SwiftUI Line Graph Animation using Vector Arithmetic

Why do you want to avoid Metal? Enabling its support is as easy as wrapping your LineGraphShapes into Group and modifying it with a drawingGroup(). Try it out:

...
Group {
    let gradient = LinearGradient(
        gradient: Gradient(colors: [Color.red, Color.blue]),
        startPoint: .leading,
        endPoint: .trailing
    )
    
    LineGraphShape(points: points[selectedPointType], closePath: true)
        .fill(gradient)
    
    LineGraphShape(points: points[selectedPointType], closePath: false)
        .stroke(
            gradient,
            style: .init(
                lineWidth: 4.0,
                lineCap: .round,
                lineJoin: .round,
                miterLimit: 10.0
            )
        )
}
    .drawingGroup()
...

Results in a significant performance improvement 🙂