QPrinter.setDuplex(QPrinter.duplexLongSide)不工作

Question

我试图在双工模式(DuplexLongSide)中打印2页，但是即使在实例化对话框之前设置打印机设置之后，在QPrintDialog.Accepted之后确认双工设置是正确的，打印仍然是单纯的。我已经确认，我的Windows 10主机上的驱动器支持双工打印，我使用的网络打印机也支持双面打印。根据音乐人8月18日的评论，我更新了下面的例行公事：

@logger.catch
def printDialog(self, bDummy):
   if (True == td.__Debug__):
      logger.info(f"TestResultsMainWindow: printDialog...bDummy:{bDummy}")
   #end td.__Debug__

   # Give the user a QPrintDialog to allow them to print the currently-displayed
   # results from the active tab.
   #printer = QPrinter(QPrinter.HighResolution)
   printer = QPrinter()
   printer.setDoubleSidedPrinting(True)
   #printer.setDuplex(QPrinter.DuplexAuto)
   printer.setDuplex(QPrinter.DuplexLongSide)
   printer.setResolution(self.DefaultPrintDotsPerInch)

   if (printer.doubleSidedPrinting()):
      if (True == td.__Debug__):
         logger.debug("QPrinter: doubleSidedPrinting printing!")
      #end td.__Debug__
   else:
      if (True == td.__Debug__):
         logger.debug("QPrinter: singleSidedPrinting printing!")
      #end td.__Debug__
   #end if (printer.doubleSidedPrinting())
   if (True == td.__Debug__):
      logger.debug(f"QPrinter mode: {printer.duplex()}")
   #end td.__Debug__

   # Instantiate the dialog with the current printer settings
   dialog = QPrintDialog(printer, self.mainWindow)

   if (dialog.exec_() == QPrintDialog.Accepted):

      if (printer.doubleSidedPrinting()):
         if (True == td.__Debug__):
            logger.debug("Check again...QPrinter: doubleSidedPrinting printing!")
         #end td.__Debug__
      else:
         if (True == td.__Debug__):
            logger.debug("Check again...QPrinter: singleSidedPrinting printing!")
         #end td.__Debug__
      #end if (printer.doubleSidedPrinting())
      if (True == td.__Debug__):
         logger.debug(f"Check again...QPrinter mode: {printer.duplex()}")
      #end td.__Debug__

      if (True == td.__Debug__):
         logger.debug(f"{self.name}: create pixmap of the currently-displayed results and send it to the printer")
      #end td.__Debug__
      # Open the PDF...
      tmpPdfFileHandle = fitz.open(self.pdfFilename)
      mat = fitz.Matrix(self.ImagePrintZoomX, self.ImagePrintZoomY) # zoom factor 1.25x in each direction
      if (True == td.__Debug__):
         logger.debug(f"printDialog: NumPages of {self.pdfFilename} is {len(tmpPdfFileHandle)}")
      #end td.__Debug__

      painter = QtGui.QPainter()
      # We're beginning to print a new page on the printer...
      #printer.newPage()
      for pdfPage in tmpPdfFileHandle:

         # Get the page itself
         pagePixmap = pdfPage.get_pixmap(matrix=mat, alpha=False) # render the page to an image that can be printed
         #pagePixmap = pdfPage.getPixmap(alpha=False) # render the page to an image that can be printed
         pagePixmap.save("page-%i.png" % pdfPage.number)

         # Now convert to PyQt5 QImage
         image=QImage(pagePixmap.samples,
                      pagePixmap.width, pagePixmap.height,
                      pagePixmap.stride, # length of one image line in bytes
                      QImage.Format_RGB888)

         # Convert the image to a PyQt5 QPixmap
         qt5Pixmap = QPixmap.fromImage(image)

         # Now print the page
         #painter = QtGui.QPainter()
         painter.begin(printer)
         # Send the page to the printer...
         painter.drawImage(10, 30, qt5Pixmap.toImage())
         # We're done sending this page to the printer...
         painter.end()
      #end for pdfPage in tmpPdfFileHandle
   else:
      if (True == td.__Debug__):
         logger.info(f"{self.name}: printDialog...canceled the print")
      #end td.__Debug__
   #end if (dialog.exec_() == QPrintDialog.Accepted)
#end printDialog()

