Python中使用matplotlib绘制mqtt数据实时图像功能

效果图

mqtt发布

本代码中publish是一个死循环，数据一直往外发送。

import random
import time
from paho.mqtt import client as mqtt_client
import json
from datetime import datetime

broker = 'broker.emqx.io'
port = 1883
topic = "/python/mqtt/li"
client_id = f'python-mqtt-{random.randint(0, 1000)}'  # 随机生成客户端id


def connect_mqtt():
  def on_connect(client, userdata, flags, rc):
      if rc == 0:
          print("Connected to MQTT Broker!")
      else:
          print("Failed to connect, return code %d\n", rc)

  client = mqtt_client.Client(client_id)
  client.on_connect = on_connect
  client.connect(broker, port)
  return client


def publish(client):
  while True:
      time.sleep(0.01)
      msg = json.dumps({"MAC": "0123456789",
                        "samplerate": 12,
                        "sampletime": str(datetime.utcnow().strftime('%Y/%m/%d-%H:%M:%S.%f')[:-3]),
                        "battery": 0.5,
                        "acc": [
                            [random.randint(200, 350), -random.randint(200, 350), -random.randint(200, 350), random.randint(200, 350), random.randint(200, 350), random.randint(200, 350)],
                            [random.randint(200, 350), -random.randint(200, 350), -random.randint(200, 350), random.randint(200, 350), random.randint(200, 350), random.randint(200, 350)],
                            [random.randint(200, 350), -random.randint(200, 350), -random.randint(200, 350), random.randint(200, 350), random.randint(200, 350), random.randint(200, 350)],
                            [random.randint(200, 350), -random.randint(200, 350), -random.randint(200, 350), random.randint(200, 350), random.randint(200, 350), random.randint(200, 350)],
                            [random.randint(200, 350), -random.randint(200, 350), -random.randint(200, 350), random.randint(200, 350), random.randint(200, 350), random.randint(200, 350)],
                            [random.randint(200, 350), -random.randint(200, 350), -random.randint(200, 350), random.randint(200, 350), random.randint(200, 350), random.randint(200, 350)],
                            [random.randint(200, 350), -random.randint(200, 350), -random.randint(200, 350), random.randint(200, 350), random.randint(200, 350), random.randint(200, 350)],
                            [random.randint(200, 350), -random.randint(200, 350), -random.randint(200, 350), random.randint(200, 350), random.randint(200, 350), random.randint(200, 350)],
                            [random.randint(200, 350), -random.randint(200, 350), -random.randint(200, 350), random.randint(200, 350), random.randint(200, 350), random.randint(200, 350)],
                            [random.randint(200, 350), -random.randint(200, 350), -random.randint(200, 350), random.randint(200, 350), random.randint(200, 350), random.randint(200, 350)],
                            [random.randint(200, 350), -random.randint(200, 350), -random.randint(200, 350), random.randint(200, 350), random.randint(200, 350), random.randint(200, 350)],
                            [random.randint(200, 350), -random.randint(200, 350), -random.randint(200, 350), random.randint(200, 350), random.randint(200, 350), random.randint(200, 350)],
                        ]})
      result = client.publish(topic, msg)
      status = result[0]
      if status == 0:
          print(f"Send `{msg}` to topic `{topic}`")
      else:
          print(f"Failed to send message to topic {topic}")


def run():
  client = connect_mqtt()
  client.loop_start()
  publish(client)


if __name__ == '__main__':
  run()

mqtt订阅

from paho.mqtt import client as mqtt_client
import time
import os

broker = 'broker.emqx.io'
port = 1883
topic = "/python/mqtt/li"

def connect_mqtt(client_id):
  """    MQTT 连接函数。    """
  def on_connect(client, userdata, flags, rc):
      """
      连接回调函数
      在客户端连接后被调用，在该函数中可以依据 rc 来判断客户端是否连接成功。
      """
      if rc == 0:
          print("Connected to MQTT Broker! return code %d" % rc)
      else:
          print("Failed to connect, return code %d\n", rc)

  client = mqtt_client.Client(client_id)
  # client.username_pw_set('uname', 'upwd')  # 链接mqtt所需的用户名和密码，没有可不写
  client.on_connect = on_connect
  client.connect(broker , port)
  return client


