【发布时间】：2019-10-22 12:17:09
【问题描述】：
我正在尝试编写一个程序，该程序通过串行从 arduino 获取串行数据，并实时绘制它。我使用 matplotlib 编写了代码，但我希望对结果感到满意，所以我试图让它在 pyqtgraph 上工作（学习如何使用它的资源要少得多）。我的问题是代码显示了一个空图。似乎 _update 只被调用了一次，但是当我把它放在一个循环中时，图表甚至都没有显示。
我已经编写了一些其他代码来执行我想要的操作，即实时绘制数据，并在数据通过阈值后在数据上绘制新线，以显示线性回归。我从这里 (https://github.com/JaFeKl/joystick_real_time_plot_with_pyqtgraph/blob/master/real_time_plot.py) 得到了一个示例，因为我希望我的代码是可调用的（在一个函数中，但我无法让它工作。到目前为止，我正在从 python 中生成数据以简化调试
import sys
import pyqtgraph as pg
import pyqtgraph.exporters
from pyqtgraph.Qt import QtGui, QtCore
import numpy as np
import serial
# test
import math
import time
class Graph(QtGui.QMainWindow):
def __init__(self, parent=None):
super(Graph, self).__init__(parent)
self.n = 3
self.mainbox = QtGui.QWidget()
self.setCentralWidget(self.mainbox)
self.mainbox.setLayout(QtGui.QVBoxLayout())
self.canvas = pg.GraphicsLayoutWidget() # create GrpahicsLayoutWidget obejct
self.mainbox.layout().addWidget(self.canvas)
# Set up plot
self.analogPlot = self.canvas.addPlot(title='Signal from serial port')
self.analogPlot.setYRange(-1,1123) # set axis range
self.analogPlot.setXRange(-1,1123)
self.analogPlot.showGrid(x=True, y=True, alpha=0.5) # show Grid
x_axis = self.analogPlot.getAxis('bottom')
y_axis = self.analogPlot.getAxis('left')
font=QtGui.QFont()
font.setPixelSize(20)
x_axis.tickFont = font
y_axis.tickFont = font
x_axis.setLabel(text='Tensão [V]') # set axis labels
y_axis.setLabel(text='Corrente [mA]')
self.plts = []
self.intplts = []
colors = ['r', 'b', 'w', 'y', 'g', 'm', 'c', 'k']
for i in range(self.n):
self.plts.append([])
self.intplts.append([])
for i in range(self.n):
if len(self.plts) <= len(colors):
self.plts[i]=(self.analogPlot.plot(pen= pg.mkPen(colors[i], width=6)))
for i in range(self.n):
if len(self.plts) <= len(colors)*2:
self.intplts.append(self.analogPlot.plot(pen= pg.mkPen(colors[i+3], width=3)))
#Data
self.datay = []
self.datax = []
for i in range(self.n):
self.datax.append([])
self.datay.append([])
# set up image exporter (necessary to be able to export images)
QtGui.QApplication.processEvents()
self.exporter=pg.exporters.ImageExporter(self.canvas.scene())
self.image_counter = 1
# start updating
self.t=0
self._update()
def _update(self):
time.sleep(0.01)
if self.t<= 30:
#line = raw.readline()
#data.append(int(line))
self.datay[0].append(math.sin(self.t+(math.pi/2)))
self.datay[1].append(math.sin(self.t+(5*math.pi/4)))
self.datay[2].append(math.sin(self.t))
self.datax[0].append(self.t)
self.datax[1].append(self.t)
self.datax[2].append(self.t)
self.t+=0.1
self.plts[0].setData(self.datax[0], self.datay[0])
self.plts[1].setData(self.datax[1], self.datay[1])
self.plts[2].setData(self.datax[2], self.datay[2])
app.processEvents()
elif self.t>=30 and self.t<=30.1 :
self.t+=1
if __name__ == '__main__':
app = QtGui.QApplication(sys.argv)
plot = Graph()
plot.show()
sys.exit(app.exec_())
我希望得到类似于此代码的结果（仅没有线性回归）
import pyqtgraph as pg
import pyqtgraph.exporters
from pyqtgraph.Qt import QtGui, QtCore
import numpy as np
# linear regression
from scipy import stats
#Arduino
#import find_arduino
#import find_buad
import serial
import math
import time
#port = find_arduino.FindArduino()
#baud = find_buad.FindBaudRate()
ard=None
def Con():
global ard
ard = serial.Serial(port,baud,timeout=5)
time.sleep(2) # wait for Arduino
ard.close()
# define the data
theTitle = "pyqtgraph plot"
datay = [[],[],[]]
datax = [[],[],[]]
x2 = []
T=[]
t=0
y1L=[]
x1L=[]
# create plot
### START QtApp #####
app = QtGui.QApplication([]) # you MUST do this once (initialize things)
####################
win = pg.GraphicsWindow(title="Signal from serial port") # creates a window
plt = win.addPlot(title="Realtime plot") # creates empty space for the plot in the window
font=QtGui.QFont()
font.setPixelSize(20)
plt.getAxis("bottom").tickFont = font
plt.getAxis("left").tickFont = font
plt1 = plt.plot(pen=pg.mkPen('r', width=6))
plt2= plt.plot(pen=pg.mkPen('b', width=6))
plt3= plt.plot(pen=pg.mkPen('w', width=6))
plt1I = plt.plot(pen=pg.mkPen('y', width=3))
plt2I = plt.plot(pen=pg.mkPen('g', width=3))
plt3I = plt.plot(pen=pg.mkPen('m', width=3))
plt.showGrid(x=True,y=True)
def update():
global plt1,plt2,plt3, t, plt1I, plt2I, plt3I
if t<= 30:
#line = raw.readline()
#data.append(int(line))
datay[0].append(math.sin(t+(math.pi/2)))
datay[1].append(math.sin(t+(5*math.pi/4)))
datay[2].append(math.sin(t))
datax[0].append(t)
datax[1].append(t)
datax[2].append(t)
t+=0.1
plt1.setData(datax[0],datay[0])
plt2.setData(datax[1],datay[1])
plt3.setData(datax[2],datay[2])
app.processEvents()
time.sleep(0.01)
elif t>=30 and t<=30.1 :
#plt1I.setData([0,1,2],[5,3,1])
#app.processEvents()
interp(plt1I, plt2I, plt3I)
t+=1
else:
app.processEvents()
def interp(pt1, pt2, pt3):
slope, intercept, r_value, p_value, std_err = stats.linregress(datax[0][10:],datay[0][10:])
x=[]
y=[]
print(slope)
for i in datax[0][10:]:
x.append(i)
y.append(intercept+slope*i)
pt1.setData(x,y)
slope, intercept, r_value, p_value, std_err = stats.linregress(datax[1][10:],datay[1][10:])
x=[]
y=[]
print(slope)
for i in datax[0][10:]:
x.append(i)
y.append(intercept+slope*i)
pt2.setData(x, y)
slope, intercept, r_value, p_value, std_err = stats.linregress(datax[2][10:],datay[2][10:])
x=[]
y=[]
print(slope)
for i in datax[0][10:]:
x.append(i)
y.append(intercept+slope*i)
pt3.setData(x,y)
app.processEvents()
timer = QtCore.QTimer()
timer.timeout.connect(update)
timer.start(0)
### MAIN PROGRAM #####
# this is a brutal infinite loop calling your realtime data plot
# make this interpret the incoming data
#Con()
#Communicate(1)
while True: update()
### END QtApp ####
pg.QtGui.QApplication.exec_() # you MUST put this at the end
##################
【问题讨论】：