Simple pinch to zoom View extension, allowing for limits to zoom scale

readme.md

Notes

• Should check this still makes sense. There is a @GestureState thing but I think it was easier not to use that when wanted to have limits.

ZoomableView.swift

import SwiftUI

enum Config {
    static let zoomRange: ClosedRange<CGFloat> = 0.05...1.0
}

extension View {
  func zoomable(scale: Binding<CGFloat>) -> some View {
    ZoomableView(scale: scale) {
      self
    }
  }
}

struct ZoomableView<Child: View>: View {
  @Binding var scale: CGFloat
  var child: Child
  @State private var lastScaleValue: CGFloat = 1.0
  
  init(scale: Binding<CGFloat>, @ViewBuilder content: () -> Child) {
    child = content()
    _scale = scale
  }
  
  var body: some View {
    child.gesture(MagnificationGesture().onChanged { val in
        let delta = val / lastScaleValue
        // Pain seems like need to save this?
        lastScaleValue = val
      let newScale = scale * delta
        if newScale < Config.zoomRange.lowerBound {
            scale = Config.zoomRange.lowerBound
        } else if newScale > Config.zoomRange.upperBound {
            scale = Config.zoomRange.upperBound
        } else {
            scale = newScale
        }
    }.onEnded { val in
        lastScaleValue = 1.0
    })
  }
}