Extract window chrome domain from ContentView

.github/swift-file-length-budget.tsv

@@ -3,18 +3,18 @@
 # Reduce counts as files shrink. CI fails if tracked files exceed this budget.
 34475	CLI/cmux.swift
 17583	Sources/AppDelegate.swift
-16578	Sources/ContentView.swift
+15920	Sources/ContentView.swift
 14225	Sources/TerminalController.swift
-12645	Sources/Workspace.swift
+12646	Sources/Workspace.swift
 12115	cmuxTests/AppDelegateShortcutRoutingTests.swift
-11718	Sources/GhosttyTerminalView.swift
-11387	Sources/Panels/BrowserPanel.swift
+11731	Sources/GhosttyTerminalView.swift
+11388	Sources/Panels/BrowserPanel.swift
 9331	cmuxTests/CLINotifyProcessIntegrationRegressionTests.swift
 7931	Sources/Panels/BrowserPanelView.swift
 7356	cmuxTests/WorkspaceUnitTests.swift
 7221	cmuxTests/WorkspaceRemoteConnectionTests.swift
 6317	cmuxTests/SessionPersistenceTests.swift
-6222	cmuxTests/GhosttyConfigTests.swift
+6223	cmuxTests/GhosttyConfigTests.swift
 6154	Sources/TabManager.swift
 6153	CLI/cmux_open.swift
 6074	Sources/TextBoxInput.swift
@@ -24,10 +24,10 @@
 4516	Sources/cmuxApp.swift
 4467	Sources/Panels/FilePreviewPanel.swift
 4401	cmuxTests/BrowserPanelTests.swift
-4227	Sources/BrowserWindowPortal.swift
+4225	Sources/BrowserWindowPortal.swift
 3937	Sources/Feed/FeedPanelView.swift
 3926	cmuxTests/TabManagerUnitTests.swift
-3903	cmuxTests/WindowAndDragTests.swift
+3896	cmuxTests/WindowAndDragTests.swift
 3734	Packages/iOS/CmuxMobileTerminal/Sources/CmuxMobileTerminal/GhosttySurfaceView.swift
 3699	cmuxTests/CLIGenericHookPersistenceTests.swift
 3397	Sources/CmuxConfig.swift
@@ -42,7 +42,7 @@
 2395	Sources/Mobile/MobileHostService.swift
 2355	Sources/FileExplorerView.swift
 2328	cmuxTests/CJKIMEInputTests.swift
-2259	Sources/TerminalWindowPortal.swift
+2257	Sources/TerminalWindowPortal.swift
 2236	Sources/TerminalNotificationStore.swift
 2117	cmuxTests/CmuxConfigTests.swift
 2092	cmuxTests/ShortcutAndCommandPaletteTests.swift
@@ -185,7 +185,6 @@
 558	Packages/macOS/CmuxGit/Sources/CmuxGit/Parsing/GitMetadataService+Config.swift
 556	Sources/Panels/BrowserAutomation.swift
 551	Packages/macOS/CmuxSettingsUI/Sources/CmuxSettingsUI/Sections/BrowserSection.swift
-547	Sources/Windowing/WindowGlassEffect.swift
 541	Packages/macOS/CmuxControlSocket/Sources/CmuxControlSocket/Coordinator/Pane/ControlCommandCoordinator+Pane.swift
 540	Packages/macOS/CmuxWorkspaces/Sources/CmuxWorkspaces/Coordinators/WorkspaceReorderCoordinator.swift
 539	CLI/CMUXCLI+Themes.swift

Packages/macOS/CmuxAppKitSupportUI/Package.swift

@@ -13,9 +13,17 @@ let package = Package(
             targets: ["CmuxAppKitSupportUI"]
         ),
     ],
+    dependencies: [
+        .package(path: "../CmuxFoundation"),
+        .package(path: "../CmuxWorkspaceWindow"),
+    ],
     targets: [
         .target(
             name: "CmuxAppKitSupportUI",
+            dependencies: [
+                "CmuxFoundation",
+                "CmuxWorkspaceWindow",
+            ],
             swiftSettings: [
                 .swiftLanguageMode(.v6),
                 .enableUpcomingFeature("ExistentialAny"),

