Multithreading PyQt5将第二个函数添加到线程但不工作
之前,我尝试使用烧瓶同时执行以下操作:Multithreading PyQt5将第二个函数添加到线程但不工作,multithreading,pyqt5,Multithreading,Pyqt5,之前,我尝试使用烧瓶同时执行以下操作: 显示实时视频流 显示实时数据流 控制机器人车 由于以上只是演示,视频流性能不够好,我决定将整个应用程序更改为PyQt5,以便进一步开发和生产。现在我可以创建GUI来很好地显示实时视频流,而实时数据流无法很好地完成。错误是 QObject::startTimer:计时器只能用于以QThread启动的线程 以下是整个节目。请帮助查看添加线程问题中的错误。谢谢 import sys from PyQt5 import QtWidgets, QtCore, Q
- 显示实时视频流
- 显示实时数据流
- 控制机器人车
import sys
from PyQt5 import QtWidgets, QtCore, QtGui
import cv2
from vidgear.gears import CamGear
from random import random
data_list=[]
fps=60
options_cam={"CAP_PROP_FRAME_WIDTH":640,"CAP_PROP_FRAME_HEIGHT":480,"CAP_PROP_FPS":fps}
stream=CamGear(source=0,logging=False,**options_cam).start()
class MainWindow(QtWidgets.QWidget):
def __init__(self,*args):
super(MainWindow, self).__init__()
self.setWindowTitle('Vehicle control')
self.grid_layout=QtWidgets.QGridLayout()
self.video_label = QtWidgets.QLabel('Video streaming',self)
self.video_frame = QtWidgets.QLabel(self)
self.grid_layout.addWidget(self.video_label,0,0)
self.grid_layout.addWidget(self.video_frame,1,0)
self.data_label = QtWidgets.QLabel('Data streaming',self)
self.data_frame = QtWidgets.QListWidget(self)
self.grid_layout.addWidget(self.data_label,0,1)
self.grid_layout.addWidget(self.data_frame,1,1)
self.setLayout(self.grid_layout)
#self.thread=QtCore.QThread()
#self.thread.started.connect(self.nextFrameSlot)
#self.thread.start()
self.timer=QtCore.QTimer()
self.timer.timeout.connect(self.video_stream)
self.timer.start(0)
self.thread=QtCore.QThread()
self.thread.start()
self.timer2=QtCore.QTimer()
self.timer2.moveToThread(self.thread)
self.timer2.timeout.connect(self.data_stream)
self.timer2.start(0)
def video_stream(self):
frame = stream.read()
# My webcam yields frames in BGR format
frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
img = QtGui.QImage(frame, frame.shape[1], frame.shape[0], QtGui.QImage.Format_RGB888)
pix = QtGui.QPixmap.fromImage(img)
self.video_frame.setPixmap(pix)
QtCore.QThread.sleep(0)
def data_stream(self):
print("data stream")
stream_data=round(random()*10,3)
data_list.insert(0,str(stream_data)+'\n')
if len(data_list)>10:
del data_list[-1]
for i in range(len(data_list)):
self.data_frame.addItem(data_list[i])
self.data_frame.show()
QtCore.QThread.sleep(1000)
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
window = MainWindow()
window.show()
sys.exit(app.exec_())
编辑:
谢谢@musicamante的回答。我已经按照如下方式更新了代码,但是对于视频流仍然存在错误“segmentation fault”,而如果我只针对数据流运行,则可以显示更新的列表。那么setPixmap函数有什么问题呢?再次感谢
import sys
from PyQt5 import QtWidgets, QtCore, QtGui
import cv2
from vidgear.gears import CamGear
from random import random
fps=60
options_cam={"CAP_PROP_FRAME_WIDTH":480,"CAP_PROP_FRAME_HEIGHT":480,"CAP_PROP_FPS":fps}
stream=CamGear(source=0,logging=False,**options_cam).start()
class CamGrabber(QtCore.QThread):
frame = QtCore.pyqtSignal(QtGui.QImage)
def run(self):
while True:
new_frame = stream.read()
new_frame = cv2.cvtColor(new_frame, cv2.COLOR_BGR2RGB)
img = QtGui.QImage(new_frame, new_frame.shape[1], new_frame.shape[0], QtGui.QImage.Format_RGB888)
self.frame.emit(img)
class DataProvider(QtCore.QThread):
data = QtCore.pyqtSignal(object)
def run(self):
while True:
newData = round(random()*10,3)
self.data.emit(newData)
QtCore.QThread.sleep(1)
class MainWindow(QtWidgets.QWidget):
def __init__(self,*args):
super(MainWindow, self).__init__()
self.setWindowTitle('Vehicle control')
self.grid_layout=QtWidgets.QGridLayout()
self.video_label = QtWidgets.QLabel('Video streaming',self)
self.video_frame = QtWidgets.QLabel(self)
self.grid_layout.addWidget(self.video_label,0,0)
self.grid_layout.addWidget(self.video_frame,1,0)
self.data_label = QtWidgets.QLabel('Data streaming',self)
self.data_frame = QtWidgets.QListWidget(self)
self.grid_layout.addWidget(self.data_label,0,1)
self.grid_layout.addWidget(self.data_frame,1,1)
self.setLayout(self.grid_layout)
