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;

 1 BOOL G_ImageFromIDResource( UINT nID, LPCTSTR sTR,Gdiplus::Image *&pImg )
 2 {
 3     HINSTANCE hInst = AfxGetResourceHandle();
 4     HRSRC hRsrc = ::FindResource (hInst,MAKEINTRESOURCE(nID),sTR); // type
 5     if (!hRsrc)
 6         return FALSE;
 7     // load resource into memory
 8     DWORD len = SizeofResource(hInst, hRsrc);
 9     BYTE* lpRsrc = (BYTE*)LoadResource(hInst, hRsrc);
10     if (!lpRsrc)
11         return FALSE;
12     // Allocate global memory on which to create stream
13     HGLOBAL m_hMem = GlobalAlloc(GMEM_FIXED, len);
14     BYTE* pmem = (BYTE*)GlobalLock(m_hMem);
15     memcpy(pmem,lpRsrc,len);
16     GlobalUnlock(m_hMem);
17     IStream* pstm;
18     CreateStreamOnHGlobal(m_hMem,FALSE,&pstm);
19     // load from stream
20     pImg=Gdiplus::Image::FromStream(pstm);
21     // free/release stuff
22     pstm->Release();
23     FreeResource(lpRsrc);
24     GlobalFree(m_hMem);
25     return TRUE;
26 }

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();