def subscribe(client: mqtt_client, a_topic):
  """     订阅消息       """
  def on_message(client, userdata, msg):
      """
      消息回调函数
      在客户端从 MQTT Broker 收到消息后被调用，在该函数中我们将打印出订阅的 topic 名称以及接收到的消息内容。
       * 这里可添加自定义数据处理程序
      """
      print('From topic : %s\n\tmsg : %s' % (msg.topic, msg.payload.decode()))

  client.subscribe(topic)
  client.on_message = on_message


def run(client_id, topic):
  client = connect_mqtt(client_id)
  subscribe(client, topic)
  client.loop_forever()

if __name__ == '__main__':
  run('test_eartag-003-python-li', 'zk100/gw/#')

matplotlib绘制动态图

import matplotlib.pyplot as plt
import numpy as np

count = 100  # 图中最多数据量

ax = list(range(count))  # 保存图1数据
ay = [0] * 100
bx = list(range(count))  # 保存图2数据
by = [0] * 100
num = count  # 计数

plt.ion()  # 开启一个画图的窗口进入交互模式，用于实时更新数据
plt.rcParams['figure.figsize'] = (10, 10)  # 图像显示大小
plt.rcParams['font.sans-serif'] = ['SimHei']  # 防止中文标签乱码，还有通过导入字体文件的方法
plt.rcParams['axes.unicode_minus'] = False
plt.rcParams['lines.linewidth'] = 0.5  # 设置曲线线条宽度
plt.tight_layout()
while True:
  plt.clf()  # 清除刷新前的图表，防止数据量过大消耗内存
  plt.suptitle("总标题", fontsize=30)  # 添加总标题，并设置文字大小
  g1 = np.random.random()  # 生成随机数画图
  # 图表1
  ax.append(num)  # 追加x坐标值
  ay.append(g1)  # 追加y坐标值
  agraphic = plt.subplot(2, 1, 1)
  agraphic.set_title('子图表标题1')  # 添加子标题
  agraphic.set_xlabel('x轴', fontsize=10)  # 添加轴标签
  agraphic.set_ylabel('y轴', fontsize=20)
  plt.plot(ax[-count:], ay[-count:], 'g-')  # 等于agraghic.plot(ax,ay,'g-')
  # 图表2
  bx.append(num)
  by.append(g1)
  bgraghic = plt.subplot(2, 1, 2)
  bgraghic.set_title('子图表标题2')
  bgraghic.plot(bx[-count:], by[-count:], 'r^')

  plt.pause(0.001)  # 设置暂停时间，太快图表无法正常显示
  num = num + 1

matplotlib绘制mqtt数据实时图像

• 单线程

先启动mqtt订阅服务
mqtt订阅中有阻塞，更新数据后因订阅服务没有结束，导致绘图程序无法绘图
先启动绘图程序
绘图程序本身也是个循环，拿不到mqtt的实时数据，图像无法更新

• 两个服务加入协程，也不行。具体原因还不知道，容后补充。
• mqtt作为线程启动，可解决上述问题

import json
import random
from paho.mqtt import client as mqtt_client
import time
import datetime
from math import ceil, floor
import matplotlib.pyplot as plt
import _thread

# 公共变量
broker = 'broker.emqx.io'
topic = "/python/mqtt/li"
port = 1883
client_id = f'python-mqtt-li-{random.randint(0, 100)}'

show_num = 300

x_num = [-1]  # 计数
acc1 = []
acc2 = []
acc3 = []
acc4 = []
acc5 = []
acc6 = []
stime = []


"""mqtt subscribe topic"""
def str_microsecond_datetime2int_13timestamp(str_microsecond_datetime):
  """将字符串型【毫秒级】格式化时间 转为 【13位】整型时间戳"""
  datetime_obj = datetime.datetime.strptime(str_microsecond_datetime, "%Y/%m/%d-%H:%M:%S.%f")
  obj_stamp = int(time.mktime(datetime_obj.timetuple()) * 1000.0 + datetime_obj.microsecond / 1000.0) / 1000.0
  return obj_stamp