self.camObject = CamGrabber()
self.camObject.frame.connect(self.newFrame)
self.camObject.start()
self.dataProvider = DataProvider()
self.dataProvider.data.connect(self.newData)
self.dataProvider.start()
def newFrame(self, img):
self.video_frame.setPixmap(QtGui.QPixmap.fromImage(img))
def newData(self, data):
self.data_frame.insertItem(0,str(data))
if self.data_frame.count() > 10:
self.data_frame.takeItem(9)
if __name__ == '__main__':
import sys
app = QtWidgets.QApplication(sys.argv)
window = MainWindow()
window.show()
sys.exit(app.exec_())```
QTimer错误基本上意味着QTimer只能从其存在的线程启动 除此之外,GUI元素应始终直接从主线程访问或修改,而不是从另一个线程访问或修改。
为了实现这一点,您需要创建一个单独的“工作线程”,并利用信号/插槽机制与主线程通信
class CamGrabber(QtCore.QThread):
frame = QtCore.pyqtSignal(QtGui.QImage)
def run(self):
while True:
frame = stream.read()
frame = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
img = QtGui.QImage(frame, frame.shape[1], frame.shape[0], QtGui.QImage.Format_RGB888)
self.frame.emit(img)
class DataProvider(QtCore.QThread):
data = QtCore.pyqtSignal(object)
def run(self):
while True:
newData = round(random()*10,3)
self.data.emit(newData)
# note that QThread.sleep unit is seconds, not milliseconds
QtCore.QThread.sleep(1)
class MainWindow(QtWidgets.QWidget):
def __init__(self,*args):
super(MainWindow, self).__init__()
self.setWindowTitle('Vehicle control')
self.grid_layout=QtWidgets.QGridLayout()
self.video_label = QtWidgets.QLabel('Video streaming',self)
self.video_frame = QtWidgets.QLabel(self)
self.grid_layout.addWidget(self.video_label,0,0)
self.grid_layout.addWidget(self.video_frame,1,0)
self.data_label = QtWidgets.QLabel('Data streaming',self)
self.data_frame = QtWidgets.QListWidget(self)
self.grid_layout.addWidget(self.data_label,0,1)
self.grid_layout.addWidget(self.data_frame,1,1)
self.setLayout(self.grid_layout)
self.camObject = CamGrabber()
self.camObject.frame.connect(self.newFrame)
self.camObject.start()
self.dataProvider = DataProvider()
self.dataProvider.data.connect(self.newData)
self.dataProvider.start()
def newFrame(self, img):
self.video_frame.setPixmap(QtGui.QPixmap.fromImage(img))
def newData(self, data):
self.data_frame.addItem(str(data))
if self.data_frame.count() > 10:
self.data_frame.takeItem(0)
如果出于任何原因,您希望控制通过QTimer从主线程获取数据,则可以使用队列:
from queue import Queue
class DataProvider(QtCore.QObject):
data = QtCore.pyqtSignal(object)
def __init__(self):
super().__init__()
self.queue = Queue()
def run(self):
while True:
multi = self.queue.get()
# simulate a time consuming process
QtCore.QThread.sleep(5)
newData = round(multi * 10, 3)
self.data.emit(newData)
def pushData(self, data):
self.queue.put(data)
class MainWindow(QtWidgets.QWidget):
def __init__(self,*args):
# ...
self.requestTimer = QtCore.QTimer()
self.requestTimer.setInterval(1000)
self.requestTimer.timeout.connect(self.requestData)
# this will cause the timer to be executed only once after each time
# start() is called, so no new requests will overlap
self.requestTimer.setSingleShot(True)
self.requestTimer.start()
def requestData(self):
value = random()
print('requesting data with value {}'.format(value))
self.dataProvider.pushData(value)
print('waiting for result')
def newFrame(self, img):
self.video_frame.setPixmap(QtGui.QPixmap.fromImage(img))
def newData(self, data):
print('data received')
self.data_frame.addItem(str(data))
if self.data_frame.count() > 10:
self.data_frame.takeItem(0)
# restart the timer
self.requestTimer.start()
首先谢谢你的回答。但在我的代码中实现它时,发现对于数据流,它可以工作,而对于视频流,它不能与错误消息“segmentation fault”一起工作。检查后,我发现错误应该来自
setPixmap(QtGui.QPixmap.fromImage(img)
,但仍然无法修复。那么我能做什么?再次感谢!@mckingwan我不确定,因为我无法使用您的库对其进行测试,但请尝试为设置pixmap的函数设置pyqtSlot修饰符:@QtCore.pyqtSlot(QtGui.QImage)
。我已经试过了,但还是一样。虽然我看到视频流有时只能进行一秒钟,然后显示错误。我不知道CamGear,我相信read()
应该等待可用的数据,但可能没有。我稍后会进行一些搜索。不要紧,我发现了这里的错误:视频流的分辨率应该缩小。最后我有以下设置:在选项中,我将分辨率设置为1280x720,然后在执行self.frame.emit(img)之前
我添加了行img=img.scaled(640480)
来修复它。无论如何,感谢您的大力帮助!