Refactor glass effect into TerminalGlassView and add inactive window tint overlay

macos/Sources/Features/Terminal/TerminalViewContainer.swift

@@ -6,9 +6,8 @@ import SwiftUI
 class TerminalViewContainer<ViewModel: TerminalViewModel>: NSView {
     private let terminalView: NSView
 
-    /// Glass effect view for liquid glass background when transparency is enabled
+    /// Combined glass effect and inactive tint overlay view
     private var glassEffectView: NSView?
-    private var glassTopConstraint: NSLayoutConstraint?
     private var derivedConfig: DerivedConfig
 
     init(ghostty: Ghostty.App, viewModel: ViewModel, delegate: (any TerminalViewDelegate)? = nil) {
@@ -27,6 +26,10 @@ class TerminalViewContainer<ViewModel: TerminalViewModel>: NSView {
         fatalError("init(coder:) has not been implemented")
     }
 
+    deinit {
+        NotificationCenter.default.removeObserver(self)
+    }
+
     /// To make ``TerminalController/DefaultSize/contentIntrinsicSize``
     /// work in ``TerminalController/windowDidLoad()``,
     /// we override this to provide the correct size.
@@ -50,6 +53,20 @@ class TerminalViewContainer<ViewModel: TerminalViewModel>: NSView {
             name: .ghosttyConfigDidChange,
             object: nil
         )
+
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(windowDidBecomeKey(_:)),
+            name: NSWindow.didBecomeKeyNotification,
+            object: nil
+        )
+
+        NotificationCenter.default.addObserver(
+            self,
+            selector: #selector(windowDidResignKey(_:)),
+            name: NSWindow.didResignKeyNotification,
+            object: nil
+        )
     }
 
     override func viewDidMoveToWindow() {
@@ -72,36 +89,139 @@ class TerminalViewContainer<ViewModel: TerminalViewModel>: NSView {
         derivedConfig = newValue
         DispatchQueue.main.async(execute: updateGlassEffectIfNeeded)
     }
+
+    @objc private func windowDidBecomeKey(_ notification: Notification) {
+        guard let window = notification.object as? NSWindow,
+              window == self.window else { return }
+        updateGlassTintOverlay(isKeyWindow: true)
+    }
+
+    @objc private func windowDidResignKey(_ notification: Notification) {
+        guard let window = notification.object as? NSWindow,
+              window == self.window else { return }
+        updateGlassTintOverlay(isKeyWindow: false)
+    }
 }
 
