fix transpanreyc error

app.py

@@ -44,7 +44,7 @@ pipe.enable_xformers_memory_efficient_attention()
 
 
 def resize_for_condition_image(input_image: Image.Image, resolution: int, canvas_width: int = None, canvas_height: int = None):
-    input_image = input_image.convert("RGB")
+    input_image = input_image.convert("RGBA")  # Ensure the image has an alpha channel
     W, H = input_image.size
 
     # Create a blank canvas with the specified dimensions
@@ -66,7 +66,9 @@ def resize_for_condition_image(input_image: Image.Image, resolution: int, canvas
     # Paste the resized QR code 2/3rds of the way over the canvas
     qr_x = int(canvas_width * (2 / 3)) - (W // 2)  # Adjust x-coordinate to 2/3 of the canvas
     qr_y = (canvas_height - H) // 2  # Center the QR code vertically
-    canvas.paste(input_image, (qr_x, qr_y), input_image)
+
+    # Use the alpha channel of the input_image as the mask
+    canvas.paste(input_image, (qr_x, qr_y), input_image.split()[3])  # Alpha channel as mask
     return canvas