Capture ink signatures using SignatureViewController

There are two options for getting the image of an ink signature from a SignatureViewController.

Option 1

Subclass the SignatureViewController and override its done(_:) method to access its drawView. This will create the ink signature.

Once you have the ink signature, you can use Annotation.image(size:options:) to create a UIImage of the ink annotation, like so:

class CustomSignatureViewController: SignatureViewController {
    override func done(_ sender: Any?) {
        super.done(sender)


        // The current document.
        let document = ...
        let pageInfo = document.pageInfoForPage(at:0)!
        let pointSequences = self.drawView.pointSequences.map{ $0.map({ NSValue.valueWithDrawingPoint($0) }) }
        let pdfSpaceLines = ConvertViewLines(pdfLines: pointSequences, pageInfo: pageInfo, viewBounds: self.drawView.frame)
        let lines = pdfSpaceLines.map { $0.map({ $0.drawingPointValue }) }
        let inkAnnotation = InkAnnotation(lines: lines)


        // Create the `UIImage` from the ink annotation in your `SignatureViewController`.
        let image = inkAnnotation.image(size: inkAnnotation.boundingBox.size, options: nil)
    }
}

Option 2

If, for whatever reason, the SignatureViewController is presented in a context in which a Document isn’t available to get a reference PDFPageInfo object to perform the annotation calculations, you can call DrawView.drawHierarchy(in:afterScreenUpdates:)(opens in a new tab) within an image rendering context to get a direct image out of DrawView:

class CustomSignatureViewController: SignatureViewController {
    override func done(_ sender: Any?) {
        super.done(sender)


        let rect = ...
        let renderer = UIGraphicsImageRenderer(size: rect.size)
        let image = renderer.image { _ in
            self.drawView.drawHierarchy(in: rect, afterScreenUpdates: true)
        }
    }
}

For more details about accessing properties from a SignatureViewController and its drawView property, take a look at SignAllPagesExample.swift(opens in a new tab) from our Nutrient Catalog app.