Update app.py

app.py

@@ -1,16 +1,21 @@
 import gradio as gr
 import imageio
+import numpy as np
 
-def dummy(img):
-  imageio.imwrite("output_image.png", img["mask"])
-  return img["image"], img["mask"]
+def dummy(img, invert_mask):
+  mask = img["mask"]
+  if invert_mask and mask is not None:
+    mask = 255 - np.array(mask)
+  imageio.imwrite("output_image.png", mask)
+  return img["image"], mask
 
 with gr.Blocks() as demo:
   with gr.Row():
     img = gr.Image(tool="sketch", label="base image", show_label=True)
     img1 = gr.Image()
     img2 = gr.Image(label="mask image", show_label=True)
+  invert = gr.Checkbox(label="Invert mask")
   btn = gr.Button()
-  btn.click(dummy, img, [img1, img2])
+  btn.click(dummy, [img, invert], [img1, img2])
 
 demo.launch(debug=True)