Demo code update to draw a heart shape

README.md

@@ -2,27 +2,59 @@
 A ROS2 TurtleSim  Python Controller similar to turtle_teleop_key, but
 using python turtle command scripts for controlling instead of key strokes.
 
+Running this example wiill result in the following output:
+![turtle_sim_pythonop_demo](./doc/turtlesim_pythonop_demo.png)
+
 Read the [ROS2 turtlesim Tutorial](https://docs.ros.org/en/jazzy/Tutorials/Beginner-CLI-Tools/Introducing-Turtlesim/Introducing-Turtlesim.html)
 if you are unfamiliar with this evironment.
 
-# Installation and Running as ROS package
+The following Python turtle commands are supported. See the 
+[Python Turtle](https://docs.python.org/3/library/turtle.html) page for command
+details.
+
+* Movement
+
+        forward(), backward(), right(), left(), goto(), setpos(), teleport(), setx(),
+        sety(), setheading(), home(), circle()
+
+* State
+
+        position(), towards(), xcor(), ycor(), heading(), distance(), clear()
+
+* Pen Control
+
+         pendown(), penup()
 
-1. Clone this repository into a ros2 workspace src folder
+
+## Installation and Running as ROS2 package
+
+1. Clone this repository into a ROS2 workspace src folder
 2. Build workspace with `colcon build` followed by `source install/local_setup.bash`
 3. In another terminal launch the turtlesim package as described in the ROS2 Tutorial
 
-        sudo apt install ros-jazzy-turtlesim
+        sudo apt install ros-$ROS_DISTRO-turtlesim
         ros2 run turtlesim turtlesim_node
 
 3. Run this package from the workspace with
 
         run turtlesim_teleop_python pythonop_turtle
 
-# Interactive Test
+## Parameter
+
+The package provides the following custom parameters:
+
+| Parameter     | Type  |Description                                       | Default |
+|---------------|-------|--------------------------------------------------| --------|
+| delay         | float | Delay between sending update messages in seconds.|  1.0    |
+| scale_angular | float | Scale factor for angular movements.              |  1.0    |
+| scale_linear  | float | Scale factor for linear movements.               |  1.0    |
+
+
+## Interactive Usage
 
 Interactive testing is working by going into 
 `turtlesim_teleop_python/turtlesim_teleop_python` folder
-and start python3. Then execute the commands below as an example:
+and start python3 from there. Then execute the commands below as an example:
 
 ```python
 import rclpy

turtlesim_teleop_python/pythonop_turtle.py

@@ -82,6 +82,8 @@ def clear(self) -> None:
         """Send clear request."""
         request = Empty.Request()
         self._clear_srv.call_async(request)
+        self._delay()
+
 
     def penup(self) -> None:
         """Lift the pen up."""
@@ -92,6 +94,8 @@ def penup(self) -> None:
         request.width = 3
         request.off = 1
         self._setPen_srv.call_async(request)
+        self._delay()
+
 
     pu = penup
     up = penup
@@ -105,6 +109,7 @@ def pendown(self) -> None:
         request.width = 3
         request.off = 0
         self._setPen_srv.call_async(request)
+        self._delay()
 
     def delay(self, dl=None) -> float:
         """Set or get update turtle update delay in seconds."""
@@ -137,7 +142,8 @@ def goto(self, x, y) -> None:
         request.y = float(self.ycor()) * self._scale_linear
         request.theta = math.radians(self.heading() * self._scale_angular)
         self._teleport_abs_srv.call_async(request)
-        rclpy.spin_once(self, timeout_sec=0.0)
+        self._delay()
+
 
     def _rotate(self, angle):
         super()._rotate(angle)
@@ -159,12 +165,14 @@ def _update_geometry(self, distance: float = 0.0, angle: float = 0.0) -> None:
             msg.linear.x = float(distance) * self._scale_linear
             self._publisher.publish(msg)
 
-        # tiwst message delay
+        self._delay()
+
+    def _delay(self, n=None):
+        """Message delay wait."""
         wait_for_time = time.time() + self._twist_delay
         while time.time() < wait_for_time:
             rclpy.spin_once(self, timeout_sec=0.0)
 
-
 def main(args=None):
     """Application runnable enty point."""
     rclpy.init(args=args)
@@ -176,26 +184,36 @@ def main(args=None):
 
 def demo(turtle: TurtleTwistPublisher) -> None:
     """Do some turtle fun."""
-    turtle.penup()
     turtle.clear()
+    turtle.penup()
     turtle.home()
+    turtle.left(90.0)
+    turtle.forward(1.0)
     turtle.pendown()
-    turtle.left(90)
-    turtle.forward(5)
-    turtle.right(160)
-    turtle.forward(5.5)
-    turtle.left(160)
-    turtle.forward(5)
-    turtle.right(90)
-    turtle.forward(3)
-    turtle.backward(1.5)
-    turtle.right(90)
-    turtle.forward(5)
+    turtle.circle(radius=1.0, extent=180.1)
+    turtle.right(180.0)
+    turtle.circle(radius=1.0, extent=180.1)
+    x = turtle.xcor()
+    y = turtle.ycor()
+    for i in range(0,181, 30):
+        print(i)
+        print(math.cos(math.radians(float(i))))
+        turtle.goto(
+            x + 1.0 - math.cos(math.radians(float(i))),
+            y - i /90)
+
+    x = turtle.xcor()
+    y = turtle.ycor()
+    for i in range(0,181, 30):
+        print(i)
+        print(math.cos(math.radians(float(i))))
+        turtle.goto(
+            x + 1.0 + math.cos(math.radians(180.0 + float(i))),
+            y + i /90)
+
     turtle.penup()
-    turtle.goto(2, 2)
-    turtle.pendown()
-    turtle.circle(1.5)
+    turtle.home()
 
 
-if __name__ == "__main__":
+if __name__ == "__main__":  
     main()