MFC--C++

创建一个成员变量

private:
	CPoint m_ptOrigin;

鼠标左键点击消息

void CDrawView::onLButtonDown(UINT nFlags, CPoint point) 
{
	m_ptOrigin=point;
	CView::onLButtonDown(nFlags, point);
}

鼠标左键松开消息

void CDrawView::onLButtonUp(UINT nFlags, CPoint point) 
{
	CDC* pDC = GetDC();
	pDC->MoveTo(m_ptOrigin);
	pDC->LineTo(point);
	ReleaseDC(pDC);
	
	CView::onLButtonUp(nFlags, point);
}

void CDrawView::onLButtonUp(UINT nFlags, CPoint point) 
{
    CPen pen(PS_SOLID,2,RGB(255,0,0));
	CClientDC dc(this);
	CPen* pOldPen =dc.SelectObject(&pen);
	dc.MoveTo(m_ptOrigin);
	dc.LineTo(point);
	dc.SelectObject(pOldPen);
	
	CView::onLButtonUp(nFlags, point);
}

void CDrawView::onLButtonUp(UINT nFlags, CPoint point) 
{
    //创建一个红色画刷
	CBrush brush(RGB(255,0,0));
	//创建并获得设备描述表
	CClientDC dc(this);
	//利用红色画刷填充鼠标拖拽过程中形成的矩形区域
	dc.FillRect(CRect(m_ptOrigin,point),&brush);
	
	CView::onLButtonUp(nFlags, point);
}

引入资源

图片只支持.bmp格式的

void CDarwView::onLButtonUp(UINT nFlags, CPoint point) 
{
	CClientDC dc(this);
	CPen pen(PS_SOLID,5,RGB(255,255,0));//线的类型，粗度，
	dc.SelectObject(&pen);//安装画笔
	
	CBitmap bitmap;
	bitmap.LoadBitmap(IDB_BITMAP1);
	CBrush brush(&bitmap);
	dc.SelectObject(&brush);
	dc.Rectangle(m_ptOrigin.x,m_ptOrigin.y,point.x,point.y);
	
    CView::onLButtonUp(nFlags, point);
}