I'm making a macOS app in SwiftUI with the new NavigationSplitView. If a user resizes the sidebar, I'd like that new width to be remembered and restored when the app next loads.
A preference can be read in like so...
#State private var width = UserDefaults.standard.float(forKey: "sidebarWidth")
...
NavigationSplitView {
...
}.navigationSplitViewColumnWidth(ideal: width)
But this isn't a binding, so the width isn't updated when it changes.
Is it possible to save the current sidebar width when it changes (or when the app closes), so that it might later be restored?
Many thanks!
This is a function to retrieve the width:
extension View {
#ViewBuilder func onWidthChange(_ action: #escaping (CGFloat) -> Void) -> some View {
self
.background(
GeometryReader { reader in
Color.clear
.onChange(of: reader.frame(in: .global).width) { newValue in
action(newValue)
}
}
)
}
}
Usage:
Text("Hi")
.onWidthChange { newWidth in
//save width
}
I have a ZStack that I set the color to black and then add a VideoPlayer. When I rotate the device there are still flashes of white around the player. I have played with all sorts of ideas and background colors, foreground colors, opacity and nothing has worked. I just want the background to be black so it looks like a smooth rotation. Anybody have any suggestions or fixes? Here's my code:
import Foundation
import SwiftUI
import AVKit
struct VideoDetail: View {
var videoIDString: String
var videoThumbURL: String
#State var player = AVPlayer()
var body: some View {
ZStack {
Color.black
.edgesIgnoringSafeArea(.all)
let videoURL: String = videoIDString
VideoPlayer(player: player)
//.frame(height: 200)
.edgesIgnoringSafeArea(.all)
.onAppear {
player = AVPlayer(url: URL(string: videoURL)!)
player.play()
}
.onDisappear {
player.pause()
}
}
.navigationBarHidden(true)
.background(Color.black.edgesIgnoringSafeArea(.all))
}
}
I was having the same issue and came across a solution: you can set the background color of the hosting window's root view controller's view. You don't have direct access to this within SwiftUI, so in order to do this you can use a method described in this answer.
Just copy the withHostingWindow View extension including HostingWindowFinder somewhere and use the following code in your view to set the background color to black:
var body: some View {
ZStack {
// ...
}
.withHostingWindow { window in
window?.rootViewController?.view.backgroundColor = UIColor.black
}
}
After this, the white corners when rotating should be gone!
Just add
ZStack{
...
}.preferredColorScheme(ColorScheme.dark)
I feel your pain. This is a SwiftUI bug. The way that SwiftUI currently works is that it contains your view tree within a UIKit view. For the most part SwiftUI and UIKit cooperate with one another pretty well, but one particular area that struggles seems to be synchronising UIKit and SwiftUI animations.
Therefore, when the device rotates, it's actually UIKit driving the animation, so SwiftUI has to make a best guess of where it might be on the animation curve but its guess is pretty poor.
The best thing we can do right now is file feedback. Duplicated bug reports are how Apple prioritise what to work on, so the more bug reports from everyone the better. It doesn't have to be long. Title it something like 'SwiftUI animation artefacts on device rotation', and write 'Duplicate of FB10376122' for the description to reference an existing report on the same topic.
Anyway, in the meantime, we can at least grab the UIKit view of the enclosing window and set the background colour on there instead. This workaround is limited as 1) it doesn't change the apparent 'jumpiness' of the above mentioned synchronisation between the UIKit and SwiftUI animations, and 2) will only help if your background is a block colour.
That said, here's a WindowGroup replacement and view modifier pair that ties together this workaround to play as nicely as possible with the rest of SwiftUI.
Example usage:
import SwiftUI
#main
struct MyApp: App {
var body: some Scene {
// Should be at the very top of your view tree within your `App` conforming type
StyledWindowGroup {
ContentView()
// view modifier can be anywhere in your view tree
.preferredWindowColor(.black)
}
}
}
To use, copy the contents below into a file named StyledWindowGroup.swift and add to your project:
import SwiftUI
/// Wraps a regular `WindowGroup` and enables use of the `preferredWindowColor(_ color: Color)` view modifier
/// from anywhere within its contained view tree. Use in place of a regular `WindowGroup`
public struct StyledWindowGroup<Content: View>: Scene {
#ViewBuilder let content: () -> Content
public init(content: #escaping () -> Content) {
self.content = content
}
public var body: some Scene {
WindowGroup {
content()
.backgroundPreferenceValue(PreferredWindowColorKey.self) { color in
WindowProxyHostView(backgroundColor: color)
}
}
}
}
// MARK: - Convenience View Modifer
extension View {
/// Sets the background color of the hosting window.
