在自己编写类时有两点值得注意：

附源文件

//

//

#ifndef _CBITMAPFILE_H_

#define _CBITMAPFILE_H_

class CBitmapFile : public CGdiObject

{

DECLARE_DYNAMIC(CBitmapFile)

public:

static CBitmapFile* PASCAL FromHandle(HBITMAP hBitmap);

// Constructors

CBitmapFile();

BOOL LoadBitmap(LPCTSTR lpszFileName);

BOOL CreateBitmap(int nWidth, int nHeight, UINT nBitCount, const void* lpBits);

BOOL CreateBitmapIndirect(LPBITMAPINFO lpBitmapInfo, const void* lpBits);

// Attributes

operator HBITMAP() const;

int GetBitmap(BITMAP* pBitMap);

protected:

// Attributes

int GetColorNumber(WORD wBitCount);

public:

// Operations

DWORD SetBitmapBits(DWORD dwCount, const void* lpBits);

DWORD GetBitmapBits(DWORD dwCount, LPVOID lpBits);

// Implementation

public:

virtual ~CBitmapFile();

};

#endif

//

//

#include "BitmapFile.h"

#include <memory.h>

IMPLEMENT_DYNAMIC(CBitmapFile,CGdiObject);

CBitmapFile* PASCAL CBitmapFile::FromHandle(HBITMAP hBitmap)

{

return (CBitmapFile*) CGdiObject::FromHandle(hBitmap);

}

CBitmapFile::CBitmapFile()

{

}

BOOL CBitmapFile::LoadBitmap(LPCTSTR lpszFileName)

{

CFile file;

if(!file.Open(lpszFileName,CFile::modeRead|CFile::shareDenyWrite))

{

MessageBox(NULL,"BMP file open error!","warning",MB_OK);

return FALSE;

}

BITMAPFILEHEADER bfhHeader;

file.Read(&bfhHeader,sizeof(BITMAPFILEHEADER));

if(bfhHeader.bfType!=((WORD) ('M'<<8)|'B'))

{

MessageBox(NULL,"The file is not a BMP file!","warning",MB_OK);

return FALSE;

}

if(bfhHeader.bfSize!=file.GetLength())

{

MessageBox(NULL,"The BMP file header error!","warning",MB_OK);

return FALSE;

}

UINT uBmpInfoLen=(UINT) bfhHeader.bfOffBits-sizeof(BITMAPFILEHEADER);

LPBITMAPINFO lpBitmap=(LPBITMAPINFO) new BYTE[uBmpInfoLen];

file.Read((LPVOID) lpBitmap,uBmpInfoLen);

if((* (LPDWORD)(lpBitmap))!=sizeof(BITMAPINFOHEADER))

{

MessageBox(NULL,"The BMP is not Windows 3.0 format!","warning",MB_OK);

return FALSE;

}

DWORD dwBitlen=bfhHeader.bfSize - bfhHeader.bfOffBits;

LPVOID lpBits=new BYTE[dwBitlen];

file.ReadHuge(lpBits,dwBitlen);

file.Close();

BOOL bSuccess=CreateBitmapIndirect(lpBitmap, lpBits);

delete lpBitmap;

delete lpBits;

if(!bSuccess)

return FALSE;

return TRUE;

}

BOOL CBitmapFile::CreateBitmap(int nWidth, int nHeight, UINT nBitCount,

const void* lpSrcBits)

{

ASSERT(nBitCount==1||nBitCount==4||nBitCount==8

||nBitCount==16||nBitCount==24||nBitCount==32);

LPBITMAPINFO lpBitmap;

lpBitmap=(BITMAPINFO*) new BYTE[sizeof(BITMAPINFOHEADER) +

GetColorNumber(nBitCount) * sizeof(RGBQUAD)];

lpBitmap->bmiHeader.biSize=sizeof(BITMAPINFOHEADER);

lpBitmap->bmiHeader.biWidth=nWidth;

lpBitmap->bmiHeader.biHeight=nHeight;

lpBitmap->bmiHeader.biBitCount=nBitCount;

lpBitmap->bmiHeader.biPlanes=1;

lpBitmap->bmiHeader.biCompression=BI_RGB;

lpBitmap->bmiHeader.biSizeImage=0;

lpBitmap->bmiHeader.biClrUsed=0;

BOOL bSuccess=CreateBitmapIndirect(lpBitmap, lpSrcBits);

delete lpBitmap;

if(!bSuccess)

return FALSE;

return TRUE;

}

BOOL CBitmapFile::CreateBitmapIndirect(LPBITMAPINFO lpBitmapInfo, const void* lpSrcBits)

{

DeleteObject();

LPVOID lpBits;

CDC *dc=new CDC;

dc->CreateCompatibleDC(NULL);

HBITMAP hBitmap=::CreateDIBSection(dc->m_hDC,lpBitmapInfo,DIB_RGB_COLORS,

&lpBits,NULL,0);

ASSERT(hBitmap!=NULL);

delete dc;

Attach(hBitmap);

BITMAP bmp;

GetBitmap(&bmp);

DWORD dwCount=(DWORD) bmp.bmWidthBytes * bmp.bmHeight;

if(SetBitmapBits(dwCount,lpSrcBits)!=dwCount)

{

MessageBox(NULL,"DIB build error!","warning",MB_OK);

return FALSE;

}

return TRUE;

}

CBitmapFile::operator HBITMAP() const

{

return (HBITMAP)(this == NULL ? NULL : m_hObject);

}

int CBitmapFile::GetBitmap(BITMAP* pBitMap)

{

ASSERT(m_hObject != NULL);

return ::GetObject(m_hObject, sizeof(BITMAP), pBitMap);

}

int CBitmapFile::GetColorNumber(WORD wBitCount)

{

ASSERT(wBitCount==1||wBitCount==4||wBitCount==8

||wBitCount==16||wBitCount==24||wBitCount==32);

switch(wBitCount)

{

case 1:

return 2;

case 4:

return 16;

case 8:

return 256;

default:

return 0;

}

}

DWORD CBitmapFile::SetBitmapBits(DWORD dwCount, const void* lpBits)

{

if(lpBits!=NULL)

{

}

return 0;

}

DWORD CBitmapFile::GetBitmapBits(DWORD dwCount, LPVOID lpBits)

{

if(lpBits!=NULL)

{

BITMAP bmp;

GetBitmap(&bmp);

memcpy(lpBits,bmp.bmBits,dwCount);

return dwCount;

}

else

return 0;

}

CBitmapFile::~CBitmapFile()

{

CGdiObject::DeleteObject();

}