jpeg.cpp

《精通 vc++ 图像编程》的源代码

// Jpeg.cpp: implementation of the CJpeg class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include <stdio.h>

#include "Jpeg.h"

#ifdef __cplusplus
	extern "C" {
#endif // __cplusplus

#include "jpeglib.h"

#ifdef __cplusplus
	}
#endif // __cplusplus

//
//
//

/*
 * <setjmp.h> is used for the optional error recovery mechanism shown in
 * the second part of the example.
 */

#include <setjmp.h>

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

// error handler, to avoid those pesky exit(0)'s

struct my_error_mgr {
  struct jpeg_error_mgr pub;	/* "public" fields */

  jmp_buf setjmp_buffer;	/* for return to caller */
};

typedef struct my_error_mgr * my_error_ptr;

//
//
//

METHODDEF(void) my_error_exit (j_common_ptr cinfo);

//
//	to handle fatal errors.
//	the original JPEG code will just exit(0). can't really
//	do that in Windows....
//

METHODDEF(void) my_error_exit (j_common_ptr cinfo)
{
	/* cinfo->err really points to a my_error_mgr struct, so coerce pointer */
	my_error_ptr myerr = (my_error_ptr) cinfo->err;

	char buffer[JMSG_LENGTH_MAX];

	/* Create the message */
	(*cinfo->err->format_message) (cinfo, buffer);

	/* Always display the message. */
	MessageBox(GetActiveWindow(),buffer,"JPEG Fatal Error",MB_ICONSTOP);


	/* Return control to the setjmp point */
	longjmp(myerr->setjmp_buffer, 1);
}

// store a scanline to our data buffer
void j_putRGBScanline(BYTE *jpegline, 
						 int widthPix,
						 BYTE *outBuf,
						 int row);

void j_putGrayScanlineToRGB(BYTE *jpegline, 
						 int widthPix,
						 BYTE *outBuf,
						 int row);

//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CJpeg::CJpeg()
{
	m_strJPEGError = "No Error"; // yet
	m_pDib = NULL;
}

CJpeg::CJpeg(CDib *pDib)
{
	m_strJPEGError = "No Error"; // yet
	m_pDib = NULL;
	SetDib(pDib);
}

CJpeg::~CJpeg()
{
	if (m_pDib != NULL)
		delete m_pDib;
}

// free allocate memory
void CJpeg::FreeBuffer(BYTE *Buffer)
{
	delete[] Buffer;
}

// get error string
CString CJpeg::GetErrorString()
{
	return m_strJPEGError;
}

// load gif file
BOOL CJpeg::Load(LPCSTR lpstrFileName)
{
	UINT uWidth, uHeight, uWidthDW;

	// read the GIF to a packed buffer of RGB bytes
	BYTE *lpTmpBuffer = ReadJPEGFile(lpstrFileName, &uWidth, &uHeight);
	if (lpTmpBuffer == NULL)
		return FALSE;

	// do this before DWORD-alignment!!!
	// swap red and blue for display
	BGRFromRGB(lpTmpBuffer, uWidth, uHeight);

	// now DWORD-align for display
	BYTE *lpBuffer = MakeDwordAlign(lpTmpBuffer, uWidth, uHeight, &uWidthDW);
	FreeBuffer(lpTmpBuffer);

	// flip for display
	VertFlipBuf(lpBuffer, uWidthDW, uHeight);

	BITMAPINFOHEADER bmiHeader;
	bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
	bmiHeader.biWidth = uWidth;
	bmiHeader.biHeight = uHeight;
	bmiHeader.biPlanes = 1;
	bmiHeader.biBitCount = 24;
	bmiHeader.biCompression = BI_RGB;
	bmiHeader.biSizeImage = 0;
	bmiHeader.biXPelsPerMeter = 0;
	bmiHeader.biYPelsPerMeter = 0;
	bmiHeader.biClrUsed = 0;
	bmiHeader.biClrImportant = 0;

    // Allocate enough memory for the new CF_DIB, and copy bits 
	DWORD dwHeaderSize = sizeof(BITMAPINFOHEADER);
	DWORD dwBitsSize = WIDTHBYTES(uWidth*24) * uHeight;
    HDIB hDIB = GlobalAlloc(GHND, dwHeaderSize + dwBitsSize); 
	if (hDIB == NULL)
		return FALSE;

    LPBYTE lpDIB = (LPBYTE)GlobalLock(hDIB); 
    memcpy(lpDIB, (LPBYTE)&bmiHeader, dwHeaderSize); 
    memcpy(FindDIBBits((LPBYTE)lpDIB), lpBuffer, dwBitsSize); 
	FreeBuffer(lpBuffer);

	if (m_pDib != NULL)
		delete m_pDib;

	m_pDib = new CDib();
	m_pDib->Attach(hDIB);

	return TRUE;
}

// save Jpeg file
BOOL CJpeg::Save(LPCSTR lpstrFileName, CDib* pDib, BOOL bColor, int nQuality)
{
	if (pDib == NULL)
		pDib = m_pDib;
	if (pDib == NULL)
		return FALSE;

	HDIB hDib = CopyHandle(pDib->GetHandle());
	if (hDib == NULL)
		return FALSE;

	CDib* pDibTmp = new CDib;
	pDibTmp->Attach(hDib);

	if (pDibTmp->GetBitCount() != 24)
		pDibTmp->ConvertFormat(24);

	UINT uWidth  = pDibTmp->GetWidth();
	UINT uHeight = pDibTmp->GetHeight();