/// - Note: Requires calling view is contained within a `StyledWindowGroup` scene
public func preferredWindowColor(_ color: Color) -> some View {
preference(key: PreferredWindowColorKey.self, value: color)
}
}
// MARK: - Preference Key
fileprivate struct PreferredWindowColorKey: PreferenceKey {
static let defaultValue = Color.white
static func reduce(value: inout Color, nextValue: () -> Color) { }
}
// MARK: - Window Proxy View Pair
fileprivate struct WindowProxyHostView: UIViewRepresentable {
let backgroundColor: Color
func makeUIView(context: Context) -> WindowProxyView {
let view = WindowProxyView(frame: .zero)
view.isHidden = true
return view
}
func updateUIView(_ view: WindowProxyView, context: Context) {
view.rootViewBackgroundColor = backgroundColor
}
}
fileprivate final class WindowProxyView: UIView {
var rootViewBackgroundColor = Color.white {
didSet { updateRootViewColor(on: window) }
}
override func willMove(toWindow newWindow: UIWindow?) {
updateRootViewColor(on: newWindow)
}
private func updateRootViewColor(on window: UIWindow?) {
guard let rootViewController = window?.rootViewController else { return }
rootViewController.view.backgroundColor = UIColor(rootViewBackgroundColor)
}
}
How do I properly implement NSView constraints on the NSTextView below so it interacts with SwiftUI .frame()?
Goal
An NSTextView that, upon new lines, expands its frame vertically to force a SwiftUI parent view to render again (i.e., expand a background panel that's under the text + push down other content in VStack). The parent view is already wrapped in a ScrollView. Since the SwiftUI TextEditor is ugly and under-featured, I'm guessing several others new to MacOS will wonder how to do the same.
Update
#Asperi pointed out a sample for UIKit buried in another thread. I tried adapting that for AppKit, but there's some loop in the async recalculateHeight function. I'll look more at it with coffee tomorrow. Thanks Asperi. (Whoever you are, you are the SwiftUI SO daddy.)
Problem
The NSTextView implementation below edits merrily, but disobeys SwiftUI's vertical frame. Horizontally all is obeyed, but texts just continues down past the vertical height limit. Except, when switching focus away, the editor crops that extra text... until editing begins again.
What I've Tried
Sooo many posts as models. Below are a few. My shortfall I think is misunderstanding how to set constraints, how to use NSTextView objects, and perhaps overthinking things.
I've tried implementing an NSTextContainer, NSLayoutManager, and NSTextStorage stack together in the code below, but no progress.
I've played with GeometryReader inputs, no dice.
I've printed LayoutManager and TextContainer variables on textdidChange(), but am not seeing dimensions change upon new lines. Also tried listening for .boundsDidChangeNotification / .frameDidChangeNotification.
GitHub: unnamedd MacEditorTextView.swift <- Removed its ScrollView, but couldn't get text constraints right after doing so
SO: Multiline editable text field in SwiftUI <- Helped me understand how to wrap, removed the ScrollView
SO: Using a calculation by layoutManager <- My implementation didn't work
Reddit: Wrap NSTextView in SwiftUI <- Tips seem spot on, but lack AppKit knowledge to follow
SO: Autogrow height with intrinsicContentSize <- My implementation didn't work
SO: Changing a ScrollView <- Couldn't figure out how to extrapolate
SO: Cocoa tutorial on setting up an NSTextView
Apple NSTextContainer Class
Apple Tracking the Size of a Text View
ContentView.swift
import SwiftUI
import Combine
struct ContentView: View {
#State var text = NSAttributedString(string: "Testing.... testing...")
let nsFont: NSFont = .systemFont(ofSize: 20)
var body: some View {
// ScrollView would go here
VStack(alignment: .center) {
GeometryReader { geometry in
NSTextEditor(text: $text.didSet { text in react(to: text) },
nsFont: nsFont,
geometry: geometry)
.frame(width: 500, // Wraps to width
height: 300) // Disregards this during editing
.background(background)
}
Text("Editing text above should push this down.")
