利用MFC简单的显示一个bmp图像

利用MFC简单的显示一个bmp图像,如有错误，欢迎指正

首先建立一个MFC AOOwizard（exe）单文档

然后插入一个基类，命名CDib

然后编辑Dib.cpp如下

// Dib.cpp: implementation of the CDib class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "test.h"
#include "Dib.h"

#ifdef _DEBUG
#undef THIS_FILE
static char THIS_FILE[]=__FILE__;
#define new DEBUG_NEW
#endif

//////////////////////////////////////////////////////////////////////
// Construction/Destruction：构造函数和析构函数
//////////////////////////////////////////////////////////////////////

CDib::CDib()
{
//成员初始化
m_pDibData = NULL;
m_pDibBits = NULL;
m_pGrayScale = NULL;
m_npoint.x=0;
m_npoint.y=0;

}

CDib::CDib( CDib& Dib)
{
CDib *pDib = &Dib;
if (pDib == NULL)
{
return;
}
this->m_nDibSize = pDib->m_nDibSize;
this->m_pDibData = new unsigned char[pDib->m_nDibSize];
memset(this->m_pDibData,0,this->m_nDibSize);
memcpy(this->m_pDibData,pDib->m_pDibData,m_nDibSize);
m_pBitmapInfoHeader = (BITMAPINFOHEADER*)this->m_pDibData;
m_nWidth = m_pBitmapInfoHeader->biWidth;
m_nHeight = m_pBitmapInfoHeader->biHeight;
this->m_npoint.x = 0;
this->m_npoint.y = 0;
if (m_pBitmapInfoHeader->biBitCount > 8)
{
m_nPaletteEntries = 0;
} else
{
m_nPaletteEntries = 1 << m_pBitmapInfoHeader->biBitCount;
}
if (m_nPaletteEntries != 0)
{
m_pPaletteEntry = (PALETTEENTRY*)(m_pDibData+sizeof(BITMAPINFOHEADER));
}else
{
m_pPaletteEntry = NULL;
}
m_pDibBits = m_pDibData + sizeof(BITMAPINFOHEADER) + m_nPaletteEntries * sizeof(RGBQUAD);
m_nWidthBytes = WIDTHBYTES(m_nWidth*m_pBitmapInfoHeader->biBitCount);

m_pGrayScale = NULL;
}

CDib::~CDib()//析构函数，用于释放内存空间
{
if (m_pDibData != NULL)
{
delete []m_pDibData;
m_pDibData = NULL;
m_pDibBits = NULL;
}
if (m_pGrayScale != NULL)
{
delete []m_pGrayScale;
m_pGrayScale = NULL;
}

}

void CDib::LoadFile( const char* pFiLeName)
{
if (m_pDibData != NULL)
{
delete []m_pDibData;
m_pDibData = NULL;
m_pBitmapInfoHeader = NULL;
m_pDibBits = NULL;
m_pPaletteEntry = NULL;
}
if (m_pGrayScale != NULL)
{
delete []m_pGrayScale;
m_pGrayScale = NULL;
}

CFile file; //CFile 时MFC文件类的基类，具体用法可以参考MSDN
if(!file.Open(pFiLeName,CFile::modeRead|CFile::shareDenyRead,NULL))
{ //已读模式打开位图文件
AfxMessageBox("File can't to be opened!",MB_OK);
return;
}
BITMAPFILEHEADER BFH;
file.Read(&BFH,sizeof(BITMAPFILEHEADER));
if (BFH.bfType !='MB')//判断此文件是否是位图，Ox4d42代表BMP
{
AfxMessageBox("not a bitmap file!",MB_OK);
return;
}
m_nDibSize = file.GetLength() - sizeof(BITMAPFILEHEADER);//计算除位图文件头的空间大小
m_pDibData = new unsigned char[m_nDibSize]; //分配空间，并初始化为0
memset(m_pDibData,0,m_nDibSize);//初始化内存，防止读出字符末尾出现乱码
file.Read(m_pDibData,m_nDibSize); //读取除位图头文件的所有数据，需要了解Cfile的用法
m_pBitmapInfoHeader = (BITMAPINFOHEADER*)m_pDibData;//设置位图指针信息
m_nWidth = m_pBitmapInfoHeader->biWidth;
m_nHeight = m_pBitmapInfoHeader->biHeight;
m_nWidthBytes = WIDTHBYTES(m_nWidth*m_pBitmapInfoHeader->biBitCount);
if (m_pBitmapInfoHeader->biBitCount > 8)
{
m_nPaletteEntries = 0;
m_pPaletteEntry = NULL;
} else
{
m_nPaletteEntries = 1 << m_pBitmapInfoHeader->biBitCount;
m_pPaletteEntry = (PALETTEENTRY*)(m_pDibData+sizeof(BITMAPINFOHEADER));
}
m_pDibBits = m_pDibData + sizeof(BITMAPINFOHEADER) + m_nPaletteEntries * sizeof(RGBQUAD);
}

