feat: initialize OpenCV window thread in main functions

Author: marc-hanheide

src/cmp3103m_ros2_code_fragments/cmp3103m_ros2_code_fragments/colour_center.py

@@ -70,7 +70,8 @@ def camera_callback(self, data):
 
 def main(args=None):
     print('Starting colour_center.py.')
-
+    cv2.startWindowThread()
+    
     rclpy.init(args=args)
 
     colour_center = ColourCenter()

src/cmp3103m_ros2_code_fragments/cmp3103m_ros2_code_fragments/colour_chaser.py

@@ -91,6 +91,7 @@ def camera_callback(self, data):
 
 def main(args=None):
     print('Starting colour_chaser.py.')
+    cv2.startWindowThread()
 
     rclpy.init(args=args)
 

src/cmp3103m_ros2_code_fragments/cmp3103m_ros2_code_fragments/colour_chaser2.py

@@ -101,7 +101,7 @@ def timer_callback(self):
 
 def main(args=None):
     print('Starting colour_chaser.py.')
-
+    cv2.startWindowThread()
     rclpy.init(args=args)
 
     colour_chaser = ColourChaser()

src/cmp3103m_ros2_code_fragments/cmp3103m_ros2_code_fragments/colour_contours.py

@@ -85,7 +85,8 @@ def camera_callback(self, data):
 
 def main(args=None):
     print('Starting colour_contours.py.')
-
+    cv2.startWindowThread()
+    
     rclpy.init(args=args)
 
     colour_contours = ColourContours()

src/cmp3103m_ros2_code_fragments/cmp3103m_ros2_code_fragments/colour_mask.py

@@ -45,7 +45,7 @@ def camera_callback(self, data):
 
 def main(args=None):
     print('Starting colour_mask.py.')
-
+    cv2.startWindowThread()
     rclpy.init(args=args)
 
     colour_mask = ColourMask()

src/cmp3103m_ros2_code_fragments/cmp3103m_ros2_code_fragments/colour_mask2.py

@@ -44,7 +44,8 @@ def camera_callback(self, data):
 
 def main(args=None):
     print('Starting colour_mask.py.')
-
+    cv2.startWindowThread()
+    
     rclpy.init(args=args)
 
     colour_mask = ColourMask()

src/cmp3103m_ros2_code_fragments/cmp3103m_ros2_code_fragments/colour_mover.py

@@ -93,6 +93,7 @@ def camera_callback(self, data):
 
 def main(args=None):
     print('Starting colour_mover.py.')
+    cv2.startWindowThread()
 
     rclpy.init(args=args)
 

src/cmp3103m_ros2_code_fragments/cmp3103m_ros2_code_fragments/opencv_bridge.py

@@ -82,7 +82,8 @@ def camera_callback(self, data):
 
 def main(args=None):
     print('Starting opencv_bridge.py.')
-
+    cv2.startWindowThread()
+    
     rclpy.init(args=args)
 
     opencv_bridge = OpencvBridge()