MFC 鼠标实时画线

1.首先添加成员变量:

	bool bIsDrawing;      //画线标志
	int DrawLinewidth;    //线条宽度
	CPoint ptDrawOrigin;  //当前线段的起始点
	HCURSOR Hcross;       //光标形状

 

2. 添加鼠标消息响应函数：

OnLButtonDown(UINT nFlags, CPoint point);
OnMouseMove(UINT nFlags, CPoint point);
OnLButtonUp(UINT nFlags, CPoint point);

 

3.在OnLButtonDown(UINT nFlags, CPoint point);中添加下面代码：

	SetCapture();
	::SetCursor(Hcross);
	ptDrawOrigin = point;
	bIsDrawing = true;

 

4.在OnMouseMove(UINT nFlags, CPoint point);中添加下面代码：

	if(bIsDrawing)
	{
		CPen pen(PS_DOT, DrawLinewidth, RGB(255, 0, 0));//构造画笔对象
		CClientDC dc(this);
		CPen *pOldPen = dc.SelectObject(&pen);//将画笔选入DC
		dc.MoveTo(ptDrawOrigin);
		dc.LineTo(point);
		dc.SelectObject(pOldPen);//恢复先前的画笔
		ptDrawOrigin = point;
	}

5.在OnLButtonUp(UINT nFlags, CPoint point);中添加下面代码:

	if(bIsDrawing)
	{
		bIsDrawing=false;
		ReleaseCapture();
	}

 

6.在OnInitDialog()中添加初始化代码:

	bIsDrawing =false;                     //初始化绘图状态
	DrawLinewidth = 10;                    //设置线条宽度
	Hcross = LoadCursor(NULL, IDC_CROSS); //十字型光标
//	Hcross = LoadCursor(NULL, IDC_ARROW); //正常箭头光标
	::SetCursor(Hcross);

 

源码下载:

http://download.youkuaiyun.com/detail/c_s_d_n_user/5310651