Python中如何使用matplotlib绘制mqtt数据实时图像功能

这篇文章主要讲解了"Python中如何使用matplotlib绘制mqtt数据实时图像功能"，文中的讲解内容简单清晰，易于学习与理解，下面请大家跟着小编的思路慢慢深入，一起来研究和学习"Python中如何使用matplotlib绘制mqtt数据实时图像功能"吧！

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

mqtt发布

本代码中publish是一个死循环，数据一直往外发送。

import randomimport timefrom paho.mqtt import client as mqtt_clientimport jsonfrom datetime import datetimebroker = 'broker.emqx.io'port = 1883topic = "/python/mqtt/li"client_id = f'python-mqtt-{random.randint(0, 1000)}'  # 随机生成客户端iddef 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 clientdef 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_clientimport timeimport osbroker = 'broker.emqx.io'port = 1883topic = "/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 clientdef 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_messagedef 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 pltimport numpy as npcount = 100  # 图中最多数据量ax = list(range(count))  # 保存图1数据ay = [0] * 100bx = list(range(count))  # 保存图2数据by = [0] * 100num = 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'] = Falseplt.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 jsonimport randomfrom paho.mqtt import client as mqtt_clientimport timeimport datetimefrom math import ceil, floorimport matplotlib.pyplot as pltimport _thread# 公共变量broker = 'broker.emqx.io'topic = "/python/mqtt/li"port = 1883client_id = f'python-mqtt-li-{random.randint(0, 100)}'show_num = 300x_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_stampdef 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) + secondafterdef 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 clientdef 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_messagedef 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 + 1if __name__ == '__main__':    # 多线程    _thread.start_new_thread(run, ())    draw_figure()

感谢各位的阅读，以上就是"Python中如何使用matplotlib绘制mqtt数据实时图像功能"的内容了，经过本文的学习后，相信大家对Python中如何使用matplotlib绘制mqtt数据实时图像功能这一问题有了更深刻的体会，具体使用情况还需要大家实践验证。这里是，小编将为大家推送更多相关知识点的文章，欢迎关注！