}
}
var background: some View {
...
}
// Seeing how updates come back; I prefer setting them on textDidEndEditing to work with a database
func react(to text: NSAttributedString) {
print(#file, #line, #function, text)
}
}
// Listening device into #State
extension Binding {
func didSet(_ then: #escaping (Value) ->Void) -> Binding {
return Binding(
get: {
return self.wrappedValue
},
set: {
then($0)
self.wrappedValue = $0
}
)
}
}
NSTextEditor.swift
import SwiftUI
struct NSTextEditor: View, NSViewRepresentable {
typealias Coordinator = NSTextEditorCoordinator
typealias NSViewType = NSTextView
#Binding var text: NSAttributedString
let nsFont: NSFont
var geometry: GeometryProxy
func makeNSView(context: NSViewRepresentableContext<NSTextEditor>) -> NSTextEditor.NSViewType {
return context.coordinator.textView
}
func updateNSView(_ nsView: NSTextView, context: NSViewRepresentableContext<NSTextEditor>) { }
func makeCoordinator() -> NSTextEditorCoordinator {
let coordinator = NSTextEditorCoordinator(binding: $text,
nsFont: nsFont,
proxy: geometry)
return coordinator
}
}
class NSTextEditorCoordinator : NSObject, NSTextViewDelegate {
let textView: NSTextView
var font: NSFont
var geometry: GeometryProxy
#Binding var text: NSAttributedString
init(binding: Binding<NSAttributedString>,
nsFont: NSFont,
proxy: GeometryProxy) {
_text = binding
font = nsFont
geometry = proxy
textView = NSTextView(frame: .zero)
textView.autoresizingMask = [.height, .width]
textView.textColor = NSColor.textColor
textView.drawsBackground = false
textView.allowsUndo = true
textView.isAutomaticLinkDetectionEnabled = true
textView.displaysLinkToolTips = true
textView.isAutomaticDataDetectionEnabled = true
textView.isAutomaticTextReplacementEnabled = true
textView.isAutomaticDashSubstitutionEnabled = true
textView.isAutomaticSpellingCorrectionEnabled = true
textView.isAutomaticQuoteSubstitutionEnabled = true
textView.isAutomaticTextCompletionEnabled = true
textView.isContinuousSpellCheckingEnabled = true
textView.usesAdaptiveColorMappingForDarkAppearance = true
// textView.importsGraphics = true // 100% size, layoutManger scale didn't fix
// textView.allowsImageEditing = true // NSFileWrapper error
// textView.isIncrementalSearchingEnabled = true
// textView.usesFindBar = true
// textView.isSelectable = true
// textView.usesInspectorBar = true
// Context Menu show styles crashes
super.init()
textView.textStorage?.setAttributedString($text.wrappedValue)
textView.delegate = self
}
// Calls on every character stroke
func textDidChange(_ notification: Notification) {
switch notification.name {
case NSText.boundsDidChangeNotification:
print("bounds did change")
case NSText.frameDidChangeNotification:
print("frame did change")
case NSTextView.frameDidChangeNotification:
print("FRAME DID CHANGE")
case NSTextView.boundsDidChangeNotification:
print("BOUNDS DID CHANGE")
default:
return
}
// guard notification.name == NSText.didChangeNotification,
// let update = (notification.object as? NSTextView)?.textStorage else { return }
// text = update
}
// Calls only after focus change
func textDidEndEditing(_ notification: Notification) {
guard notification.name == NSText.didEndEditingNotification,
let update = (notification.object as? NSTextView)?.textStorage else { return }
text = update
}
}
Quick Asperi's answer from a UIKit thread
Crash
*** Assertion failure in -[NSCGSWindow setSize:], NSCGSWindow.m:1458
[General] Invalid parameter not satisfying:
size.width >= 0.0
&& size.width < (CGFloat)INT_MAX - (CGFloat)INT_MIN
&& size.height >= 0.0
&& size.height < (CGFloat)INT_MAX - (CGFloat)INT_MIN
import SwiftUI
struct AsperiMultiLineTextField: View {
private var placeholder: String
private var onCommit: (() -> Void)?
