feat: add system tray resident mode support

.gitignore

@@ -1,6 +1,7 @@
 build/bin
 node_modules
-frontend/dist
+frontend/dist/*
+!frontend/dist/.gitkeep
 frontend/coverage
 # macOS
 .DS_Store

frontend/src/SettingsWindow.tsx

@@ -19,6 +19,7 @@ function SettingsWindow() {
     const [exportFolder, setExportFolder] = useState("");
     const [jpegQuality, setJpegQuality] = useState("auto");
     const [enableBetaUpdates, setEnableBetaUpdates] = useState<boolean>(false);
+    const [residentMode, setResidentMode] = useState<boolean>(true);
 
     // Frame Settings
     const [aspectRatioPreset, setAspectRatioPreset] = useState<string>("4300:3618");
@@ -48,6 +49,7 @@ function SettingsWindow() {
         setExportFolder(s.exportFolder || "");
         setJpegQuality(s.jpegQuality || "auto");
         setEnableBetaUpdates(s.enableBetaUpdates ?? false);
+        setResidentMode(s.residentMode ?? true);
 
         setAspectRatioPreset(s.aspectRatioPreset || "4300:3618");
         setCustomRatioW(s.customRatioW || 4300);
@@ -105,6 +107,7 @@ function SettingsWindow() {
         s.exportFolder = exportFolder;
         s.jpegQuality = jpegQuality;
         s.enableBetaUpdates = enableBetaUpdates;
+        s.residentMode = residentMode;
         s.aspectRatioPreset = aspectRatioPreset;
         s.customRatioW = customRatioW;
         s.customRatioH = customRatioH;
@@ -237,6 +240,18 @@ function SettingsWindow() {
                                 </label>
                                 <small style={{ display: 'block', marginTop: '0.5rem', marginLeft: '1.5rem', color: 'var(--text-secondary)', textAlign: 'left' }}>Receive pre-release (beta) versions of ExifFrame automatically.</small>
                             </div>
+                            <div className="input-group">
+                                <label style={{ display: 'flex', alignItems: 'center', gap: '0.5rem', cursor: 'pointer', fontWeight: 'normal', margin: 0, color: 'var(--text-primary)', fontSize: '0.85rem' }}>
+                                    <input 
+                                        type="checkbox" 
+                                        checked={residentMode} 
+                                        onChange={(e) => setResidentMode(e.target.checked)} 
+                                        style={{ margin: 0, width: 'auto', height: 'auto', cursor: 'pointer' }}
+                                    />
+                                    Keep running in system tray
+                                </label>
+                                <small style={{ display: 'block', marginTop: '0.5rem', marginLeft: '1.5rem', color: 'var(--text-secondary)', textAlign: 'left' }}>When enabled, closing the window keeps ExifFrame running in the menu bar. Changes take effect after restarting the app.</small>
+                            </div>
                         </div>
                     )}
                     {activeTab === 'frame' && (

main.go

@@ -4,14 +4,20 @@ import (
 	"embed"
 	"log"
 	"runtime"
+	"sync/atomic"
 
 	"github.com/wailsapp/wails/v3/pkg/application"
 	"github.com/wailsapp/wails/v3/pkg/events"
 )
 
+//go:embed build/trayicon.png
+var trayIcon []byte
+
 //go:embed all:frontend/dist
 var assets embed.FS
 
+var isQuitting atomic.Bool
+
 func buildMenu(app *App) *application.Menu {
 	appMenu := application.NewMenu()
 
@@ -77,6 +83,11 @@ func main() {
 	handler := NewImageHandler(appStruct)
 	appStruct.handler = handler
 
+	// Read resident mode setting (read once at startup; changes require restart).
+	settingsMu.RLock()
+	residentMode := currentSettings.ResidentMode
+	settingsMu.RUnlock()
+
 	app := application.New(application.Options{
 		Name:        "ExifFrame",
 		Description: "ExifFrame",
@@ -88,7 +99,11 @@ func main() {
 			Middleware: handler.Middleware,
 		},
 		Mac: application.MacOptions{
-			ApplicationShouldTerminateAfterLastWindowClosed: true,
+			ApplicationShouldTerminateAfterLastWindowClosed: !residentMode,
+		},
+		ShouldQuit: func() bool {
+			isQuitting.Store(true)
+			return true
 		},
 	})
 	app.Menu.SetApplicationMenu(buildMenu(appStruct))
@@ -119,6 +134,51 @@ func main() {
 		}
 	})
 
+	// --- System Tray (Resident Mode) ---
+	if residentMode {
+		// Intercept window close: hide instead of destroy.
+		win.RegisterHook(events.Common.WindowClosing, func(e *application.WindowEvent) {
+			if isQuitting.Load() {
+				return
+			}
+			win.Hide()
+			e.Cancel()
+		})
+
+		// Build tray right-click menu.
+		trayMenu := application.NewMenu()
+		trayMenu.Add("Show ExifFrame").OnClick(func(ctx *application.Context) {
+			win.Show()
+			win.Focus()
+		})
+		trayMenu.Add("Preferences...").OnClick(func(ctx *application.Context) {
+			appStruct.OpenSettingsWindow()
+		})
+		trayMenu.AddSeparator()
+		trayMenu.Add("Quit ExifFrame").OnClick(func(ctx *application.Context) {
+			application.Get().Quit()
+		})
+
+		systray := app.SystemTray.New()
+		if runtime.GOOS == "darwin" {
+			systray.SetTemplateIcon(trayIcon) // Auto-adapts to dark/light mode on macOS
+		} else {
+			systray.SetIcon(trayIcon)
+		}
+		systray.SetMenu(trayMenu)
+		systray.SetTooltip("ExifFrame")
+
+		// Left-click toggles main window visibility.
+		systray.OnClick(func() {
+			if win.IsVisible() {
+				win.Hide()
+			} else {
+				win.Show()
+				win.Focus()
+			}
+		})
+	}
+
 	err := app.Run()
 	if err != nil {
 		log.Fatal("Error:", err)

settings.go

@@ -55,6 +55,9 @@ type Settings struct {
 
 	// Updater settings
 	EnableBetaUpdates bool `json:"enableBetaUpdates"`
+
+	// System tray settings
+	ResidentMode bool `json:"residentMode"`
 }
 
 var (
@@ -101,6 +104,7 @@ func init() {
 		VisibilityTemperature:  true,
 		VisibilityTime:         true,
 		EnableBetaUpdates:      false,
+		ResidentMode:           true,
 	}
 	loadSettings()
 }