利用OpenGL添加AutoCAD中的平移与缩放功能

1、添加openGL库，同过在dialog中添加picture控件来悬挂openGL视窗，悬挂方式如下：

BOOL CDemoSectionDlg::InitPic()//初始化openGL视窗
{
    CWnd *wnd = GetDlgItem(IDC_RENDER);//IDC_RENDER为picture控件ID
    hrenderDC=::GetDC(wnd->m_hWnd); //hrenderDC为类成员变量HDC hrenderDC;  //设备上下文
    if(SetWindowPixelFormat(hrenderDC)==FALSE) 
        return 0; 
    if(CreateViewGLContext(hrenderDC)==FALSE) 
        return 0; 
    CRect rc;
    wnd->GetClientRect(&rc);//rc为控件的大小。
    glViewport(0, 0, (GLsizei)(rc.Width()), (GLsizei)(rc.Height())); 
    glMatrixMode(GL_PROJECTION); 
    glEnableClientState(GL_VERTEX_ARRAY); 
    glEnableClientState(GL_TEXTURE_COORD_ARRAY); 
    return TRUE;
}
BOOL CDemoSectionDlg::CreateViewGLContext(HDC hDC) //创建view GL Context
{ 
    hrenderRC = wglCreateContext(hDC);    //hrenderRC为类成员变量HGLRC hrenderRC;  //渲染上下文 
    if(hrenderRC==NULL) 
        return FALSE;   
    if(wglMakeCurrent(hDC,hrenderRC)==FALSE) 
        return FALSE; 
    return TRUE; 
}
BOOL CDemoSectionDlg::SetWindowPixelFormat(HDC hDC) //设定像素格式
{ 
    PIXELFORMATDESCRIPTOR pixelDesc; 
    
    pixelDesc.nSize = sizeof(PIXELFORMATDESCRIPTOR); 
    pixelDesc.nVersion = 1; 
    
    pixelDesc.dwFlags = PFD_DRAW_TO_WINDOW |  
        PFD_SUPPORT_OPENGL | 
        PFD_DOUBLEBUFFER | 
        PFD_TYPE_RGBA; 
    
    pixelDesc.iPixelType = PFD_TYPE_RGBA; 
    pixelDesc.cColorBits = 32; 
    pixelDesc.cRedBits = 0; 
    pixelDesc.cRedShift = 0; 
    pixelDesc.cGreenBits = 0; 
    pixelDesc.cGreenShift = 0; 
    pixelDesc.cBlueBits = 0; 
    pixelDesc.cBlueShift = 0; 
    pixelDesc.cAlphaBits = 0; 
    pixelDesc.cAlphaShift = 0; 
    pixelDesc.cAccumBits = 0; 
    pixelDesc.cAccumRedBits = 0; 
    pixelDesc.cAccumGreenBits = 0; 
    pixelDesc.cAccumBlueBits = 0; 
    pixelDesc.cAccumAlphaBits = 0; 
    pixelDesc.cDepthBits = 0; 
    pixelDesc.cStencilBits = 1; 
    pixelDesc.cAuxBuffers = 0; 
    pixelDesc.iLayerType = PFD_MAIN_PLANE; 
    pixelDesc.bReserved = 0; 
    pixelDesc.dwLayerMask = 0; 
    pixelDesc.dwVisibleMask = 0; 
    pixelDesc.dwDamageMask = 0; 
    
    PixelFormat = ChoosePixelFormat(hDC,&pixelDesc); 
    if(PixelFormat==0) // Choose default 
    { 
        PixelFormat = 1; 
        if(DescribePixelFormat(hDC,PixelFormat, 
            sizeof(PIXELFORMATDESCRIPTOR),&pixelDesc)==0) 
        { 
            return FALSE; 
        } 
    } 
    
    if(SetPixelFormat(hDC,PixelFormat,&pixelDesc)==FALSE) 
        
