How I can add a drawing function in SwiftUI? - swiftui

Question

I can't draw. Unfortunately I don't know where the problem is, colour selection works and the canva is also created, only the drawing doesn't work. I have also checked that the size of the canva is correct and that the path is defined correctly. here is my code:
//
import SwiftUI
struct ContentView: View {
#State private var lines: [Line] = []
#State private var strokeColor: Color = Color.black
var body: some View {
ZStack {
Color.white
.edgesIgnoringSafeArea(.all)
VStack {
Canvas(lines: $lines, strokeColor: $strokeColor)
HStack {
Button(action: clearDrawing) {
Text("Clear")
}
ColorPicker("Stroke Color", selection: $strokeColor)
}
.padding()
}
}
}
func clearDrawing() {
lines.removeAll()
}
}
//
Here I have created the Canva and the button to delete the drawing
//
struct Canvas: View {
#Binding var lines: [Line]
#Binding var strokeColor: Color
var body: some View {
GeometryReader { geometry in
Path { path in
for line in self.lines {
path.move(to: line.points[0])
path.addLines(line.points)
}
}
.stroke(self.strokeColor, lineWidth: 3)
.frame(width: geometry.size.width, height: geometry.size.height)
.gesture(
DragGesture(minimumDistance: 0.1)
.onChanged({ value in
var lastLine = self.lines.last!
let currentPoint = value.location
lastLine.points.append(currentPoint)
})
.onEnded({ value in
self.lines.append(Line())
})
)
}
}
}
struct Line: Identifiable {
var id: UUID = UUID()
var points: [CGPoint] = []
}
struct ContentView_Previews: PreviewProvider {
static var previews: some View {
ContentView()
}
}
//
And here I have made it so that you should actually draw by touch, and that there is a colour selection