Update app.py

app.py

@@ -6,7 +6,7 @@ from insightface.app import FaceAnalysis
 import onnxruntime
 from PIL import Image
 import tempfile
-import math # Import math for debugging if needed, but not directly used in the fixed slider logic
+# import math # Not directly needed for the fixed slider logic, keep it if you need it for other debug/math operations
 
 # --- Global Configurations and Model Loading ---
 # Determine the appropriate provider for ONNX Runtime.
@@ -143,9 +143,16 @@ def update_faces_preview(target_img_pil: Image.Image):
         preview_img_bgr = draw_faces(target_np_bgr, faces)
         preview_img_rgb = cv2.cvtColor(preview_img_bgr, cv2.COLOR_BGR2RGB)
 
-        # Set the max value of the slider to (number of faces - 1) as indices are 0-based
+        # FIX: Handle num_faces = 1 explicitly for slider interactivity
+        slider_max = num_faces - 1
+        slider_interactive = True
+        if num_faces == 1:
+            slider_interactive = False # No need to slide if only one face (index 0)
+
+        # Set the max value of the slider to (num_faces - 1) as indices are 0-based.
         # This ensures minimum=0 and maximum >= 0, avoiding the math domain error.
-        return preview_img_rgb, gr.Slider(minimum=0, maximum=num_faces - 1, value=0, interactive=True), gr.File(value=None, interactive=False), f"Detected {num_faces} face(s). Select the face to swap using the slider (0-indexed)."
+        # The `interactive` flag helps prevent `log10(0)` when only one option exists.
+        return preview_img_rgb, gr.Slider(minimum=0, maximum=slider_max, value=0, interactive=slider_interactive), gr.File(value=None, interactive=False), f"Detected {num_faces} face(s). Select the face to swap using the slider (0-indexed)."
 
 def face_swap_simswap(source_img_pil: Image.Image, target_img_pil: Image.Image, face_index: int):
     """