libjpeg - Independent JPEG Group

JPEG 관련 free 라이브러리를 제공하는 홈페이지이다.
검색을 해보니 jpeg decompress를 하면 bmp으로 나오도록 지원을 하는 듯 하다.

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001	/////////////////////////////////////////////////////////////////////////////

002	// Creation 30/12/2003

003

//

004

//

005	//                             JPG2BMP.C

006	//                             ---------

007

//

008

//

009	// Sylvain MARECHAL - sylvain.marechal1@libertysurf.fr

010	/////////////////////////////////////////////////////////////////////////////

011

//

012	//  Convert a jpg to a bmp file

013	//  look at jpeg-6b/djpeg.c for more details

014

//

015	/////////////////////////////////////////////////////////////////////////////

016	#include "cdjpeg.h"     /* Common decls for cjpeg/djpeg applications */

017	#include "jversion.h"       /* for version message */

018

019	#include "ctype.h"      /* to declare isprint() */

020

021	#ifdef USE_CCOMMAND     /* command-line reader for Macintosh */

022	#ifdef __MWERKS__

023	#include "sioux.h"              /* Metrowerks needs this */

024	#include "console.h"        /* ... and this */

025

#endif

026	#ifdef THINK_C

027	#include "console.h"        /* Think declares it here */

028

#endif

029

#endif

030	#include "jpg2bmp.h"        /* for version message */

031

032

033	/* Create the add-on message string table. */

034

/*

035	#define JMESSAGE(code,string)   string ,

036

037	static const char * const cdjpeg_message_table[] = {

038	#include "cderror.h"

039

NULL

040

};

041

*/

042	//#define MAIN

043	#ifdef MAIN

044	// The test program

045	int main( int argc, char * argv[] )

046

{

047	if( argc != 3 )

048

{

049	printf( "Usage : %s [file_in.jpg] [file_out.bmp]\n" );

050

return 1;

051

}

052	return Jpg2Bmp( argv[1], argv[2] );

053

}

054

#endif

055

056

057

058	int Jpg2Bmp( char * pszJpgFile, char * pszBmpFile )

059

{

060	struct jpeg_decompress_struct cinfo;

061	struct jpeg_error_mgr jerr;

062	djpeg_dest_ptr dest_mgr = NULL;

063	FILE * input_file;

064	FILE * output_file;

065	JDIMENSION num_scanlines;

066

067	/* Initialize the JPEG decompression object with default error handling. */

068	cinfo.err = jpeg_std_error(&jerr);

069	jpeg_create_decompress(&cinfo);

070	/* Add some application-specific error messages (from cderror.h) */

071	//  jerr.addon_message_table = cdjpeg_message_table;

072	jerr.first_addon_message = JMSG_FIRSTADDONCODE;

073	jerr.last_addon_message = JMSG_LASTADDONCODE;

074

075	/* Open the input file. */

076	if ((input_file = fopen(pszJpgFile, READ_BINARY)) == NULL) {

077	return -1;

078

}

079

080	/* Open the output file. */

081	if ((output_file = fopen(pszBmpFile, WRITE_BINARY)) == NULL) {

082	return -1;

083

}

084

085	/* Specify data source for decompression */

086	jpeg_stdio_src(&cinfo, input_file);

087

088	/* Read file header, set default decompression parameters */

089	(void) jpeg_read_header(&cinfo, TRUE);

090

091	/* Adjust default decompression parameters by re-parsing the options */

092	//file_index = parse_switches(&cinfo, argc, argv, 0, TRUE);

093

094	/* Initialize the output module now to let it override any crucial

095	* option settings (for instance, GIF wants to force color quantization).

096

*/

097	dest_mgr = jinit_write_bmp(&cinfo, FALSE);

098	dest_mgr->output_file = output_file;

099

100	/* Start decompressor */

101	(void) jpeg_start_decompress(&cinfo);

102

103	/* Write output file header */

104	(*dest_mgr->start_output) (&cinfo, dest_mgr);

105

106	/* Process data */

107	while (cinfo.output_scanline < cinfo.output_height) {

108	num_scanlines = jpeg_read_scanlines(&cinfo, dest_mgr->buffer,

109	dest_mgr->buffer_height);

110	(*dest_mgr->put_pixel_rows) (&cinfo, dest_mgr, num_scanlines);

111

}

112

113	/* Finish decompression and release memory.

114	* I must do it in this order because output module has allocated memory

115	* of lifespan JPOOL_IMAGE; it needs to finish before releasing memory.

116

*/

117	(*dest_mgr->finish_output) (&cinfo, dest_mgr);

118	(void) jpeg_finish_decompress(&cinfo);

119	jpeg_destroy_decompress(&cinfo);

120

121	/* Close files, if we opened them */

122	fclose(input_file);

123	fclose(output_file);

124

125	/* All done. */

126	return jerr.num_warnings ? -1 : 0;

127

}

[예제 : ce.sharif.edu/~haghshenas/files/c/jpg2bmp.c]

[공식 : http://www.ijg.org/]