如何在PyQt5中使用QCamera单击照片？

Question

PyQT5 QCamera未单击照片

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我试图参考他们的官方PyQt5 QCamera文档，但不太明白

1. 我已经创建了一个带有按钮的主窗口
2. 单击按钮，执行clickphoto功能
3. 单击照片功能仅在可用相机列表长度>；0，否则打印错误

from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtWidgets import *
from PyQt5.QtMultimedia import *
from PyQt5.QtMultimediaWidgets import *
import os
class Ui_MainWindow(object):
    def clickphoto(self):
        print("clickphoto Called !")
        available_cameras = QCameraInfo.availableCameras()
        if len(available_cameras)>0:
            print(available_cameras[0].description())
            try:
                camera = QCamera(available_cameras[0])
                camera.setCaptureMode(QCamera.CaptureStillImage)
                camera.start()
                capture = QCameraImageCapture(camera)
                capture.capture(str(os.getcwd())+"//"+"999.jpg")

                # i also tried capture.capture("999.jpg") still no output 
                # (checked in Pictures folder)

            except Exception as e:
                print("Exception occured, ",e)
        else:
            print("Error")

    def setupUi(self, MainWindow):
        MainWindow.setObjectName("MainWindow")
        MainWindow.resize(251, 271)
        self.centralwidget = QtWidgets.QWidget(MainWindow)
        self.centralwidget.setObjectName("centralwidget")
        self.clickphotobtn = QtWidgets.QPushButton(self.centralwidget)
        self.clickphotobtn.setGeometry(QtCore.QRect(90, 110, 75, 23))
        self.clickphotobtn.setObjectName("clickphotobtn")

        # click event !!
        self.clickphotobtn.clicked.connect(self.clickphoto)

        MainWindow.setCentralWidget(self.centralwidget)
        self.menubar = QtWidgets.QMenuBar(MainWindow)
        self.menubar.setGeometry(QtCore.QRect(0, 0, 251, 23))
        self.menubar.setObjectName("menubar")
        MainWindow.setMenuBar(self.menubar)
        self.statusbar = QtWidgets.QStatusBar(MainWindow)
        self.statusbar.setObjectName("statusbar")
        MainWindow.setStatusBar(self.statusbar)

        self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.clickphotobtn.setText(_translate("MainWindow", "Capture"))


if __name__ == "__main__":
    import sys
    app = QtWidgets.QApplication(sys.argv)
    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

输出

PS C:\Users\Beast80K\Documents\Auto Brightness> & C:/Users/Beast80K/AppData/Local/Programs/Python/Python39/python.exe "c:/Users/Beast80K/Documents/Auto Brightness/trycappic.py"
clickphoto Called !
USB2.0 PC CAMERA
Unsupported media type: "{32595559-0000-0010-8000-00AA00389B71}"
Unsupported media type: "{32595559-0000-0010-8000-00AA00389B71}"
Unsupported media type: "{32595559-0000-0010-8000-00AA00389B71}"
Unsupported media type: "{32595559-0000-0010-8000-00AA00389B71}"
Unsupported media type: "{32595559-0000-0010-8000-00AA00389B71}"

• Python 3.9.6
• Qt版本：5.15.2
• Windows 10 21h1（操作系统版本19043.1237）

Answer 1

您必须考虑到：

1. 检查设备是否能够拍照

2. 照片的捕获是异步的，因此您必须使用信号来了解设备是否已准备好拍照，以及是否已完成照片的保存

import os
from pathlib import Path
from typing import ChainMap
import uuid

from PyQt5.QtWidgets import QApplication, QMainWindow
from PyQt5.QtMultimedia import QCamera, QCameraImageCapture, QCameraInfo

from gui import Ui_MainWindow

CURRENT_DIRECTORY = Path(__file__).resolve().parent
PHOTO_DIRECTORY = CURRENT_DIRECTORY / "photos"

PHOTO_DIRECTORY.mkdir(parents=True, exist_ok=True)


class MainWindow(QMainWindow):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.ui = Ui_MainWindow()
        self.ui.setupUi(self)

        self.ui.clickphotobtn.clicked.connect(self.handle_clicked)

    def handle_clicked(self):
        self.capture()

    def capture(self):
        for camera_info in QCameraInfo.availableCameras():
            camera = QCamera(camera_info, self)
            if not camera.isCaptureModeSupported(QCamera.CaptureStillImage):
                print("Camera cannot capture images")
                continue
            camera.setCaptureMode(QCamera.CaptureStillImage)
            camer.errorOccurred.connect(self.handle_errorOccurred)
            camera.start()
            image_capture = QCameraImageCapture(camera, self)
            image_capture.readyForCaptureChanged.connect(
                self.handle_readyForCaptureChanged
            )
            image_capture.imageSaved.connect(self.handle_imageSaved)
            camera.searchAndLock()

    def handle_readyForCaptureChanged(self, ok):
        if ok:
            image_capture = self.sender()
            image_capture.capture(os.fspath(PHOTO_DIRECTORY / str(uuid.uuid4())))
            camera = image_capture.mediaObject()
            if isinstance(camera, QCamera):
                camera.unlock()

    def handle_imageSaved(self):
        image_capture = self.sender()
        camera = image_capture.mediaObject()
        if isinstance(camera, QCamera):
            camera.stop()
            camera.deleteLater()
        image_capture.deleteLater()

    def handle_errorOccurred(self, error):
        print(error, self.sender().errorString())

if __name__ == "__main__":
    import sys

    app = QApplication(sys.argv)
    w = MainWindow()
    w.show()
    sys.exit(app.exec_())

注意：不建议修改QtDesigner生成的代码，因此必须还原该文件并将其命名为gui.py