Packages/macOS/CmuxAppKitSupportUI/README.md

@@ -0,0 +1,86 @@
+# CmuxAppKitSupportUI
+
+AppKit/SwiftUI support pieces for the macOS app, grouped by concern. Each top-level folder is
+one concern: `WindowChrome/` (this is what the ContentView extraction added), plus the
+pre-existing `AboutTitlebarDebug/`, `Mouse/`, `Popover/`, and `Scroll/`. Most types are small
+`Sendable` value types or narrow `@MainActor` controllers, so resolution logic can be unit
+tested without a live window.
+
+## WindowChrome/
+
+"Window chrome" is everything cmux paints around and behind the terminal: the window
+background, the native titlebar backdrop, the sidebar material, the hairline borders, and the
+macOS 26 glass effect. There are many small types because the chrome is resolved in stages so
+each stage stays testable: read current state into a `*Snapshot`, resolve it into a
+`*Plan`/`*Policy`, then a `@MainActor` controller applies the plan to a real `NSWindow` and
+returns a `*Result`. The value types are pure and unit-tested; the AppKit mutation lives only
+in the controllers.
+
+Files are grouped into subfolders by the chrome concern they serve. One major public type per
+file, named after the type.
+
+### Appearance/
+Resolves the window's overall appearance for one render pass.
+- `WindowTerminalAppearanceSnapshot.swift`: current terminal colors/opacity chrome must match.
+- `WindowAppearanceUserSettingsSnapshot.swift`: the user settings that influence appearance.
+- `WindowAppearanceResolver.swift`: combines those two snapshots into a `WindowAppearanceSnapshot`.
+- `WindowAppearanceSnapshot.swift`: the resolved appearance value (colors, opacity, rendering-mode helpers) for one pass.
+- `WindowRootBackdropResolution.swift`: the root-backdrop result returned when a pane supplies its own color.
+
+### Backdrop/
+The window background fill and how it is applied to AppKit.
+- `WindowBackdropRole.swift`: which chrome surface a backdrop targets (root, titlebar, etc.).
+- `WindowBackdropPolicy.swift`: the rendering policy chosen for a surface.
+- `WindowBackdropHostingPhase.swift`: which AppKit hosting strategy is used.
+- `WindowBackdropGlassPlan.swift`: tint and glass style when the backdrop uses native glass.
+- `WindowBackdropPlan.swift`: the full set of `NSWindow` mutations for a resolved backdrop.
+- `WindowBackdropControllerDependencies.swift`: protocol of app-provided side effects the controller needs (injected).
+- `WindowBackdropController.swift`: `@MainActor` type that applies a plan/snapshot to an `NSWindow`.
+- `WindowBackdropApplicationResult.swift`: what changed after the controller ran.
+- `WindowBackdropLayer.swift`: SwiftUI view that renders the resolved backdrop for one role.
+- `LayerBackedBackdropColor.swift`: internal non-hit-testing AppKit color fill for transparent windows.
+
+### Glass/
+The macOS 26 `NSGlassEffectView` window glass, with an `NSVisualEffectView` fallback.
+- `WindowGlassEffectStyle.swift`: the native glass style applied when glass is available.
+- `WindowGlassSettingsSnapshot.swift`: persisted plus terminal-driven settings for the glass root.
+- `WindowGlassEffectManaging.swift`: protocol seam for applying and inspecting the glass hierarchy.
+- `WindowGlassEffect.swift`: `@MainActor` implementation of that seam (native glass + fallback).
+- `WindowGlassEffect+Views.swift`: internal AppKit view helpers used by `WindowGlassEffect`.
+- `GhosttyBackgroundBlur+WindowGlassEffectStyle.swift`: maps a Ghostty blur mode to a glass style.
+
+### Titlebar/
+The native AppKit titlebar.
+- `NativeTitlebarBackdropCoordinator.swift`: `@MainActor` type that hides/restores the native titlebar backdrop.
+- `TitlebarLeadingInsetReader.swift`: SwiftUI reader for the inset needed to clear traffic lights and accessories.
+
+### Border/
+The hairline borders between chrome surfaces.
+- `WindowChromeBorderOrientation.swift`: orientation of a one-pixel border.
+- `WindowChromeBorder.swift`: SwiftUI one-pixel border derived from the chrome background color.
+
+### Color/
+Color math shared across chrome.
+- `WindowChromeColorResolver.swift`: separator color, compositing, and readable-scheme math.
+
+### Sidebar/
+The sidebar backdrop material and its persisted options.
+- `SidebarBackdropSettingsSnapshot.swift`: persisted sidebar backdrop settings as a value.
+- `SidebarBackdropMaterialPolicy.swift`: the resolved AppKit material settings for the sidebar.
+- `SidebarVisualEffectBackground.swift`: internal wrapper view (native glass, falls back to visual effect).
+- `WindowChromeSidebarPresetOption.swift`: `sidebarPreset` setting values.
+- `WindowChromeSidebarMaterialOption.swift`: `sidebarMaterial` setting values.
+- `WindowChromeSidebarBlendModeOption.swift`: `sidebarBlendMode` setting values.
+- `WindowChromeSidebarStateOption.swift`: `sidebarState` setting values.
+- `WindowChromeSidebarTintDefaults.swift`: legacy default sidebar tint constants.
+
+### TerminalSurface/
+How an individual terminal surface paints its own background.
+- `GhosttyTerminalBackdropRenderingMode.swift`: who owns the terminal backdrop pixels.
+- `TerminalSurfaceBackgroundFillOwner.swift`: which layer paints a surface background.
+- `TerminalSurfaceBackgroundFillPlan.swift`: the resolved fill decision for one surface.
+
+### Overlay/
+Where window-level overlays are inserted in the AppKit hierarchy.
+- `WindowContentOverlayInstallationTarget.swift`: the container/reference pair to install into.
+- `WindowContentOverlayTargetResolver.swift`: resolves the insertion point for a window.

