update example code

app.py

@@ -1,44 +1,76 @@
 from interactive_pipe import interactive_pipeline, interactive
+import argparse
+from typing import Tuple
 import numpy as np
 
+# --- Define processing blocks ---
 
-@interactive(angle=(45., [0., 360.]))
-def gen_color(angle=45.):
-    lin_coord = np.linspace(-1, 1, 256)
-    X, Y = np.meshgrid(lin_coord, lin_coord)
-    ang = np.deg2rad(angle)
-    im = np.cos(ang) * X + np.sin(ang) * Y
-    im = np.clip(1+im, 0, 1)
-    im = np.stack(
-        [im, im[::-1], im[:, ::-1]],
-        axis=-1
-    )
-    return im
 
+def gen_color(
+    green: float = 0.8,
+    decay: int = 1
+) -> np.ndarray:  # 1 image output
+    coord = np.linspace(0., 1., 256)
+    X, Y = np.meshgrid(np.exp(-coord*decay), coord)
+    return np.stack([X, green*Y, Y[::-1]], -1)
 
-@interactive(
-    flip=(True, "Flip Image"),
-    mirror=(True, "Mirror Image")
-)
-def flip_image(img, flip=True, mirror=True):
-    img = img[::-1] if flip else img
-    img = img[:, ::-1] if mirror else img
-    return img
 
+def flip_img(
+    img: np.ndarray,  # 1 image input
+    flip: bool = True
+) -> Tuple[np.ndarray, np.ndarray]:  # 2 image outputs
+    out = img[::-1] if flip else img.copy()
+    return out, img[:, ::-1]
 
-markdown_description = "# Code to build this app on gradio \n"
-markdown_description += "```python\n"+open(__file__, 'r').read()+"```"
 
+def amplify(
+    img: np.ndarray,  # 1 image input
+    amp: str = "L"
+) -> np.ndarray:  # 1 image output
+    return 1/{"S": 4, "M": 3, "L": 2, "XL": 1}[amp] * img
 
-@interactive_pipeline(
-    gui="gradio",
-    markdown_description=markdown_description
-)
-def simple_pipe():
+# --- Define pipeline = a sequence of processing blocks ---
+
+
+def pipe() -> Tuple[np.ndarray, np.ndarray, np.ndarray]:
     inp = gen_color()
-    out = flip_image(inp)
-    return [inp, out]
+    out_flip, out_mirror = flip_img(inp)
+    out = amplify(out_mirror)
+    return [inp, out_flip, out]  # Display 3 images side by side
+
+
+# --- Add interactivity ---
+
+def add_controls() -> None:
+    # Add controls to the processing blocks
+    interactive(
+        green=(1., [0., 1.], "Green amount"),  # float <-> continuous slider
+        decay=(2, [0, 10], "Color decay")  # int <-> discrete slider
+    )(gen_color)
+    interactive(
+        amp=("L", ["S", "M", "L", "XL"], "Amplify")  # str <-> dropdown menu
+    )(amplify)
+    interactive(
+        flip=(True, "Flip")  # bool <-> checkbox
+    )(flip_img)
+
+
+def launch(backend="gradio", markdown_description="") -> None:
+    # Decorate pipeline which becomes interactive
+    playable_pipe = interactive_pipeline(
+        gui=backend,
+        markdown_description=markdown_description
+    )(pipe)
+    playable_pipe()  # Launch the interactive pipeline
 
 
+# --------------------------------------------------
 if __name__ == "__main__":
-    simple_pipe()
+    parser = argparse.ArgumentParser()
+    parser.add_argument("-b", "--backend", default="gradio",
+                        choices=["gradio", "qt", "mpl"], type=str)
+    args = parser.parse_args()
+    markdown_description = "# Code to build this app on gradio \n\n"
+    markdown_description += "```python\n"+open(__file__, 'r').read()+"```"
+    add_controls()
+    launch(args.backend, markdown_description)