Playing around with SwiftUI Sliders, copying Carlyn

slidertest.swift

//
//  slidertest - copy into a blank Playground
//
//  Created by Tod Kurt on 7/17/22.
//

import SwiftUI


// given 0-1 val, return 0-1 with log curve
func logtaper(_ v: Double) -> Double {
    return log10(1 + 9*v) // log10(1) = 0, log10(10) = 1
}
// given 0-1 val, return 0-1 with x^2 curve
func squaredtaper(_ v: Double) -> Double {
    return (v*v)
}
// give 0-1 val, return 0-1 with sqrt(x) curve, (similar to logtaper)
func sqrttaper(_ v: Double) -> Double {
    return sqrt(v)
}

// normalize val to 0-1, apply taper
// return value within vmin-max
func mapToTaper( val:Double, vmin:Double, vmax:Double,
                 taper: (Double)->Double ) -> Double {
    let vrange = vmax - vmin
    let normalized_val = (val-vmin) / vrange
    return vmin + (vrange * taper(normalized_val))
}

struct ContentView: View {
    @State var sliderVal1:Double = 15
    @State var sliderVal2:Double = 15
    @State var sliderVal3:Double = 15
    
    var sliderVal1Display:Double {
        get { mapToTaper(val:sliderVal1, vmin:10,vmax:20, taper:logtaper) }
    }
    var sliderVal2Display:Double {
        get { mapToTaper(val:sliderVal2, vmin:10,vmax:20, taper:squaredtaper) }
    }
    var sliderVal3Display:Double {
        get { mapToTaper(val:sliderVal3, vmin:10,vmax:20, taper:sqrttaper) }
    }
    
    var body: some View {
        VStack {
            Text(String(format: "sliderLog %2.1f", sliderVal1Display))
                .padding()
            Slider(value:$sliderVal1, in:10...20)
            Text(String(format: "sliderSquared %2.1f", sliderVal2Display))
                .padding()
            Slider(value:$sliderVal2, in:10...20)
            Text(String(format: "sliderSqrt %2.1f", sliderVal3Display))
                .padding()
            Slider(value:$sliderVal3, in:10...20)
            
        }
    }
}

struct ContentView_Previews: PreviewProvider {
    static var previews: some View {
        ContentView()
    }
}