Window to bitmap converter

HBITMAP WindowToBitmap(HWND hwnd,RECT* dims=NULL){
HDC hdcWnd,hdcBitmap;
int w=100,h=100;
HBITMAP hbmBitmap;
HBITMAP hbmOld;
hdcWnd=GetDC(hwnd);
 if(hdcWnd){
 RECT wnd;
    if(dims==NULL){
    GetClientRect(hwnd,&wnd);
    }
    else{
    CopyRect(&wnd,dims);
    }
 w=wnd.right;
 h=wnd.bottom;
 hbmBitmap=(HBITMAP)CreateCompatibleBitmap(hdcWnd,w,h);
 }
 if(!hbmBitmap){
  if(hdcWnd){
  RECT wnd;
  GetWindowRect(hwnd,&wnd);
  w=wnd.right;
  h=wnd.bottom;
  hbmBitmap=CreateCompatibleBitmap(hdcWnd,w,h);
  }
 }
 if(!hbmBitmap){
 std::cout<<"Bitmap missing! "<<std::endl;
 }
hdcBitmap=CreateCompatibleDC(hdcWnd);
hbmOld=(HBITMAP)SelectObject((HDC)hdcBitmap,(HGDIOBJ)(HBITMAP)hbmBitmap);
BitBlt(hdcBitmap,0,0,w,h,hdcWnd,0,0,SRCCOPY);
SelectObject((HDC)hdcBitmap,(HGDIOBJ)(HBITMAP)hbmOld);
DeleteDC(hdcBitmap);
ReleaseDC(hwnd,hdcWnd);
return hbmBitmap;
}