写cpp代码让ros小乌龟先画个圆再在圆中画六边形

在ROS（Robot Operating System）中，你可以使用` turtlesim`包来控制小乌龟并绘制图形。以下是一个简单的示例，展示了如何使用C++编写代码，首先画一个圆，然后在圆内画一个六边形：

#include <ros/ros.h>
#include <geometry_msgs/Pose.h>
#include < turtlesim/turtlesim.h>

class TurtlePainter {
public:
    void circleCallback(const geometry_msgs::Pose& pose) {
        // 创建Turtle消息对象
        turtlesim::PenState pen = turtlesim::PenState();
        pen.down = true;
        pen.color.r = 0; // 设置颜色（这里假设红色）

        // 绘制圆
        for (int i = 0; i <= 360; ++i) {
            ros::Time t = ros::Time::now() + ros::Duration(0.1);
            geometry_msgs::PoseStamped msg;
            msg.header.frame_id = "turtle1";
            msg.pose.position.x = pose.position.x + cos(radians(i * 6));
            msg.pose.position.y = pose.position.y + sin(radians(i * 6));
            msg.pose.orientation.z = sin(radians(i / 2));
            pub_pose.publish(msg, t);
        }
        pen.up = false;
        pub_pen.publish(pen); // 提起笔
    }

    void hexagonCallback(const geometry_msgs::Pose& pose) {
        pen.color.g = 255; // 设置颜色（这里假设绿色）

        // 绘制六边形
        const int sides = 6;
        double side_length = 0.5; // 这里只是一个估计值，可以根据需要调整

        for (int j = 0; j < sides; ++j) {
            for (double angle = 0; angle < 2 * M_PI; angle += 2 * M_PI / sides) {
                ros::Time t = ros::Time::now() + ros::Duration(0.1);
                geometry_msgs::PoseStamped msg;
                msg.header.frame_id = "turtle1";
                msg.pose.position.x = pose.position.x + side_length * cos(angle);
                msg.pose.position.y = pose.position.y + side_length * sin(angle);
                msg.pose.orientation.z = sin(j * 2 * M_PI / sides);
                pub_pose.publish(msg, t);
            }
        }
        pen.up = false;
        pub_pen.publish(pen); // 提起笔
    }

private:
    ros::NodeHandle nh_;
    ros::Subscriber sub_circle_, sub_hexagon_; // 圆和六边形的订阅者
    ros::Publisher pub_pose_, pub_pen_; // 小乌龟的位置和笔状态发布器
    tf2_ros::TransformListener transform_listener_; // 转换监听器
    double radians(double degrees) { return degrees * M_PI / 180.0; } // 将度转换为弧度
};

int main(int argc, char** argv) {
    ros::init(argc, argv, "turtle_drawer");
    TurtlePainter painter;

    sub_circle_ = nh_.subscribe("circle", 10, &TurtlePainter::circleCallback, &painter);
    sub_hexagon_ = nh_.subscribe("hexagon", 10, &TurtlePainter::hexagonCallback, &painter);

    pub_pose_ = nh_.advertise<geometry_msgs::PoseStamped>("turtle1/pose", 100);
    pub_pen_ = nh_.advertise<turtlesim::PenState>("turtle1/pen", 100);

    ros::spin();

    return 0;
}

这个示例假定你已经设置了两个话题：“circle”用于发送圆的位置信息，“hexagon”用于发送六边形的位置信息。你需要分别在其他节点上发布这些信息，以便触发这两个形状的绘制。