How to get tap location when using scaleEffect - ios

Question

I have a ZStack with an Image and a small circle, and some gestures for panning and zooming in/out on the Image. I want the small circle to change location based on where the user taps. Everything is working fine until I start zooming in with scaleEffect. How can I account for the current scale value when placing the circle? (See TODO: Fix tap point when scaled for where the issue is.)
struct PodMapTest: View {
#State var circlePosition = CGPoint.zero
#State var position = CGSize.zero
#State var scale: CGFloat = 1.0
#State var lastScaleValue: CGFloat = 1.0
#State var tapPoint: CGPoint = CGPoint.zero
#State var dragSize: CGSize = CGSize.zero
#State var lastDrag: CGSize = CGSize.zero
#GestureState private var dragOffset = CGSize.zero
var body: some View {
VStack {
Spacer()
ZStack {
Image("floorPlan")
.resizable()
self.circle
}
.scaledToFit()
.animation(.linear)
.scaleEffect(self.scale)
.offset(self.dragSize)
.gesture(MagnificationGesture().onChanged { val in
let delta = val / self.lastScaleValue
self.lastScaleValue = val
self.scale = self.scale * delta
}.onEnded { val in
// without this the next gesture will be broken
self.lastScaleValue = 1.0
}
)
.simultaneousGesture(DragGesture(minimumDistance: 1, coordinateSpace: .local).onChanged({ val in
print("dragging map")
self.tapPoint = val.startLocation
self.dragSize = CGSize(width: val.translation.width + self.lastDrag.width, height: val.translation.height + self.lastDrag.height)
})
.onEnded({ (val) in
self.dragSize = CGSize(width: val.translation.width + self.lastDrag.width, height: val.translation.height + self.lastDrag.height)
self.lastDrag = self.dragSize
}))
.simultaneousGesture(DragGesture(minimumDistance: 0, coordinateSpace: .local).onChanged({ (val) in
// TODO: Fix tap point when scaled
let tapPoint = CGPoint(x: val.startLocation.x - self.dragSize.width, y: val.startLocation.y - self.dragSize.height)
self.circlePosition = tapPoint
}))
Spacer()
}
}
var circle: some View {
Circle()
.frame(width: 20, height: 20, alignment: .center)
.position(circlePosition)
}
}