1.10  开发技巧与难点分析（4）

（14）在对话框的WM_SIZE消息中添加代码，当对话框的大小改变时重新绘制对话框的标题、边框及按钮。代码如下：

CPoint pos(30,1);  
m_MinRect.CopyRect(CRect(m_RTitleRc.left+pos.x
,(m_TitleDrawHeight   
    +2*m_BorderHeight -m_ButtonHeight)/2+pos.y,
m_ButtonWidth,m_ButtonHeight));  //最小化按钮区域  
pos.x = 55;  
m_MaxRect.CopyRect(CRect(m_RTitleRc.left+pos.x,
(m_TitleDrawHeight  
    +2*m_BorderHeight -m_ButtonHeight)/2+pos.y,m_
ButtonWidth,m_ButtonHeight));  //最大化按钮区域  
pos.x = 80;  
m_CloseRect.CopyRect(CRect(m_RTitleRc.left+pos.x,
(m_TitleDrawHeight  
    +2*m_BorderHeight -m_ButtonHeight)/2+pos.y,m_
ButtonWidth,m_ButtonHeight));  //关闭按钮区域  
Invalidate();     

（15）处理对话框的WM_NCMOUSEMOVE消息，当鼠标移动到标题栏按钮上时，绘制标题栏按钮的热点效果；当鼠标离开标题栏按钮时，恢复标题栏按钮原来的效果。代码如下：

void CCaptureDlg::OnNcMouseMove(UINT nHitTest, CPoint point)   
{  
    CRect tempMin,tempMax,tempClose,ClientRect;  
    CWindowDC WindowDC (this);                   
//CWindowDC类对象  
    CDC memDC;  
    memDC.CreateCompatibleDC(&WindowDC);      
//创建内存设备环境  
    BITMAPINFO bInfo;   
    CBitmap LeftLine;  
    int x,y;  
    GetWindowRect(ClientRect);   
    tempMin.CopyRect(CRect(m_MinRect.left+ ClientRect.left,ClientRect.top  
        +m_MinRect.top,m_MinRect.right+m_MinRect.left+ ClientRect.left,  
        m_MinRect.bottom+m_MinRect.top+ClientRect.top));
//设置最小化按钮区域  
    tempMax.CopyRect(CRect(m_MaxRect.left+ ClientRect.left,ClientRect.top  
        +m_MaxRect.top,m_MaxRect.right+m_MaxRect.left+ ClientRect.left,  
        m_MaxRect.bottom+m_MaxRect.top+ClientRect.top));
//设置最大化按钮区域  
    tempClose.CopyRect(CRect(m_CloseRect.left+ ClientRect.left,ClientRect.top  
        +m_CloseRect.top,m_CloseRect.right+m_CloseRect.left+ ClientRect.left,  
        m_CloseRect.bottom+m_CloseRect.top+ClientRect.top));
//设置关闭按钮区域  
    if(tempMin.PtInRect(point))                    
//鼠标在最小化按钮上移动时，更改按钮显示的位图  
    {  
        if(m_ButtonState != bsMin)  
        {  
            LeftLine.LoadBitmap(IDB_MINHOTBT)           ; 
//加载最小化按钮位图资源  
            LeftLine.GetObject(sizeof(bInfo),&bInfo); 
            x = bInfo.bmiHeader.biWidth;             
//获得位图宽度  
            y = bInfo.bmiHeader.biHeight;            
//获得位图高度  
            memDC.SelectObject(&LeftLine);  
            WindowDC.StretchBlt(m_MinRect.left,
m_MinRect.top,m_MinRect.right,  
                m_MinRect.bottom,&memDC,0,0,x,y,SRCCOPY); 
//绘制最小化按钮  
            m_IsDrawForm = FALSE;  
            m_ButtonState = bsMin;    
            LeftLine.Detach();  
        }  
    }  
    else if(tempMax.PtInRect(point))  
    {  
        if(m_ButtonState!=bsMax && m_ButtonState!=bsRes)  
        {  
            LeftLine.LoadBitmap(IDB_MAXHOTBT);         
//加载最大化按钮位图资源  
            LeftLine.GetObject(sizeof(bInfo),&bInfo);  
            x = bInfo.bmiHeader.biWidth;               
//获得位图宽度  
            y = bInfo.bmiHeader.biHeight;            
//获得位图高度  
            memDC.SelectObject(&LeftLine);  
            WindowDC.StretchBlt(m_MaxRect.left,m_MaxRect.
top,m_MaxRect.right,  
                m_MaxRect.bottom,&memDC,0,0,x,y,SRCCOPY); 
//绘制最大化按钮  
            m_IsDrawForm = FALSE;  
            if (m_IsMax)  
            {  
                m_ButtonState = bsMax;  
            }  
            else  
            {  
                m_ButtonState = bsRes;  
            }  
            LeftLine.Detach();  
        }  
    }  
    else if(tempClose.PtInRect(point))  
    {  
        if(m_ButtonState != bsClose)  
        {  
            LeftLine.LoadBitmap(IDB_CLOSEHOTBT);       
//加载关闭按钮位图资源  
            LeftLine.GetObject(sizeof(bInfo),&bInfo);  
            x = bInfo.bmiHeader.biWidth;               
//获得位图宽度  
            y = bInfo.bmiHeader.biHeight;           
//获得位图高度  
            memDC.SelectObject(&LeftLine);  
            WindowDC.StretchBlt(m_CloseRect.left,
m_CloseRect.top,m_CloseRect.right,  
                m_CloseRect.bottom,&memDC,0,0,x,y,SRCCOPY);     //绘制关闭按钮  
            m_IsDrawForm = FALSE;  
            m_ButtonState = bsClose;  
            LeftLine.Detach();    
        }  
    }  
    else  
    {  
        if(m_IsDrawForm == FALSE)  
        {  
            if(m_ButtonState == bsMin)  
                DrawDialog( FMINBUTTON);           
//重绘最小化按钮  
            else if(m_ButtonState == bsClose)  
                DrawDialog( FCLOSEBUTTON);                      //重绘关闭按钮  
            else if(m_ButtonState == bsMax || 
m_ButtonState==bsRes)  
                DrawDialog( FMAXBUTTON);                        //重绘最大化按钮  
        }  
        m_ButtonState = bsNone;  
    }  
    LeftLine.DeleteObject();  
    ReleaseDC(&memDC);  
    CDialog::OnNcMouseMove(nHitTest, point);  
}