图形绘制处理逻辑VC

// 逻辑1：先从资源中读取背景资源，然后将绘图对象与DC绑定，通过绘图对象绘出背景
// 逻辑2：先从资源中读取背景资源，新建一个MEMDC，将绘图对象与MEMDC绑定，并且
// 通过绘图对象在内存中绘制图形, 最后将MEMDC中的数据复制给绘图DC绘图

Gdiplus::Image* m_pPngBg;

BOOL G_ImageFromIDResource( UINT nID, LPCTSTR sTR,Gdiplus::Image *&pImg )
{
    HINSTANCE hInst = AfxGetResourceHandle();
    HRSRC hRsrc = ::FindResource (hInst,MAKEINTRESOURCE(nID),sTR); // type
    if (!hRsrc)
        return FALSE;
    // load resource into memory
    DWORD len = SizeofResource(hInst, hRsrc);
    BYTE* lpRsrc = (BYTE*)LoadResource(hInst, hRsrc);
    if (!lpRsrc)
        return FALSE;
    // Allocate global memory on which to create stream
    HGLOBAL m_hMem = GlobalAlloc(GMEM_FIXED, len);
    BYTE* pmem = (BYTE*)GlobalLock(m_hMem);
    memcpy(pmem,lpRsrc,len);
    GlobalUnlock(m_hMem);
    IStream* pstm;
    CreateStreamOnHGlobal(m_hMem,FALSE,&pstm);
    // load from stream
    pImg=Gdiplus::Image::FromStream(pstm);
    // free/release stuff
    pstm->Release();
    FreeResource(lpRsrc);
    GlobalFree(m_hMem);
    return TRUE;
}

方法一：方便
G_ImageFromIDResource(IDB_PNG_MONEYSEL_SELECTED, _T("PNG"), m_pPngBg);
Gdiplus::Graphics graphics(pDC->m_hDC);
graphics.DrawImage(m_pPngBg, 0, 0,m_rcClient.Width(),m_rcClient.Height());

方法二：推荐

CRect rect;
GetWindowRect(&rect);

CDC memDC;
memDC.CreateCompatibleDC(pDC);

int nWidth=m_pPngBg->GetWidth();
int nHeight=m_pPngBg->GetHeight();

CBitmap bitMemMap;
bitMemMap.CreateCompatibleBitmap(pDC,nWidth,nHeight);
memDC.SelectObject(&bitMemMap);

Gdiplus::Graphics graphics(memDC.m_hDC); // Create a GDI+ graphics object
graphics.DrawImage(m_pPngBg, 0, 0,nWidth,nHeight);

pDC->BitBlt(0,0, rect.Width(),rect.Height(),&memDC, 0, 0,SRCCOPY);

bitMemMap.DeleteObject();
memDC.DeleteDC();