Packages/macOS/CmuxAppKitSupportUI/Sources/CmuxAppKitSupportUI/WindowChrome/Appearance/WindowAppearanceResolver.swift

@@ -0,0 +1,72 @@
+import AppKit
+public import SwiftUI
+import CmuxFoundation
+
+/// Builds `WindowAppearanceSnapshot` values from injected terminal and user settings.
+public struct WindowAppearanceResolver {
+    private let terminalAppearance: WindowTerminalAppearanceSnapshot
+
+    /// Creates a resolver with the current terminal appearance injected by the app.
+    public init(terminalAppearance: WindowTerminalAppearanceSnapshot) {
+        self.terminalAppearance = terminalAppearance
+    }
+
+    /// Resolves window appearance from explicit user settings.
+    public func current(settings: WindowAppearanceUserSettingsSnapshot) -> WindowAppearanceSnapshot {
+        WindowAppearanceSnapshot(
+            terminalBackgroundColor: terminalAppearance.backgroundColor,
+            terminalBackgroundOpacity: WindowAppearanceSnapshot.clampedOpacity(terminalAppearance.backgroundOpacity),
+            terminalBackgroundBlur: terminalAppearance.backgroundBlur,
+            terminalRenderingMode: WindowAppearanceSnapshot.terminalRenderingMode(
+                usesHostLayerBackground: terminalAppearance.usesHostLayerBackground
+            ),
+            unifySurfaceBackdrops: settings.unifySurfaceBackdrops,
+            sidebarSettings: SidebarBackdropSettingsSnapshot(
+                materialRawValue: settings.sidebarMaterial,
+                blendModeRawValue: settings.sidebarBlendMode,
+                stateRawValue: settings.sidebarState,
+                tintHex: settings.sidebarTintHex,
+                tintHexLight: settings.sidebarTintHexLight,
+                tintHexDark: settings.sidebarTintHexDark,
+                tintOpacity: settings.sidebarTintOpacity,
+                cornerRadius: settings.sidebarCornerRadius,
+                blurOpacity: settings.sidebarBlurOpacity,
+                colorScheme: settings.colorScheme
+            ),
+            windowGlassSettings: WindowGlassSettingsSnapshot(
+                sidebarBlendModeRawValue: settings.sidebarBlendMode,
+                isEnabled: settings.bgGlassEnabled,
+                tintHex: settings.bgGlassTintHex,
+                tintOpacity: settings.bgGlassTintOpacity,
+                terminalBackgroundBlur: terminalAppearance.backgroundBlur,
+                terminalGlassTintColor: terminalAppearance.backgroundColor.withAlphaComponent(
+                    WindowAppearanceSnapshot.clampedOpacity(terminalAppearance.backgroundOpacity)
+                )
+            )
+        )
+    }
+
+    /// Resolves window appearance from a `UserDefaults` store.
+    public func currentFromUserDefaults(
+        defaults: UserDefaults,
+        colorScheme: ColorScheme
+    ) -> WindowAppearanceSnapshot {
+        let tintDefaults = WindowChromeSidebarTintDefaults()
+        return current(settings: WindowAppearanceUserSettingsSnapshot(
+            unifySurfaceBackdrops: defaults.object(forKey: "sidebarMatchTerminalBackground") as? Bool ?? false,
+            colorScheme: colorScheme,
+            sidebarMaterial: defaults.string(forKey: "sidebarMaterial") ?? WindowChromeSidebarMaterialOption.sidebar.rawValue,
+            sidebarBlendMode: defaults.string(forKey: "sidebarBlendMode") ?? WindowChromeSidebarBlendModeOption.withinWindow.rawValue,
+            sidebarState: defaults.string(forKey: "sidebarState") ?? WindowChromeSidebarStateOption.followWindow.rawValue,
+            sidebarTintHex: defaults.string(forKey: "sidebarTintHex") ?? tintDefaults.hex,
+            sidebarTintHexLight: defaults.string(forKey: "sidebarTintHexLight"),
+            sidebarTintHexDark: defaults.string(forKey: "sidebarTintHexDark"),
+            sidebarTintOpacity: defaults.object(forKey: "sidebarTintOpacity") as? Double ?? tintDefaults.opacity,
+            sidebarCornerRadius: defaults.object(forKey: "sidebarCornerRadius") as? Double ?? 0.0,
+            sidebarBlurOpacity: defaults.object(forKey: "sidebarBlurOpacity") as? Double ?? 1.0,
+            bgGlassEnabled: defaults.object(forKey: "bgGlassEnabled") as? Bool ?? false,
+            bgGlassTintHex: defaults.string(forKey: "bgGlassTintHex") ?? "#000000",
+            bgGlassTintOpacity: defaults.object(forKey: "bgGlassTintOpacity") as? Double ?? 0.03
+        ))
+    }
+}