#Binding private var text: NSAttributedString
private var internalText: Binding<NSAttributedString> {
Binding<NSAttributedString>(get: { self.text } ) {
self.text = $0
self.showingPlaceholder = $0.string.isEmpty
}
}
#State private var dynamicHeight: CGFloat = 100
#State private var showingPlaceholder = false
init (_ placeholder: String = "", text: Binding<NSAttributedString>, onCommit: (() -> Void)? = nil) {
self.placeholder = placeholder
self.onCommit = onCommit
self._text = text
self._showingPlaceholder = State<Bool>(initialValue: self.text.string.isEmpty)
}
var body: some View {
NSTextViewWrapper(text: self.internalText, calculatedHeight: $dynamicHeight, onDone: onCommit)
.frame(minHeight: dynamicHeight, maxHeight: dynamicHeight)
.background(placeholderView, alignment: .topLeading)
}
#ViewBuilder
var placeholderView: some View {
if showingPlaceholder {
Text(placeholder).foregroundColor(.gray)
.padding(.leading, 4)
.padding(.top, 8)
}
}
}
fileprivate struct NSTextViewWrapper: NSViewRepresentable {
typealias NSViewType = NSTextView
#Binding var text: NSAttributedString
#Binding var calculatedHeight: CGFloat
var onDone: (() -> Void)?
func makeNSView(context: NSViewRepresentableContext<NSTextViewWrapper>) -> NSTextView {
let textField = NSTextView()
textField.delegate = context.coordinator
textField.isEditable = true
textField.font = NSFont.preferredFont(forTextStyle: .body)
textField.isSelectable = true
textField.drawsBackground = false
textField.allowsUndo = true
/// Disabled these lines as not available/neeed/appropriate for AppKit
// textField.isUserInteractionEnabled = true
// textField.isScrollEnabled = false
// if nil != onDone {
// textField.returnKeyType = .done
// }
textField.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
return textField
}
func makeCoordinator() -> Coordinator {
return Coordinator(text: $text, height: $calculatedHeight, onDone: onDone)
}
func updateNSView(_ NSView: NSTextView, context: NSViewRepresentableContext<NSTextViewWrapper>) {
NSTextViewWrapper.recalculateHeight(view: NSView, result: $calculatedHeight)
}
fileprivate static func recalculateHeight(view: NSView, result: Binding<CGFloat>) {
/// UIView.sizeThatFits is not available in AppKit. Tried substituting below, but there's a loop that crashes.
// let newSize = view.sizeThatFits(CGSize(width: view.frame.size.width, height: CGFloat.greatestFiniteMagnitude))
// tried reportedSize = view.frame, view.intrinsicContentSize
let reportedSize = view.fittingSize
let newSize = CGSize(width: reportedSize.width, height: CGFloat.greatestFiniteMagnitude)
if result.wrappedValue != newSize.height {
DispatchQueue.main.async {
result.wrappedValue = newSize.height // !! must be called asynchronously
}
}
}
final class Coordinator: NSObject, NSTextViewDelegate {
var text: Binding<NSAttributedString>
var calculatedHeight: Binding<CGFloat>
var onDone: (() -> Void)?
init(text: Binding<NSAttributedString>, height: Binding<CGFloat>, onDone: (() -> Void)? = nil) {
self.text = text
self.calculatedHeight = height
self.onDone = onDone
}
func textDidChange(_ notification: Notification) {
guard notification.name == NSText.didChangeNotification,
let textView = (notification.object as? NSTextView),
let latestText = textView.textStorage else { return }
text.wrappedValue = latestText
NSTextViewWrapper.recalculateHeight(view: textView, result: calculatedHeight)
}
func textView(_ textView: NSTextView, shouldChangeTextIn: NSRange, replacementString: String?) -> Bool {
if let onDone = self.onDone, replacementString == "\n" {
textView.resignFirstResponder()
onDone()
return false
}
return true
}
}
}
Solution thanks to #Asperi's tip to convert his UIKit code in this post. A few things had to change:
NSView also lacks the view.sizeThatFits() for a proposed bounds change, so I found that the view's .visibleRect would work instead.