def int2datetime(int_float_timestamp):
  """
  有小数点：分离小数点，整数转为格式化时间，小数点直接跟在后面
  无小数点：从第10位进行分离，
  所以本函数只适用于时间戳整数位数大于9且小于11.
  """
  if '.' in str(int_float_timestamp):
      int_float = str(int_float_timestamp).split('.')
      date = time.localtime(int(int_float[0]))
      tempDate = time.strftime("%Y/%m/%d-%H:%M:%S", date)
      secondafter = '.' + str(int_float[1])
      return str(tempDate) + secondafter


def parse_mqttmsg(msg):
  """解析mqt头数据   MAC samplerate sampletime battery acc"""
  content = json.loads(msg.payload.decode())
  span = 1000 / content['samplerate'] * 10
  time_span = [ceil(span) / 10 / 1000, floor(span) / 10 / 1000]
  sampletime = content['sampletime']
  sampletime_int = str_microsecond_datetime2int_13timestamp(sampletime)
  acc = content['acc']
  for i in range(len(acc)):
      x_num.append(x_num[-1] + 1)
      acc1.append(acc[i][0])
      acc2.append(acc[i][1])
      acc3.append(acc[i][2])
      acc4.append(acc[i][3])
      acc5.append(acc[i][4])
      acc6.append(acc[i][5])
      if i != 0:
          sampletime_int += time_span[i % 2]
          stime.append(int2datetime(round(sampletime_int * 1000, 0) / 1000))
      else:
          stime.append(sampletime)
      print(x_num[-1], stime[-1], acc1[-1], acc2[-1], acc3[-1], acc4[-1], acc5[-1], acc6[-1])


def connect_mqtt():
  def on_connect(client, userdata, flags, rc):
      if rc == 0:
          print("Connected to MQTT Broker!")
      else:
          print("Failed to connect, return code %d\n", rc)
          pass

  client = mqtt_client.Client(client_id)
  client.on_connect = on_connect
  client.connect(broker, port)
  return client


def subscribe(client: mqtt_client):
  def on_message(client, userdata, msg):
      # print(f"Received `{msg.payload.decode()}` from `{msg.topic}` topic")
      parse_mqttmsg(msg)

  client.subscribe(topic)
  client.on_message = on_message


def run():
  client = connect_mqtt()
  subscribe(client)
  client.loop_forever()


""" draw figures """
def draw_figure():
  plt.ion()  # 开启一个画图的窗口进入交互模式，用于实时更新数据
  plt.rcParams['figure.figsize'] = (10, 10)  # 图像显示大小
  plt.rcParams['font.sans-serif'] = ['SimHei']  # 防止中文标签乱码，还有通过导入字体文件的方法
  plt.rcParams['axes.unicode_minus'] = False
  plt.rcParams['lines.linewidth'] = 0.5  # 设置曲线线条宽度


  count = 0
  while True:
      plt.clf()  # 清除刷新前的图表，防止数据量过大消耗内存
      plt.suptitle("总标题", fontsize=30)  # 添加总标题，并设置文字大小
      plt.tight_layout()

      # 图表1
      agraphic = plt.subplot(2, 1, 1)
      agraphic.set_title('子图表标题1')  # 添加子标题
      agraphic.set_xlabel('x轴', fontsize=10)  # 添加轴标签
      agraphic.set_ylabel('y轴', fontsize=20)
      plt.plot(x_num[1:][-show_num:], acc1[-show_num:], 'g-')
      try:
          xtricks = list(range(len(acc1) - show_num, len(acc1), 10))  # **1**
          xlabels = [stime[i] for i in xtricks]  # **2**
          plt.xticks(xtricks, xlabels, rotation=15)
      except:
          pass

      # 图表2
      bgraghic = plt.subplot(2, 1, 2)
      bgraghic.set_title('子图表标题2')
      bgraghic.set_xlabel('x轴', fontsize=10)  # 添加轴标签
      bgraghic.set_ylabel('y轴', fontsize=20)
      bgraghic.plot(x_num[1:][-show_num:], acc2[-show_num:], 'r^')

      plt.pause(0.001)  # 设置暂停时间，太快图表无法正常显示
      count = count + 1


if __name__ == '__main__':
  # 多线程
  _thread.start_new_thread(run, ())
  draw_figure()

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原文链接：https://blog.csdn.net/m0_46744629/article/details/120072063