plot - 使用 matplotlib 或 pyqtgraph 绘制实时数据

Question

我有设备连接到我的串行端口，我需要轮询它们，然后在图中显示该数据。我目前正在使用 matplotlib(缓慢地)进行这项工作。我最多可以连接 64 个设备，每个设备可以有 20 条数据需要更新。我已经设置了它，以便可以创建一个新窗口并可以添加一条数据以进行绘制。每打开一个额外的绘图窗口，我的更新速度就会大大减慢。
我试过在 matplotlib 中使用 blit 动画，但它不是很流畅，我可以看到更新中的异常。我已经尝试过 PyQtGraph，但找不到任何关于如何使用这个包的文档，现在我正在尝试 PyQwt，但无法安装它(主要是因为我的公司不会让我们安装一个包处理 .gz 文件)。
任何想法或建议将不胜感激。

import sys
from PyQt4.QtCore import (Qt, QModelIndex, QObject, SIGNAL, SLOT, QTimer, QThread,  QSize, QString, QVariant)
from PyQt4 import QtGui

from matplotlib.figure import Figure
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
from plot_toolbar import NavigationToolbar2QT as NavigationToolbar
import matplotlib.dates as md
import psutil as p
import time
import datetime as dt
import string
import ui_plotting
import pickle

try:
  _fromUtf8 = QString.fromUtf8
except AttributeError:
  _fromUtf8 = lambda s: s

class Monitor(FigureCanvas):
"""Plot widget to display real time graphs"""
  def __init__(self, timenum):
    self.timenum=timenum
    self.main_frame = QtGui.QWidget()
    self.timeTemp1 = 0
    self.timeTemp2 = 0
    self.temp = 1
    self.placeHolder = []
    self.y_max = 0
    self.y_min = 100

# initialization of the canvas
#        self.dpi = 100
#        self.fig = Figure((5.0, 4.0), dpi=self.dpi)
    self.fig = Figure()
    FigureCanvas.__init__(self, self.fig)
#        self.canvas = FigureCanvas(self.fig)
#        self.canvas.setParent(self.main_frame)
# first image setup
#        self.fig = Figure()
#        self.fig.subplots_adjust(bottom=0.5)
    self.ax = self.fig.add_subplot(111)
    self.mpl_toolbar = NavigationToolbar(self.fig.canvas, self.main_frame,False)
    self.mpl_toolbar.setFixedHeight(24)

# set specific limits for X and Y axes
#        now=dt.datetime.fromtimestamp(time.mktime(time.localtime()))       
#        self.timenum = now.strftime("%H:%M:%S.%f")
    self.timeSec = 0      
    self.x_lim = 100
    self.ax.set_xlim(0, self.x_lim)
    self.ax.set_ylim(0, 100)
    self.ax.get_xaxis().grid(True)
    self.ax.get_yaxis().grid(True)
# and disable figure-wide autoscale
    self.ax.set_autoscale_on(False)
    self.ax.set_xlabel('Time in Seconds')
# generates first "empty" plots
    self.timeb = []
    self.user = []
    self.l_user = []
    self.l_user = [[] for x in xrange(50)]
    for i in range(50):
        self.l_user[i], = self.ax.plot(0,0)


# add legend to plot
#        self.ax.legend()


def addTime(self,t1,t2):
    timeStamp = t1+"000"
#   print "timeStamp",timeStamp
    timeStamp2 = t2+"000"
    test = string.split(timeStamp,":")
    test2 = string.split(test[2],".")        
    testa = string.split(timeStamp2,":")
    testa2 = string.split(testa[2],".")

    sub1 = int(testa[0])-int(test[0])
    sub2 = int(testa[1])-int(test[1])
    sub3 = int(testa2[0])-int(test2[0])
    sub4 = int(testa2[1])-int(test2[1])

    testing = dt.timedelta(hours=sub1,minutes=sub2,seconds=sub3,microseconds=sub4)

    self.timeSec = testing.total_seconds()

def timerEvent(self, evt, timeStamp, val, lines):
    temp_min = 0
    temp_max = 0
# Add user arrays for each user_l array used, don't reuse user arrays
    if self.y_max<max(map(float, val)):
        self.y_max = max(map(float, val))
    if self.y_min>min(map(float, val)):
        self.y_min = min(map(float, val))            
#       print "val: ",val
    if lines[len(lines)-1]+1 > len(self.user):
        for k in range((lines[len(lines)-1]+1)-len(self.user)):
            self.user.append([])


