In windows printing, convert src bitmap to dest bitmap using CompositeBitmap.

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/fsdk_mgr.h"
 #include "../include/fpdfview.h"
 #include "../include/fsdk_rendercontext.h"
@@ skipping 365 matching lines @@
 
         if (bBackgroundAlphaNeeded) 
         {
                 if (pBitmap)
                 {
                         CFX_WindowsDevice WinDC(dc);
                         
                         if (WinDC.GetDeviceCaps(FXDC_DEVICE_CLASS) == FXDC_PRINTER)
                         {
                                 CFX_DIBitmap* pDst = FX_NEW CFX_DIBitmap;
-                                pDst->Create(pBitmap->GetWidth(), pBitmap->GetHeight(),FXDIB_Rgb32);
-                                FXSYS_memcpy(pDst->GetBuffer(), pBitmap->GetBuffer(), pBitmap->GetPitch()*pBitmap->GetHeight());
-//                              WinDC.SetDIBits(pDst,0,0);
+                                int pitch = pBitmap->GetPitch();
+                                pDst->Create(size_x, size_y, FXDIB_Rgb32);
+                                FXSYS_memset(pDst->GetBuffer(), -1, pitch*size_y);
+                                pDst->CompositeBitmap(0, 0, size_x, size_y, pBitmap, 0, 0, FXDIB_BLEND_NORMAL, NULL, FALSE, NULL);
                                 WinDC.StretchDIBits(pDst,0,0,size_x,size_y);
                                 delete pDst;
                         }
                         else
                                 WinDC.SetDIBits(pBitmap,0,0);
 
                 }
         }
 #else
         // get clip region
@@ skipping 393 matching lines @@
 {
         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);
 }