Bugs:
There is a bobble on first render (from smaller vertically to the proper size). I thought it was caused by the recalculateHeight(), which would print out some smaller values initially. A gating statement there stopped those values, but the bobble is still there.
Currently I set the placeholder text's inset by a magic number, which should be done based on the NSTextView's attributes, but I didn't find anything usable yet. If it has the same font I guess I could just add a space or two in front of the placeholder text and be done with it.
Hope this saves some others making SwiftUI Mac apps some time.
import SwiftUI
// Wraps the NSTextView in a frame that can interact with SwiftUI
struct MultilineTextField: View {
private var placeholder: NSAttributedString
#Binding private var text: NSAttributedString
#State private var dynamicHeight: CGFloat // MARK TODO: - Find better way to stop initial view bobble (gets bigger)
#State private var textIsEmpty: Bool
#State private var textViewInset: CGFloat = 9 // MARK TODO: - Calculate insetad of magic number
var nsFont: NSFont
init (_ placeholder: NSAttributedString = NSAttributedString(string: ""),
text: Binding<NSAttributedString>,
nsFont: NSFont) {
self.placeholder = placeholder
self._text = text
_textIsEmpty = State(wrappedValue: text.wrappedValue.string.isEmpty)
self.nsFont = nsFont
_dynamicHeight = State(initialValue: nsFont.pointSize)
}
var body: some View {
ZStack {
NSTextViewWrapper(text: $text,
dynamicHeight: $dynamicHeight,
textIsEmpty: $textIsEmpty,
textViewInset: $textViewInset,
nsFont: nsFont)
.background(placeholderView, alignment: .topLeading)
// Adaptive frame applied to this NSViewRepresentable
.frame(minHeight: dynamicHeight, maxHeight: dynamicHeight)
}
}
// Background placeholder text matched to default font provided to the NSViewRepresentable
var placeholderView: some View {
Text(placeholder.string)
// Convert NSFont
.font(.system(size: nsFont.pointSize))
.opacity(textIsEmpty ? 0.3 : 0)
.padding(.leading, textViewInset)
.animation(.easeInOut(duration: 0.15))
}
}
// Creates the NSTextView
fileprivate struct NSTextViewWrapper: NSViewRepresentable {
#Binding var text: NSAttributedString
#Binding var dynamicHeight: CGFloat
#Binding var textIsEmpty: Bool
// Hoping to get this from NSTextView,
// but haven't found the right parameter yet
#Binding var textViewInset: CGFloat
var nsFont: NSFont
func makeCoordinator() -> Coordinator {
return Coordinator(text: $text,
height: $dynamicHeight,
textIsEmpty: $textIsEmpty,
nsFont: nsFont)
}
func makeNSView(context: NSViewRepresentableContext<NSTextViewWrapper>) -> NSTextView {
return context.coordinator.textView
}
func updateNSView(_ textView: NSTextView, context: NSViewRepresentableContext<NSTextViewWrapper>) {
NSTextViewWrapper.recalculateHeight(view: textView, result: $dynamicHeight, nsFont: nsFont)
}
fileprivate static func recalculateHeight(view: NSView, result: Binding<CGFloat>, nsFont: NSFont) {
// Uses visibleRect as view.sizeThatFits(CGSize())
// is not exposed in AppKit, except on NSControls.
let latestSize = view.visibleRect
if result.wrappedValue != latestSize.height &&
// MARK TODO: - The view initially renders slightly smaller than needed, then resizes.