# append new data to the datasets
#        print "timenum=",self.timenum
    self.addTime(self.timenum, timeStamp)
    self.timeb.append(self.timeSec)
    for j in range((lines[len(lines)-1]+1)):
        if j >49:
            break
        if j not in lines:
            del self.user[j][:]
            self.user[j].extend(self.placeHolder)
            self.user[j].append(0)
        else:
            if len(self.timeb) > (len(self.user[j])+1):
                self.user[j].extend(self.placeHolder)
            self.user[j].append(str(val[lines.index(j)])) 

    for i in range(len(lines)):
        if i>49:
            break
        self.l_user[lines[i]].set_data(self.timeb, self.user[lines[i]])
# force a redraw of the Figure

#        if self.y_max < 2:
#            self.y_max = 2
#        if self.y_min < 2:
#            self.y_min = 0 
    if self.y_min > -.1 and self.y_max < .1:            
        temp_min = -1
        temp_max = 1
    else:
        temp_min = self.y_min-(self.y_min/10)
        temp_max = self.y_max+(self.y_max/10)


    self.ax.set_ylim(temp_min, temp_max)
    if self.timeSec >= self.x_lim:
        if str(self.x_lim)[0]=='2':
            self.x_lim = self.x_lim * 2.5
        else:
            self.x_lim = self.x_lim * 2
        self.ax.set_xlim(0, self.x_lim)
#        self.fig.canvas.restore_region(self.fig.canvas)
#        self.ax.draw_artist(self.l_user[lines[0]])
#        self.fig.canvas.blit(self.ax.bbox)
    self.fig.canvas.draw()

#        self.draw()

    self.placeHolder.append(None)

class List(QtGui.QListWidget):

  def __init__(self, parent):
    super(List, self).__init__(parent)

    font = QtGui.QFont()
    font.setFamily(_fromUtf8("Century Gothic"))
    font.setPointSize(7)
    self.setFont(font)
    self.setDragDropMode(4)
    self.setAcceptDrops(True)
    self.row = []
    self.col = []
    self.disName = []
    self.lines = []
    self.counter = 0
    self.setStyleSheet("background-color:#DDDDDD")
    self.colors = ["blue", "green", "red", "deeppink", "black", "slategray", "sienna", "goldenrod", "teal", "orange", "orchid", "lightskyblue", "navy", "darkgreen", "indigo", "firebrick", "deepskyblue", "lightskyblue", "darkseagreen", "gold"]

def dragEnterEvent(self, e):
    if e.mimeData().hasFormat("application/x-qabstractitemmodeldatalist"):
#            print "currentRow : ", self.currentRow()
#            print "self.col: ", self.col
#            print "self.row: ", self.row
#            print "self.col[]: ", self.col.pop(self.currentRow())
#            print "self.row[]: ", self.row.pop(self.currentRow())

        self.col.pop(self.currentRow())
        self.row.pop(self.currentRow())
        self.disName.pop(self.currentRow())
        self.lines.pop(self.currentRow())
        self.takeItem(self.currentRow())
    if e.mimeData().hasFormat("application/pubmedrecord"):
        e.accept()
    else:
        e.ignore() 


def dropEvent(self, e):

    items = 0
    data = e.mimeData()
    bstream = data.retrieveData("application/pubmedrecord", QVariant.ByteArray)
    selected = pickle.loads(bstream.toByteArray())
    e.accept()
#        print selected
#        if self.count() != 0:
#            j = (self.lines[self.count()-1]%len(self.colors))+1

