text: #pragma once
  /*
   * Copyright (c) 2014 Adobe Systems Incorporated. All rights reserved.
   *
   * Permission is hereby granted, free of charge, to any person obtaining a
   * copy of this software and associated documentation files (the "Software"),
   * to deal in the Software without restriction, including without limitation
   * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   * and/or sell copies of the Software, and to permit persons to whom the
   * Software is furnished to do so, subject to the following conditions:
   *
   * The above copyright notice and this permission notice shall be included in
   * all copies or substantial portions of the Software.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
   * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
   * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
   * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
   * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
   * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
   * DEALINGS IN THE SOFTWARE.
   */
  #include "cef_window.h"
  
  
  class cef_buffered_dc 
  {
  public:
      cef_buffered_dc(cef_window* window, HDC hdc = NULL) 
          : mWnd(window)
          , mWindowDC(hdc)
          , mDcMem(NULL)
          , mBitmap(NULL)
          , mBmOld(NULL)
          , mWidth(0)
          , mHeight(0)
          , mReleaseDcOnDestroy(false)
      {
          CommonInit();
      }
  
      operator HDC() 
      {
          return mDcMem;
      }
  
      HDC GetWindowDC() 
      {
          return mWindowDC;
      }
  
      ~cef_buffered_dc() 
      {
          Destroy();
      }
  
  private:
      cef_buffered_dc()
      {
      }
  
      cef_buffered_dc(const cef_buffered_dc& other)
      {
      }
  
  protected:
      void CommonInit() 
      {
          if (mWnd) {
              if (mWindowDC == NULL) {
                  mWindowDC = mWnd->GetDC();
                  mReleaseDcOnDestroy = true;
              }
  
              RECT rectWindow;
              mWnd->GetWindowRect(&rectWindow);
              mWidth = ::RectWidth(rectWindow);
              mHeight = ::RectHeight(rectWindow);
  
              mDcMem = ::CreateCompatibleDC(mWindowDC);
              mBitmap = ::CreateCompatibleBitmap(mWindowDC, mWidth, mHeight);
              mBmOld = ::SelectObject(mDcMem, mBitmap);
          }
      }
  
      void Destroy() 
      {
          if (mWnd) {
              ::BitBlt(mWindowDC, 0, 0, mWidth, mHeight, mDcMem, 0, 0, SRCCOPY);
  
              ::SelectObject(mDcMem, mBmOld);
              ::DeleteObject(mBitmap);
              ::DeleteDC(mDcMem);
          
              if (mReleaseDcOnDestroy) {
                  mWnd->ReleaseDC(mWindowDC);
              }
          }
      }
  
      cef_window* mWnd;
      HDC         mWindowDC;
      HDC         mDcMem;
      HBITMAP     mBitmap;
      HGDIOBJ     mBmOld;
      int         mWidth; 
      int         mHeight;
      bool        mReleaseDcOnDestroy;
  };