SwiftUI UIRepresentable aspect ratio changes when device is rotated - swiftui

Question

I have the following code
class UIViewTestClass: UIView {
override func draw(_ rect: CGRect) {
"Test".draw(at: CGPoint(x: rect.midX, y: rect.midY))
let context = UIGraphicsGetCurrentContext()
context?.addRect(rect)
context?.stroke(rect)
}
}
struct TestUIView: UIViewRepresentable {
typealias UIViewType = UIView
func makeUIView(context: Context) -> UIView {
let result = UIViewTestClass()
result.backgroundColor = UIColor(.white)
return result
}
func updateUIView(_ uiView: UIView, context: Context) {
}
}
struct ContentView: View {
var body: some View {
TestUIView()
.frame(maxWidth: .infinity, maxHeight: .infinity)
// .aspectRatio(contentMode: .fit)
.padding()
}
}
It works fine when the view is presented but when the device is rotated the letters get stretched out or squeezed. Also, if I include the aspectRatio(contentMode: .fit) the text is correct but the view now only takes up a part of the frame.
How can I prevent this from happening?

Answer 1

For a UIView, the draw(_ rect: CGRect) func is only called when UIKit decides it needs to be called.
If you put a print("inside draw()") statement in there, you'll see that it is not called when you rotate the device.
For UIKit implementation, we can implement layoutSubviews() add a call to setNeedsDisplay() to tell UIKit to call draw().
I don't use SwiftUI ... but quick try looks like this will work:
class UIViewTestClass: UIView {
override func draw(_ rect: CGRect) {
"Test".draw(at: CGPoint(x: rect.midX, y: rect.midY))
let context = UIGraphicsGetCurrentContext()
context?.addRect(rect)
context?.stroke(rect)
}
override func layoutSubviews() {
super.layoutSubviews()
setNeedsDisplay()
}
}