下面是我在“打印”对话框中选择“打印”按钮后看到的情况：

2022-08-24 09:36:57.940 DEBUG \ lruTestDriver:printDialog:633 - QPrinter: doubleSidedPrinting printing！2022-08-24 09:36:59.297 DEBUG \ lruTestDriver:printDialog:641 - QPrinter模式:2 2022-08-24 09:37:05.361调试lruTestDriver:printDialog:651 - Check again...QPrinter: doubleSidedPrinting打印！2022-08-24 09:37:07.087调试lruTestDriver:printDialog again...QPrinter模式:2 2022-08- 0824 09:37:08.429 \x{e76f}\x{e76f} TestResultsMainWindow:创建当前显示的结果的像素映射，并将其发送到打印机2022-08-24 :37:10.537 DEBUG lruTestDriver: printDialog: 669 -printDialog: NumPages of is 549_TestResults_2022-08-24_09-36-31.pdf为2。

Answer 1

解决这个问题的方法是使用QPrinter.newPage()方法。这种方法本质上要么翻转打印机上的页面(如果打印是双工的话)，要么将另一张纸输入打印机(如果打印是单纯的)。还请注意，QPainter.begin()和QPainter.end()方法在for循环之外，因为for循环中的所有内容都要打印出来。

@logger.catch
def printDialog(self, bDummy):
   if (True == td.__Debug__):
      logger.info(f"TestResultsMainWindow: printDialog...bDummy:{bDummy}")
   #end td.__Debug__

   # Give the user a QPrintDialog to allow them to print the currently-displayed
   # results from the active tab.
   printer = QPrinter()
   printer.setDoubleSidedPrinting(True)
   printer.setDuplex(QPrinter.DuplexLongSide)
   printer.setResolution(self.DefaultPrintDotsPerInch)

   if (printer.doubleSidedPrinting()):
      if (True == td.__Debug__):
         logger.debug("QPrinter: doubleSidedPrinting printing!")
      #end td.__Debug__
   else:
      if (True == td.__Debug__):
         logger.debug("QPrinter: singleSidedPrinting printing!")
      #end td.__Debug__
   #end if (printer.doubleSidedPrinting())
   if (True == td.__Debug__):
      logger.debug(f"QPrinter mode: {printer.duplex()}")
   #end td.__Debug__

   # Instantiate the dialog
   dialog = QPrintDialog(printer, self.mainWindow)

   if (dialog.exec_() == QPrintDialog.Accepted):

      if (printer.doubleSidedPrinting()):
         if (True == td.__Debug__):
            logger.debug("Check again...QPrinter: doubleSidedPrinting printing!")
         #end td.__Debug__
      else:
         if (True == td.__Debug__):
            logger.debug("Check again...QPrinter: singleSidedPrinting printing!")
         #end td.__Debug__
      #end if (printer.doubleSidedPrinting())
      if (True == td.__Debug__):
         logger.debug(f"Check again...QPrinter mode: {printer.duplex()}")
      #end td.__Debug__

      if (True == td.__Debug__):
         logger.debug(f"{self.name}: create pixmap of the currently-displayed results and send it to the printer")
      #end td.__Debug__
      # Open the PDF...
      tmpPdfFileHandle = fitz.open(self.pdfFilename)
      mat = fitz.Matrix(self.ImagePrintZoomX, self.ImagePrintZoomY) # zoom factor 1.25x in each direction
      if (True == td.__Debug__):
         logger.debug(f"printDialog: NumPages of {self.pdfFilename} is {len(tmpPdfFileHandle)}")
      #end td.__Debug__

      painter = QtGui.QPainter()
      # We're beginning to print a new page on the printer...
      painter.begin(printer)
      page = 1
      for pdfPage in tmpPdfFileHandle:

         # Get the page itself
         pagePixmap = pdfPage.get_pixmap(matrix=mat, alpha=False) # render the page to an image that can be printed
         #pagePixmap = pdfPage.getPixmap(alpha=False) # render the page to an image that can be printed
         pagePixmap.save("page-%i.png" % pdfPage.number)

         # Now convert to PyQt5 QImage
         image=QImage(pagePixmap.samples,
                      pagePixmap.width, pagePixmap.height,
                      pagePixmap.stride, # length of one image line in bytes
                      QImage.Format_RGB888)

         # Convert the image to a PyQt5 QPixmap
         qt5Pixmap = QPixmap.fromImage(image)

         # Send the image to the printer...
         painter.drawImage(10, 30, qt5Pixmap.toImage())
         # We're done sending this page to the printer...
         if (len(tmpPdfFileHandle) > page):
             # Assume 1 side of a page per image. If duplex printing is set
             # then newPage() will cause printing to the other side
             printer.newPage()
             page = page + 1
      #end for pdfPage in tmpPdfFileHandle
      painter.end()
   else:
      if (True == td.__Debug__):
         logger.info(f"{self.name}: printDialog...canceled the print")
      #end td.__Debug__
   #end if (dialog.exec_() == QPrintDialog.Accepted)
#end printDialog()