iOS 18 Widgets: Notes about updating the widget

BackdeployedWidgetAccentedRenderingMode.swift

import SwiftUI
import WidgetKit

@available(iOS, deprecated: 18.0, message: "use WidgetAccentedRenderingMode instead")
enum BackdeployedWidgetAccentedRenderingMode {
    case accented
    case accentedDesaturated
    case desaturated
    case fullColor
    
    @available(iOS 18.0, *)
    func toRenderingMode() -> WidgetAccentedRenderingMode {
        switch self {
        case .accented: .accented
        case .accentedDesaturated: .accentedDesaturated
        case .desaturated: .desaturated
        case .fullColor: .fullColor
        }
    }
}

extension Image {
    @available(iOS, deprecated: 18.0, message: "use widgetAccentedRenderingMode instead")
    @ViewBuilder
    func backdeployedWidgetAccentedRenderingMode(
        _ mode: BackdeployedWidgetAccentedRenderingMode
    ) -> some View {
        if #available(iOS 18.0, *) {
            self.widgetAccentedRenderingMode(mode.toRenderingMode())
        }
        else {
            self
        }
    }
}

CutContentFromView.swift

// If you want to get black text on a white background,
// there is only one way out - to cut it out of the background
Circle()
    .fill(.white)
    .frame(width: 20, height: 20, alignment: .center)
    .mask(
        ZStack {
            Circle()
                .fill(Color.white)

            Text(model.formattedDayNumber)
                .font(.system(size: 9, weight: .bold))
                .foregroundColor(.black)

        }
        .compositingGroup()
        .luminanceToAlpha()
    )

DayView+widgetAccentable.swift

Circle()
    .fill(model.isCurrent ? .white : .clear)
    // No need for widgetAccentable(false) as it's not accentable by default

Text("21")
    .font(.system(size: 15))
    .foregroundColor(model.isCurrent ? .black : .white)
    .widgetAccentable(model.isCurrent) // Accent only the current day

EnvironmentValues+isFullColorWidget.swift

import SwiftUI

extension EnvironmentValues {
    @available(iOS, deprecated: 16.0, message: "use `widgetRenderingMode` instead")
    var isFullColorWidget: Bool {
        get {
            if #available(iOS 16.0, *) {
                widgetRenderingMode == .fullColor
            }
            else {
                self[FullColorWidgetKey.self]
            }
        }
    }
}

private enum FullColorWidgetKey: EnvironmentKey {
    static let defaultValue = true
}

Image+widgetAccentedRenderingMode.swift

Image("userAvatar")
    .resizable()
    .widgetAccentedRenderingMode(.fullColor)

PeridoDayView+widgetRenderingMode.swift

struct PeridoDayView: View {
  @Environment(\.widgetRenderingMode) 
  private var widgetRenderingMode
    
  var body: some View {
    DayRangeView()
      .foregroundStyle(
        widgetRenderingMode == .fullColor ? .periodColor : .white60Color
      )
  }
}

View+backdeployedWidgetAccentable.swift

import SwiftUI

extension View {
    @available(iOS, deprecated: 16.0, message: "use widgetAccentable(_:)` instead")
    @ViewBuilder
    func backdeployedWidgetAccentable(
        _ accentable: Bool = true
    ) -> some View {
        if #available(iOS 16.0, *) {
            self
                .widgetAccentable(accentable)
        }
        else {
            self
        }
    }
}