bresenhamview.cpp

使用Bresenham算法进行划线

// BresenhamView.cpp : implementation of the CBresenhamView class
//

#include "stdafx.h"
#include "Bresenham.h"
#include "math.h"

#include "BresenhamDoc.h"
#include "BresenhamView.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CBresenhamView

IMPLEMENT_DYNCREATE(CBresenhamView, CView)

BEGIN_MESSAGE_MAP(CBresenhamView, CView)
	//{{AFX_MSG_MAP(CBresenhamView)
	ON_WM_LBUTTONDOWN()
	//}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CBresenhamView construction/destruction

CBresenhamView::CBresenhamView()
{
	// TODO: add construction code here

}

CBresenhamView::~CBresenhamView()
{
}

BOOL CBresenhamView::PreCreateWindow(CREATESTRUCT& cs)
{
	// TODO: Modify the Window class or styles here by modifying
	//  the CREATESTRUCT cs

	return CView::PreCreateWindow(cs);
}

/////////////////////////////////////////////////////////////////////////////
// CBresenhamView drawing

void CBresenhamView::OnDraw(CDC* pDC)
{


	   pDC->TextOut(0,0,"Press the left mouse button please!!!");
	   int Dx=abs(EndPoint.x-StartPoint.x),Dy=abs(EndPoint.y-StartPoint.y);
	   int p= 2*Dy-Dx;
	   int p0= 2*Dx-Dy;
	   int AddDy = 2*Dy, AddDyMinusDx =2*(Dy-Dx);
	   int AddDx = 2*Dx, AddDxMinusDy =2*(Dx-Dy);
	   
	   CPoint Point;
	   //斜率
	   double k;
	   k = ((EndPoint.y -StartPoint.y)*0.1)/((EndPoint.x -StartPoint.x)*0.1);
	   
  //当 斜率大于0小于1.0的时候。	
	   if(k<1.0 &&k >=0)
	   { 
		   if(StartPoint.x>EndPoint.x)
		   {
			   Point=EndPoint;
			   EndPoint=StartPoint;
		   }
		   else 
			   Point=StartPoint;
		   pDC->SetPixel(Point.x,Point.y,RGB(255,0,0));
		   while(Point.x<EndPoint.x)
		   {
			   Point.x++;
			   if(p<0)
				   p+=AddDy;
			   else if(p>=0)
			   {
				   Point.y++;
				   p+=AddDyMinusDx;
			   }
			   pDC->SetPixel(Point.x,Point.y,RGB(255,0,0));
		   }
	   }
  //斜率大于1.0
	   else if(k>=1.0)
	   {
		   if(StartPoint.x>EndPoint.x)
		   {
			   Point=EndPoint;
			   EndPoint=StartPoint;
		   }
		   else 
			   Point=StartPoint;
		   pDC->SetPixel(Point.x,Point.y,RGB(255,0,0));
		   while(Point.y<EndPoint.y)
		   {
			   Point.y++;
			   if(p0<0)
				   p0+=AddDx;
			   else 
			   {
				   Point.x++;
				   p0+=AddDxMinusDy;
			   }
			   pDC->SetPixel(Point.x,Point.y,RGB(255,0,0));
		   }
		   
	   }
	   //斜率在0到－1.0之间	   
	   else if(k>-1.0&&k<0)
	   {		   
		   if(StartPoint.x>EndPoint.x)
		   {
			   Point=EndPoint;
			   EndPoint=StartPoint;
			   StartPoint=Point;
		   }
		   else 
		   {
			   Point=StartPoint;
		   }
		   pDC->SetPixel(Point.x,Point.y,RGB(255,0,0));
		   while(Point.x<EndPoint.x)
		   {
			   Point.x++;
			   if(p<0)
				   p+=AddDy;
			   else if(p>=0)
			   {
				   Point.y--;
				   p+=AddDyMinusDx;
			   }
			   pDC->SetPixel(Point.x,Point.y,RGB(255,0,0));
		   }
	   }
	   //斜率小于-1.0
	   else if(k<-1.0)
	   {
		   if(StartPoint.x>EndPoint.x)
		   {
			   Point=EndPoint;
			   EndPoint=StartPoint;
		   }
		   else 
		   {
			   Point=StartPoint;
		   }
		   pDC->SetPixel(Point.x,Point.y,RGB(255,0,0));
		   while(Point.y>EndPoint.y)
		   {
			   Point.y--;
			   if(p0<0)
				   p0+=AddDx;
			   else 
			   {
				   Point.x++;
				   p0+=AddDxMinusDy;
			   }
			   pDC->SetPixel(Point.x,Point.y,RGB(255,0,0));
		   }
	   }	   

	   

}

/////////////////////////////////////////////////////////////////////////////
// CBresenhamView diagnostics

#ifdef _DEBUG
void CBresenhamView::AssertValid() const
{
	CView::AssertValid();
}

void CBresenhamView::Dump(CDumpContext& dc) const
{
	CView::Dump(dc);
}

CBresenhamDoc* CBresenhamView::GetDocument() // non-debug version is inline
{
	ASSERT(m_pDocument->IsKindOf(RUNTIME_CLASS(CBresenhamDoc)));
	return (CBresenhamDoc*)m_pDocument;
}
#endif //_DEBUG

/////////////////////////////////////////////////////////////////////////////
// CBresenhamView message handlers

void CBresenhamView::OnLButtonDown(UINT nFlags, CPoint point) 
{
	// TODO: Add your message handler code here and/or call default
	
	CView::OnLButtonDown(nFlags, point);
    CDC *pDC=GetDC();     //CDC类是专门用于画图
    static int m=1;
	if(m%2==0)
	{
		EndPoint=point;
		str2.Format("%d  %d",EndPoint.x,EndPoint.y);
		pDC->SetPixel(EndPoint,RGB(255,0,0));
        OnDraw(pDC);
		//DrawLines();
	}	
	else 
	{
		StartPoint = point;
        Str1.Format("%d  %d",StartPoint.x,StartPoint.y);
	    pDC->SetPixel(StartPoint,RGB(255,0,0));
   
	}
	m++;
	

}