如何绘制圆角矩形而不填充它（在MFC中）？

Question

Another drawing question for you MFC/GDI gurus out there... :-)

I'm using MFC, and I'm doing some drawing with a CDC object. That works fine.

But now I want to draw a rectangle with rounded corners, the line being a couple of pixels wide. But I dont want any filling to occur! There is a method CDC::RoundRect - I just set the pen I want and get a beautiful rounded rectangle with that pen. But CDC::RoundRect also fills the rectangle with the current brush.

Is there any way to draw just the line, with no filling? Any other method I haven't found? Or can I create some sort of "null brush" that doesn't alter what's in the middle of the rectangle?

I'd be very grateful for some good advice!

/Anders from Sweden

Answer 1

Just select a NULL brush before drawing the rounded rectangle, like

CPen pen;
CBrush* pOldBrush;
CPen* pOldPen;
if (!pen.CreatePenIndirect(&m_logpen))
    return;
pOldBrush = (CBrush*)pDC->SelectStockObject(NULL_BRUSH);
pOldPen = pDC->SelectObject(&pen);
pDC->RoundRect(m_rect, m_roundness);
pDC->SelectObject(pOldBrush);
pDC->SelectObject(pOldPen);