    {  
        return FALSE; 
    }   
    return TRUE; 
}

2、在视窗上画图，函数如下：

void CDemoSectionDlg::RenderScene(double x,double y)    
{ 
    
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); 
    
    
    glLoadIdentity(); 
    glScalef(ScralSize,ScralSize,0.0);
    xTimes = 1.4;
    yTimes = 0.9;
    xLength = 2*B01+2*B02+2*B03+B04;//H01,H02,H03,B01,B02等需要通过edit控件获取,表示各部分尺寸
    yLength = H01+H02+H03;
    xRange = xTimes/xLength;//xLength通过相应尺寸计算出x向最大尺寸，xTimes为openGL绘图在x方向的放大倍数
    yRange = yTimes/yLength;//yLength通过相应尺寸计算出y向最大尺寸，yTimes为openGL绘图在y方向的放大倍数
    glTranslatef(x*1.0f,y*1.0f,0.0f);
    glTranslatef(-xTimes/2,yTimes/2,0);
    glColor3f(1.0f,1.0f,1.0f);//设置当前色为白色
    glBegin(GL_LINE_LOOP);
    glVertex2f(0.0*xRange,0.0);
    glVertex2f(0.0*xRange,-H01*yRange);
    glVertex2f(B01*xRange,-(H01+H02)*yRange);
    glVertex2f(B01*xRange,-(H01+H02+H03)*yRange);
    glVertex2f((B01+B02+B03+B04+B03+B02)*xRange,-(H01+H02+H03)*yRange);
    glVertex2f((B01+B02+B03+B04+B03+B02)*xRange,-(H01+H02)*yRange);
    glVertex2f((B01+B02+B03+B04+B03+B02+B01)*xRange,-H01*yRange);
    glVertex2f((B01+B02+B03+B04+B03+B02+B01)*xRange,0.0*yRange);
    glEnd();
    glBegin(GL_LINE_LOOP);
    glVertex2f((B01+B02)*xRange,-(H31+H11)*yRange);
    glVertex2f((B01+B02)*xRange,-(H01+H02+H03-H32-H12)*yRange);
    glVertex2f((B01+B02+B11)*xRange,-(H01+H02+H03-H32)*yRange);
    glVertex2f((B01+B02+B03-B12)*xRange,-(H01+H02+H03-H32)*yRange);
    glVertex2f((B01+B02+B03)*xRange,-(H01+H02+H03-H32-H22)*yRange);
    glVertex2f((B01+B02+B03)*xRange,-(H31+H21)*yRange);
    glVertex2f((B01+B02+B03-B22)*xRange,-H31*yRange);
    glVertex2f((B01+B02+B21)*xRange,-H31*yRange);
    glEnd();
    
    glBegin(GL_LINE_LOOP);
    glVertex2f((B01+B02+B03+B04)*xRange,-(H31+H11)*yRange);
    glVertex2f((B01+B02+B03+B04)*xRange,-(H01+H02+H03-H32-H12)*yRange);
    glVertex2f((B01+B02+B03+B04+B11)*xRange,-(H01+H02+H03-H32)*yRange);
    glVertex2f((B01+B02+B03+B03+B04-B12)*xRange,-(H01+H02+H03-H32)*yRange);
    glVertex2f((B01+B02+B03+B03+B04)*xRange,-(H01+H02+H03-H32-H22)*yRange);
    glVertex2f((B01+B02+B03+B03+B04)*xRange,-(H31+H21)*yRange);
    glVertex2f((B01+B02+B03+B03+B04-B22)*xRange,-H31*yRange);
    glVertex2f((B01+B02+B03+B04+B21)*xRange,-H31*yRange);
    glEnd();
    
