Allow showing the print preview frame non modally.

Still show the print preview app modally by default, i.e. disabling all the
other windows, but also allow disabling only the preview parent or nothing at
all.

Closes #13108.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67619 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/prntbase.h

@@ -54,6 +54,19 @@ enum wxPrinterError
     wxPRINTER_ERROR
 };
 
+// Preview frame modality kind used with wxPreviewFrame::Initialize()
+enum wxPreviewFrameModalityKind
+{
+    // Disable all the other top level windows while the preview is shown.
+    wxPreviewFrame_AppModal,
+
+    // Disable only the parent window while the preview is shown.
+    wxPreviewFrame_WindowModal,
+
+    // Don't disable any windows.
+    wxPreviewFrame_NonModal
+};
+
 //----------------------------------------------------------------------------
 // wxPrintFactory
 //----------------------------------------------------------------------------
@@ -386,7 +399,8 @@ public:
     virtual ~wxPreviewFrame();
 
     void OnCloseWindow(wxCloseEvent& event);
-    virtual void Initialize();
+    virtual void Initialize(wxPreviewFrameModalityKind kind
+                                = wxPreviewFrame_AppModal);
     virtual void CreateCanvas();
     virtual void CreateControlBar();
 
@@ -398,6 +412,9 @@ protected:
     wxPrintPreviewBase*   m_printPreview;
     wxWindowDisabler*     m_windowDisabler;
 
+    wxPreviewFrameModalityKind m_modalityKind;
+
+
 private:
     void OnChar(wxKeyEvent& event);