Python - 實時繪圖

Question

我寫了一個簡單的python腳本來顯示我的傳感器數據（從串行讀取）。 我想了解當我點擊任何地方時圖形崩潰的原因... 是否有任何 - 如果可能，簡單的方法 - 避免腳本崩潰，如果我嘗試在計算機上執行其他操作？

此外，如果我想開發一個簡單的GUI，有人學習如何做的例子？它會避免這個問題嗎？

import serial 
import re 
import numpy as np 
import time 
from matplotlib import pyplot as plt 

SERIAL_PORT = 'COM3' 
BAUDRATE = 9600 
BUFFER_SIZE = 30 



print("initialisation ...") 
ser = serial.Serial(SERIAL_PORT, BAUDRATE) 
buffer = [] 

plt.ion() 
fig = plt.figure() 
ydata = [0]*BUFFER_SIZE*2 
prevBuf = [0]*BUFFER_SIZE*10 
ax1=plt.axes() 

line, = plt.plot(prevBuf) 
plt.ylim([2000,10000]) 


def clean_serial(): 
    i=0 
    while i<=5: 
     data = ser.readline() 
     print data 
     i+=1 
    ser.flush() 


def extract_number(rawdata): 
    return float(re.sub("[^0-9.]", " ", rawdata)) 

def process_buffer(buf): 

    prevBuf[len(prevBuf)-BUFFER_SIZE:] = buf 

    line.set_xdata(np.arange(len(prevBuf))) 
    line.set_ydata(prevBuf) 

    ydataMax = max(prevBuf)+10 
    ydataMin = min(prevBuf)-100 
    plt.ylim([ydataMin,ydataMax]) 
    plt.draw() 


    prevBuf[:] = prevBuf[BUFFER_SIZE:]+buf 

print("cleaning serial") 
clean_serial() 

print("reading value from serial") 
while True: 
    data = extract_number(ser.readline()) 
    buffer.append(data) 
    if len(buffer)>= BUFFER_SIZE: 
     process_buffer(buffer) 
     buffer=[] 


ser.close() 

其輸出：script crashing

謝謝！

Answer 1

我寫了一個Python應用程序可能對您有用：

################################################################### 
#                 # 
#      PLOTTING A LIVE GRAPH      # 
#     ----------------------------     # 
#   EMBED A MATPLOTLIB ANIMATION INSIDE YOUR    # 
#   OWN GUI!            # 
#                 # 
################################################################### 


import sys 
import os 
from PyQt4 import QtGui 
from PyQt4 import QtCore 
import functools 
import numpy as np 
import random as rd 
import matplotlib 
matplotlib.use("Qt4Agg") 
from matplotlib.figure import Figure 
from matplotlib.animation import TimedAnimation 
from matplotlib.lines import Line2D 
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas 
import time 
import threading 



def setCustomSize(x, width, height): 
    sizePolicy = QtGui.QSizePolicy(QtGui.QSizePolicy.Fixed, QtGui.QSizePolicy.Fixed) 
    sizePolicy.setHorizontalStretch(0) 
    sizePolicy.setVerticalStretch(0) 
    sizePolicy.setHeightForWidth(x.sizePolicy().hasHeightForWidth()) 
    x.setSizePolicy(sizePolicy) 
    x.setMinimumSize(QtCore.QSize(width, height)) 
    x.setMaximumSize(QtCore.QSize(width, height)) 

'''''' 

class CustomMainWindow(QtGui.QMainWindow): 

    def __init__(self): 

     super(CustomMainWindow, self).__init__() 

     # Define the geometry of the main window 
     self.setGeometry(300, 300, 800, 400) 
     self.setWindowTitle("my first window") 

     # Create FRAME_A 
     self.FRAME_A = QtGui.QFrame(self) 
     self.FRAME_A.setStyleSheet("QWidget { background-color: %s }" % QtGui.QColor(210,210,235,255).name()) 
     self.LAYOUT_A = QtGui.QGridLayout() 
     self.FRAME_A.setLayout(self.LAYOUT_A) 
     self.setCentralWidget(self.FRAME_A) 

     # Place the zoom button 
     self.zoomBtn = QtGui.QPushButton(text = 'zoom') 
     setCustomSize(self.zoomBtn, 100, 50) 
     self.zoomBtn.clicked.connect(self.zoomBtnAction) 
     self.LAYOUT_A.addWidget(self.zoomBtn, *(0,0)) 

     # Place the matplotlib figure 
     self.myFig = CustomFigCanvas() 
     self.LAYOUT_A.addWidget(self.myFig, *(0,1)) 

     # Add the callbackfunc to .. 
     myDataLoop = threading.Thread(name = 'myDataLoop', target = dataSendLoop, args = (self.addData_callbackFunc,)) 
     myDataLoop.start() 

     self.show() 

    '''''' 


    def zoomBtnAction(self): 
     print("zoom in") 
     self.myFig.zoomIn(5) 