/////////竖向左标注/////////
    glColor3f(1.0f,1.0f,0.0f);//设置当前色为黄色
    DrawLine(CPoint(-HLineDist,0),CPoint(-HLineDist,-H01),0,1,1);
    DrawLine(CPoint(-HLineDist,-H01),CPoint(-HLineDist,-(H01+H02)),0,1,1);
    DrawLine(CPoint(-HLineDist,-(H01+H02)),CPoint(-HLineDist,-(H01+H02+H03)),0,1,1);
/////////横向下标注/////////
    DrawLine(CPoint(0,-(H01+H02+H03+BLineDist)),CPoint(B01,-(H01+H02+H03+BLineDist)),0,1,1);
    DrawLine(CPoint(B01,-(H01+H02+H03+BLineDist)),CPoint((B01+B02),-(H01+H02+H03+BLineDist)),0,1,1);
    DrawLine(CPoint((B01+B02),-(H01+H02+H03+BLineDist)),CPoint((B01+B02+B03),-(H01+H02+H03+BLineDist)),0,1,1);
    DrawLine(CPoint((B01+B02+B03),-(H01+H02+H03+BLineDist)),CPoint((B01+B02+B03+B04),-(H01+H02+H03+BLineDist)),0,1,1);
    DrawLine(CPoint((B01+B02+B03+B04),-(H01+H02+H03+BLineDist)),CPoint((B01+B02+B03+B04+B03),-(H01+H02+H03+BLineDist)),0,1,1);
    DrawLine(CPoint((B01+B02+B03+B04+B03),-(H01+H02+H03+BLineDist)),CPoint((B01+B02+B03+B04+B03+B02),-(H01+H02+H03+BLineDist)),0,1,1);
    DrawLine(CPoint((B01+B02+B03+B04+B03+B02),-(H01+H02+H03+BLineDist)),CPoint((B01+B02+B03+B04+B03+B02+B01),-(H01+H02+H03+BLineDist)),0,1,1);
    //glRasterPos2f(0.5f, 0.0f);
    SelectFont(15, GB2312_CHARSET, "Times New Roman");
    DrawCNString("HO1",-HTxtDist,-(H01/2+7));
    DrawCNString("HO2",-HTxtDist,-(H01+H02/2+7));
    DrawCNString("HO3",-HTxtDist,-(H01+H02+H03/2+7));
    DrawCNString("BO1",(B01/2-40),-BTxtDist);
    DrawCNString("BO2",(B01+B02/2-40),-BTxtDist);
    DrawCNString("BO3",(B01+B02+B03/2-40),-BTxtDist);
    DrawCNString("BO4",(B01+B02+B03+B04/2-40),-BTxtDist);
    DrawCNString("BO3",(B01+B02+B03+B04+B03/2-40),-BTxtDist);
    DrawCNString("BO2",(B01+B02+2*B03+B04+B02/2-40),-BTxtDist);
    DrawCNString("BO1",(B01+2*B02+2*B03+B04+B01/2-40),-BTxtDist);
    int B21 = 60,H11=25;
    DrawLine(CPoint(B01+B02+B03/2,0),CPoint(B01+B02+B03/2,-H11),0,1,1);
    DrawCNString("H11",B01+B02+B21,-(H11/2+7));
    SwapBuffers(hrenderDC); 
}
void CDemoSectionDlg::DrawCNString(const char* str,int x,int y) 
{
    glColor3f(0.0f, 0.0f, 1.0f);
    int len, i;
    wchar_t* wstring;
    HDC hDC = wglGetCurrentDC();
    GLuint list = glGenLists(1);
    glRasterPos2f(x*xRange,y*yRange);
    // 计算字符的个数
    // 如果是双字节字符的（比如中文字符），两个字节才算一个字符
    // 否则一个字节算一个字符
    len = 0;
    for(i=0; str[i]!='\0'; ++i)
    {
        if( IsDBCSLeadByte(str[i]) )
            ++i;
        ++len;
    }
    
    // 将混合字符转化为宽字符
    wstring = (wchar_t*)malloc((len+1) * sizeof(wchar_t));
    MultiByteToWideChar(CP_ACP, MB_PRECOMPOSED, str, -1, wstring, len);
    wstring[len] = L'\0';
    
    // 逐个输出字符
    for(i=0; i<len; ++i)
    {
        wglUseFontBitmapsW(hDC, wstring[i], 1, list);
        glCallList(list);
    }
    
