class CBitmap : public CGdiObject{ DECLARE_DYNAMIC(CBitmap)public: static CBitmap* PASCAL FromHandle(HBITMAP hBitmap);// Constructors CBitmap(); BOOL LoadBitmap(LPCTSTR lpszResourceName); BOOL LoadBitmap(UINT nIDResource); BOOL LoadOEMBitmap(UINT nIDBitmap); // for OBM_/OCR_/OIC_#ifndef _AFX_NO_AFXCMN_SUPPORT BOOL LoadMappedBitmap(UINT nIDBitmap, UINT nFlags = 0, LPCOLORMAP lpColorMap = NULL, int nMapSize = 0);#endif BOOL CreateBitmap(int nWidth, int nHeight, UINT nPlanes, UINT nBitcount, const void* lpBits); BOOL CreateBitmapIndirect(LPBITMAP lpBitmap); BOOL CreateCompatibleBitmap(CDC* pDC, int nWidth, int nHeight); BOOL CreateDiscardableBitmap(CDC* pDC, int nWidth, int nHeight);// Attributes operator HBITMAP() const; int GetBitmap(BITMAP* pBitMap);// Operations DWORD SetBitmapBits(DWORD dwCount, const void* lpBits); DWORD GetBitmapBits(DWORD dwCount, LPVOID lpBits) const; CSize SetBitmapDimension(int nWidth, int nHeight); CSize GetBitmapDimension() const;// Implementationpublic: virtual ~CBitmap();#ifdef _DEBUG virtual void Dump(CDumpContext& dc) const;#endif}; 父
CGdiObjectclass CGdiObject : public CObject{ DECLARE_DYNCREATE(CGdiObject)public:// Attributes HGDIOBJ m_hObject; // must be first data member operator HGDIOBJ() const; HGDIOBJ GetSafeHandle() const; static CGdiObject* PASCAL FromHandle(HGDIOBJ hObject); static void PASCAL DeleteTempMap(); BOOL Attach(HGDIOBJ hObject); HGDIOBJ Detach();// Constructors CGdiObject(); // must Create a derived class object BOOL DeleteObject();// Operations#pragma push_macro("GetObject")#undef GetObject int _AFX_FUNCNAME(GetObject)(int nCount, LPVOID lpObject) const; int GetObject(int nCount, LPVOID lpObject) const;#pragma pop_macro("GetObject") UINT GetObjectType() const; BOOL CreateStockObject(int nIndex); BOOL UnrealizeObject(); BOOL operator==(const CGdiObject& obj) const; BOOL operator!=(const CGdiObject& obj) const;// Implementationpublic: virtual ~CGdiObject();#ifdef _DEBUG virtual void Dump(CDumpContext& dc) const; virtual void AssertValid() const;#endif}; 1 装载已导入工程的位图资源
// 装载位图 CBitmap bmp; bmp.LoadBitmap(IDB_BITMAP);
2 装载位图文件
为了能让CBitmap能够装载位图文件，必须调用API函数LoadImage
HANDLE LoadImage( HINSTANCE hinst, // handle of the instance containing the image LPCTSTR lpszName, // name or identifier of image UINT uType, // type of image int cxDesired, // desired width int cyDesired, // desired height UINT fuLoad // load flags);
装载： Example 1:
HBITMAP hBmp = (HBITMAP)LoadImage(NULL, m_fileName, IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE | LR_DEFAULTCOLOR | LR_DEFAULTSIZE);
Example 2:
HBITMAP hBmp = (HBITMAP)::LoadImage(AfxGetInstanceHandle(), "BG.bmp", IMAGE_BITMAP, 0,0, LR_LOADFROMFILE);
将装载后得到的HBITMAP资源句柄 与 CBitmap 对象 相连
if (hBmp != NULL) { CBitmap *pBmp = CBitmap::FromHandle(hBmp); } 或
CBitmap bmp; if (hBmp != NULL) { bmp.DeleteObject(); bmp.Attach(hBmp); } 3 显示位图
CBitmap bmp; bmp.LoadBitmap(IDB_BITMAP1); BITMAP bm; bmp.GetBitmap(&bm); CDC dc; dc.CreateCompatibleDC(pDC); CBitmap*pOldBmp=(CBitmap *)dc.SelectObject(&bmp); pDC->BitBlt(0,0,bm.bmWidth,bm.bmHeight,&dc,0,0,SRCCOPY); pDC->SelectObject(pOldBmp); bmp.DeleteObject(); bmp.LoadBitmap(IDB_BITMAP2);
4 删除资源
CBitmap bmp; bmp.LoadBitmap(IDB_BITMAP); CBitmap *pOld=pDC->SelectObject(&bmp); // 此时位图对象还在pDC中，因此不能马上删除 // 而是先将位图从DC中选出 然后再删除 pDC->SelectObject(pOld); bmp.DeleteObject();
5 CBitmap 析构
当CBitmap作为局部变量 在其退出作用范围后，会发生析构，这时候CBitmap会将其对应的位图资源（hBitmap ）释放掉。
若想继续使用该位图资源hBitmap，则在退出作用范围前，应将位图资源hBitmap和CBitmap对象通过Detach()函数进行分离
HBITMAP CMyClass::Load(){ CBitmap bmp; bmp.LoadBitmap(IDB_BITMAP); // 通过Detach 将资源与对象分离，这样bmp析构后，资源仍存在 // 否则 ，bmp析构时，会将位图资源一起析构掉，这样出了局部范围外，就不可再使用这个位图资源了 return bmp.Detach();} 6 在仅获得HBITMAP资源句柄情况下，如何获得这个资源的BITMAP信息
BITMAP bm;GetObject(hBitmap,sizeof(BITMAP),&bm);
//-------------------在内存中建立区域以存放所得位图-------------------// hBitmapSrc 为 CBitmap中保存的矩形原图资源句柄// hDC 句柄 // 在内存中开辟位图资源，用以保存原图HBITMAP CopyHBitmap(HBITMAP hBitmapSrc,HDC hDC){ BITMAP bm; HBITMAP hBitmapDst; HDC hdcSrc,hdcDst; GetObject(hBitmapSrc,sizeof(BITMAP),&bm); hBitmapDst=CreateCompatibleBitmap(hDC,bm.bmWidth,bm.bmHeight); hdcSrc=CreateCompatibleDC(hDC); hdcDst=CreateCompatibleDC(hDC); SelectObject(hdcSrc,hBitmapSrc); SelectObject(hdcDst,hBitmapDst); BitBlt(hdcDst,0,0,bm.bmWidth,bm.bmHeight,hdcSrc,0,0,SRCCOPY); DeleteDC(hdcSrc); DeleteDC(hdcDst); return hBitmapDst;}