工具使用-如何使用ROS在RViz中显示Markers（python版 points and lines 示例）

Introduction

我们先来看看Marker 中定义了那些类型：

rosmsg show visualization_msgs/Marker

uint8 ARROW=0
uint8 CUBE=1
uint8 SPHERE=2
uint8 CYLINDER=3
uint8 LINE_STRIP=4
uint8 LINE_LIST=5
uint8 CUBE_LIST=6
uint8 SPHERE_LIST=7
uint8 POINTS=8

% 上面声明了9种类型

uint8 TEXT_VIEW_FACING=9
uint8 MESH_RESOURCE=10
uint8 TRIANGLE_LIST=11
uint8 ADD=0
uint8 MODIFY=0
uint8 DELETE=2
uint8 DELETEALL=3
std_msgs/Header header
uint32 seq
time stamp
string frame_id
string ns
int32 id
int32 type
int32 action
geometry_msgs/Pose pose # pose包含的属性
geometry_msgs/Point position
float64 x
float64 y
float64 z
geometry_msgs/Quaternion orientation
float64 x
float64 y
float64 z
float64 w
geometry_msgs/Vector3 scale
float64 x
float64 y
float64 z
std_msgs/ColorRGBA color
float32 r
float32 g
float32 b
float32 a
duration lifetime
bool frame_locked
geometry_msgs/Point[] points # 对应一个list
float64 x
float64 y
float64 z
std_msgs/ColorRGBA[] colors
float32 r
float32 g
float32 b
float32 a
string text
string mesh_resource
bool mesh_use_embedded_materials

当type=POINTS时， points中的每一个点对应改为之上画一个点， type=LINE_STRIP时，表示poinits中任意两个相邻的点存在连线， type=LINE_LIST中的points内点不会将线连在一起，于是相邻点连线，但不存在共享定点的连线，比如第0个点和第1个点连线，第2个点和第3个点连线。

Publisher Node

roscd using_markers/scripts
vim points_and_lines.py

points_and_lines.py的内容：

#!/usr/bin/env python
import rospy
import numpy as np
from visualization_msgs.msg import Marker
from geometry_msgs.msg import Point

def main():
    rospy.init_node("points_and_lines", anonymous=True)
    pub = rospy.Publisher("visualization_marker", Marker, queue_size=10)
    rate = rospy.Rate(30)
    f = 0.0
    while not rospy.is_shutdown():
        types = [Marker.POINTS, Marker.LINE_STRIP, Marker.LINE_LIST]
        markers = [Marker() for _ in ['points', 'line_strip', 'line_list']]
        for i, m in enumerate(markers):  # 分别处理不同的marker 
            m.header.frame_id = '/my_frame'
            m.header.stamp = rospy.Time.now()
            m.ns = 'points_and_lines'
            m.pose.orientation.w = 1.0
            m.action = Marker.ADD
            m.id = i
            m.type = types[i]
            m.color.a = 1.0
            if i == 0: # point
                m.scale.x = 0.2
                m.scale.y = 0.2
                m.color.g = 1.0
            elif i == 1:  # line_strip
                m.scale.x = 0.1
                m.color.b = 1.0
            elif i == 2:
                m.scale.x = 0.1
                m.color.r = 1.0
        for i in range(100):  # 给每一个marker添加points
            y = 5 * np.sin(f + i/100.0 * 2 * np.pi)
            z = 5 * np.cos(f + i/100.0 * 2 * np.pi)
            p = Point(i-50, y, z)
            markers[0].points.append(p)
            markers[1].points.append(p)
            markers[2].points.extend([p, Point(i-50, y, z+1)])
        for m in markers:
            pub.publish(m)
        rate.sleep()
        f += 0.04
        
if __name__=='__main__':
    main()

好像相对于上篇文章内容并没有添加新的东西。主要就是不同类型中points列表的设置。

Building and Viewing

# ～/catkin_ws
catkin_make
. devel/setup.bash

两个终端：

rosrun using_markers points_and_lines.py

rosrun rviz rviz

然后在rviz的左边栏将Fixed Frame 值改为 /my_frame

左下角添加Add msg的类型Marker， 然后就能看到结果了。