void CDib::Draw(CDC *pDC)//CDC *PDC表示设备环境指针
{
if (m_pDibData != NULL)
{
::StretchDIBits(pDC->m_hDC,0,0,m_nWidth,m_nHeight,0,0,m_nWidth,m_nHeight,m_pDibBits,(BITMAPINFO*)m_pDibData,DIB_RGB_COLORS,SRCCOPY);
}

}

void CDib::Draw( CDC *pDC, CRect rect)
{
if (m_pDibData != NULL)
{
CPoint point;
point.x = rect.CenterPoint().x-m_nWidth/2;
point.y = rect.CenterPoint().y-m_nHeight/2;
::StretchDIBits(pDC->m_hDC,point.x,point.y,m_nWidth,m_nHeight,0,0,m_nWidth,m_nHeight,m_pDibBits,(BITMAPINFO*)m_pDibData,DIB_RGB_COLORS,SRCCOPY);
}

}

void CDib::Draw( CDC *pDC, CPoint point)
{
if (m_pDibData != NULL)
{
::StretchDIBits(pDC->m_hDC,point.x,point.y,m_nWidth,m_nHeight,0,0,m_nWidth,m_nHeight,m_pDibBits,(BITMAPINFO*)m_pDibData,DIB_RGB_COLORS,SRCCOPY);
}

}

void CDib::SaveFile(const char* pFileName)
{
if (m_pDibData == NULL)
{
AfxMessageBox("No Opened file!",MB_OK);
return;
}
CFile file;
if (!file.Open(pFileName,CFile::modeCreate|CFile::modeWrite,NULL))
{
AfxMessageBox("Can't be created!",MB_OK);
return;
}
BITMAPFILEHEADER BFH;
BFH.bfOffBits = sizeof(BITMAPFILEHEADER)+sizeof(BITMAPINFOHEADER)+m_nPaletteEntries*sizeof(RGBQUAD);
BFH.bfSize = sizeof(BITMAPFILEHEADER)+m_nDibSize;
BFH.bfType = 'MB';
file.WriteHuge(&BFH,sizeof(BITMAPFILEHEADER));
file.WriteHuge(m_pDibData,m_nDibSize);
file.Close();

}然后编辑Dib.h头文件如下
// Dib.h: interface for the CDib class.
// 内容：设备无关位图类-头文件
// 功能：
// 位图的加载与保存
// 位图信息的获取
// 位图的显示
// 位图的转换
// 位图的相关判断
//////////////////////////////////////////////////////////////////////

#if !defined(AFX_DIB_H__59295F39_2E7D_4532_B8B8_FC19EF32EFF6__INCLUDED_)
#define AFX_DIB_H__59295F39_2E7D_4532_B8B8_FC19EF32EFF6__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
#define WIDTHBYTES(i)((i+31)/32*4)

class CDib
{
public:
CDib(); //构造函数，初始化数据成员
CDib(CDib&);
virtual ~CDib(); // 析构函数，用于在撤销对象前，完成一些清理工作，如：释放内存空间等

public:
void LoadFile(const char* ); //从文件加载位图
//只有一个const，如果const位于*左侧，表示指针所指数据是常量，不能通过解引用修改该数据；指针本身是变量，可以指向其他的内存单元
//只有一个const，如果const位于*右侧，表示指针本身是常量，不能指向其他内存地址；指针所指的数据可以通过解引用修改。
//两个const，*左右各一个，表示指针和指针所指数据都不能修改。
void Draw(CDC*);
void Draw(CDC*, CRect);
void Draw(CDC*, CPoint); //显示位图
void SaveFile(const char* ); //将位图保存到文件

public:
unsigned char* m_pDibData;
unsigned char* m_pDibBits;
long m_nDibSize;
long m_nWidth,m_nHeight;
BITMAPINFOHEADER* m_pBitmapInfoHeader;
PALETTEENTRY* m_pPaletteEntry;
long m_nPaletteEntries;
long m_nWidthBytes;
CPoint m_npoint;
long *m_pGrayScale;

};

#endif // !defined(AFX_DIB_H__59295F39_2E7D_4532_B8B8_FC19EF32EFF6__INCLUDED_)未完 待续