    // 回收所有临时资源
    free(wstring);
    glDeleteLists(list, 1);
    glColor3f(1.0f, 1.0f, 0.0f);
}
void CDemoSectionDlg::SelectFont(int size, int charset, const char* face)
{
    HFONT hFont = CreateFontA(size, 0, 0, 0, FW_MEDIUM, 0, 0, 0,
        charset, OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS,
        DEFAULT_QUALITY, DEFAULT_PITCH | FF_SWISS, face);
    HFONT hOldFont = (HFONT)SelectObject(wglGetCurrentDC(), hFont);
    DeleteObject(hOldFont);
}
void CDemoSectionDlg::DrawLine(CPoint nS,CPoint nE, BOOL IsAt,BOOL IsArrow,BOOL WithBorder)
{//该函数可以通过nS与nE定义带箭头标线的长度与位置来做标注，带有箭头，代码较多是因为添加了横向与竖向自动识别，
//IsAt标识暂时没用，表示相对当前激活点划线还是相对坐标原点划线。
//IsArrow标识是否带箭头
//WithBorder标识是否带边界线
    if(IsAt)
    {
        glBegin(GL_LINES);
        glVertex2f((nS.x)*xRange,(nS.y)*yRange);
        glVertex2f((nS.x+nE.x)*xRange,(nS.y+nE.y)*yRange);
        glEnd();
        if(WithBorder&&nE.x==0)
        {
            glBegin(GL_LINES);
            glVertex2f((nS.x-25)*xRange,(nS.y)*yRange);
            glVertex2f((nS.x+25)*xRange,(nS.y)*yRange);
            glEnd();
            glBegin(GL_LINES);
            glVertex2f((nS.x+nE.x-25)*xRange,(nS.y+nE.y)*yRange);
            glVertex2f((nS.x+nE.x+25)*xRange,(nS.y+nE.y)*yRange);
            glEnd();
        }
        if(WithBorder&&nE.y==0)
        {
            glBegin(GL_LINES);
            glVertex2f((nS.x)*xRange,(nS.y-25)*yRange);
            glVertex2f((nS.x)*xRange,(nS.y+25)*yRange);
            glEnd();
            glBegin(GL_LINES);
            glVertex2f((nS.x+nE.x)*xRange,(nS.y+nE.y-25)*yRange);
            glVertex2f((nS.x+nE.x)*xRange,(nS.y+nE.y+25)*yRange);
            glEnd();
        }
        if(IsArrow&&(nE.x==0))
        {
            //glVertex2f((nS.x)*xRange,(nS.y)*yRange);
            if(nE.y<0)
            {
                glBegin(GL_LINES);
                glVertex2f((nS.x+nE.x-6)*xRange,(nS.y+nE.y+18)*yRange);
                glVertex2f((nS.x+nE.x)*xRange,(nS.y+nE.y)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x+nE.x)*xRange,(nS.y+nE.y)*yRange);
                glVertex2f((nS.x+nE.x+6)*xRange,(nS.y+nE.y+18)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x-6)*xRange,(nS.y-18)*yRange);
                glVertex2f((nS.x)*xRange,(nS.y)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x)*xRange,(nS.y)*yRange);
                glVertex2f((nS.x+6)*xRange,(nS.y-18)*yRange);
                glEnd();
            }
            else
            {
                glBegin(GL_LINES);
                glVertex2f((nS.x+nE.x-6)*xRange,(nS.y+nE.y-18)*yRange);
                glVertex2f((nS.x+nE.x)*xRange,(nS.y+nE.y)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x+nE.x)*xRange,(nS.y+nE.y)*yRange);
                glVertex2f((nS.x+nE.x+6)*xRange,(nS.y+nE.y-18)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x-6)*xRange,(nS.y+18)*yRange);
                glVertex2f((nS.x)*xRange,(nS.y)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x)*xRange,(nS.y)*yRange);
                glVertex2f((nS.x+6)*xRange,(nS.y+18)*yRange);
                glEnd();
            }
            
