覆盖draw(with:,in:)方法时，它们会按预期显示。

不起作用

  // paths made using pdf coordinate space
  let paths: [UIBezierPath] = []
  // find bounding box of all the paths
  let bounds = paths.reduce(CGMutablePath(), { acc, nxt in
    acc.addPath(nxt.cgPath)
    return acc
  }).boundingBoxOfPath.insetBy(dx: -50, dy: -50)

  let border = PDFBorder()
  border.lineWidth = 2.5
  border.style = .solid

  annotation = PDFAnnotation(
    bounds: bounds, 
    forType: .ink, 
    withProperties: [
      PDFAnnotationKey.inklist: paths,
      PDFAnnotationKey.border: border,
      PDFAnnotationKey.color: UIColor.red,
      PDFAnnotationKey.interiorColor: UIColor.red,
    ])

  // Also tried these things / other fiddling but same results
  annotation.backgroundColor = UIColor.red
  annotation.shouldDisplay = true
  for path in paths {
    annotation.add(path)
  }

效果很好，但不符合pdf规范

let paths: [UIBezierPath] = []
let bounds = paths.reduce(CGMutablePath(), { acc, nxt in
  acc.addPath(nxt.cgPath)
  return acc
}).boundingBoxOfPath.insetBy(dx: -50, dy: -50)
annotation = InkAnnotation(bounds: bounds, paths: paths)

/// Overrides draw method to add paths manually
class InkAnnotation: PDFAnnotation {
  var pathList: [UIBezierPath] = []

  public init(bounds: CGRect, paths: [UIBezierPath]) {
    self.pathList = paths
    super.init(bounds: bounds, forType: .ink, withProperties: nil)
  }

  required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
  }

  override func draw(with box: PDFDisplayBox, in context: CGContext) {
    UIGraphicsPushContext(context)
    context.saveGState()
    context.setStrokeColor(UIColor.red.cgColor)
    context.setLineWidth(2.5)

    for path in pathList {
      context.addPath(path.cgPath)
      context.strokePath()
    }

    context.strokePath()
    context.restoreGState()
    UIGraphicsPopContext()
  }
}

非常感谢任何帮助！