Review feedback.

Signed-off-by: Chris Lalancette <[email protected]>

Author: clalancette

image_tools_py/README.md

@@ -1,14 +1,16 @@
 ## Image Tools Demo in Python
 
-This is a demonstration of the Quality of Service (QoS) features of ROS 2 using Python.
+This is a demonstration of the Quality of Service (QoS) features of ROS 2 using
+Python.
 There are two programs implemented here: cam2image_py, and showimage_py.
 
 ### CAM2IMAGE_PY
-This is a Python program that will take data from an attached camera, and publish the
-data to a topic called "image", with the type sensor_msgs/msg/Image.  If a camera
-isn't available, this program can also generate a default image and smoothly "move"
-it across the screen, simulating motion.  The usage output from the program looks like
-this:
+This is a Python program that will take data from an attached camera, and
+publish the data to a topic called "image", with the type
+`sensor_msgs/msg/Image`.
+If a camera isn't available, this program can also generate a default image and
+smoothly "move" it across the screen, simulating motion.  The usage output from
+the program looks like this:
 
 ```
 usage: cam2image_py [-h] [-b] [-d DEPTH] [-f FREQUENCY] [-k {0,1}] [-r {0,1}]
@@ -39,25 +41,30 @@ optional arguments:
                         Image height (default: 240)
 ```
 
-The -d, -k, and -r parameters control various aspects of the QoS implementation, and
-are the most interesting to play with when testing out QoS.
+The `-d`, `-k`, and `-r` parameters control various aspects of the QoS
+implementation, and are the most interesting to play with when testing out QoS.
 
 Note that this program also subscribes to a topic called "flip_image" of type
-std_msgs/msg/Bool.  If flip_image is set to False, the data coming out of the camera
-is sent as usual.  If flip_image is set to True, the data coming out of the camera is
-flipped around the Y axis.
-
-If the -s parameter is set to 1, then this program opens up a (local) window to show
-the images that are being published.  However, these images are *not* coming in through
-the ROS 2 pub/sub model, so this window cannot show off the QoS parameters (it is mostly
-useful for debugging).  See SHOWIMAGE_PY below for a program that can show QoS over the
-pub/sub model.
+`std_msgs/msg/Bool`.
+If "flip_image" is set to `False`, the data coming out of the camera is sent as
+usual.
+If "flip_image" is set to `True`, the data coming out of the camera is flipped
+around the Y axis.
+
+If the `-s` parameter is set to 1, then this program opens up a (local) window
+to show the images that are being published.
+However, these images are *not* coming in through the ROS 2 pub/sub model, so
+this window cannot show off the QoS parameters (it is mostly useful for
+debugging).
+See SHOWIMAGE_PY below for a program that can show QoS over the pub/sub model.
 
 ### SHOWIMAGE_PY
-This is a Python program that subscribes to the "image" topic, waiting for data.  As
-new data comes in, this program accepts the data and can optionally render it to
-the screen.  The usage output from the program looks like this:
+This is a Python program that subscribes to the "image" topic, waiting for data.
+As new data comes in, this program accepts the data and can optionally render
+it to the screen.
+The usage output from the program looks like this:
 
+```
 usage: showimage_py [-h] [-d QUEUE_DEPTH] [-k {0,1}] [-r {0,1}] [-s {0,1}]
                     [-t TOPIC]
 
@@ -75,32 +82,34 @@ optional arguments:
                         Show the camera stream (default: 1)
   -t TOPIC, --topic TOPIC
                         use topic TOPIC instead of the default (default: image)
+```
 
-The -d, -k, and -r parameters control various aspects of the QoS implementation, and
-are the most interesting to play with when testing out QoS.
+The `-d`, `-k`, and `-r` parameters control various aspects of the QoS
+implementation, and are the most interesting to play with when testing out QoS.
 
-If the -s parameter is set to 1, then this program opens up a window to show the images
-that have been received over the ROS 2 pub/sub model.  This program should be used
-in conjunction with cam2image_py to demonstrate the ROS 2 QoS capabilities over lossy/slow
-links.
+If the `-s` parameter is set to 1, then this program opens up a window to show
+the images that have been received over the ROS 2 pub/sub model.
+This program should be used in conjunction with cam2image_py to demonstrate the
+ROS 2 QoS capabilities over lossy/slow links.
 