 // MARK: Glass
 
+/// An `NSView` that contains a liquid glass background effect and
+/// an inactive-window tint overlay.
+#if compiler(>=6.2)
+@available(macOS 26.0, *)
+private class TerminalGlassView: NSView {
+    private let glassEffectView: NSGlassEffectView
+    private var glassTopConstraint: NSLayoutConstraint?
+    private let tintOverlay: NSView
+    private var tintTopConstraint: NSLayoutConstraint?
+
+    init(topOffset: CGFloat) {
+        self.glassEffectView = NSGlassEffectView()
+        self.tintOverlay = NSView()
+        super.init(frame: .zero)
+
+        translatesAutoresizingMaskIntoConstraints = false
+
+        // Glass effect view fills this view.
+        glassEffectView.translatesAutoresizingMaskIntoConstraints = false
+        addSubview(glassEffectView)
+        glassTopConstraint = glassEffectView.topAnchor.constraint(
+            equalTo: topAnchor,
+            constant: topOffset
+        )
+        if let glassTopConstraint {
+            NSLayoutConstraint.activate([
+                glassTopConstraint,
+                glassEffectView.leadingAnchor.constraint(equalTo: leadingAnchor),
+                glassEffectView.bottomAnchor.constraint(equalTo: bottomAnchor),
+                glassEffectView.trailingAnchor.constraint(equalTo: trailingAnchor),
+            ])
+        }
+
+        // Tint overlay sits above the glass effect.
+        tintOverlay.translatesAutoresizingMaskIntoConstraints = false
+        tintOverlay.wantsLayer = true
+        tintOverlay.alphaValue = 0
+        addSubview(tintOverlay, positioned: .above, relativeTo: glassEffectView)
+        tintTopConstraint = tintOverlay.topAnchor.constraint(
+            equalTo: topAnchor,
+            constant: topOffset
+        )
+        if let tintTopConstraint {
+            NSLayoutConstraint.activate([
+                tintTopConstraint,
+                tintOverlay.leadingAnchor.constraint(equalTo: leadingAnchor),
+                tintOverlay.bottomAnchor.constraint(equalTo: bottomAnchor),
+                tintOverlay.trailingAnchor.constraint(equalTo: trailingAnchor),
+            ])
+        }
+    }
+
+    @available(*, unavailable)
+    required init?(coder: NSCoder) {
+        fatalError("init(coder:) has not been implemented")
+    }
+
+    /// Configures the glass effect style, tint color, corner radius, and
+    /// updates the inactive tint overlay based on window key status.
+    func configure(
+        style: NSGlassEffectView.Style,
+        backgroundColor: NSColor,
+        backgroundOpacity: Double,
+        cornerRadius: CGFloat?,
+        isKeyWindow: Bool
+    ) {
+        glassEffectView.style = style
+        glassEffectView.tintColor = backgroundColor.withAlphaComponent(backgroundOpacity)
+        if let cornerRadius {
+            glassEffectView.cornerRadius = cornerRadius
+        }
+        updateKeyStatus(isKeyWindow, backgroundColor: backgroundColor)
+    }
+
+    /// Updates the top inset offset for both the glass effect and tint overlay.
+    /// Call this when the safe area insets change (e.g., during layout).
+    func updateTopInset(_ offset: CGFloat) {
+        glassTopConstraint?.constant = offset
+        tintTopConstraint?.constant = offset
+    }
+
+    /// Updates the tint overlay visibility based on window key status.
+    func updateKeyStatus(_ isKeyWindow: Bool, backgroundColor: NSColor) {
+        let tint = tintProperties(for: backgroundColor)
+        tintOverlay.layer?.backgroundColor = tint.color.cgColor
+        tintOverlay.alphaValue = isKeyWindow ? 0 : tint.opacity
+    }
+
+    /// Computes a saturation-boosted tint color and opacity for the inactive overlay.
+    private func tintProperties(for color: NSColor) -> (color: NSColor, opacity: CGFloat) {
+        let isLight = color.isLightColor
+        let vibrant = color.adjustingSaturation(by: 1.2)
+        let overlayOpacity: CGFloat = isLight ? 0.35 : 0.85
+        return (vibrant, overlayOpacity)
+    }
+}
+#endif // compiler(>=6.2)
+
 private extension TerminalViewContainer {
 #if compiler(>=6.2)
     @available(macOS 26.0, *)
-    func addGlassEffectViewIfNeeded() -> NSGlassEffectView? {
-        if let existed = glassEffectView as? NSGlassEffectView {
+    func addGlassEffectViewIfNeeded() -> TerminalGlassView? {
+        if let existed = glassEffectView as? TerminalGlassView {
             updateGlassEffectTopInsetIfNeeded()
             return existed
         }
         guard let themeFrameView = window?.contentView?.superview else {
             return nil
         }
-        let effectView = NSGlassEffectView()
+        let effectView = TerminalGlassView(topOffset: -themeFrameView.safeAreaInsets.top)
         addSubview(effectView, positioned: .below, relativeTo: terminalView)
-        effectView.translatesAutoresizingMaskIntoConstraints = false
-        glassTopConstraint = effectView.topAnchor.constraint(
-            equalTo: topAnchor,
-            constant: -themeFrameView.safeAreaInsets.top
-        )
-        if let glassTopConstraint {
-            NSLayoutConstraint.activate([
-                glassTopConstraint,
-                effectView.leadingAnchor.constraint(equalTo: leadingAnchor),
-                effectView.bottomAnchor.constraint(equalTo: bottomAnchor),
-                effectView.trailingAnchor.constraint(equalTo: trailingAnchor),
-            ])
-        }
+        NSLayoutConstraint.activate([
+            effectView.topAnchor.constraint(equalTo: topAnchor),
+            effectView.leadingAnchor.constraint(equalTo: leadingAnchor),
+            effectView.bottomAnchor.constraint(equalTo: bottomAnchor),
+            effectView.trailingAnchor.constraint(equalTo: trailingAnchor),
+        ])
         glassEffectView = effectView
         return effectView
     }
@@ -112,26 +232,35 @@ private extension TerminalViewContainer {
         guard #available(macOS 26.0, *), derivedConfig.backgroundBlur.isGlassStyle else {
             glassEffectView?.removeFromSuperview()
             glassEffectView = nil
-            glassTopConstraint = nil
             return
         }
         guard let effectView = addGlassEffectViewIfNeeded() else {
             return
         }
+
+        let style: NSGlassEffectView.Style
         switch derivedConfig.backgroundBlur {
         case .macosGlassRegular:
-            effectView.style = NSGlassEffectView.Style.regular
+            style = NSGlassEffectView.Style.regular
         case .macosGlassClear:
-            effectView.style = NSGlassEffectView.Style.clear
+            style = NSGlassEffectView.Style.clear
         default:
-            break
+            style = NSGlassEffectView.Style.regular
         }
         let backgroundColor = (window as? TerminalWindow)?.preferredBackgroundColor ?? NSColor(derivedConfig.backgroundColor)
-        effectView.tintColor = backgroundColor
-            .withAlphaComponent(derivedConfig.backgroundOpacity)
-        if let window, window.responds(to: Selector(("_cornerRadius"))), let cornerRadius = window.value(forKey: "_cornerRadius") as? CGFloat {
-            effectView.cornerRadius = cornerRadius
+
+        var cornerRadius: CGFloat?
+        if let window, window.responds(to: Selector(("_cornerRadius"))) {
+            cornerRadius = window.value(forKey: "_cornerRadius") as? CGFloat
         }
+
+        effectView.configure(
+            style: style,
+            backgroundColor: backgroundColor,
+            backgroundOpacity: derivedConfig.backgroundOpacity,
+            cornerRadius: cornerRadius,
+            isKeyWindow: window?.isKeyWindow ?? true
+        )
 #endif // compiler(>=6.2)
     }
 
