Add cancel functionality to Dashboard GUI processing

dashboard_gui.py

@@ -1711,6 +1711,10 @@ class DashboardGUI:
         self.process_btn = ttk.Button(form_frame, text="🚀 Start Processing", command=self._run_process)
         self.process_btn.grid(row=1, column=0, sticky=tk.W, pady=(20, 0))
         
+        # Cancel button (initially hidden/disabled)
+        self.cancel_btn = tk.Button(form_frame, text="✖ Cancel", command=self._cancel_process, state="disabled")
+        self.cancel_btn.grid(row=1, column=0, sticky=tk.E, pady=(20, 0))
+        
         # Progress bar
         self.progress_var = tk.DoubleVar()
         self.progress_bar = ttk.Progressbar(form_frame, variable=self.progress_var, 
@@ -1993,42 +1997,33 @@ class DashboardGUI:
                 messagebox.showerror("Process", "Please enter a valid positive integer for limit.", parent=self.root)
                 return
 
+        # Allow cancellation across worker thread
+        self._process_stop_event = threading.Event()
+
         def worker():
             try:
                 # Disable the button and initialize progress
                 self.process_btn.config(state="disabled", text="⏳ Processing...")
+                self.cancel_btn.config(state="normal")
                 self.progress_var.set(0)
                 self.progress_status_var.set("Starting processing...")
                 self.status_label.config(text="Processing...")
                 
-                # Simulate progress updates (since we don't have real progress from on_process)
-                def update_progress():
-                    for i in range(101):
-                        if i <= 20:
-                            self.progress_status_var.set("Initializing face detection...")
-                        elif i <= 40:
-                            self.progress_status_var.set("Loading photos...")
-                        elif i <= 60:
-                            self.progress_status_var.set("Detecting faces...")
-                        elif i <= 80:
-                            self.progress_status_var.set("Processing face encodings...")
-                        elif i <= 95:
-                            self.progress_status_var.set("Saving results...")
-                        else:
-                            self.progress_status_var.set("Finalizing...")
-                        
-                        self.progress_var.set(i)
-                        self.root.update_idletasks()
-                        time.sleep(0.05)  # Small delay to show progress
+                # Prepare real progress callback to be invoked per photo
+                def progress_callback(index, total, filename):
+                    try:
+                        percent = int((index / max(total, 1)) * 100)
+                        def _update():
+                            self.progress_var.set(percent)
+                            self.progress_status_var.set(f"Processing {index}/{total}: {filename}")
+                        self.root.after(0, _update)
+                    except Exception:
+                        pass
                 
-                # Start progress updates in a separate thread
-                progress_thread = threading.Thread(target=update_progress, daemon=True)
-                progress_thread.start()
+                # Run the actual processing with real progress updates and stop event
+                result = self.on_process(limit_value, progress_callback, self._process_stop_event)
                 
-                # Run the actual processing
-                result = self.on_process(limit_value)
-                
-                # Ensure progress reaches 100%
+                # Ensure progress reaches 100% at the end
                 self.progress_var.set(100)
                 self.progress_status_var.set("Processing completed successfully!")
                 
@@ -2043,7 +2038,23 @@ class DashboardGUI:
             finally:
                 # Re-enable the button regardless of success or failure
                 self.process_btn.config(state="normal", text="🚀 Start Processing")
+                self.cancel_btn.config(state="disabled")
+                # Clear stop event
+                self._process_stop_event = None
 
         threading.Thread(target=worker, daemon=True).start()
 
 
+    def _cancel_process(self):
+        """Signal the running process to stop, if any."""
+        try:
+            if getattr(self, "_process_stop_event", None) is not None:
+                self._process_stop_event.set()
+                # Inform the user via UI immediately
+                def _update():
+                    self.progress_status_var.set("Cancelling...")
+                    self.cancel_btn.config(state="disabled")
+                self.root.after(0, _update)
+        except Exception:
+            pass
+