Decrease the margins around the page in the print preview.

Don't hard code 40 pixel margins, this may be too big on small screens.

Use twice the default border size between the dialog elements instead, this is
still pretty arbitrary but at least smaller.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@66541 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/common/prntbase.cpp

@@ -1658,8 +1658,8 @@ void wxPrintPreviewBase::Init(wxPrintout *printout,
     m_previewFailed = false;
     m_currentPage = 1;
     m_currentZoom = 70;
-    m_topMargin = 40;
-    m_leftMargin = 40;
+    m_topMargin =
+    m_leftMargin = 2*wxSizerFlags::GetDefaultBorder();
     m_pageWidth = 0;
     m_pageHeight = 0;
     m_printingPrepared = false;