Python 使用 PYQT5 中的 PrinterDialog 将 PIL 图像发送到打印机 - 问题 PyQT5 窗口关闭

问题描述

我正在尝试使用 PYQt5 中的打印按钮 (self.printBtn.clicked.connect(self.do_printout) ...) 发送 PIL 图像.

Im trying to send a PIL image using a print button (self.printBtn.clicked.connect(self.do_printout) ...) from my PYQt5.

问题是，如果我按取消"和打印"，主窗口就会关闭.使用 app.exec() 关闭子程序也没有成功.(Python 3.7、PyQT5 和 Windows 操作系统)

The problem is that the main window closes if I press "Cancel" and also when I press "Print". Closing the subroutine using app.exec() was also not successful.(Python 3.7, PyQT5 and Windows OS)

import sys
from PyQt5 import QtGui, QtWidgets, QtPrintSupport
from PyQt5.QtGui import QPixmap
from PyQt5 import QtCore
from PIL import Image
from PIL.ImageQt import ImageQt

class App():
    def __init__(self, im):
        super().__init__()

        self.im = im
        dialog = QtPrintSupport.QPrintDialog()
        printer = QtPrintSupport.QPrinter()
        if dialog.exec_() == QtWidgets.QDialog.Accepted:
            self.handle_paint_request(printer, im)

    def handle_paint_request(self, printer, im):

        printer.setOrientation(QtPrintSupport.QPrinter.Landscape)
        printer.setPaperSize(QtPrintSupport.QPrinter.A4)
        printer.setPageSize(QtPrintSupport.QPrinter.A4)
        printer.setPageMargins(0, 0, 0, 0, QtPrintSupport.QPrinter.Millimeter)

        painter = QtGui.QPainter(printer)
        painter.begin(printer)

        im = ImageQt(im)
        image = QtGui.QPixmap.fromImage(im)
        screen = image
        painter.drawPixmap(10, 10, screen)
        painter.end()

def do_print(im):
    app = QtWidgets.QApplication(sys.argv)
    gui = App(im)

if __name__ == '__main__':
    im = Image.open("shot.png").convert("RGB")
    do_print(im)

我尝试了不同的方法 - 使用 win32print、win32ui、win32gui 可能是另一种选择:如果您有知识以这种方式打印 PIL 图像，请告诉我.Timgolden 也不适合我 (http://timgolden.me.uk/python/win32_how_do_i/print.html).我不想仅将其他 gui 包用于打印.重要的是能够使用 PrinterDialog 选择打印机.感谢您的帮助！

I tried different approaches - using win32print, win32ui, win32gui could be an alternative: if you have knowledge to print PIL image this way let me know. Timgolden was nor working for me (http://timgolden.me.uk/python/win32_how_do_i/print.html).I dont want to use other gui packages just for printing.Important is to be able to select the printer using a PrinterDialog.Thx for your help!

这是一个更完整的设置:

Here is a more complete setup:

import sys
from PyQt5.QtWidgets import QApplication, QWidget, QLabel,  QPushButton
from PyQt5.QtGui import QIcon, QPixmap
from PyQt5 import QtGui, QtWidgets, QtPrintSupport, QtCore
from PIL import Image
from PIL.ImageQt import ImageQt

class App(QWidget):

    def __init__(self, im):
        super().__init__()
        self.title = 'PyQt5 image'
        self.left = 100
        self.top = 100
        self.width = 640
        self.height = 480
        self.im = im

        self.setWindowTitle(self.title)
        self.setGeometry(self.left, self.top, self.width, self.height)

        label = QLabel(self)

        qim = ImageQt(self.im).copy()
        self.im = QtGui.QPixmap.fromImage(qim)

        print(type(self.im))
        label.setPixmap(self.im)
        self.resize(self.im.width(), self.im.height())

        cb = QPushButton('Print', self)
        cb.move(self.width, self.height +200)
        cb.setGeometry(QtCore.QRect(0, 550, 799, 40))
        cb.clicked.connect(self.show_cat)
        self.show()

    def show_cat(self):
        printer = QtPrintSupport.QPrinter()
        dialog = QtPrintSupport.QPrintDialog(printer)

        if dialog.exec_() == QtWidgets.QDialog.Accepted:
            self.handle_paint_request(printer)

    def handle_paint_request(self, printer):
        printer.setOrientation(QtPrintSupport.QPrinter.Landscape)
        printer.setPaperSize(QtPrintSupport.QPrinter.A4)
        printer.setPageSize(QtPrintSupport.QPrinter.A4)
        printer.setPageMargins(0, 0, 0, 0, QtPrintSupport.QPrinter.Millimeter)

        # Create painter
        painter = QtGui.QPainter(printer)        # Start painter
        painter.drawPixmap(10, 10, self.im)
        painter.end()

class Ui_MainWindow(object):

    def setupUi(self, MainWindow):
        MainWindow.resize(506, 312)
        self.centralwidget = QtWidgets.QWidget(MainWindow)

        # adding pushbutton
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setText("Print")
        self.pushButton.setGeometry(QtCore.QRect(200, 150, 93, 28))

        # adding signal and slot
        self.pushButton.clicked.connect(self.do_print)

        MainWindow.setCentralWidget(self.centralwidget)
        #self.retranslateUi(MainWindow)
        QtCore.QMetaObject.connectSlotsByName(MainWindow)

    def do_print(self):
        app = QApplication(sys.argv)
        im = Image.open("shot.png").convert("RGB")
        ex = App(im)

if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)

