From 6e034126bd5877346156d98b1ca68e7c9135491f Mon Sep 17 00:00:00 2001
From: haixuanTao <tao.xavier@outlook.com>
Date: Thu, 11 Aug 2022 18:05:33 +0200
Subject: [PATCH] Add webcam and plot python example

---
 examples/python-dataflow/dataflow.yml       | 20 +++++++++
 examples/python-dataflow/plot_cv2.py        | 49 +++++++++++++++++++++
 examples/python-dataflow/requirements.txt   |  1 +
 examples/python-dataflow/webcam_operator.py | 45 +++++++++++++++++++
 4 files changed, 115 insertions(+)
 create mode 100644 examples/python-dataflow/dataflow.yml
 create mode 100644 examples/python-dataflow/plot_cv2.py
 create mode 100644 examples/python-dataflow/requirements.txt
 create mode 100644 examples/python-dataflow/webcam_operator.py

diff --git a/examples/python-dataflow/dataflow.yml b/examples/python-dataflow/dataflow.yml
new file mode 100644
index 00000000..8561be2c
--- /dev/null
+++ b/examples/python-dataflow/dataflow.yml
@@ -0,0 +1,20 @@
+communication:
+  zenoh:
+    prefix: /example-python-dataflow
+
+nodes:
+  - id: node-1
+    operators:
+    - id: python_webcam
+      python: webcam_operator.py
+      inputs:
+        timer: dora/timer/millis/100
+      outputs:
+        - image
+
+  - id: node-2
+    operators:
+    - id: python_plot
+      python: plot_cv2.py
+      inputs:
+        image: node-1/python_webcam/image
diff --git a/examples/python-dataflow/plot_cv2.py b/examples/python-dataflow/plot_cv2.py
new file mode 100644
index 00000000..50bc9e2b
--- /dev/null
+++ b/examples/python-dataflow/plot_cv2.py
@@ -0,0 +1,49 @@
+from enum import Enum
+from typing import Callable
+
+import cv2
+import numpy as np
+
+
+class DoraStatus(Enum):
+    CONTINUE = 0
+    STOP = 1
+
+
+class Operator:
+    """
+    Example operator incrementing a counter every times its been called.
+
+    The current value of the counter is sent back to dora on `counter`.
+    """
+
+    def __init__(self):
+        self.counter = 0
+
+    def on_input(
+        self,
+        input_id: str,
+        value: bytes,
+        send_output: Callable[[str, bytes], None],
+    ) -> DoraStatus:
+        """Handle input by incrementing count by one.
+
+        Args:
+            input_id (str): Id of the input declared in the yaml configuration
+            value (bytes): Bytes message of the input
+            send_output (Callable[[str, bytes]]): Function enabling sending output back to dora.
+        """
+        self.counter += 1
+        if input_id == "image":
+            frame = np.frombuffer(value, dtype="uint8")
+            frame = np.reshape(frame, (480, 640, 3))
+            cv2.imshow("frame", frame)
+            if cv2.waitKey(1) & 0xFF == ord("q"):
+                return DoraStatus.STOP
+        if self.counter > 20:
+            return DoraStatus.STOP
+        else:
+            return DoraStatus.CONTINUE
+
+    def drop_operator(self):
+        cv2.destroyAllWindows()
diff --git a/examples/python-dataflow/requirements.txt b/examples/python-dataflow/requirements.txt
new file mode 100644
index 00000000..fb10efbf
--- /dev/null
+++ b/examples/python-dataflow/requirements.txt
@@ -0,0 +1 @@
+pip install opencv-python
\ No newline at end of file
diff --git a/examples/python-dataflow/webcam_operator.py b/examples/python-dataflow/webcam_operator.py
new file mode 100644
index 00000000..8eedc550
--- /dev/null
+++ b/examples/python-dataflow/webcam_operator.py
@@ -0,0 +1,45 @@
+from enum import Enum
+from typing import Callable
+
+import cv2
+
+
+class DoraStatus(Enum):
+    CONTINUE = 0
+    STOP = 1
+
+
+class Operator:
+    """
+    Example operator incrementing a counter every times its been called.
+
+    The current value of the counter is sent back to dora on `counter`.
+    """
+
+    def __init__(self):
+        self.video_capture = cv2.VideoCapture(0)
+
+    def on_input(
+        self,
+        input_id: str,
+        value: bytes,
+        send_output: Callable[[str, bytes], None],
+    ) -> DoraStatus:
+        """Handle input by incrementing count by one.
+
+        Args:
+            input_id (str): Id of the input declared in the yaml configuration
+            value (bytes): Bytes message of the input
+            send_output (Callable[[str, bytes]]): Function enabling sending output back to dora.
+        """
+
+        ret, frame = self.video_capture.read()
+        if ret:
+            send_output("image", frame.tobytes())
+        else:
+            print("did not sent video")
+
+        return DoraStatus.CONTINUE
+
+    def drop_operator(self):
+        self.video_capture.release()