Speed Up TextEditing on Long Text - text

Question

With the following code performance degrades drastically as the text gets longer due to the view getting redrawn for every character typed (due to textViewDidChange). There are also a number of nasty side effects as well, such as insertion of sentence breaks likely due to autocorrect or some other mechanism. If I comment out or eliminate the textViewDidChange function, performance is much better and the side effects disappear, but then I no longer can capture the text to save it or interrogate it on the fly.
Does anyone know of a way around this? I thought that if I could just not refresh the text variable until the focus was moved to a different view, then I could capture the text before it needs to be saved. If that might work, I can't determine how to trap the focus change. I have tried implementing textViewDidEndEditing but that only gets triggered when the parent view ends editing. I'm using a save button and want to capture the text then.
I realize that there is a TextEditor view available, but it is just as slow on large text so I assume it is doing the same thing.
import SwiftUI
struct TextView: UIViewRepresentable {
#Binding var text: String
#Binding var textStyle: UIFont.TextStyle
func makeUIView(context: Context) -> UITextView {
let textView = UITextView()
textView.delegate = context.coordinator
textView.font = UIFont.preferredFont(forTextStyle: textStyle)
textView.autocapitalizationType = .none
textView.isSelectable = true
textView.isUserInteractionEnabled = true
return textView
}
func updateUIView(_ uiView: UITextView, context: Context) {
uiView.text = text
uiView.font = UIFont.preferredFont(forTextStyle: textStyle)
}
func makeCoordinator() -> Coordinator {
Coordinator($text)
}
class Coordinator: NSObject, UITextViewDelegate {
var text: Binding<String>
init(_ text: Binding<String>) {
self.text = text
}
func textViewDidChange(_ textView: UITextView) {
self.text.wrappedValue = textView.text
}
}
}
Content View
import SwiftUI
struct ContentView: View {
#State private var message = ""
#State private var textStyle = UIFont.TextStyle.body
var body: some View {
ZStack(alignment: .topTrailing) {
TextView(text: $message, textStyle: $textStyle)
.padding(.horizontal)
Button(action: {
self.textStyle = (self.textStyle == .body) ? .title1 : .body
}) {
Image(systemName: "textformat")
.imageScale(.large)
.frame(width: 40, height: 40)
.foregroundColor(.white)
.background(Color.purple)
.clipShape(Circle())
}
.padding()
}
}
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}