iOS Text Drawing to Context is Clear

Question

I have a simple application which I've added a custom line chart to. While drawing this chart in on of my UIViews everything is fine, but when I added the chart to a simplified view I suddenly experience a situation where all the text I draw is clear/not present.

There are some static variables involved because of the way the animations need to be handled (iOS/Android/Web) compatibility in the algorithm so the full example is rather complex.

To explain this I added a simple drawing method at the end of my CALayer.draw override

    //TEST CODE
    let box = CGRect(x: 0, y: 0, width: 100, height: 100)
    let textToDraw = "I AM A TEST"
    let font = UIFont.boldSystemFont(ofSize: 10)
    let boxSize = fontSize.space
    let paragraphStyle = NSMutableParagraphStyle()
    paragraphStyle.alignment = .right
    let attrs = [
        NSFontAttributeName: font,
        NSParagraphStyleAttributeName: paragraphStyle,
        NSForegroundColorAttributeName: UIColor.black
    ]


    ctx.setStrokeColor(UIColor.orange.cgColor)
    ctx.beginPath()
    ctx.move(to: CGPoint.zero)
    ctx.addLine(to: CGPoint(x: box.width, y: box.height))
    ctx.addLine(to: CGPoint(x: box.origin.x + box.width, y: box.origin.y + box.height))
    ctx.strokePath()

    //                print("fontSize:\(fontSize) string:\(textToDraw)")
    //textToDraw.draw(with: offset , options: .usesLineFragmentOrigin, attributes: attrs, context: nil)
    textToDraw.draw( in: box, withAttributes: attrs)

However, and this is frustrating, if I visit the OTHER view where the chart draws (or any other custom drawings happens) I end up with this:

I'm having trouble tracing this down and I have a (justifiably) annoyed client.

The Code for "reloading the view" is basically view.dismiss(animated:true) followed by a performSegue("brokenView")

Has anyone run into this behavior before? Are there any pointers you can offer to getting the text to stick. I'm at the point I'm debating dropping a hidden UIView with drawing on my home screen to fix it but there has to be a better way.

The orange lines were put in to verify that my "bounding boxes" were not off the screen.

The layer in question is basically this:

iOS Text Drawing to Context is Clear

0 Answers