Add markdown description

app.py

@@ -125,4 +125,8 @@ if __name__ == "__main__":
                         choices=["gradio", "qt", "mpl"], default="gradio")
     args = parser.parse_args()
     img = Image.load_image("image_sample.jpg")
-    interactive_pipeline(gui=args.backend)(image_editing_pipeline)(img)
+    markdown_description = r"# Tone mapping: S-curve" + "\n" \
+        r"$$\text{shadow boost} \in [-1, 1]$$  $$\text{highlight boost} \in [-1, 1]$$  $$\text{contrast} \in [-1, 1]$$  $$\text{exposure} \in [-1, 1]$$" + "\n" \
+        "If Tone curves are applied to RGB colors separately, you'll get serious color shifts. It is much better when tone curve is applied to the luminance channel." + "\n"
+    interactive_pipeline(gui=args.backend, markdown_description=markdown_description)(
+        image_editing_pipeline)(img)