Fixed other QPrinter compat. issues

Author: PierreRaybaut

qwt/plot_renderer.py

@@ -242,7 +242,11 @@ def renderDocument(
         if fmt in ("pdf", "ps"):
             printer = QPrinter()
             if fmt == "pdf":
-                printer.setOutputFormat(QPrinter.PdfFormat)
+                try:
+                    printer.setOutputFormat(QPrinter.PdfFormat)
+                except AttributeError:
+                    # PyQt6 on Linux
+                    printer.setPrinterName("")
             else:
                 printer.setOutputFormat(QPrinter.PostScriptFormat)
             printer.setColorMode(QPrinter.Color)

qwt/tests/test_bodedemo.py

@@ -265,19 +265,14 @@ def print_(self, unattended=False):
         dialog = QPrintDialog(printer)
         if unattended:
             # Configure QPrinter object to print to PDF file
-            printer.setOutputFormat(QPrinter.PdfFormat)
+            printer.setPrinterName("")
             printer.setOutputFileName(FNAME_PDF)
             dialog.accept()
             ok = True
         else:
             ok = dialog.exec_()
         if ok:
             renderer = QwtPlotRenderer()
-            if QPrinter.GrayScale == printer.colorMode():
-                renderer.setDiscardFlag(QwtPlotRenderer.DiscardBackground)
-                renderer.setDiscardFlag(QwtPlotRenderer.DiscardCanvasBackground)
-                renderer.setDiscardFlag(QwtPlotRenderer.DiscardCanvasFrame)
-                renderer.setLayoutFlag(QwtPlotRenderer.FrameWithScales)
             renderer.renderTo(self.plot, printer)
 
     def exportDocument(self):