@@ -142,7 +271,16 @@ private extension TerminalViewContainer {
         }
         guard glassEffectView != nil else { return }
         guard let themeFrameView = window?.contentView?.superview else { return }
-        glassTopConstraint?.constant = -themeFrameView.safeAreaInsets.top
+        (glassEffectView as? TerminalGlassView)?.updateTopInset(-themeFrameView.safeAreaInsets.top)
+#endif // compiler(>=6.2)
+    }
+
+    func updateGlassTintOverlay(isKeyWindow: Bool) {
+#if compiler(>=6.2)
+        guard #available(macOS 26.0, *) else { return }
+        guard glassEffectView != nil else { return }
+        let backgroundColor = (window as? TerminalWindow)?.preferredBackgroundColor ?? NSColor(derivedConfig.backgroundColor)
+        (glassEffectView as? TerminalGlassView)?.updateKeyStatus(isKeyWindow, backgroundColor: backgroundColor)
 #endif // compiler(>=6.2)
     }
 

macos/Sources/Helpers/Extensions/NSColor+Extension.swift

@@ -24,6 +24,14 @@ extension NSColor {
         appleColorList?.allKeys.map { $0.lowercased() } ?? []
     }
 
+    /// Returns a new color with its saturation multiplied by the given factor, clamped to [0, 1].
+    func adjustingSaturation(by factor: CGFloat) -> NSColor {
+        var h: CGFloat = 0, s: CGFloat = 0, b: CGFloat = 0, a: CGFloat = 0
+        let hsbColor = self.usingColorSpace(.sRGB) ?? self
+        hsbColor.getHue(&h, saturation: &s, brightness: &b, alpha: &a)
+        return NSColor(hue: h, saturation: min(max(s * factor, 0), 1), brightness: b, alpha: a)
+    }
+
     /// Calculates the perceptual distance to another color in RGB space.
     func distance(to other: NSColor) -> Double {
         guard let a = self.usingColorSpace(.sRGB),