        }
        if(IsArrow&&(nE.y==0))
        {
            //glVertex2f((nS.x)*xRange,(nS.y)*yRange);
            if(nE.x<0)
            {
                glBegin(GL_LINES);
                glVertex2f((nS.x+nE.x+18)*xRange,(nS.y+nE.y+6)*yRange);
                glVertex2f((nS.x+nE.x)*xRange,(nS.y+nE.y)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x+nE.x)*xRange,(nS.y+nE.y)*yRange);
                glVertex2f((nS.x+nE.x+18)*xRange,(nS.y+nE.y-6)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x-18)*xRange,(nS.y+6)*yRange);
                glVertex2f((nS.x)*xRange,(nS.y)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x)*xRange,(nS.y)*yRange);
                glVertex2f((nS.x-18)*xRange,(nS.y-6)*yRange);
                glEnd();
            }
            else
            {
                glBegin(GL_LINES);
                glVertex2f((nS.x+nE.x-18)*xRange,(nS.y+nE.y+6)*yRange);
                glVertex2f((nS.x+nE.x)*xRange,(nS.y+nE.y)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x+nE.x)*xRange,(nS.y+nE.y)*yRange);
                glVertex2f((nS.x+nE.x-18)*xRange,(nS.y+nE.y-6)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x+18)*xRange,(nS.y+6)*yRange);
                glVertex2f((nS.x)*xRange,(nS.y)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x)*xRange,(nS.y)*yRange);
                glVertex2f((nS.x+18)*xRange,(nS.y-6)*yRange);
                glEnd();
            }
            
        }
    }
    else
    {
        //glVertex2f((nS.x)*xRange,(nS.y)*yRange);
        //glVertex2f((nS.x+nE.x)*xRange,(nS.y+nE.y)*yRange);
        glBegin(GL_LINES);
        glVertex2f(nS.x*xRange,nS.y*yRange);
        glVertex2f(nE.x*xRange,nE.y*yRange);
        glEnd();
        if(WithBorder&&(nE.x-nS.x==0))
        {
            glBegin(GL_LINES);
            glVertex2f((nS.x-25)*xRange,(nS.y)*yRange);
            glVertex2f((nS.x+25)*xRange,(nS.y)*yRange);
            glEnd();
            glBegin(GL_LINES);
            glVertex2f((nE.x-25)*xRange,(nE.y)*yRange);
            glVertex2f((nE.x+25)*xRange,(nE.y)*yRange);
            glEnd();
        }
        if(WithBorder&&(nE.y-nS.y==0))
        {
            glBegin(GL_LINES);
            glVertex2f((nS.x)*xRange,(nS.y-25)*yRange);
            glVertex2f((nS.x)*xRange,(nS.y+25)*yRange);
            glEnd();
            glBegin(GL_LINES);
            glVertex2f((nE.x)*xRange,(nE.y-25)*yRange);
            glVertex2f((nE.x)*xRange,(nE.y+25)*yRange);
            glEnd();
        }
        if(IsArrow&&(nE.x-nS.x==0))
        {
            //glVertex2f((nS.x)*xRange,(nS.y)*yRange);
            if(nE.y-nS.y<0)
            {
                glBegin(GL_LINES);
                glVertex2f((nE.x-6)*xRange,(nE.y+18)*yRange);
                glVertex2f((nE.x)*xRange,(nE.y)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nE.x)*xRange,(nE.y)*yRange);
                glVertex2f((nE.x+6)*xRange,(nE.y+18)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x-6)*xRange,(nS.y-18)*yRange);
                glVertex2f((nS.x)*xRange,(nS.y)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x)*xRange,(nS.y)*yRange);
                glVertex2f((nS.x+6)*xRange,(nS.y-18)*yRange);
                glEnd();
            }
            else
            {
                glBegin(GL_LINES);
                glVertex2f((nE.x-6)*xRange,(nE.y-18)*yRange);
                glVertex2f((nE.x)*xRange,(nE.y)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nE.x)*xRange,(nE.y)*yRange);
                glVertex2f((nE.x+6)*xRange,(nE.y-18)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x-6)*xRange,(nS.y+18)*yRange);
                glVertex2f((nS.x)*xRange,(nS.y)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x)*xRange,(nS.y)*yRange);
                glVertex2f((nS.x+6)*xRange,(nS.y+18)*yRange);
                glEnd();
            }
            
