Simplify FPDF_RenderPage().

fpdfsdk/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 "public/fpdfview.h"
 
 #include <memory>
 
@@ skipping 557 matching lines @@
                                        int size_y,
                                        int rotate,
                                        int flags) {
   CPDF_Page* pPage = CPDFPageFromFPDFPage(page);
   if (!pPage)
     return;
 
   CPDF_PageRenderContext* pContext = new CPDF_PageRenderContext;
   pPage->SetRenderContext(WrapUnique(pContext));
 
   CFX_DIBitmap* pBitmap = nullptr;

[Tom Sepez, 2016/09/27 21:25:32]

Can this be an unique_ptr?  It looks like it only gets assigned to if
bNewBitmap, hence its fine to have it go out of scope as null even if thats not
the case?

[Lei Zhang, 2016/09/27 21:49:46]

Done.

-  FX_BOOL bBackgroundAlphaNeeded = pPage->BackgroundAlphaNeeded();
-  FX_BOOL bHasImageMask = pPage->HasImageMask();
-  if (bBackgroundAlphaNeeded || bHasImageMask) {
+  const bool bNewBitmap =
+      pPage->BackgroundAlphaNeeded() || pPage->HasImageMask();
+  if (bNewBitmap) {
     pBitmap = new CFX_DIBitmap;
     pBitmap->Create(size_x, size_y, FXDIB_Argb);
     pBitmap->Clear(0x00ffffff);
     CFX_FxgeDevice* pDevice = new CFX_FxgeDevice;
     pContext->m_pDevice.reset(pDevice);
     pDevice->Attach(pBitmap, false, nullptr, false);
   } else {
     pContext->m_pDevice.reset(new CFX_WindowsDevice(dc));
   }
 
   FPDF_RenderPage_Retail(pContext, page, start_x, start_y, size_x, size_y,
                          rotate, flags, TRUE, nullptr);
 
-  if (bBackgroundAlphaNeeded || bHasImageMask) {
-    if (pBitmap) {
-      CFX_WindowsDevice WinDC(dc);
+  if (bNewBitmap) {
+    ASSERT(pBitmap);
 
-      if (WinDC.GetDeviceCaps(FXDC_DEVICE_CLASS) == FXDC_PRINTER) {
-        CFX_DIBitmap* pDst = new CFX_DIBitmap;
-        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, nullptr, FALSE, nullptr);
-        WinDC.StretchDIBits(pDst, 0, 0, size_x, size_y);
-        delete pDst;
-      } else {
-        WinDC.SetDIBits(pBitmap, 0, 0);
-      }
+    CFX_WindowsDevice WinDC(dc);
+    if (WinDC.GetDeviceCaps(FXDC_DEVICE_CLASS) == FXDC_PRINTER) {
+      std::unique_ptr<CFX_DIBitmap> pDst = WrapUnique(new CFX_DIBitmap);
+      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, nullptr, FALSE, nullptr);
+      WinDC.StretchDIBits(pDst.get(), 0, 0, size_x, size_y);
+    } else {
+      WinDC.SetDIBits(pBitmap, 0, 0);
     }
+    delete pBitmap;
   }
-  if (bBackgroundAlphaNeeded || bHasImageMask)
-    delete pBitmap;
 
   pPage->SetRenderContext(std::unique_ptr<CPDF_PageRenderContext>());
 }
 #endif  // defined(_WIN32)
 
 DLLEXPORT void STDCALL FPDF_RenderPageBitmap(FPDF_BITMAP bitmap,
                                              FPDF_PAGE page,
                                              int start_x,
                                              int start_y,
                                              int size_x,
@@ skipping 504 matching lines @@
   if (!buffer) {
     *buflen = len;
   } else if (*buflen >= len) {
     memcpy(buffer, utf16Name.c_str(), len);
     *buflen = len;
   } else {
     *buflen = -1;
   }
   return (FPDF_DEST)pDestObj;
 }