mfc use paintbrush to draw lines

win10, vc6; create a new single-document project;

Add the message processing function of the left mouse button up to the visual class;

Add a member variable to the class header file: CPoint m_ptOrigin;

Initialized in the constructor of the CPP file depending on the class,

CMypenView::CMypenView()
{
    // TODO: add construction code here
    m_ptOrigin.x=20;
    m_ptOrigin.y=20;
}

The effect of not using a brush is as follows;

After creating a 10 pixel wide, red brush, the line drawing effect is as follows;

The left mouse button bounces the code;

void CMypenView::OnLButtonUp(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default
	//HDC hdc;
	//hdc = ::GetDC(m_hWnd);
	//MoveToEx(hdc,m_ptOrigin.x, m_ptOrigin.y,NULL);
	//LineTo(hdc, point.x, point.y);
	//::ReleaseDC(m_hWnd,hdc);

	CWindowDC dc(this);
	CPen pen(PS_SOLID, 10, RGB(255,0,0));
	CPen *ptr = dc.SelectObject(&pen);
	dc.MoveTo(m_ptOrigin);
	dc.LineTo(point);
	dc.SelectObject(ptr);
	
	CView::OnLButtonUp(nFlags, point);
}

CPen *ptr = dc.SelectObject(&pen);

    The pen is a CPen object; after creating the pen, use dc.SelectObject to select the device description table; draw a line again to use the pen; the return value of the above statement is the original pen; use dc.SelectObject(ptr) after drawing the picture Select the original brush into the device description table;

The style of the brush is defined as follows,

PS_SOLID: solid line
PS_DOT: dotted line
PS_DASH: dashed line PS_DASHDOT: dashed line
PS_DASHDOTDOT: dashed line with
two dots
PS_NULL: transparent line
PS_INSIDEFRAME: along the inner border