#        else:
#            j=0
    while items < len(selected):
        j=self.counter
        if j >= len(self.colors)-1:
            j = self.counter%len(self.colors)
        m = len(self.lines)
        self.lines.append(self.counter)
#            if m != 0:
#                n = self.lines[m-1]
#                self.lines.append(n+1)
#            else:
#                self.lines.append(0)
        self.col.append(str(selected[items]))
        items = items+1
        self.row.append(str(selected[items]))
        items = items+1
        self.disName.append(str(selected[items]))
        listItem = QtGui.QListWidgetItem()
        listItem.setText(str(selected[items]))

        listItem.setTextColor(QtGui.QColor(self.colors[j]))
        self.addItem(listItem)            
        items = items+1

        self.counter += 1
def dragLeaveEvent(self, event):
    event.accept()  


class PlotDlg(QtGui.QDialog):
  NextID = 0
  filename = 'Plot'
  def __init__(self,time, callback, parent=None):
    super(PlotDlg, self).__init__(parent)
    self.id = PlotDlg.NextID
    PlotDlg.NextID += 1
    self.callback = callback
    self.setWindowFlags(Qt.Window | Qt.WindowMinimizeButtonHint | Qt.WindowMaximizeButtonHint)
    self.setAttribute(Qt.WA_DeleteOnClose,True)
    self.value = []
    print "time=",time
    self.time = time
    self.dc = Monitor(self.time)
#        self.threadPool = []

    self.listWidget = List(self)
    sizePolicy = QtGui.QSizePolicy(QtGui.QSizePolicy.Fixed, QtGui.QSizePolicy.MinimumExpanding)
    sizePolicy.setHorizontalStretch(0)
    self.listWidget.setSizePolicy(sizePolicy)
    self.listWidget.setMaximumSize(QSize(150, 16777215))

    grid = QtGui.QGridLayout()
    grid.setSpacing(0)
    grid.setContentsMargins(0, 0, 0, 0)
    grid.addWidget(self.dc.mpl_toolbar,0,0,1,12)
    grid.addWidget(self.listWidget,1,1)
    grid.addWidget(self.dc,1,0)
    grid.setColumnMinimumWidth(1,110)

    self.setLayout(grid)

def update(self, clear=0):
    if clear == 1:
 now=dt.datetime.fromtimestamp(time.mktime(time.localtime()))                         
        self.dc.timenum = now.strftime("%H:%M:%S.%f") 

        self.dc.timeSec = 0
        self.dc.x_lim = 100
        self.dc.y_max = 0
        self.dc.y_min = 100            
        del self.dc.timeb[:]
        del self.dc.user[:]
        del self.dc.placeHolder[:]

#            del self.dc.l_user[:]
#            self.dc.l_user = [[] for x in xrange(50)]
#            for i in range(50):
#                self.dc.l_user[i], = self.dc.ax.plot(0,0)
        for i in range(50):
            self.dc.l_user[i].set_data(0, 0)

#            print self.dc.l_user
#            print self.dc.user

        self.dc.ax.set_xlim(0, self.dc.x_lim)
        self.dc.fig.canvas.draw()
#        print self.value
#        print str(self.time)
#        print "time:",str(self.time)
#        self.threadPool.append( GenericThread(self.dc.timerEvent,None, str(self.time), self.value, self.listWidget.lines) )
#        self.threadPool[len(self.threadPool)-1].start()

    self.dc.timerEvent(None, str(self.time), self.value, self.listWidget.lines) 

def closeEvent(self, event):
#        self.update(1)
    self.callback(self.id)
    PlotDlg.NextID -= 1

class GenericThread(QThread):
  def __init__(self, function, *args, **kwargs):
    QThread.__init__(self)
    self.function = function
    self.args = args
    self.kwargs = kwargs

  def __del__(self):
    self.wait()

  def run(self):
    self.function(*self.args,**self.kwargs)
    return 

Answer 1

pyqtgraph website有一个绘图库的比较，包括 matplotlib、chaco 和 pyqwt。总结是:

Matplotlib 是事实上的标准绘图库，但不是为速度而构建的。

Chaco 专为速度而设计，但难以安装/部署

PyQwt 目前已废弃

PyQtGraph 专为速度和易于安装而构建