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    Python中使用matplotlib绘制mqtt数据实时图像功能

    作者：A_Coding_man 时间：2021-09-13 17:55

    目录
    • 效果图
    • mqtt发布
    • mqtt订阅
    • matplotlib绘制动态图
    • matplotlib绘制mqtt数据实时图像

    效果图

    请添加图片描述

    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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