    '''''' 

    def addData_callbackFunc(self, value): 
     # print("Add data: " + str(value)) 
     self.myFig.addData(value) 



''' End Class ''' 


class CustomFigCanvas(FigureCanvas, TimedAnimation): 

    def __init__(self): 

     self.addedData = [] 
     print(matplotlib.__version__) 

     # The data 
     self.xlim = 200 
     self.n = np.linspace(0, self.xlim - 1, self.xlim) 
     a = [] 
     b = [] 
     a.append(2.0) 
     a.append(4.0) 
     a.append(2.0) 
     b.append(4.0) 
     b.append(3.0) 
     b.append(4.0) 
     self.y = (self.n * 0.0) + 50 

     # The window 
     self.fig = Figure(figsize=(5,5), dpi=100) 
     self.ax1 = self.fig.add_subplot(111) 


     # self.ax1 settings 
     self.ax1.set_xlabel('time') 
     self.ax1.set_ylabel('raw data') 
     self.line1 = Line2D([], [], color='blue') 
     self.line1_tail = Line2D([], [], color='red', linewidth=2) 
     self.line1_head = Line2D([], [], color='red', marker='o', markeredgecolor='r') 
     self.ax1.add_line(self.line1) 
     self.ax1.add_line(self.line1_tail) 
     self.ax1.add_line(self.line1_head) 
     self.ax1.set_xlim(0, self.xlim - 1) 
     self.ax1.set_ylim(0, 100) 


     FigureCanvas.__init__(self, self.fig) 
     TimedAnimation.__init__(self, self.fig, interval = 50, blit = True) 

    def new_frame_seq(self): 
     return iter(range(self.n.size)) 

    def _init_draw(self): 
     lines = [self.line1, self.line1_tail, self.line1_head] 
     for l in lines: 
      l.set_data([], []) 

    def addData(self, value): 
     self.addedData.append(value) 

    def zoomIn(self, value): 
     bottom = self.ax1.get_ylim()[0] 
     top = self.ax1.get_ylim()[1] 
     bottom += value 
     top -= value 
     self.ax1.set_ylim(bottom,top) 
     self.draw() 


    def _step(self, *args): 
     # Extends the _step() method for the TimedAnimation class. 
     try: 
      TimedAnimation._step(self, *args) 
     except Exception as e: 
      self.abc += 1 
      print(str(self.abc)) 
      TimedAnimation._stop(self) 
      pass 

    def _draw_frame(self, framedata): 
     margin = 2 
     while(len(self.addedData) > 0): 
      self.y = np.roll(self.y, -1) 
      self.y[-1] = self.addedData[0] 
      del(self.addedData[0]) 


     self.line1.set_data(self.n[ 0 : self.n.size - margin ], self.y[ 0 : self.n.size - margin ]) 
     self.line1_tail.set_data(np.append(self.n[-10:-1 - margin], self.n[-1 - margin]), np.append(self.y[-10:-1 - margin], self.y[-1 - margin])) 
     self.line1_head.set_data(self.n[-1 - margin], self.y[-1 - margin]) 
     self._drawn_artists = [self.line1, self.line1_tail, self.line1_head] 



''' End Class ''' 


# You need to setup a signal slot mechanism, to 
# send data to your GUI in a thread-safe way. 
# Believe me, if you don't do this right, things 
# go very very wrong.. 
class Communicate(QtCore.QObject): 
    data_signal = QtCore.pyqtSignal(float) 

''' End Class ''' 



def dataSendLoop(addData_callbackFunc): 
    # Setup the signal-slot mechanism. 
    mySrc = Communicate() 
    mySrc.data_signal.connect(addData_callbackFunc) 

    # Simulate some data 
    n = np.linspace(0, 499, 500) 
    y = 50 + 25*(np.sin(n/8.3)) + 10*(np.sin(n/7.5)) - 5*(np.sin(n/1.5)) 
    i = 0 

    while(True): 
     if(i > 499): 
      i = 0 
     time.sleep(0.1) 
     mySrc.data_signal.emit(y[i]) # <- Here you emit a signal! 
     i += 1 
    ### 
### 




if __name__== '__main__': 
    app = QtGui.QApplication(sys.argv) 
    QtGui.QApplication.setStyle(QtGui.QStyleFactory.create('Plastique')) 
    myGUI = CustomMainWindow() 


    sys.exit(app.exec_()) 

'''''' 

只是嘗試一下。將這些代碼複製粘貼到一個新的python文件中，然後運行它。你應該得到一個漂亮的，平滑移動圖形：

的實際數據在dataSendLoop（..）函數發送。這個函數在一個單獨的線程中運行。請注意，數據在該功能中的代碼行中發送：

mySrc.data_signal.emit(...) 

只需將要添加的括號內的值。下一次刷新屏幕時，該值將被添加到移動圖形中。