Pyqt+matplotlib 实现实时画图

Pyqt+matplotlib实现画图实时更新：

需求分析：项目中根据测得的数据在界面上实时绘制
运行环境：Python 3.7 + Matplotlib 3.0.2 + PyQt 5
matplot官网给的相应的例子：

import sys
import time

import numpy as np

from matplotlib.backends.qt_compat import QtCore, QtWidgets, is_pyqt5
if is_pyqt5():
    from matplotlib.backends.backend_qt5agg import (
        FigureCanvas, NavigationToolbar2QT as NavigationToolbar)
else:
    from matplotlib.backends.backend_qt4agg import (
        FigureCanvas, NavigationToolbar2QT as NavigationToolbar)
from matplotlib.figure import Figure


class ApplicationWindow(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()
        self._main = QtWidgets.QWidget()
        self.setCentralWidget(self._main)
        layout = QtWidgets.QVBoxLayout(self._main)

        static_canvas = FigureCanvas(Figure(figsize=(5, 3)))
        layout.addWidget(static_canvas)
        self.addToolBar(NavigationToolbar(static_canvas, self))

        dynamic_canvas = FigureCanvas(Figure(figsize=(5, 3)))
        layout.addWidget(dynamic_canvas)
        self.addToolBar(QtCore.Qt.BottomToolBarArea,
                        NavigationToolbar(dynamic_canvas, self))

        self._static_ax = static_canvas.figure.subplots()
        t = np.linspace(0, 10, 501)
        self._static_ax.plot(t, np.tan(t), ".")

        self._dynamic_ax = dynamic_canvas.figure.subplots()
        self._timer = dynamic_canvas.new_timer(
            100, [(self._update_canvas, (), {})])
        self._timer.start()

    def _update_canvas(self):
        self._dynamic_ax.clear()
        t = np.linspace(0, 10, 101)
        # Shift the sinusoid as a function of time.
        self._dynamic_ax.plot(t, np.sin(t + time.time()))
        self._dynamic_ax.figure.canvas.draw()


if __name__ == "__main__":
    qapp = QtWidgets.QApplication(sys.argv)
    app = ApplicationWindow()
    app.show()
    qapp.exec_()

上图中的散点为静止的，下面的图为动态的，类似行波，一直在行走，是应为用了**self._dynamic_ax.plot(t, np.sin(t + time.time()))**函数，但是这个和我想得实时画图不太一样，在项目中要根据生成的数据实时绘图，因此x轴的元素和y轴的元素个数是逐渐增加的。

通过阅读上述 _update_canvas 函数代码以及 dynamic_canvas.new_timer 可以使得每次调用_update_canvas是的相应的x的元素和y轴的元素增加更改后的代码如下：

import sys
import time

import numpy as np

from matplotlib.backends.qt_compat import QtCore, QtWidgets, is_pyqt5
if is_pyqt5():
    from matplotlib.backends.backend_qt5agg import (
        FigureCanvas, NavigationToolbar2QT as NavigationToolbar)
else:
    from matplotlib.backends.backend_qt4agg import (
        FigureCanvas, NavigationToolbar2QT as NavigationToolbar)
from matplotlib.figure import Figure


class ApplicationWindow(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()
        self._main = QtWidgets.QWidget()
        self.setCentralWidget(self._main)
        layout = QtWidgets.QVBoxLayout(self._main)

        static_canvas = FigureCanvas(Figure(figsize=(5, 3)))
        layout.addWidget(static_canvas)
        self.addToolBar(NavigationToolbar(static_canvas, self))

        dynamic_canvas = FigureCanvas(Figure(figsize=(5, 3)))
        layout.addWidget(dynamic_canvas)
        self.addToolBar(QtCore.Qt.BottomToolBarArea,
                        NavigationToolbar(dynamic_canvas, self))

        self._static_ax = static_canvas.figure.subplots()
        t = np.linspace(0, 10, 501)
        self._static_ax.plot(t, np.tan(t), ".")

        self.x = []  #建立空的x轴数组和y轴数组
        self.y = []
        self.n = 0

        self._dynamic_ax = dynamic_canvas.figure.subplots()
        self._timer = dynamic_canvas.new_timer(
            100, [(self._update_canvas, (), {})])
        self._timer.start()

        


    def _update_canvas(self):
        self.n += 1
        if self.n == 200:            #画200个点就停止，根据实际情况确定终止条件
            self._timer.stop()     

        self._dynamic_ax.clear()
        self.x.append(np.pi/100*self.n) #x加入一个值，后一个值比前一个大pi/100
        xx = np.array(self.x)
        # t = np.linspace(0, 10, 101)
        # Shift the sinusoid as a function of time.
        self._dynamic_ax.plot(xx, np.sin(xx))
        self._dynamic_ax.set_xlim(0,7)
        self._dynamic_ax.set_ylim(-1,1)
        self._dynamic_ax.figure.canvas.draw()


if __name__ == "__main__":
    qapp = QtWidgets.QApplication(sys.argv)
    app = ApplicationWindow()
    app.show()
    qapp.exec_()

上面的图仍然静止，下面的可以实时显示