MoveToEx, LineTo, Ellipse实例

调用MoveToEx，LineTo，Ellipse函数，实现如下实例：

使用WTL框架，选择Dialog类型，在MainDlg中定义两个private方法：

// draw arrow
void draw_arrow(int nStartX, int nStartY, int nLength) throw()
{
	::MoveToEx(m_hdc, nStartX, nStartY, NULL);
	::LineTo(m_hdc, nStartX + nLength, nStartY);
	::LineTo(m_hdc, nStartX + nLength - 5, nStartY - 5);
	::MoveToEx(m_hdc, nStartX + nLength, nStartY, NULL);
	::LineTo(m_hdc, nStartX + nLength - 5, nStartY + 5);
}
// draw node
void draw_node(int nCenterX, int nCenterY, int nRadius, LPCTSTR szTag, BOOL bCurrent = FALSE) throw()
{
	::Ellipse(m_hdc, nCenterX - nRadius, nCenterY - nRadius,
			nCenterX + nRadius, nCenterY + nRadius);
	if(bCurrent)
		::Ellipse(m_hdc, nCenterX - nRadius*0.4, nCenterY - nRadius*0.4, 
				nCenterX + nRadius*0.4, nCenterY + nRadius*0.4);
	::TextOut(m_hdc, nCenterX - 15, nCenterY + nRadius + 5, szTag, 2);
}

draw_arrow方法的作用是绘制带箭头的线段。draw_node方法的作用是绘制节点，它包含圆形及其下方的标记字符串。参数bCurrent表示本次所绘制的节点是否为当前阶段，本例选择“青年”为当前阶段，该节点的由两个同心圆与普通节点区分开来。

为MainDlg添加对WM_PAINT的消息处理，其响应方法如下所示：

LRESULT OnPaint(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/)
{
	PAINTSTRUCT ps;
	BeginPaint(&ps);
	m_hdc = ps.hdc;
	// draw life stages
	TCHAR* strStages[] = { _T("婴儿"), _T("幼儿"), _T("童年"), _T("少年"),
							_T("青年"), _T("中年"), _T("老年") };
	int nX = 20;
	RECT rc;
	GetClientRect(&rc);
	int nY = rc.bottom / 2;
	int nArrowLength = 50;
	int nRadius = 18;
	int nCurrent = 4; // current is "青年"
	draw_node(nX + nRadius, nY, nRadius, strStages[0], nCurrent == 0);
	for( int i = 0; i < 6; ++i ) {
		draw_arrow(nX + nRadius * 2 + i * nArrowLength + 2 * i * nRadius, nY, nArrowLength);
		draw_node(nX + nRadius * 3 + nArrowLength + i * nArrowLength + 2 * i * nRadius,
				nY, nRadius, strStages[i+1], nCurrent == i + 1);
	} // end for
	EndPaint(&ps);
	return 0;
}

在绘制的时候，除第一个节点之前不带有arrow外，其余6个节点都含有arrow，因此需对第一个节点进行特殊处理，将它的绘制放在for循环之外。整个工程的源码可点击下列链接下载：

http://pan.baidu.com/netdisk/singlepublic?fid=559720_2849936413