// I thought the statement below would prevent the #State dynamicHeight, which
// sets itself AFTER this view renders, from causing it. Unfortunately that's not
// the right cause of that redawing bug.
latestSize.height > (nsFont.pointSize + 1) {
DispatchQueue.main.async {
result.wrappedValue = latestSize.height
print(#function, latestSize.height)
}
}
}
}
// Maintains the NSTextView's persistence despite redraws
fileprivate final class Coordinator: NSObject, NSTextViewDelegate, NSControlTextEditingDelegate {
var textView: NSTextView
#Binding var text: NSAttributedString
#Binding var dynamicHeight: CGFloat
#Binding var textIsEmpty: Bool
var nsFont: NSFont
init(text: Binding<NSAttributedString>,
height: Binding<CGFloat>,
textIsEmpty: Binding<Bool>,
nsFont: NSFont) {
_text = text
_dynamicHeight = height
_textIsEmpty = textIsEmpty
self.nsFont = nsFont
textView = NSTextView(frame: .zero)
textView.isEditable = true
textView.isSelectable = true
// Appearance
textView.usesAdaptiveColorMappingForDarkAppearance = true
textView.font = nsFont
textView.textColor = NSColor.textColor
textView.drawsBackground = false
textView.setContentCompressionResistancePriority(.defaultLow, for: .horizontal)
// Functionality (more available)
textView.allowsUndo = true
textView.isAutomaticLinkDetectionEnabled = true
textView.displaysLinkToolTips = true
textView.isAutomaticDataDetectionEnabled = true
textView.isAutomaticTextReplacementEnabled = true
textView.isAutomaticDashSubstitutionEnabled = true
textView.isAutomaticSpellingCorrectionEnabled = true
textView.isAutomaticQuoteSubstitutionEnabled = true
textView.isAutomaticTextCompletionEnabled = true
textView.isContinuousSpellCheckingEnabled = true
super.init()
// Load data from binding and set font
textView.textStorage?.setAttributedString(text.wrappedValue)
textView.textStorage?.font = nsFont
textView.delegate = self
}
func textDidChange(_ notification: Notification) {
// Recalculate height after every input event
NSTextViewWrapper.recalculateHeight(view: textView, result: $dynamicHeight, nsFont: nsFont)
// If ever empty, trigger placeholder text visibility
if let update = (notification.object as? NSTextView)?.string {
textIsEmpty = update.isEmpty
}
}
func textDidEndEditing(_ notification: Notification) {
// Update binding only after editing ends; useful to gate NSManagedObjects
$text.wrappedValue = textView.attributedString()
}
}
I found nice gist code created by unnamedd.
https://gist.github.com/unnamedd/6e8c3fbc806b8deb60fa65d6b9affab0
Sample Usage:
MacEditorTextView(
text: $text,
isEditable: true,
font: .monospacedSystemFont(ofSize: 12, weight: .regular)
)
.frame(minWidth: 300,
maxWidth: .infinity,
minHeight: 100,
maxHeight: .infinity)
.padding(12)
.cornerRadius(8)
I want the view containing 2 rectangles floating in the bottom of the screen, whatever the orientation is portrait or landscape.
code is a test, when orientationDidChangeNotification happened, I Found UIDevice.current.orientation.isPortrait and UIScreen.main.bounds.height often have wrong value, why?
Anyway, test code is just reset offset = 0 in onRotated(). but it doesn't work; otherwise onTapGesture works fine.
Q1: Is it a wrong way for SwiftUI? SceneDelegate.orientationDidChangeNotification -> contentView.onRotated()?
Q2: why do UIDevice.current.orientation.isPortrait and UIScreen.main.bounds.height often have wrong value?
Q3: How to let a view float at the bottom of screen in both portrait and landscape?
let height: CGFloat = 100
struct TestView: View {
#State var offset = (UIScreen.main.bounds.height - height) / 2
var body: some View {
ZStack {
Text("+")
VStack(spacing: 0) {
Rectangle().fill(Color.blue)
Rectangle().fill(Color.red)
}
.frame(width: 100, height: height)
.offset(y: offset)
.onTapGesture {
self.offset = 0
}
}
}
func onRotated() {
// let isPortrait = UIDevice.current.orientation.isPortrait
offset = 0//(UIScreen.main.bounds.height - height) / 2
// print("\(isPortrait), screen height = \(UIScreen.main.bounds.height)")
}
}
class SceneDelegate: UIResponder, UIWindowSceneDelegate {
var window: UIWindow?
func scene(_ scene: UIScene, willConnectTo session: UISceneSession, options connectionOptions: UIScene.ConnectionOptions) {
let contentView = TestView()
if let windowScene = scene as? UIWindowScene {
NotificationCenter.default.addObserver(forName: UIDevice.orientationDidChangeNotification, object: nil, queue: nil) { notification in
contentView.onRotated()
}
let window = UIWindow(windowScene: windowScene)
window.rootViewController = UIHostingController(rootView: contentView)
self.window = window
window.makeKeyAndVisible()
}
}
...
