Magnification Gestureのズーム率を引き継ぐ方法

[tsonobe1]

https://stackoverflow.com/questions/58341820/isnt-there-an-easy-way-to-pinch-to-zoom-in-an-image-in-swiftui/58468234#58468234

https://dev.classmethod.jp/articles/swiftui-pinch-in-out/