UIImage With Color & Centered Text - ios

Question

I'm trying to add a convenience initialiser to the UIImage which will allow me to create an image with a given text centred in the middle, and given background color:
I've got the following code:
public convenience init?(color: UIColor, withText: String, withTextColor: UIColor, size: CGSize = CGSize(width: 1, height: 1)) {
let rect = CGRect(origin: .zero, size: size)
UIGraphicsBeginImageContextWithOptions(rect.size, false, 0.0)
color.setFill()
UIRectFill(rect)
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
let label = UILabel()
label.text = withText
label.textAlignment = .center
label.font = UIFont.boldSystemFont(ofSize: 40)
label.textColor = withTextColor
guard let cgImage = image?.cgImage else { return nil }
self.init(cgImage: cgImage)
}
This creates the image with the correct background color - I'm not sure how to embed the UILabel in the middle of the image though.
EDIT

Answer 1

Attributed strings know how to draw themselves, so you don't need a label. They also can tell you how big they are or even wrap to fit an available width. Here is playground that shows how to get an image from any attributed string:
import UIKit
import PlaygroundSupport
extension NSAttributedString {
func asImage(size: CGSize = .init(width: .max, height: .max)) -> UIImage {
UIGraphicsImageRenderer(bounds: boundingRect(with: size, options: [.usesLineFragmentOrigin], context: nil)).image { context in
self.draw(at: .zero)
}
}
}
let attributedString = NSAttributedString.init(string: "testing", attributes: [NSAttributedString.Key.foregroundColor : UIColor.white])
let image = attributedString.asImage()
let imageView = UIImageView(image: image)
PlaygroundPage.current.liveView = imageView

Answer 2

Here is the convenience initialiser drawing white text in the centre of a red image:
convenience init?(letters: String) {
let style = NSMutableParagraphStyle()
style.alignment = NSTextAlignment.center
let sizeOfImage = CGSize(width: 120, height: 120)
let font = UIFont(name: "Georgia", size: 50)!
let imageText = NSAttributedString(string: letters, attributes: [.font: font, .foregroundColor: UIColor.white, .paragraphStyle: style])
let textHight = font.lineHeight
let renderer = UIGraphicsImageRenderer(size: sizeOfImage)
let image = renderer.image { context in
UIColor.red.setFill()
context.fill(CGRect(origin: .zero, size: sizeOfImage))
imageText.draw(in: CGRect(origin: CGPoint(x: 0, y: (sizeOfImage.height - textHight) / 2), size: sizeOfImage))
}
self.init(cgImage: image.cgImage!)
}