fix gradient background

Session/Onboarding/FakeChatView.swift

@@ -46,12 +46,12 @@ final class FakeChatView : UIView {
         stackView.axis = .vertical
         stackView.spacing = spacing
         stackView.alignment = .fill
-        stackView.set(.width, to: UIScreen.main.bounds.width)
         let vInset = Values.smallSpacing
         stackView.layoutMargins = UIEdgeInsets(top: vInset, leading: Values.veryLargeSpacing, bottom: vInset, trailing: Values.veryLargeSpacing)
         stackView.isLayoutMarginsRelativeArrangement = true
         scrollView.addSubview(stackView)
         stackView.pin(to: scrollView)
+        stackView.set(.width, to: .width, of: scrollView)
         addSubview(scrollView)
         scrollView.pin(to: self)
         let height = chatBubbles.reduce(0) { $0 + $1.systemLayoutSizeFitting(UIView.layoutFittingExpandedSize).height } + CGFloat(chatBubbles.count - 1) * spacing + 2 * vInset

Session/Shared/BaseVC.swift

@@ -28,6 +28,13 @@ class BaseVC : UIViewController {
         NotificationCenter.default.addObserver(self, selector: #selector(appDidBecomeActive(_:)), name: .OWSApplicationDidBecomeActive, object: nil)
     }
     
+    override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
+        if hasGradient {
+            let frame = CGRect(x: 0, y: 0, width: size.width, height: size.height)
+            setUpGradientBackground(frame: frame)
+        }
+    }
+    
     internal func ensureWindowBackground() {
         let appMode = AppModeManager.shared.currentAppMode
         switch appMode {
@@ -38,11 +45,11 @@ class BaseVC : UIViewController {
         }
     }
 
-    internal func setUpGradientBackground() {
+    internal func setUpGradientBackground(frame: CGRect = UIScreen.main.bounds) {
         hasGradient = true
         view.backgroundColor = .clear
         let gradient = Gradients.defaultBackground
-        view.setGradient(gradient)
+        view.setGradient(gradient, frame: frame)
     }
 
     internal func setUpNavBarStyle() {

SessionUIKit/Style Guide/Gradients.swift

@@ -16,9 +16,9 @@ public final class Gradient : NSObject {
 
 @objc public extension UIView {
 
-    @objc func setGradient(_ gradient: Gradient) {
+    @objc func setGradient(_ gradient: Gradient, frame: CGRect = UIScreen.main.bounds) {
         let layer = CAGradientLayer()
-        layer.frame = UIScreen.main.bounds
+        layer.frame = frame
         layer.colors = [ gradient.start.cgColor, gradient.end.cgColor ]
         if let existingSublayer = self.layer.sublayers?[0], existingSublayer is CAGradientLayer {
             self.layer.replaceSublayer(existingSublayer, with: layer)