Use dark blur for navbar

In the light theme, using the "light" blur allows the bar to seem invisible
when over white content. Similarly for the "dark" blur over black content.

Signal/src/ViewControllers/ConversationView/ConversationInputToolbar.m

@@ -92,8 +92,7 @@ const CGFloat kMaxTextViewHeight = 98;
         CGFloat alpha = OWSNavigationBar.backgroundBlurMutingFactor;
         self.backgroundColor = [Theme.toolbarBackgroundColor colorWithAlphaComponent:alpha];
 
-        UIBlurEffect *blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];
-        UIVisualEffectView *blurEffectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];
+        UIVisualEffectView *blurEffectView = [[UIVisualEffectView alloc] initWithEffect:Theme.barBlurEffect];
         [self addSubview:blurEffectView];
         [blurEffectView autoPinEdgesToSuperviewEdges];
     }

SignalMessaging/Views/OWSNavigationBar.swift

@@ -40,57 +40,76 @@ public class OWSNavigationBar: UINavigationBar {
 
     @objc
     public static let backgroundBlurMutingFactor: CGFloat = 0.5
-    var blurEffectView: UIView?
+    var blurEffectView: UIVisualEffectView?
 
     override init(frame: CGRect) {
         super.init(frame: frame)
 
-        if !UIAccessibilityIsReduceTransparencyEnabled() {
+        applyTheme()
+
+        NotificationCenter.default.addObserver(self, selector: #selector(callDidChange), name: .OWSWindowManagerCallDidChange, object: nil)
+        NotificationCenter.default.addObserver(self, selector: #selector(didChangeStatusBarFrame), name: .UIApplicationDidChangeStatusBarFrame, object: nil)
+        NotificationCenter.default.addObserver(self,
+                                               selector: #selector(themeDidChange),
+                                               name: .ThemeDidChange,
+                                               object: nil)
+    }
+
+    // MARK: Theme
+
+    private func applyTheme() {
+        if UIAccessibilityIsReduceTransparencyEnabled() {
+            self.blurEffectView?.removeFromSuperview()
+            let color = Theme.navbarBackgroundColor
+            let backgroundImage = UIImage(color: color)
+            self.setBackgroundImage(backgroundImage, for: .default)
+        } else {
             // Make navbar more translucent than default. Navbars remove alpha from any assigned backgroundColor, so
             // to achieve transparency, we have to assign a transparent image.
             let color = Theme.navbarBackgroundColor.withAlphaComponent(OWSNavigationBar.backgroundBlurMutingFactor)
             let backgroundImage = UIImage(color: color)
             self.setBackgroundImage(backgroundImage, for: .default)
-            let blurEffect = UIBlurEffect(style: .light)
-            let blurEffectView = UIVisualEffectView(effect: blurEffect)
-            blurEffectView.isUserInteractionEnabled = false
-            self.blurEffectView = blurEffectView
+
+            let blurEffect = Theme.barBlurEffect
+
+            let blurEffectView: UIVisualEffectView = {
+                if let existingBlurEffectView = self.blurEffectView {
+                    return existingBlurEffectView
+                }
+
+                let blurEffectView = UIVisualEffectView()
+                blurEffectView.isUserInteractionEnabled = false
+
+                self.blurEffectView = blurEffectView
+                self.insertSubview(blurEffectView, at: 0)
+
+                // navbar frame doesn't account for statusBar, so, same as the built-in navbar background, we need to exceed
+                // the navbar bounds to have the blur extend up and behind the status bar.
+                blurEffectView.autoPinEdgesToSuperviewEdges(with: UIEdgeInsets(top: -statusBarHeight, left: 0, bottom: 0, right: 0))
+
+                return blurEffectView
+            }()
+
+            blurEffectView.effect = blurEffect
 
             // remove hairline below bar.
             self.shadowImage = UIImage()
 
-            self.insertSubview(blurEffectView, at: 0)
             // On iOS11, despite inserting the blur at 0, other views are later inserted into the navbar behind the blur,
             // so we have to set a zindex to avoid obscuring navbar title/buttons.
             blurEffectView.layer.zPosition = -1
 
-            // navbar frame doesn't account for statusBar, so, same as the built-in navbar background, we need to exceed
-            // the navbar bounds to have the blur extend up and behind the status bar.
-            blurEffectView.autoPinEdgesToSuperviewEdges(with: UIEdgeInsets(top: -statusBarHeight, left: 0, bottom: 0, right: 0))
         }
-
-        NotificationCenter.default.addObserver(self, selector: #selector(callDidChange), name: .OWSWindowManagerCallDidChange, object: nil)
-        NotificationCenter.default.addObserver(self, selector: #selector(didChangeStatusBarFrame), name: .UIApplicationDidChangeStatusBarFrame, object: nil)
-        NotificationCenter.default.addObserver(self,
-                                               selector: #selector(themeDidChange),
-                                               name: .ThemeDidChange,
-                                               object: nil)
     }
 
-    // MARK: Layout
-
     @objc
     public func themeDidChange() {
         Logger.debug("\(self.logTag) in \(#function)")
-
-        guard self.backgroundImage(for: .default) != nil else {
-            return
-        }
-        let color = Theme.navbarBackgroundColor.withAlphaComponent(OWSNavigationBar.backgroundBlurMutingFactor)
-        let backgroundImage = UIImage(color: color)
-        self.setBackgroundImage(backgroundImage, for: .default)
+        applyTheme()
     }
 
+    // MARK: Layout
+
     @objc
     public func callDidChange() {
         Logger.debug("\(self.logTag) in \(#function)")

SignalMessaging/categories/Theme.h

@@ -47,6 +47,7 @@ extern NSString *const ThemeDidChangeNotification;
 @property (class, readonly, nonatomic) UIBarStyle barStyle;
 @property (class, readonly, nonatomic) UISearchBarStyle searchBarStyle;
 @property (class, readonly, nonatomic) UIColor *searchBarBackgroundColor;
+@property (class, readonly, nonatomic) UIBlurEffect *barBlurEffect;
 
 @end
 

SignalMessaging/categories/Theme.m

@@ -123,6 +123,12 @@ NSString *const ThemeKeyThemeEnabled = @"ThemeKeyThemeEnabled";
     return (Theme.isDarkThemeEnabled ? [UIColor colorWithWhite:0.35f alpha:1.f] : UIColor.ows_light02Color);
 }
 
++ (UIBlurEffect *)barBlurEffect
+{
+    return Theme.isDarkThemeEnabled ? [UIBlurEffect effectWithStyle:UIBlurEffectStyleDark]
+                                    : [UIBlurEffect effectWithStyle:UIBlurEffectStyleLight];
+}
+
 #pragma mark -
 
 + (UIBarStyle)barStyle