a minimal SwiftUI view that implements background blur on macOS

VisualEffectBackground.swift

import SwiftUI

public struct VisualEffectBackground: NSViewRepresentable {
	var material: NSVisualEffectView.Material = .contentBackground
	var blendingMode: NSVisualEffectView.BlendingMode = .behindWindow
	var isEmphasized = false
	
	public init(material: NSVisualEffectView.Material = .contentBackground, blendingMode: NSVisualEffectView.BlendingMode = .behindWindow, emphasized: Bool = false) {
		self.material = material
		self.blendingMode = blendingMode
		self.isEmphasized = emphasized
	}
	
	public func makeNSView(context: Context) -> NSVisualEffectView {
		NSVisualEffectView()
	}
	
	public func updateNSView(_ nsView: NSVisualEffectView, context: Context) {
		nsView.material = material
		nsView.blendingMode = blendingMode
		nsView.isEmphasized = isEmphasized
	}
}

public extension View {
	func visualEffectBackground(material: NSVisualEffectView.Material = .sidebar, blendingMode: NSVisualEffectView.BlendingMode = .behindWindow, emphasized: Bool = false) -> some View {
		background(
			VisualEffectBackground(material: material, blendingMode: blendingMode, emphasized: emphasized)
		)
	}
}