VC中的简单绘图

在VC6中建立了一个名为CDrawPicView的基于单文档的工程，相关的知识在后面的程序及注释中

// DrawPicView.h中的主要内容如下：
class CDrawPicView : public CView
{
protected: // create from serialization only
 CDrawPicView();
 DECLARE_DYNCREATE(CDrawPicView)

// Attributes
public:
 CDrawPicDoc* GetDocument();

// Operations
public:

// Overrides
 // ClassWizard generated virtual function overrides
 //{{AFX_VIRTUAL(CDrawPicView)
 public:
 virtual void OnDraw(CDC* pDC);  // overridden to draw this view
 virtual BOOL PreCreateWindow(CREATESTRUCT& cs);
 protected:
 virtual BOOL OnPreparePrinting(CPrintInfo* pInfo);
 virtual void OnBeginPrinting(CDC* pDC, CPrintInfo* pInfo);
 virtual void OnEndPrinting(CDC* pDC, CPrintInfo* pInfo);
 //}}AFX_VIRTUAL

// Implementation
public:
 virtual ~CDrawPicView();
#ifdef _DEBUG
 virtual void AssertValid() const;
 virtual void Dump(CDumpContext& dc) const;
#endif

protected:

// Generated message map functions
protected:
 //{{AFX_MSG(CDrawPicView)
 afx_msg void OnLButtonDown(UINT nFlags, CPoint point);
 afx_msg void OnLButtonUp(UINT nFlags, CPoint point);
 afx_msg void OnMouseMove(UINT nFlags, CPoint point);
 afx_msg void OnRButtonDown(UINT nFlags, CPoint point);
 afx_msg void OnRButtonUp(UINT nFlags, CPoint point);
 //}}AFX_MSG
 DECLARE_MESSAGE_MAP()
private:
 CPoint m_OldPoint;
 bool m_drawflag;
 CPoint m_originalpoint;
};

 

//DrawPicView.cpp中的核心代码如下

// DrawPicView.cpp : implementation of the CDrawPicView class
//

#include "stdafx.h"
#include "DrawPic.h"

#include "DrawPicDoc.h"
#include "DrawPicView.h"

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

/
// CDrawPicView

IMPLEMENT_DYNCREATE(CDrawPicView, CView)

BEGIN_MESSAGE_MAP(CDrawPicView, CView)
 //{{AFX_MSG_MAP(CDrawPicView)
 ON_WM_LBUTTONDOWN()
 ON_WM_LBUTTONUP()
 ON_WM_MOUSEMOVE()
 ON_WM_RBUTTONDOWN()
 ON_WM_RBUTTONUP()
 //}}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()

/
// CDrawPicView construction/destruction

CDrawPicView::CDrawPicView()
{
 // TODO: add construction code here
    m_originalpoint=0;
 m_OldPoint=0;
 m_drawflag=false;
}

CDrawPicView::~CDrawPicView()
{
}

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

 return CView::PreCreateWindow(cs);
}

/
// CDrawPicView drawing

void CDrawPicView::OnDraw(CDC* pDC)
{
 CDrawPicDoc* pDoc = GetDocument();
 ASSERT_VALID(pDoc);
 // TODO: add draw code for native data here
}

/
// CDrawPicView printing

BOOL CDrawPicView::OnPreparePrinting(CPrintInfo* pInfo)
{
 // default preparation
 return DoPreparePrinting(pInfo);
}

void CDrawPicView::OnBeginPrinting(CDC* , CPrintInfo* )
{
 // TODO: add extra initialization before printing
}

void CDrawPicView::OnEndPrinting(CDC* , CPrintInfo* )
{
 // TODO: add cleanup after printing
}

/
// CDrawPicView diagnostics

/
// CDrawPicView message handlers

void CDrawPicView::OnLButtonDown(UINT nFlags, CPoint point)
{
 // TODO: Add your message handler code here and/or call default
 m_originalpoint=point;//点击鼠标左键就获取一个起始点
 m_drawflag=true;
 CView::OnLButtonDown(nFlags, point);
}

void CDrawPicView::OnLButtonUp(UINT nFlags, CPoint point)
{
 // TODO: Add your message handler code here and/or call default
 //利用SDK的全局函数实现画线功能
 //获得窗口的设备描述表
 HDC hdc=::GetDC(m_hWnd);//若不加冒号，会默认为CWnd类的成员函数
 //移动到线条的起点
 MoveToEx(hdc,m_originalpoint.x,m_originalpoint.y,NULL);
 //画线
 LineTo(hdc,point.x,point.y);
 //释放设备描述表
 ::ReleaseDC(m_hWnd,hdc);
 m_drawflag=false;
 CView::OnLButtonUp(nFlags, point);
}

void CDrawPicView::OnMouseMove(UINT nFlags, CPoint point)
{
 // TODO: Add your message handler code here and/or call default
 
 //利用MFC的CDC类实现画带边框的扇形功能,需添加一个CPoint类型的变量m_OldPoint
 CDC *pDC=GetDC();
 pDC->SetROP2(R2_MASKNOTPEN);//设置绘图模式的函数，(final pixel = (NOT pen) AND screen pixel).
 CPen pen(PS_SOLID,2,RGB(255,0,0));//构造一个GDI对象,虚线线性只在画笔宽度不大于1时才有效
 CPen* poldpen=pDC->SelectObject(&pen);//返回先前被选对象的指针
 pDC->MoveTo(m_originalpoint);
 pDC->LineTo(point);
 pDC->LineTo(m_OldPoint);
 m_OldPoint=point;
 pDC->SelectObject(poldpen);//将先前的GDI对象选人设备描述表，以便恢复先前的状态
 ReleaseDC(pDC);
 
   
 CView::OnMouseMove(nFlags, point);
}

void CDrawPicView::OnRButtonDown(UINT nFlags, CPoint point)
{
 // TODO: Add your message handler code here and/or call default
 
 //透明画刷
 //CBrush并没有提供创建透明画刷的功能
 CWindowDC dc(this);
 //创建一个空画刷
 //GetObject函数返回的是一个画刷句柄，返回类型是HGDIOBJECT,需强制转为HBRUSH类型
 //CBrush类提供了一个将画刷句柄转换为画刷对象的静态成员函数
 CBrush *pbrush=CBrush::FromHandle((HBRUSH)GetStockObject(NULL_BRUSH));
 //将空画刷选人设备描述表
 CBrush *poldbrush=dc.SelectObject(pbrush);
 //绘制一个矩形
 dc.Rectangle(CRect(m_originalpoint,point));
 //恢复先前的画刷
 dc.SelectObject(poldbrush);
 CView::OnRButtonDown(nFlags, point);
}

void CDrawPicView::OnRButtonUp(UINT nFlags, CPoint point)
{
 // TODO: Add your message handler code here and/or call default
 

 //创建一个简单的蓝色画刷，设备描述表中有一个默认的白色画刷
 //CBrush brush(RGB(0,0,255));
 //创建位图对象
 CBitmap bitmap;
 //CBitmap类提供了LoadBitmap、CreateBitmap、CreateBitmIndirect等初始化函数
 bitmap.LoadBitmap(IDB_BITMAP);
 //创建位图画刷
 CBrush brush(&bitmap);
 //创建并获得设备描述表
 CClientDC dc(this);
 //利用红色画刷填充矩形区域
 //FillRect直接利用指定画刷填充矩形，因此不需将画刷提前选人设备描述表
 dc.FillRect(CRect(m_originalpoint,point),&brush);
 CView::OnRButtonUp(nFlags, point);
}