PDFKit Ink Annotations - ios

Question

I've been working on a PDF editor / annotator using the iOS PDFKit framework. When I create annotations using the default options, they end up rendering strangely or not at all (which I've determined means they are rendering just outside the bounds of the annotation, since setting the annotation bounds to say {0,0,4000,4000} works). Now the obvious thing here is that I'm setting the bounds incorrectly, however when I subclass PDFAnnotation and override the draw(with:,in:) method they appear as expected.
Doesn't work
// 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)
}
Works great, but doesn't conform to the pdf spec
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()
}
}
Any help is greatly appreciated!