BMP 24 32 显示 翻转

原文地址：http://blog.youkuaiyun.com/hxmcnu/article/details/12359731

 参数定义

private:
	BYTE * BmpBuffer;//24BMP位图数据
	long bmpWidth ;
	long bmpHeight;
	BYTE *p32BitBuf;//32位BMP数据
	int totalSize;//数据大小
	int bytes_per_line;//每行的字节数
	int m_nAlpha1;//32位BMP中alpha值，用于调节通明度
public:
	bool Open24BMP();
	bool Show24BMP();
	bool Show32BMP();
	bool Conver24To32(int m_nAlpha1);
	int Set32BitBmpAlpha(int nAlpha);

相关功能实现：

//读取一张24bit的BMP保存到个BYTE buffer里面：
bool CConverBMPDlg::Open24BMP()
{
	// 
	BYTE *pBmpBuf;
	CFileDialog GetFile(TRUE,NULL,NULL,OFN_FILEMUSTEXIST,_T("BMP(*.bmp)|*.bmp|All Files(*.*)|*.*"));
	if(IDOK == GetFile.DoModal())
	{
		CString strFilePath = GetFile.GetPathName();
		FILE *fp=NULL; 
		int ret = fopen_s(&fp,strFilePath,"rb"); 
		if(fp==0)    
		{ 
			return false; 
		} 
		BITMAPFILEHEADER fileheader={0}; 
		fread(&fileheader,sizeof(fileheader),1,fp); 
		if(fileheader.bfType!=0x4D42) 
		{ 
			fclose(fp); 
			return false ; 
		} 
		BITMAPINFOHEADER head; 
		fread(&head,sizeof(BITMAPINFOHEADER),1,fp);  
		bmpWidth = head.biWidth; 
		bmpHeight = head.biHeight; 
		WORD biBitCount = head.biBitCount; 
		if(biBitCount != 24) 
		{ 
			::AfxMessageBox(_T("choose a 24 bit bmp")); 
			fclose(fp); 
			return false ; 
		} 
		bytes_per_line = (bmpWidth * biBitCount/8+3)/4*4;
		totalSize = bytes_per_line*bmpHeight; 
		pBmpBuf = new BYTE[totalSize]; // 24 bit buf
		size_t size = 0; 
		while(true) 
		{ 
			int iret = fread(&pBmpBuf[size],1,1,fp); 
			if(iret == 0) 
				break; 
			size = size + iret; 
		} 
		fclose(fp); 
	}

 
	/
	//上面读出来的是翻转的，下面正过来：
	//flip
	BYTE *buffer; 
	int index;
	BmpBuffer = new BYTE[totalSize];//24位BMP Buffer
	buffer = new BYTE[totalSize];//temp buf to flip 24bit bmp map
	memcpy(buffer,pBmpBuf,totalSize);
	for (index=0; index < bmpHeight; index++)
		memcpy(&BmpBuffer[((bmpHeight-1) - index)*bytes_per_line],
		&buffer[index*bytes_per_line], bytes_per_line);
	delete[] buffer;
	buffer = NULL;
	return true;
}
bool CConverBMPDlg::Show24BMP()
{
	//显示一下:
	show 24bit
	int i,j; 
	CClientDC dc(this); 
	int pitch = bmpWidth % 4; 
	for(i=0;i<bmpHeight;i++) 
	{ 
	 int realPitch = i * pitch; 
	 for(j=0;j<bmpWidth;j++) 
	 { 
	  dc.SetPixel(j,i,RGB( 
	   BmpBuffer[(i*bmpWidth+j)*3+2+realPitch], 
	   BmpBuffer[(i*bmpWidth+j)*3+1+realPitch], 
	   BmpBuffer[(i*bmpWidth+j)*3+realPitch])); 
	 } 
	} 
	return true;
}
bool CConverBMPDlg::Conver24To32(int m_nAlpha1)
{
	 
	//将24bit转成32bit，添加Alpha通道：

	//convert to 32bit
	int _32bitBytes_per_line = (bmpWidth * 32 / 8 + 4)/4*4;
	p32BitBuf = new BYTE[_32bitBytes_per_line * bmpHeight];//32 bit buf
	int nAlpha = m_nAlpha1;//60%:153
	BYTE *pSrc = BmpBuffer;
	BYTE *pDst = p32BitBuf;
	int pitch = bmpWidth % 4; 
	for(int i=0;i<bmpHeight;i++) 
	{ 
		int realPitch = i * pitch; 
		for(int j=0;j<bmpWidth;j++) 
		{  
			pDst[(i*bmpWidth+j)*4+3+realPitch] = pSrc[(i*bmpWidth+j)*3+2+realPitch];
			pDst[(i*bmpWidth+j)*4+2+realPitch] = pSrc[(i*bmpWidth+j)*3+1+realPitch]; 
			pDst[(i*bmpWidth+j)*4+1+realPitch] = pSrc[(i*bmpWidth+j)*3+realPitch]; 
			pDst[(i*bmpWidth+j)*4+realPitch] = nAlpha;
		} 
	} 
	return true;
}
bool CConverBMPDlg::Show32BMP()
{
	//显示32bit的BMP

	Invalidate(TRUE);
	UpdateWindow();
	int i,j; 
	CClientDC dc(this);  
	int pitch =bmpWidth % 4;
	for(i=0;i<bmpHeight;i++) 
	{ 
		int realPitch = i * pitch; 
		for(j=0;j<bmpWidth;j++) 
		{ 
			int a = p32BitBuf[(i*bmpWidth+j)*4+realPitch];
			dc.SetPixel(j,i,RGB( 
				p32BitBuf[(i*bmpWidth+j)*4+3+realPitch]*(a / 255.0) +  255*(255-a)/255.0, 
				p32BitBuf[(i*bmpWidth+j)*4+2+realPitch]*(a / 255.0) +  255*(255-a)/255.0, 
				p32BitBuf[(i*bmpWidth+j)*4+1+realPitch]*(a / 255.0) +  255*(255-a)/255.0)); 
		} 
	} 
	return true;
	  
}
//设置32bit的bmp的alpha通道：
int CConverBMPDlg::Set32BitBmpAlpha(int nAlpha)
{
	int i,j;
	int pitch = bmpWidth % 4;
	for(i=0;i<bmpHeight;i++) 
	{ 
		int realPitch = i * pitch; 
		for(j=0;j<bmpWidth;j++) 0
		{ 
			p32BitBuf[(i*bmpWidth+j)*4+realPitch] = nAlpha;
		}
	}
	return 0;
} 

void RGB32Rotate180(BYTE *des,BYTE *src,int width,int height) 
{ 

    if ((!des)||(!src)) 
    { 
        return; 
    } 
       
    int n = 0; 
    int linesize = width*4;
		for (int index=0; index < height; index++)
			memcpy(&des[((height-1) - index)*linesize],&src[index*linesize], linesize);
}