        }
        if(IsArrow&&(nE.y-nS.y==0))
        {
            //glVertex2f((nS.x)*xRange,(nS.y)*yRange);
            if(nE.x-nS.x<0)
            {
                glBegin(GL_LINES);
                glVertex2f((nE.x+18)*xRange,(nE.y+6)*yRange);
                glVertex2f((nE.x)*xRange,(nE.y)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nE.x)*xRange,(nE.y)*yRange);
                glVertex2f((nE.x+18)*xRange,(nE.y-6)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x-18)*xRange,(nS.y+6)*yRange);
                glVertex2f((nS.x)*xRange,(nS.y)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x)*xRange,(nS.y)*yRange);
                glVertex2f((nS.x-18)*xRange,(nS.y-6)*yRange);
                glEnd();
            }
            else
            {
                glBegin(GL_LINES);
                glVertex2f((nE.x-18)*xRange,(nE.y+6)*yRange);
                glVertex2f((nE.x)*xRange,(nE.y)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nE.x)*xRange,(nE.y)*yRange);
                glVertex2f((nE.x-18)*xRange,(nE.y-6)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x+18)*xRange,(nS.y+6)*yRange);
                glVertex2f((nS.x)*xRange,(nS.y)*yRange);
                glEnd();
                glBegin(GL_LINES);
                glVertex2f((nS.x)*xRange,(nS.y)*yRange);
                glVertex2f((nS.x+18)*xRange,(nS.y-6)*yRange);
                glEnd();
            }
            
        }
    }
    
}

3、通过添加鼠标事件执行相应重绘：

//需先做OnInitDialog中的初始化
MouseLDStart = (0,0);
MouseLDEnd = (0,0);
LastPoint = (0,0);
MouseLDFlag=0;
CurX=0.0;
CurY=0.0;
LastX = 0.0;
LastY = 0.0;
ScralSize=1.0;
//GetDlgItem(IDC_RENDER)->GetWindowRect(&PicRect); 
GetDlgItem(IDC_RENDER)->GetWindowRect(&rc);
PicRect=rc;
ScreenToClient(&rc);
void CDemoSectionDlg::OnLButtonDown(UINT nFlags, CPoint point) 
{
    if((point.x>=rc.TopLeft().x)&&(point.x<=rc.BottomRight().x)&&
        (point.y>=rc.TopLeft().y)&&(point.y<=rc.BottomRight().y))
    {
        MouseLDStart = point;
        MouseLDFlag=TRUE;
    }
    CDialog::OnLButtonDown(nFlags, point);
}
void CDemoSectionDlg::OnLButtonUp(UINT nFlags, CPoint point) 
{
    if(MouseLDFlag)
    {
        LastX=LastX+(point.x-MouseLDStart.x)/1.0/(PicRect.Width())*2.0/ScralSize;
        LastY=LastY+(MouseLDStart.y-point.y)/1.0/(PicRect.Height())*2.0/ScralSize;
    }
    MouseLDFlag=FALSE;
    CDialog::OnLButtonUp(nFlags, point);
}
void CDemoSectionDlg::OnMouseMove(UINT nFlags, CPoint point) 
{
    if(MouseLDFlag==TRUE)
    {
        CurX=LastX+(point.x-MouseLDStart.x)/1.0/(PicRect.Width())*2.0/ScralSize;
        CurY=LastY+(MouseLDStart.y-point.y)/1.0/(PicRect.Height())*2.0/ScralSize;
        RenderScene(CurX,CurY);
    }
    CDialog::OnMouseMove(nFlags, point);
}
BOOL CDemoSectionDlg::OnMouseWheel(UINT nFlags, short zDelta, CPoint pt) 
{
    CPoint point = pt;
    ScreenToClient(&point);
    if((point.x>=rc.TopLeft().x)&&(point.x<=rc.BottomRight().x)&&
        (point.y>=rc.TopLeft().y)&&(point.y<=rc.BottomRight().y))
    {
        if(zDelta>=0)
        {
            ScralSize=ScralSize+0.1;
            RenderScene(CurX,CurY);
        }
        else
        {
            ScralSize=ScralSize-0.1;
            RenderScene(CurX,CurY);
        }
    }
    return CDialog::OnMouseWheel(nFlags, zDelta, pt);
}

4、每次重绘需执行绘图函数，函数如2；
5、最终效果如下：