MFC简易绘图

CDrawView::CDrawView(){// TODO: add construction code herem_ptOrigin=0;m_ptOld=0;m_bDraw=FALSE;}void CDrawView::OnLButtonDown(UINT nFlags, CPoint point) {// TODO: Add your message handler code here and/or call defaultm_ptOrigin=point;m_ptOld=point;m_bDraw=TRUE;}void CDrawView::OnLButtonUp(UINT nFlags, CPoint point) {// TODO: Add your message handler code here and/or call default/*//用SDK平台的函数写的//首先获取窗口的设备描述表HDC hdc;hdc=::GetDC(m_hWnd);//移动到线条的起点MoveToEx(hdc,point.x,point.y,NULL);//画线LineTo(hdc,point.x,point.y);//释放DC::ReleaseDC(m_hWnd,hdc);*///用CDC类写的/*CDC *pDC=GetDC();pDC->MoveTo(m_ptOrigin);pDC->LineTo(point);ReleaseDC(pDC);*///用CClientDC类写的/*CClientDC dc(GetParent());dc.MoveTo(m_ptOrigin);dc.LineTo(point);*///用CWindowDC类写/*CWindowDC dc(GetDesktopWindow());dc.MoveTo(m_ptOrigin);dc.LineTo(point);*//*CPen pen(PS_COSMETIC,1,RGB(255,56,0));CClientDC dc(this);CPen *pOldPen=dc.SelectObject(&pen);dc.MoveTo(m_ptOrigin);dc.LineTo(point);dc.SelectObject(pOldPen);*//*//创建红色画刷CBrush brush(RGB(255,0,0));//创建并获得DCCClientDC dc(this);//利用红色画刷填满一块矩形区域dc.FillRect(CRect(m_ptOrigin,point),&brush);*//*//创建位图对象CBitmap bitmap;//加载位图资源bitmap.LoadBitmap(IDB_BITMAP1);//创建位图画刷CBrush brush(&bitmap);CClientDC dc(this);dc.FillRect(CRect(m_ptOrigin,point),&brush);*//*CClientDC dc(this);dc.Rectangle(CRect(m_ptOrigin,point));*//*CClientDC dc(this);//获取透明画刷CBrush *pBrush=CBrush::FromHandle((HBRUSH)GetStockObject(NULL_BRUSH));CBrush *pOldBrush=dc.SelectObject(pBrush);dc.Rectangle(CRect(m_ptOrigin,point));dc.SelectObject(pOldBrush);*///画连续线条m_bDraw=FALSE;CView::OnLButtonUp(nFlags, point);}void CDrawView::OnMouseMove(UINT nFlags, CPoint point) {// TODO: Add your message handler code here and/or call defaultCClientDC dc(this);dc.SetROP2(R2_NOTCOPYPEN);CPen pen(PS_SOLID,1,RGB(255,0,0));CPen *pOldPen=dc.SelectObject(&pen);if(m_bDraw==TRUE){dc.MoveTo(m_ptOrigin);dc.LineTo(point);//每次从鼠标当前位置向上一个位置连线dc.LineTo(m_ptOld);//修改线段的起点//注释掉修改起点的这句，就可以画出类似扇形的样子//m_ptOrigin=point;m_ptOld=point;}dc.SelectObject(pOldPen);CView::OnMouseMove(nFlags, point);}

上面是部分代码

上面定义了三个Ciew类的对象，其中两个CPoint对象 m_ptOrign保存鼠标左键按下时的坐标，m_ptOld保存鼠标左键起来时的坐标。另外一个m_bDraw是BOOL变量，用来作为左键是否按下