[TD]fix page margins on pdf export (fix #15848)

src/Mod/TechDraw/Gui/PagePrinter.cpp

@@ -134,6 +134,8 @@ void PagePrinter::makePageLayout(TechDraw::DrawPage* dPage, QPageLayout& pageLay
     height = attr.pageheight;
     pageLayout.setPageSize(QPageSize(attr.paperSize));
     pageLayout.setOrientation(attr.orientation);
+    pageLayout.setMode(QPageLayout::FullPageMode);
+    pageLayout.setMargins(QMarginsF());
 }
 
 /// print the Page associated with the parent MDIViewPage as a Pdf file
@@ -149,6 +151,7 @@ void PagePrinter::printPdf(std::string file)
     QString outputFile = QString::fromUtf8(file.data(), file.size());
     QPdfWriter pdfWriter(outputFile);
     QPageLayout pageLayout = pdfWriter.pageLayout();
+    auto marginsdb = pageLayout.margins(QPageLayout::Millimeter);
     QString documentName = QString::fromUtf8(m_vpPage->getDrawPage()->getNameInDocument());
     pdfWriter.setTitle(documentName);
     // default pdfWriter dpi is 1200.
@@ -159,6 +162,7 @@ void PagePrinter::printPdf(std::string file)
     double height = A4Widthmm;
     makePageLayout(dPage, pageLayout, width, height);
     pdfWriter.setPageLayout(pageLayout);
+    marginsdb = pageLayout.margins(QPageLayout::Millimeter);
 
     // first page does not respect page layout unless painter is created after
     // pdfWriter layout is established.
@@ -229,16 +233,6 @@ void PagePrinter::printAll(QPrinter* printer, App::Document* doc)
         makePageLayout(dPage, pageLayout, width, height);
         printer->setPageLayout(pageLayout);
 
-        //for some reason the first page doesn't obey the pageLayout, so we have to print
-        //a sacrificial blank page, but we make it a feature instead of a bug by printing a
-        //table of contents on the sacrificial page.
-        // Note: if the painter(printer) occurs after the printer->setPageLayout, then the
-        // first page will obey the layout.  This would mean creating the painter inside the
-        // loop.
-        // if (firstTime) {
-        //     firstTime = false;
-        //     printBannerPage(printer, painter, pageLayout, doc, docObjs);
-        // }
         if (!firstTime) {
             printer->newPage();
         }