WHAT'S THE brushExisting??

[panli9]

I am a beginner.When I learn a Class of the MFC,I found a question.
Look at the following code that post on Microsoft.
// 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();
}

I can't understand why and what have to set 'brushExisting'?
Thanks!!


http://msdn.microsoft.com/zh-cn/library/y2c4ffxs.aspx

[panli9]

I know.
LOGBRUSH logbrush;
brushExisting.GetLogBrush( &logbrush );
CBrush brushOther( logbrush.lbColor);
No use.