图形的保存与重绘.doc

图形的保存与重绘 IDM_POINT(点)、IDM_LINE(直线)、IDM_ RECTANGLE(矩形)、IDM_ ELLIPSE (椭圆)，并分别对这四个菜单项添加命令响应，并在CGraphic2View类中添加一个私有的成员变量UINT m_nDrawType; 并在构造方法中初始化： CGraphic2View::CGraphic2View()?{?????//?TODO:?add?construction?code?here?????m_nDrawType=0;?????m_ptOrigin=0;?????m_dcMetaFile.Create();//创建一个内存的CMetaFileDC对象?}?void?CGraphic2View::OnPoint()??{?????//?TODO:?Add?your?command?handler?code?here?????m_nDrawType=1;?}??void?CGraphic2View::OnLine()??{? m_nDrawType=2;?}??void?CGraphic2View::OnRectangle()??{? ????m_nDrawType=3;?}??void?CGraphic2View::OnEllipse()??{? ????m_nDrawType=4;?} 再在CGraphic2View类中添加一个私有的成员变量m_ptOrigin用来保存原点坐标，并在构造函数中初始化。 接着再给void?CGraphic2View::OnLButtonDown(UINT?nFlags,?CPoint?point)??{? m_ptOrigin=point;//将这个点保存起来?????CView::OnLButtonDown(nFlags,?point);?}??void?CGraphic2View::OnLButtonUp(UINT?nFlags,?CPoint?point)??{?????CClientDC?dc(this);?????CBrush?*pBrush=CBrush::FromHandle((HBRUSH)GetStockObject(NULL_BRUSH));?????//创建透明画刷?????dc.SelectObject(pBrush);??????}?????switch(m_nDrawType)?????{?????case?1:?????????dc.SetPixel(point,RGB(0,0,0));?????????break;?????case?2:?????????dc.MoveTo(m_ptOrigin);?????????dc.LineTo(point);?????????break;?????case?3:?????????dc.Rectangle(CRect(m_ptOrigin,point));?????????break;?????case?4:?????????dc.Ellipse(CRect(m_ptOrigin,point));?????????break;?????}? ????CView::OnLButtonUp(nFlags,?point);?} 运行可以发现当窗口尺寸发现变化是，所绘制的图形也消失了！ 2.图形重绘 新建一个Generic Class (name:CGraph),并在这个类当中增加3个成员变量，同时为了对这3个成员进行赋值，定义一个带参数的构造函数，如下： public:?????CPoint?m_ptOrigin;?????CPoint?m_ptEnd;?????UINT?m_nDrawType;?????CGraph();?????CGraph(UINT?m_nDrawType,CPoint?m_ptOrigin,CPoint?m_ptEnd);? 并在源文件Graph.cpp当中，对这个类的成员变量赋值： CGraph::CGraph(UINT?m_nDrawType,CPoint?m_ptOrigin,CPoint?m_ptEnd)?{?????//对这个类的成员变量赋值?????this-m_nDrawType=m_nDrawType;//图形类型?????this-m_ptOrigin=m_ptOrigin;//图形原点?????this-m_ptEnd=m_ptEnd;//图形终点?}? Graphic2View类当中，新增加一个成员变量CPtrArray m_ptrArray; 这个集合类型的变量用来保存CGraph对象，并在CGraphic2Vi