fix: add debug logs for mask processing; verify output changes to diagnose removal issues

api/main.py

@@ -193,6 +193,10 @@ def inpaint(req: InpaintRequest, _: None = Depends(bearer_auth)) -> Dict[str, st
     img_rgba = _load_rgba_image(file_store[req.image_id]["path"])
     mask_img = Image.open(file_store[req.mask_id]["path"])  # may be RGB/gray/RGBA
     mask_rgba = _load_rgba_mask_from_image(mask_img)
+    
+    # Debug: check mask before processing
+    white_pixels = int((mask_rgba[:,:,0] > 128).sum())
+    log.info(f"Inpaint request: mask has {white_pixels} white pixels, invert_mask={req.invert_mask}")
 
     if req.passthrough:
         result = np.array(img_rgba.convert("RGB"))

src/core.py

@@ -486,9 +486,14 @@ def process_inpaint(image, mask, invert_mask=True):
         else:
             mask = np.maximum(mask, alpha_channel)  # opaque → white
     
-    # Apply invert_mask if needed (for special cases where black=remove)
+    # Apply invert_mask if needed
+    # When invert_mask=False: black pixels (0) should become white (255) to remove
+    # When invert_mask=True (default): white pixels (255) stay white to remove (standard)
     if not invert_mask:
         mask = 255 - mask
+        print(f"Applied invert_mask=False: inverted mask - {int((mask > 128).sum())} pixels now marked for removal")
+    else:
+        print(f"Using invert_mask=True: {int((mask > 128).sum())} white pixels will be removed (standard)")
     
     mask = resize_max_size(mask, size_limit=size_limit, interpolation=interpolation)
     
@@ -504,7 +509,15 @@ def process_inpaint(image, mask, invert_mask=True):
     # Final check: ensure we have some pixels to remove
     mask_final_pixels = int((mask > 0.5).sum())
     print(f"After normalization: {mask_final_pixels} pixels marked for removal (value > 0.5)")
+    
+    if mask_final_pixels < 10:
+        print("WARNING: Very few pixels marked for removal! The mask might be empty or inverted.")
+        print("Check your mask format: white pixels (255) should indicate areas to remove when invert_mask=True")
 
     res_np_img = run(image, mask)
+    
+    # Debug: verify output changed
+    diff_pixels = int(np.sum(np.abs(res_np_img.astype(np.float32) - cv2.cvtColor(image, cv2.COLOR_RGBA2RGB).astype(np.float32)) > 5))
+    print(f"Output check: {diff_pixels} pixels differ from input (should be > 0 if removal worked)")
 
     return cv2.cvtColor(res_np_img, cv2.COLOR_BGR2RGB)