Update app.py

app.py

@@ -1,36 +1,48 @@
 import gradio as gr
 from PIL import Image
 import numpy as np
-import io
 
-def brightness_to_opacity(image):
-    # Ensure it's RGB
-    img = image.convert("RGB")
-    img_array = np.array(img)
+def brightness_to_opacity_overlay(foreground_img, background_img, invert_opacity=False):
+    if foreground_img is None or background_img is None:
+        return None
 
-    # Compute grayscale (luminance)
-    gray = np.dot(img_array[...,:3], [0.299, 0.587, 0.114]).astype(np.uint8)
+    # Resize foreground to match background
+    bg = background_img.convert("RGBA")
+    fg = foreground_img.convert("RGB").resize(bg.size)
 
-    # Use grayscale as alpha
-    alpha = gray
+    # Convert foreground to grayscale (luminance)
+    fg_array = np.array(fg)
+    luminance = np.dot(fg_array[...,:3], [0.299, 0.587, 0.114]).astype(np.uint8)
 
-    # Optional: set RGB to white (or use img_array to preserve color)
-    white_rgb = np.ones_like(img_array) * 255
-    rgba_array = np.dstack((white_rgb, alpha))
+    # Optionally invert the opacity
+    alpha = 255 - luminance if invert_opacity else luminance
 
-    # Convert to Image and return
-    result_img = Image.fromarray(rgba_array.astype(np.uint8), mode="RGBA")
-    return result_img
+    # Set RGB to white, combine with alpha
+    white_rgb = np.ones_like(fg_array) * 255
+    rgba_array = np.dstack((white_rgb, alpha)).astype(np.uint8)
+    mask_image = Image.fromarray(rgba_array, mode="RGBA")
 
-# Gradio Interface
+    # Overlay mask_image on background
+    combined = Image.alpha_composite(bg, mask_image)
+
+    return combined
+
+# Gradio UI
 iface = gr.Interface(
-    fn=brightness_to_opacity,
-    inputs=gr.Image(type="pil", label="Upload Image"),
-    outputs=gr.Image(type="pil", label="Output (Brightness → Opacity)"),
-    title="Brightness to Opacity Converter",
-    description="This tool converts image brightness into opacity. Bright areas become visible, dark areas become transparent."
+    fn=brightness_to_opacity_overlay,
+    inputs=[
+        gr.Image(type="pil", label="Mask Source (Brightness to Alpha)"),
+        gr.Image(type="pil", label="Background Image"),
+        gr.Checkbox(label="Invert Opacity", value=False)
+    ],
+    outputs=gr.Image(type="pil", label="Final Composite"),
+    title="Brightness-to-Alpha Overlay Tool",
+    description=(
+        "This tool uses the brightness of the first image as its opacity mask, "
+        "optionally inverts it, resizes it to match the second image, and overlays the result."
+    )
 )
 
-# Launch the app
+# Run the app
 if __name__ == "__main__":
     iface.launch()