Merge pull request #1437 from mitchellh/theme-auto

config: add window-theme = auto for automatic choosing based on bg color

macos/Sources/App/macOS/AppDelegate.swift

@@ -377,6 +377,11 @@ class AppDelegate: NSObject,
         // Config could change window appearance
         syncAppearance()
         
+        // Update all of our windows
+        terminalManager.windows.forEach { window in
+            window.controller.configDidReload()
+        }
+        
         // If we have configuration errors, we need to show them.
         let c = ConfigurationErrorsController.sharedInstance
         c.errors = state.config.errors
@@ -399,6 +404,11 @@ class AppDelegate: NSObject,
             let appearance = NSAppearance(named: .aqua)
             NSApplication.shared.appearance = appearance
             
+        case "auto":
+            let color = OSColor(ghostty.config.backgroundColor)
+            let appearance = NSAppearance(named: color.isLightColor ? .aqua : .darkAqua)
+            NSApplication.shared.appearance = appearance
+        
         default:
             NSApplication.shared.appearance = nil
         }

macos/Sources/Features/Terminal/TerminalController.swift

@@ -105,6 +105,10 @@ class TerminalController: NSWindowController, NSWindowDelegate,
     
     //MARK: - Methods
     
+    func configDidReload() {
+        syncAppearance()
+    }
+    
     /// Update the accessory view of each tab according to the keyboard
     /// shortcut that activates it (if any). This is called when the key window
     /// changes and when a window is closed.
@@ -151,6 +155,20 @@ class TerminalController: NSWindowController, NSWindowDelegate,
         self.relabelTabs()
     }
     
+    private func syncAppearance() {
+        guard let window = self.window as? TerminalWindow else { return }
+        
+        // We match the appearance depending on the lightness/darkness of the
+        // background color. We have to do this because our titlebars in tabs inherit
+        // our background color for the focused tab but use the macOS theme for the
+        // rest of the titlebar.
+        if (window.titlebarTabs) {
+            let color = OSColor(ghostty.config.backgroundColor)
+            let appearance = NSAppearance(named: color.isLightColor ? .aqua : .darkAqua)
+            window.appearance = appearance
+        }
+    }
+    
     //MARK: - NSWindowController
     
     override func windowWillLoad() {
@@ -214,6 +232,7 @@ class TerminalController: NSWindowController, NSWindowDelegate,
         if (ghostty.config.macosTitlebarTabs) {
             window.tabbingMode = .preferred
             window.titlebarTabs = true
+            syncAppearance()
             DispatchQueue.main.async {
                 window.tabbingMode = .automatic
             }

macos/Sources/Features/Terminal/TerminalWindow.swift

@@ -59,16 +59,6 @@ class TerminalWindow: NSWindow {
             }) {
                 toolbarTitleView.isHidden = true
             }
-            
-            // We match the appearance depending on the lightness/darkness of the
-            // background color. We have to do this because our titlebars in tabs inherit
-            // our background color for the focused tab but use the macOS theme for the
-            // rest of the titlebar.
-            if let appDelegate = NSApp.delegate as? AppDelegate {
-                let color = OSColor(appDelegate.ghostty.config.backgroundColor)
-                let appearance = NSAppearance(named: color.isLightColor ? .aqua : .darkAqua)
-                self.appearance = appearance
-            }
         } else {
             // "expanded" places the toolbar below the titlebar, so setting this style and
             // removing the toolbar ensures that the titlebar will be the default height.

src/apprt/gtk/App.zig

@@ -133,6 +133,14 @@ pub fn init(core_app: *CoreApp, opts: Options) !App {
         c.adw_style_manager_set_color_scheme(
             style_manager,
             switch (config.@"window-theme") {
+                .auto => auto: {
+                    const lum = config.background.toTerminalRGB().perceivedLuminance();
+                    break :auto if (lum > 0.5)
+                        c.ADW_COLOR_SCHEME_PREFER_LIGHT
+                    else
+                        c.ADW_COLOR_SCHEME_PREFER_DARK;
+                },
+
                 .system => c.ADW_COLOR_SCHEME_PREFER_LIGHT,
                 .dark => c.ADW_COLOR_SCHEME_FORCE_DARK,
                 .light => c.ADW_COLOR_SCHEME_FORCE_LIGHT,

src/config/Config.zig

@@ -600,9 +600,13 @@ keybind: Keybinds = .{},
 /// borders.
 @"window-decoration": bool = true,
 
-/// The theme to use for the windows. The default is `system` which means that
+/// The theme to use for the windows. Valid values:
-/// whatever the system theme is will be used. This can also be set to `light`
+///
-/// or `dark` to force a specific theme regardless of the system settings.
+///   * `auto` - Determine the theme based on the configured terminal
+///      background color.
+///   * `system` - Use the system theme.
+///   * `light` - Use the light theme regardless of system theme.
+///   * `dark` - Use the dark theme regardless of system theme.
 ///
 /// On macOS, if `macos-titlebar-tabs` is set, the window theme will be
 /// automatically set based on the luminosity of the terminal background color.
@@ -610,7 +614,7 @@ keybind: Keybinds = .{},
 /// non-terminal windows within Ghostty.
 ///
 /// This is currently only supported on macOS and Linux.
-@"window-theme": WindowTheme = .system,
+@"window-theme": WindowTheme = .auto,
 
 /// The colorspace to use for the terminal window. The default is `srgb` but
 /// this can also be set to `display-p3` to use the Display P3 colorspace.
@@ -3342,6 +3346,7 @@ pub const OSCColorReportFormat = enum {
 
 /// The default window theme.
 pub const WindowTheme = enum {
+    auto,
     system,
     light,
     dark,

src/terminal/color.zig

@@ -144,6 +144,17 @@ pub const RGB = struct {
         return std.math.pow(f64, (normalized + 0.055) / 1.055, 2.4);
     }
 
+    /// Calculates "perceived luminance" which is better for determining
+    /// light vs dark.
+    ///
+    /// Source: https://www.w3.org/TR/AERT/#color-contrast
+    pub fn perceivedLuminance(self: RGB) f64 {
+        const r_f64: f64 = @floatFromInt(self.r);
+        const g_f64: f64 = @floatFromInt(self.g);
+        const b_f64: f64 = @floatFromInt(self.b);
+        return 0.299 * (r_f64 / 255) + 0.587 * (g_f64 / 255) + 0.114 * (b_f64 / 255);
+    }
+
     test "size" {
         try std.testing.expectEqual(@as(usize, 24), @bitSizeOf(RGB));
         try std.testing.expectEqual(@as(usize, 3), @sizeOf(RGB));