brushExisting.GetLogBrush( &logbrush );是什么！！

Question

// Example for CBrush::GetLogBrush
LOGBRUSH logbrush;
brushExisting.GetLogBrush( &logbrush );
CBrush brushOther( logbrush.lbColor);// Another example
// Declare a LOGBRUSH
LOGBRUSH logBrush;// Using a bitmap for this example.
// The bitmap should be a project resource.
CBitmap bm;
bm.LoadBitmap(IDB_BRUSH);try
{
   // Create a brush
   CBrush brush1(&bm);   // Use GetLogBrush to fill the LOGBRUSH structure
   brush1.GetLogBrush(&logBrush);   // Create a second brush using the LOGBRUSH data
   CBrush brush2;
   brush2.CreateBrushIndirect(&logBrush);   // Use the first brush
   CBrush* pOldBrush = (CBrush*)pDC->SelectObject(&brush1);
   pDC->Rectangle(CRect(50,50,150,150));   // The second brush has the specified characteristics
   // of the first brush
   pDC->SelectObject(&brush2);
   pDC->Ellipse(200,50,300,150);   // Reselect the original brush
   pDC->SelectObject(pOldBrush);
}
catch(CResourceException* e)
{
   e->ReportError();
   e->Delete();
}
http://msdn.microsoft.com/zh-cn/library/y2c4ffxs.aspx

Answer 1

就是获取指定Brush的一些属性，
如果用CreateBrushIndirect创建Brush，就是以此为参数。

Answer 2

brushExisting.GetLogBrush( &logbrush );中的brushExisting也不是类对象，它可是什么对象呢？？？？

Answer 3

我终于知道了，其实
LOGBRUSH logbrush; 
brushExisting.GetLogBrush( &logbrush ); 
CBrush brushOther( logbrush.lbColor); 
是没有用的，全文上下也没用到它，它从定义的以后就是废品