add headless animation

tutorial.md

@@ -1,5 +1,5 @@
 
-# ⏯ [`interactive_pipe` website](https://balthazarneveu.github.io/interactive_pipe/)
+# ⏯ [interactive pipe website](https://balthazarneveu.github.io/interactive_pipe/)
 
 ![](https://balthazarneveu.github.io/interactive_pipe/static/interact-pipe-logo-horizontal-rgb.svg)
 
@@ -8,6 +8,35 @@
 
 **Note** : The same tutorial is also available on [Google Colab](https://colab.research.google.com/github/livalgo/interactive-pipe-examples/blob/main/interactive_pipe_tutorial.ipynb) to learn about the Jupyter notebook backend.
 
+# Analyzing the headless pipeline
+
+```python
+headless_tutorial_pipeline = interactive_pipeline(gui=None)(tutorial_pipeline)
+# gui=None allows retuning a HeadlessPipeline instance.
+headless_tutorial_pipeline.graph_representation("__tuto_pipeline")
+```
+Let's now call the pipeline several times with varying parameters.
+
+🎁 We provide a basic code sample to generate the gif animation.
+
+```python
+from PIL import Image as PILImage
+img_list = []
+for freq in np.linspace(1, 100, 10):
+    # Let's first override some of the default parameters.
+    headless_tutorial_pipeline.parameters = {
+        "gen_color": {"frequency": freq, 'isotropy': freq/100.},
+        "compare_by_splitting": {"ratio": freq/100.}}
+    # Let's execute
+    headless_tutorial_pipeline()
+    img = (255.*headless_tutorial_pipeline.results[1][1]).astype(np.uint8)
+    img_list.append(PILImage.fromarray(img))
+
+img_list[0].save("animation.gif", save_all=True, append_images=img_list[1:], duration=1, loop=1000)
+```
+
+![animation](https://huggingface.co/spaces/balthou/interactive-pipe-tutorial/resolve/main/animation.gif)
+
 # Advice
 
 
@@ -20,7 +49,7 @@
 
 #### 1.Decorate afterward   🏆 *= Recommended approach*
 - ➖ Less elegant to read (`add_interactivity` may be in a different file)
-- ➕ The decorated function can't be re-used somewhere else.
+- ➕ The decorated function can be re-used somewhere else (before being decorated).
 - ➕ Possibility to add conditions (`debug` flag)
  
 ```python
@@ -68,6 +97,13 @@ def gen_color(
 ## Pipeline visualization
 
 Internally, `interactive_pipe` builds an execution graph of the pipeline. 
+- If you're using  the `qt` backend, press `G` to build the graph. 
+- If you're in a notebook, it's possible to easily plot the graph.
+```python
+headless_tutorial_pipeline = interactive_pipeline(gui=None)(tutorial_pipeline)
+headless_tutorial_pipeline.graph_representation()
+```
+
 | pipeline's execution graph |
 | :--:| 
 | ![Pipeline](https://huggingface.co/spaces/balthou/interactive-pipe-tutorial/resolve/main/pipeline.png) |