 ### EXAMPLE USAGE
 To use the above programs, you would run them something like the following:
 
-# In the first terminal, run the data publisher.  This will connect to the 1st camera
-# available, and print out "Publishing image #" for each image it publishes.
+In the first terminal, run the data publisher.
+This will connect to the first camera available, and print out
+"Publishing image #" for each image it publishes.
 ```
 $ ros2 run image_tools_py cam2image_py
 ```
 
-# If you don't have a local camera, you can use the -b parameter to generate data on
-# the fly rather than get data from a camera:
+If you don't have a local camera, you can use the `-b` parameter to generate
+data on the fly rather than get data from a camera:
 ```
 $ ros2 run image_tools_py cam2image_py -b
 ```
 
-# In a second terminal, run the data subscriber.  This will subscribe to the "image"
-# topic and render any frames it receives.
+In a second terminal, run the data subscriber.
+This will subscribe to the "image" topic and render any frames it receives.
 ```
 $ ros2 run image_tools_py showimage_py
 ```

image_tools_py/cam2image_py.py

@@ -163,36 +163,39 @@ def flip_image_cb(msg):
 
     # Our main event loop will spin until the user presses CTRL-C to exit.
     frame_number = 1
-    while rclpy.ok():
-        # Get the frame from the video capture.
-        if args.burger_mode:
-            frame = burger_cap.render_burger(args.width, args.height)
-        else:
-            ret, frame = cam_cap.read()
-
-        # Check if the frame was grabbed correctly.
-        if frame is not None:
-            # Convert to a ROS image
-            if is_flipped:
-                # Flip the frame if needed
-                flipped_frame = cv2.flip(frame, 1)
-                convert_frame_to_message(flipped_frame, frame_number, msg)
+    try:
+        while rclpy.ok():
+            # Get the frame from the video capture.
+            if args.burger_mode:
+                frame = burger_cap.render_burger(args.width, args.height)
             else:
-                convert_frame_to_message(frame, frame_number, msg)
-
-            if args.show_camera == 1:
-                # Show the image in a window called 'cam2image_py', if requested.
-                cv2.imshow('cam2image_py', frame)
-                # Draw the image to the screen and wait 1 millisecond
-                cv2.waitKey(1)
-
-            # Publish the image message and increment the frame_id.
-            node.get_logger().info('Publishing image #%d' % (frame_number))
-            pub.publish(msg)
-            frame_number += 1
-
-        # Do some work in rclpy and wait for more to come in.
-        rclpy.spin_once(node, timeout_sec=1.0 / float(args.frequency))
+                ret, frame = cam_cap.read()
+
+            # Check if the frame was grabbed correctly.
+            if frame is not None:
+                # Convert to a ROS image
+                if is_flipped:
+                    # Flip the frame if needed
+                    flipped_frame = cv2.flip(frame, 1)
+                    convert_frame_to_message(flipped_frame, frame_number, msg)
+                else:
+                    convert_frame_to_message(frame, frame_number, msg)
+
+                if args.show_camera == 1:
+                    # Show the image in a window called 'cam2image_py', if requested.
+                    cv2.imshow('cam2image_py', frame)
+                    # Draw the image to the screen and wait 1 millisecond
+                    cv2.waitKey(1)
+
+                # Publish the image message and increment the frame_id.
+                node.get_logger().info('Publishing image #%d' % (frame_number))
+                pub.publish(msg)
+                frame_number += 1
+
+            # Do some work in rclpy and wait for more to come in.
+            rclpy.spin_once(node, timeout_sec=1.0 / float(args.frequency))
+    except KeyboardInterrupt:
+        pass
 
 
 if __name__ == '__main__':

image_tools_py/showimage_py.py

@@ -114,8 +114,11 @@ def image_cb(msg):
     node.create_subscription(
         sensor_msgs.msg.Image, args.topic, image_cb, qos_profile=custom_qos_profile)
 
-    while rclpy.ok():
-        rclpy.spin_once(node)
+    try:
+        while rclpy.ok():
+            rclpy.spin_once(node)
+    except KeyboardInterrupt:
+        pass
 
 
 if __name__ == '__main__':

image_tools_py/test/test_showimage_cam2image.py.in

@@ -110,5 +110,4 @@ class TestExecutablesDemo(unittest.TestCase):
 
     def test_reliable_qos(self):
         self._ls.run()
-        self._ls.shutdown()
         self.assertTrue(self._saw_cam2image_output and self._saw_showimage_output)