Swift 4你能用图片注释PDF吗？

Question

我对Swift编程相当陌生，我已经为工作创建了一个应用程序来简化我在现有PDF上以编程方式填写字段的任务。我捕获了一个签名作为UIImage，我想像其他字段一样将其作为注释添加到PDF中。这个是可能的吗？

// Annotate Signature
let signatureFieldBounds = CGRect(x:390, y:142, width:100, height:30)
let signatureField = PDFAnnotation(bounds: signatureFieldBounds, forType: .stamp, withProperties: nil)
signatureField.fieldName = FieldNames.signature.rawValue
signatureField.backgroundColor = UIColor.clear
sigImage?.draw(in: signatureFieldBounds)

page.addAnnotation(signatureField)

我也尝试过: signatureField.stampName = sigImage as！UIImage而不是draw函数，但这会给出错误“无法将类型为'UIImage‘的值赋给类型’String？‘”

屏幕截图显示了我得到的注释：

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任何帮助都将不胜感激！

Answer 1

这对我来说也很棘手，但我想通了。

创建自定义PDFAnnotation，然后覆盖draw方法以在pdf上下文中绘制图像。

class ImageStampAnnotation: PDFAnnotation {

var image: UIImage!

// A custom init that sets the type to Stamp on default and assigns our Image variable
init(with image: UIImage!, forBounds bounds: CGRect, withProperties properties: [AnyHashable : Any]?) {
    super.init(bounds: bounds, forType: PDFAnnotationSubtype.stamp, withProperties: properties)

    self.image = image
}

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


override func draw(with box: PDFDisplayBox, in context: CGContext) {

    // Get the CGImage of our image
    guard let cgImage = self.image.cgImage else { return }

    // Draw our CGImage in the context of our PDFAnnotation bounds
    context.draw(cgImage, in: self.bounds)

 } 
}

然后，只需将其添加到文档

guard let signatureImage = signatureImage, let page = pdfContainerView.currentPage else { return }
    let pageBounds = page.bounds(for: .cropBox)
    let imageBounds = CGRect(x: pageBounds.midX, y: pageBounds.midY, width: 200, height: 100)
    let imageStamp = ImageStampAnnotation(with: signatureImage, forBounds: imageBounds, withProperties: nil)
    page.addAnnotation(imageStamp)

我写了一篇关于如何做到这一点的中等文章，添加了一个手势识别器和一个抓取签名的画布：https://medium.com/@rajejones/add-a-signature-to-pdf-using-pdfkit-with-swift-7f13f7faad3e