Graph Drawing

Development Platform:
Visual C++

DDALineView.cpp：Code Content
							// DDALineView.cpp : implementation of the CDDALineView class
//
#include "stdafx.h"
#include "DDALine.h"
#include "newDialog.h"
#include "DDALineDoc.h"
#include "DDALineView.h"
#include <String.h>
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
/////////////////////////////////////////////////////////////////////////////
// CDDALineView
IMPLEMENT_DYNCREATE(CDDALineView, CView)
BEGIN_MESSAGE_MAP(CDDALineView, CView)
	//{{AFX_MSG_MAP(CDDALineView)
	ON_COMMAND(ID_MENUITEM32771, OnMenuitem32771)
	//}}AFX_MSG_MAP
	// Standard printing commands
	ON_COMMAND(ID_FILE_PRINT, CView::OnFilePrint)
	ON_COMMAND(ID_FILE_PRINT_DIRECT, CView::OnFilePrint)
	ON_COMMAND(ID_FILE_PRINT_PREVIEW, CView::OnFilePrintPreview)
END_MESSAGE_MAP()
/////////////////////////////////////////////////////////////////////////////
// CDDALineView construction/destruction
CDDALineView::CDDALineView()
{
	// TODO: add construction code here
}
CDDALineView::~CDDALineView()
{
}
BOOL CDDALineView::PreCreateWindow(CREATESTRUCT& cs)
{
	// TODO: Modify the Window class or styles here by modifying
	//  the CREATESTRUCT cs
	return CView::PreCreateWindow(cs);
}
/////////////////////////////////////////////////////////////////////////////
// CDDALineView drawing
void CDDALineView::OnDraw(CDC* pDC)
{
	CDDALineDoc* pDoc = GetDocument();
	ASSERT_VALID(pDoc);
	
	int width=::GetSystemMetrics(SM_CXSCREEN);
	int height=::GetSystemMetrics(SM_CYSCREEN);
	int xtemp=40;
	int ytemp;
	int pos=0;
	CString str;
	//绘制横线
	for(ytemp=height-160;ytemp>=0;ytemp-=40)
	{
		pDC->MoveTo(xtemp,ytemp);
		pDC->LineTo(width,ytemp);
		str.Format("%d",pos);		//标写坐标
		pDC->TextOut(16,ytemp-6,str);
		pos++;
	}
	//绘制竖线
	ytemp=height-160;
	pos=0;
	for(xtemp=40;xtemp<=width;xtemp+=40)
	{
		pDC->MoveTo(xtemp,0);
		pDC->LineTo(xtemp,ytemp);
		str.Format("%d",pos);		//标写坐标
		pDC->TextOut(xtemp-6,height-150,str);
		pos++;
	}
}
/////////////////////////////////////////////////////////////////////////////
// CDDALineView printing
BOOL CDDALineView::OnPreparePrinting(CPrintInfo* pInfo)
{
	// default preparation
	return DoPreparePrinting(pInfo);
}
void CDDALineView::OnBeginPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/)
{
	// TODO: add extra initialization before printing
}
void CDDALineView::OnEndPrinting(CDC* /*pDC*/, CPrintInfo* /*pInfo*/)
{
	// TODO: add cleanup after printing
}
/////////////////////////////////////////////////////////////////////////////
// CDDALineView diagnostics
#ifdef _DEBUG
void CDDALineView::AssertValid() const
{
	CView::AssertValid();
}
void CDDALineView::Dump(CDumpContext& dc) const
{
	CView::Dump(dc);
}
CDDALineDoc* CDDALineView::GetDocument() // non-debug version is inline
{
	ASSERT(m_pDocument->IsKindOf(RUNTIME_CLASS(CDDALineDoc)));
	return (CDDALineDoc*)m_pDocument;
}
#endif //_DEBUG
/////////////////////////////////////////////////////////////////////////////
// CDDALineView message handlers
void CDDALineView::OnMenuitem32771() 
{
	Invalidate();
	CDDALineDoc* pDoc = (CDDALineDoc*) GetDocument();
	newDialog ip;
	if(ip.DoModal()==IDOK)
	{
		pDoc->x0=ip.m_x0;
		pDoc->x1=ip.m_x1;
		pDoc->y0=ip.m_y0;
		pDoc->y1=ip.m_y1;
	}
	DDALine(pDoc->x0,pDoc->y0,pDoc->x1,pDoc->y1);
}
void CDDALineView::Draw(int x,int y)
{
	int height=::GetSystemMetrics(SM_CYSCREEN);
	CDC *pDC=GetDC();
	int xx,yy;
	xx=40+40*x;
	yy=height-160-40*y;
	pDC->Ellipse(xx-10,yy-10,xx+10,yy+10);
}
void CDDALineView::DDALine(int x0, int y0, int x1, int y1)
{
	int x;
	float dx,dy,y,k;
	dx=x1-x0;
	dy=y1-y0;
	k=dy/dx;
	if(k<=1 && k>=-1)		//斜率小于1
	{
		y=y0;
		for(x=x0;x<=x1;x++)
		{
			Draw(x,int(y+0.5));
			y=y+k;
		}
	}
	else		//斜率大于1
	{
		int yy;
		float xx;
		xx=x0;
		for(yy=y0;yy<=y1;yy++)
		{
			Draw(int(xx+0.5),yy);
			xx=xx+(1/k);
		}
	}
}

						