首先,我是Python的新手.我是MatLab的长期用户(工程师,而不是计算机科学家),我开始尝试将Python,NumPy,SciPy等工作到我的工作流程中.所以,请原谅我对这种精彩编程语言的明显无知！
作为我的第一次努力,我决定构建一个应用程序来与我正在开发的传感器进行交互.传感器具有微秒级分辨率(每500微秒512个高能量和512个低能量“像素”),但I / O将被阻塞.由于我将不断轮询设备,我知道线程对于保持GUI响应非常重要(GUI最终还会集成与其他设备的串行通信,并具有对传感器数据进行操作的图像处理子程序).我创建了一个MatPlotLib的线程实例来绘制来自传感器的这些“实时”数据.虽然我已经构建了独立与传感器通信的模块并验证了我知道如何在Python中实现这一点,但我从这里简单地通过生成512个8到12之间的随机数来实现数据的“模拟”以获得低能量对于高能量“像素”,“像素”和在90和110之间的512个随机数.那是线程化的.通过这里的许多例子,我还学会了使用blitting来使用MatPlotLib获得足够快的屏幕更新 – 但问题是,除非我使用time.sleep(0.02)使用线程进程休眠20ms,GUI没有反应.这可以验证,因为来自MatPlotLib的交互式X,Y数据点反馈不起作用,并且“STOP”按钮不能用于中断该过程.比time.sleep(0.02)更长的时间使GUI操作更加平滑,但代价是“数据速率”.任何比time.sleep(0.02)慢的东西都会使GUI无响应.我不确定我明白为什么.我本来打算尝试使用GUIqwt,但我想在放弃MatPlotLib之前会问这里,因为我不确定这是不是问题.我担心让线程休眠20ms将意味着我错过了来自传感器阵列的至少40个潜在数据线(40行* 500us /行= 20ms).
这是当前的代码：
import time, random, sys
from PyQt4.QtCore import *
from PyQt4.QtGui import *
from matplotlib.figure import Figure
from matplotlib.backends.backend_qt4agg import NavigationToolbar2QTAgg as NavigationToolbar
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
class ApplicationWindow(QMainWindow):
def __init__(self, parent = None):
QMainWindow.__init__(self, parent)
self.thread = Worker()
self.create_main_frame()
self.create_status_bar()
self.connect(self.thread, SIGNAL("finished()"), self.update_UI)
self.connect(self.thread, SIGNAL("terminated()"), self.update_UI)
self.connect(self.startButton, SIGNAL("clicked()"), self.start_acquisition)
self.connect(self.stopButton, SIGNAL("clicked()"), self.stop_acquisition)
self.thread.pixel_list.connect(self.update_figure)
def create_main_frame(self):
self.main_frame = QWidget()
self.dpi = 100
self.width = 10
self.height = 8
self.fig = Figure(figsize=(self.width, self.height), dpi=self.dpi)
self.axes = self.fig.add_subplot(111)
self.axes.axis((0,512,0,120))
self.canvas = FigureCanvas(self.fig)
self.canvas.setParent(self.main_frame)
self.canvas.updateGeometry()
self.canvas.draw()
self.background = None
self.lE_line, = self.axes.plot(range(512), [0 for i in xrange(512)], animated=True)
self.hE_line, = self.axes.plot(range(512), [0 for i in xrange(512)], animated=True)
self.mpl_toolbar = NavigationToolbar(self.canvas, self.main_frame)
self.startButton = QPushButton(self.tr("&Start"))
self.stopButton = QPushButton(self.tr("&Stop"))
layout = QGridLayout()
layout.addWidget(self.canvas, 0, 0)
layout.addWidget(self.mpl_toolbar, 1, 0)
layout.addWidget(self.startButton, 2, 0)
layout.addWidget(self.stopButton, 2, 1)
self.main_frame.setLayout(layout)
self.setCentralWidget(self.main_frame)
self.setWindowTitle(self.tr("XRTdev Interface"))
def create_status_bar(self):
self.status_text = QLabel("I am a status bar. I need a status to show!")
self.statusBar().addWidget(self.status_text, 1)
def start_acquisition(self):
self.thread.exiting = False
self.startButton.setEnabled(False)
self.stopButton.setEnabled(True)
self.thread.render()
def stop_acquisition(self):
self.thread.exiting = True
self.startButton.setEnabled(True)
self.stopButton.setEnabled(False)
self.cleanup_UI()
def update_figure(self, lE, hE):
if self.background == None:
self.background = self.canvas.copy_from_bbox(self.axes.bbox)
self.canvas.restore_region(self.background)
self.lE_line.set_ydata(lE)
self.hE_line.set_ydata(hE)
self.axes.draw_artist(self.lE_line)
self.axes.draw_artist(self.hE_line)
self.canvas.blit(self.axes.bbox)
def update_UI(self):
self.startButton.setEnabled(True)
self.stopButton.setEnabled(False)
self.cleanup_UI()
def cleanup_UI(self):
self.background = None
self.axes.clear()
self.canvas.draw()
class Worker(QThread):
pixel_list = pyqtSignal(list, list)
def __init__(self, parent = None):
QThread.__init__(self, parent)
self.exiting = False
def __del__(self):
self.exiting = True
self.wait()
def render(self):
self.start()
def run(self):
# simulate I/O
n = random.randrange(100,200)
while not self.exiting and n > 0:
lE = [random.randrange(5,16) for i in xrange(512)]
hE = [random.randrange(80,121) for i in xrange(512)]
self.pixel_list.emit(lE, hE)
time.sleep(0.02)
n -= 1
def main():
app = QApplication(sys.argv)
form = ApplicationWindow()
form.show()
app.exec_()
if __name__ == "__main__":
main()也许我的问题甚至不是MatPlotLib或PyQT4,而是我实现线程的方式.正如我所说,我是新手,并且正在学习.而且,我甚至不确定GUIqwt会解决任何这些问题 – 但我知道我在这里看到很多建议使用比MatPlotLib更快的东西用于GUI中的“实时”绘图.感谢您的帮助！
