如何在Bitmap中画图？（MFC）

直接在设备上下文DC中作图；

void CGdiBitmapView::OnPaintBitmap() 
{
    // TODO: Add your command handler code here
    //取得DC设备
    CDC *pDC = GetDC();
    //保存DC状态
    int nOldDC = pDC->SaveDC();
    //获取客户区大小
    RECT rect;
    GetClientRect(&rect);
    //创建与DC兼容的Bitmap
    m_pViewBitmap->CreateCompatibleBitmap(pDC, rect.right, rect.bottom);

    //选择Bitmap到DC中
    pDC->SelectObject(m_pViewBitmap);
    //背景填充为紫红色
    pDC->FillSolidRect(&rect, 333) ;

    //画图    
    POINT startPoint;
    startPoint.x = 0;
    startPoint.y = 0;

    POINT endPoint;
    endPoint.x = rect.right;
    endPoint.y = rect.bottom;

    pDC->MoveTo(startPoint);
    pDC->LineTo(endPoint);
    //释放DC资源
    pDC->RestoreDC(nOldDC);
    ReleaseDC(pDC); 
}void CGdiBitmapView::OnPaintBi