Add support to extract viewer preference

fpdfsdk/src/fpdfview.cpp

 // Copyright 2014 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
  
 // Original code copyright 2014 Foxit Software Inc. http://www.foxitsoftware.com
 
 #include "../include/fsdk_define.h"
 #include "../include/fpdfview.h"
 #include "../include/fsdk_rendercontext.h"
 #include "../include/fpdf_progressive.h"
@@ skipping 848 matching lines @@
 }
 
 DLLEXPORT FPDF_BOOL STDCALL FPDF_VIEWERREF_GetPrintScaling(FPDF_DOCUMENT document)
 {
         CPDF_Document* pDoc = (CPDF_Document*)document;
         if (!pDoc) return TRUE;
         CPDF_ViewerPreferences viewRef(pDoc);
         return viewRef.PrintScaling();
 }
 
+DLLEXPORT int STDCALL FPDF_VIEWERREF_GetNumCopies(FPDF_DOCUMENT document)
+{
+    CPDF_Document* pDoc = (CPDF_Document*)document;
+    if (!pDoc) return TRUE;
+    CPDF_ViewerPreferences viewRef(pDoc);
+    return viewRef.NumCopies();
+}
+
+DLLEXPORT FPDF_PAGERANGE STDCALL FPDF_VIEWERREF_GetPrintPageRange(FPDF_DOCUMENT document)
+{
+    CPDF_Document* pDoc = (CPDF_Document*)document;
+    if (!pDoc) return NULL;
+    CPDF_ViewerPreferences viewRef(pDoc);
+    return viewRef.PrintPageRange();
+}
+
+DLLEXPORT int STDCALL FPDF_VIEWERREF_GetDuplex(FPDF_DOCUMENT document)
+{
+    CPDF_Document* pDoc = (CPDF_Document*)document;
+    if (!pDoc) return FALSE;
+    CPDF_ViewerPreferences viewRef(pDoc);
+    return viewRef.Duplex();
+}
+
 DLLEXPORT FPDF_DEST STDCALL FPDF_GetNamedDestByName(FPDF_DOCUMENT document,FPDF_BYTESTRING name)
 {
         if (document == NULL)
                 return NULL;
         if (name == NULL || name[0] == 0) 
                 return NULL;
 
         CPDF_Document* pDoc = (CPDF_Document*)document;
         CPDF_NameTree name_tree(pDoc, FX_BSTRC("Dests"));
         return name_tree.LookupNamedDest(pDoc, name);
 }