	// convert from DIB format (DWORD aligned, vertically flipped, red and blue swapped)
	BYTE* tmp = ClearDwordAlign(pDibTmp->GetBitsPtr(),
									uWidth,
									WIDTHBYTES(uWidth * 24),
									uHeight);
	if (tmp == NULL)
		return FALSE;

	// convert from DIB
	VertFlipBuf(tmp, uWidth*3, uHeight);

	BGRFromRGB(tmp, uWidth, uHeight);

	BOOL bSuccess = WriteJPEGFile(lpstrFileName,
							tmp,
							uWidth, 
							uHeight,
							bColor,
							nQuality);

	delete pDibTmp;
	FreeBuffer(tmp);

	return bSuccess;
}

//
// copies BYTE buffer into DWORD-aligned BYTE buffer
// return addr of new buffer
//
BYTE * CJpeg::MakeDwordAlign(BYTE *dataBuf,
								 UINT widthPix,				// pixels!!
								 UINT height,
								 UINT *uiOutWidthBytes)		// bytes!!!
{
	////////////////////////////////////////////////////////////
	// what's going on here? this certainly means trouble 
	if (dataBuf==NULL)
		return NULL;

	////////////////////////////////////////////////////////////
	// how big is the smallest DWORD-aligned buffer that we can use?
	UINT uiWidthBytes;
	uiWidthBytes = WIDTHBYTES(widthPix * 24);

	DWORD dwNewsize=(DWORD)((DWORD)uiWidthBytes * 
							(DWORD)height);
	BYTE *pNew;

	////////////////////////////////////////////////////////////
	// alloc and open our new buffer
	pNew=(BYTE *)new BYTE[dwNewsize];
	if (pNew==NULL) {
		return NULL;
	}
	
	////////////////////////////////////////////////////////////
	// copy row-by-row
	UINT uiInWidthBytes = widthPix * 3;
	UINT uiCount;
	for (uiCount=0;uiCount < height;uiCount++) 
	{
		BYTE * bpInAdd;
		BYTE * bpOutAdd;
		ULONG lInOff;
		ULONG lOutOff;

		lInOff=uiInWidthBytes * uiCount;
		lOutOff=uiWidthBytes * uiCount;

		bpInAdd= dataBuf + lInOff;
		bpOutAdd= pNew + lOutOff;

		memcpy(bpOutAdd,bpInAdd,uiInWidthBytes);
	}

	*uiOutWidthBytes=uiWidthBytes;
	return pNew;
}

//
//	vertically flip a buffer 
//	note, this operates on a buffer of widthBytes bytes, not pixels!!!
//
BOOL CJpeg::VertFlipBuf(BYTE* inbuf, UINT widthBytes, UINT height)
{   
	BYTE  *tb1;
	BYTE  *tb2;

	if (inbuf==NULL)
		return FALSE;

	UINT bufsize;

	bufsize=widthBytes;

	tb1= (BYTE *)new BYTE[bufsize];
	if (tb1==NULL) 
	{
		return FALSE;
	}

	tb2= (BYTE *)new BYTE [bufsize];
	if (tb1==NULL) 
	{
		return FALSE;
	}
	
	UINT row_cnt;     
	ULONG off1=0;
	ULONG off2=0;

	for (row_cnt=0;row_cnt<(height+1)/2;row_cnt++) 
	{
		off1=row_cnt*bufsize;
		off2=((height-1)-row_cnt)*bufsize;   
		
		memcpy(tb1,inbuf+off1,bufsize);
		memcpy(tb2,inbuf+off2,bufsize);	
		memcpy(inbuf+off1,tb2,bufsize);
		memcpy(inbuf+off2,tb1,bufsize);
	}	

	delete [] tb1;
	delete [] tb2;

	return TRUE;
}        

//
//	swap Rs and Bs
//
//	Note! this does its stuff on buffers with a whole number of pixels
//	per data row!!
//
BOOL CJpeg::BGRFromRGB(BYTE *buf, UINT widthPix, UINT height)
{
	if (buf==NULL)
		return FALSE;

	UINT col, row;
	for (row=0;row<height;row++) 
	{
		for (col=0;col<widthPix;col++) 
		{
			LPBYTE pRed, pGrn, pBlu;
			pRed = buf + row * widthPix * 3 + col * 3;
			pGrn = buf + row * widthPix * 3 + col * 3 + 1;
			pBlu = buf + row * widthPix * 3 + col * 3 + 2;

			// swap red and blue
			BYTE tmp;
			tmp = *pRed;
			*pRed = *pBlu;
			*pBlu = tmp;
		}
	}
	return TRUE;
}

BYTE* CJpeg::ClearDwordAlign(BYTE *inBuf,
							UINT widthPix, 
							UINT widthBytes,
							UINT height)
{
	if (inBuf==NULL)
		return FALSE;


	BYTE *tmp;
	tmp=(BYTE *)new BYTE[height * widthPix * 3];
	if (tmp==NULL)
		return NULL;

	UINT row;

	for (row=0;row<height;row++) 
	{
		memcpy((tmp+row * widthPix * 3), 
				(inBuf + row * widthBytes), 
				widthPix * 3);
	}

	return tmp;
}


//
//	read a JPEG file
//
BYTE* CJpeg::ReadJPEGFile(LPCSTR lpstrFileName, UINT *uWidth, UINT *uHeight)
{
	// basic code from IJG Jpeg Code v6 example.c

	*uWidth=0;
	*uHeight=0;

	/* This struct contains the JPEG decompression parameters and pointers to
	* working space (which is allocated as needed by the JPEG library).
	*/
	struct jpeg_decompress_struct cinfo;
	/* We use our private extension JPEG error handler.
	* Note that this struct must live as long as the main JPEG parameter
	* struct, to avoid dangling-pointer problems.