    MainWindow = QtWidgets.QMainWindow()
    ui = Ui_MainWindow()
    ui.setupUi(MainWindow)
    MainWindow.show()
    sys.exit(app.exec_())

推荐答案

你必须在QPrintDialog中设置QPrinter，还有painter = QtGui.QPainter(print)和painter = QtGui.QPainter() Painter.begin(printer) 是等价的，所以你应该只使用这些选项之一

ou have to set the QPrinter in the QPrintDialog, also painter = QtGui.QPainter(print) andpainter = QtGui.QPainter() painter.begin(printer) are equivalent so you should only use one of these options

import sys

from PyQt5 import QtCore, QtGui, QtWidgets, QtPrintSupport

from PIL import Image
from PIL.ImageQt import ImageQt


class App:
    def __init__(self, im):
        printer = QtPrintSupport.QPrinter()
        dialog = QtPrintSupport.QPrintDialog(printer)
        if dialog.exec_() == QtWidgets.QDialog.Accepted:
            self.handle_paint_request(printer, im)

    def handle_paint_request(self, printer, im):
        printer.setOrientation(QtPrintSupport.QPrinter.Landscape)
        printer.setPaperSize(QtPrintSupport.QPrinter.A4)
        printer.setPageSize(QtPrintSupport.QPrinter.A4)
        printer.setPageMargins(0, 0, 0, 0, QtPrintSupport.QPrinter.Millimeter)

        im = ImageQt(im).copy()

        painter = QtGui.QPainter(printer)
        image = QtGui.QPixmap.fromImage(im)
        painter.drawPixmap(10, 10, image)
        painter.end()


def do_print(im):
    app = QtWidgets.QApplication(sys.argv)
    gui = App(im)


if __name__ == "__main__":
    im = Image.open("shot.png").convert("RGB")
    do_print(im)

更新:

与初始代码相比，新代码还有其他问题，分别是:

The new code has other problems compared to the initial code, which are:

• 您只需要创建一个 QApplication.
• 局部变量在作用域结束时被销毁，在你的例子中，ex"是一个局部变量，它会很快被销毁，在我们看来，它就像从未出现过一样.

另一方面，您不应该修改 Qt Designer 生成的类，而是将其用作另一个类的接口，考虑到上述情况，解决方案是:

On the other hand, you should not modify the class generated by Qt Designer but use it as an interface for another class, considering the above then the solution is:

import sys

from PyQt5 import QtCore, QtGui, QtWidgets, QtPrintSupport

from PIL import Image
from PIL.ImageQt import ImageQt


class App(QtWidgets.QWidget):
    def __init__(self, im):
        super().__init__()
        self.title = "PyQt5 image"
        self.left = 100
        self.top = 100
        self.width = 640
        self.height = 480
        self.im = im

        self.setWindowTitle(self.title)
        self.setGeometry(self.left, self.top, self.width, self.height)

        label = QtWidgets.QLabel(self)

        qim = ImageQt(self.im).copy()
        self.im = QtGui.QPixmap.fromImage(qim)

        print(type(self.im))
        label.setPixmap(self.im)
        self.resize(self.im.width(), self.im.height())

        cb = QtWidgets.QPushButton("Print", self)
        cb.move(self.width, self.height + 200)
        cb.setGeometry(QtCore.QRect(0, 550, 799, 40))
        cb.clicked.connect(self.show_cat)
        self.resize(800, 600)
        self.show()

    def show_cat(self):
        printer = QtPrintSupport.QPrinter()
        dialog = QtPrintSupport.QPrintDialog(printer)

        if dialog.exec_() == QtWidgets.QDialog.Accepted:
            # pass
            self.handle_paint_request(printer)

    def handle_paint_request(self, printer):
        printer.setOrientation(QtPrintSupport.QPrinter.Landscape)
        printer.setPaperSize(QtPrintSupport.QPrinter.A4)
        printer.setPageSize(QtPrintSupport.QPrinter.A4)
        printer.setPageMargins(0, 0, 0, 0, QtPrintSupport.QPrinter.Millimeter)

        # Create painter
        painter = QtGui.QPainter(printer)  # Start painter
        painter.drawPixmap(10, 10, self.im)
        painter.end()


class Ui_MainWindow(object):
    def setupUi(self, MainWindow):
        MainWindow.resize(506, 312)
        self.centralwidget = QtWidgets.QWidget(MainWindow)

        # adding pushbutton
        self.pushButton = QtWidgets.QPushButton(self.centralwidget)
        self.pushButton.setGeometry(QtCore.QRect(200, 150, 93, 28))

        self.label = QtWidgets.QLabel(self.centralwidget)
        self.label.setGeometry(QtCore.QRect(140, 90, 221, 20))
        self.label.setText("")

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

    def retranslateUi(self, MainWindow):
        _translate = QtCore.QCoreApplication.translate
        MainWindow.setWindowTitle(_translate("MainWindow", "MainWindow"))
        self.pushButton.setText(_translate("MainWindow", "Push Button"))


class MainWindow(QtWidgets.QMainWindow, Ui_MainWindow):
    def __init__(self, parent=None):
        super().__init__(parent)
        self.setupUi(self)
        self.pushButton.clicked.connect(self.do_print)

    def do_print(self):
        im = Image.open("shot.png").convert("RGB")
        self.ex = App(im)


if __name__ == "__main__":
    app = QtWidgets.QApplication(sys.argv)

    w = MainWindow()
    w.show()

    sys.exit(app.exec_())

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