孙鑫 Lesson4 draw

最新推荐文章于 2018-10-21 22:54:58 发布

原创最新推荐文章于 2018-10-21 22:54:58 发布 · 208 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#ClientDC #MoveTo #LineTo

本文介绍了一个使用MFC框架实现的绘图应用程序案例，详细展示了如何通过鼠标操作进行绘图，包括左键按下开始绘制、移动时更新线条及左键释放结束绘制的过程。文章重点介绍了CDrawView类中的OnLButtonDown、OnLButtonUp和OnMouseMove消息处理函数的实现细节。

先在视图的头文件中添加三个变量m_ptOld、m_ptOrigin、m_bDraw

void CDrawView::OnLButtonDown(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default
	m_ptOrigin=m_ptOld=point;
	m_bDraw=TRUE;
	CView::OnLButtonDown(nFlags, point);
}


void CDrawView::OnLButtonUp(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default
	/*HDC hdc;
	hdc=::GetDC(m_hWnd);
	MoveToEx(hdc,m_ptOrigin.x,m_ptOrigin.y,NULL);
	LineTo(hdc,point.x,point.y);
	::ReleaseDC(m_hWnd,hdc);*/
	/*CDC *pDC=GetDC();
	pDC->MoveTo(m_ptOrigin);
	pDC->LineTo(point);
	ReleaseDC(pDC);*/


	//CClientDC dc(this);
	/*CClientDC dc(GetParent());
	dc.MoveTo(m_ptOrigin);
	dc.LineTo(point);*/


	//CWindowDC dc(this);
	//CWindowDC dc(GetParent());
	/*CWindowDC dc(GetDesktopWindow());
	dc.MoveTo(m_ptOrigin);
	dc.LineTo(point);*/
	/*CPen pen(PS_DOT,1,RGB(0,255,0));
	CClientDC dc(this);
	CPen *pOldPen=dc.SelectObject(&pen);
	dc.MoveTo(m_ptOrigin);
	dc.LineTo(point);
	dc.SelectObject(pOldPen);*/
//	CBrush brush(RGB(255,0,0));


	/*CBitmap bitmap;
	bitmap.LoadBitmap(IDB_BITMAP1);
	CBrush brush(&bitmap);*/
	/*CClientDC dc(this);
	//dc.FillRect(CRect(m_ptOrigin,point),&brush);
	CBrush *pBrush=CBrush::FromHandle((HBRUSH)GetStockObject(NULL_BRUSH));
	CBrush *pOldBrush=dc.SelectObject(pBrush);
	dc.Rectangle(CRect(m_ptOrigin,point));
	dc.SelectObject(pOldBrush);*/
	m_bDraw=FALSE;
	CView::OnLButtonUp(nFlags, point);
}


void CDrawView::OnMouseMove(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default
	CClientDC dc(this);
	CPen pen(PS_SOLID,1,RGB(255,0,0));
	CPen *pOldPen=dc.SelectObject(&pen);
	if(m_bDraw==TRUE)
	{
		dc.SetROP2(R2_BLACK);
		dc.MoveTo(m_ptOrigin);
		//dc.LineTo(point);
		dc.LineTo(m_ptOld);
		//dc.MoveTo(m_ptOrigin);
		dc.MoveTo(m_ptOld);
		dc.LineTo(point);
		//m_ptOrigin=point;
		m_ptOld=point;
	}
	dc.SelectObject(pOldPen);
	CView::OnMouseMove(nFlags, point);
}