}
contentView is not a reference, it is a value, so you call .onRotated on own copy of contentView value that lives only within callback
let contentView = TestView()
if let windowScene = scene as? UIWindowScene {
NotificationCenter.default.addObserver(forName: UIDevice.orientationDidChangeNotification, object: nil, queue: nil) { notification in
contentView.onRotated() // local copy!!!
}
instead create listener for notification publisher inside TestView, so it can change self internally.
Moreover, it is not clear the intention but SwiftUI gives possibility to track size classes via EnvironmentValues.horizontalSizeClass and EnvironmentValues.verticalSizeClass which are automatically changed on device orientation, so it is possible to make your view layout depending on those environment values even w/o notification.
See here good example on how to use size classes
Suppose I have a simple SwiftUI View that is not the ContentView such as this:
struct Test: View {
var body: some View {
VStack {
Text("Test 1")
Text("Test 2")
}
}
}
How can I render this view as a UIImage?
I've looked into solutions such as :
extension UIView {
func asImage() -> UIImage {
let renderer = UIGraphicsImageRenderer(bounds: bounds)
return renderer.image { rendererContext in
layer.render(in: rendererContext.cgContext)
}
}
}
But it seems that solutions like that only work on UIView, not a SwiftUI View.
Here is the approach that works for me, as I needed to get image exactly sized as it is when placed alongside others. Hope it would be helpful for some else.
Demo: above divider is SwiftUI rendered, below is image (in border to show size)
Update: re-tested with Xcode 13.4 / iOS 15.5
Test module in project is here
extension View {
func asImage() -> UIImage {
let controller = UIHostingController(rootView: self)
// locate far out of screen
controller.view.frame = CGRect(x: 0, y: CGFloat(Int.max), width: 1, height: 1)
let size = controller.sizeThatFits(in: UIScreen.main.bounds.size)
controller.view.bounds = CGRect(origin: .zero, size: size)
controller.view.sizeToFit()
UIApplication.shared.windows.first?.rootViewController?.view.addSubview(controller.view)
let image = controller.view.asImage()
controller.view.removeFromSuperview()
return image
}
}
extension UIView {
func asImage() -> UIImage {
let renderer = UIGraphicsImageRenderer(bounds: bounds)
return renderer.image { rendererContext in
// [!!] Uncomment to clip resulting image
// rendererContext.cgContext.addPath(
// UIBezierPath(roundedRect: bounds, cornerRadius: 20).cgPath)
// rendererContext.cgContext.clip()
// As commented by #MaxIsom below in some cases might be needed
// to make this asynchronously, so uncomment below DispatchQueue
// if you'd same met crash
// DispatchQueue.main.async {
layer.render(in: rendererContext.cgContext)
// }
}
}
}
// TESTING
struct TestableView: View {
var body: some View {
VStack {
Text("Test 1")
Text("Test 2")
}
}
}
struct TestBackgroundRendering: View {
var body: some View {
VStack {
TestableView()
Divider()
Image(uiImage: render())
.border(Color.black)
}
}
private func render() -> UIImage {
TestableView().asImage()
}
}
Solution of Asperi works, but if you need image without white background you have to add this line:
controller.view.backgroundColor = .clear
And your View extension will be:
extension View {
func asImage() -> UIImage {
let controller = UIHostingController(rootView: self)
// locate far out of screen
controller.view.frame = CGRect(x: 0, y: CGFloat(Int.max), width: 1, height: 1)
UIApplication.shared.windows.first!.rootViewController?.view.addSubview(controller.view)
let size = controller.sizeThatFits(in: UIScreen.main.bounds.size)
controller.view.bounds = CGRect(origin: .zero, size: size)
controller.view.sizeToFit()
controller.view.backgroundColor = .clear
let image = controller.view.asImage()
controller.view.removeFromSuperview()
return image
}
}