FUNCTION:JPG2BMP SOURCE CODE:main_s.c LIBRARY USE:libjpeg RUNNING:test_s
0.api: int jpg2bmp(char *jpgname,char *bmpname)
input parameters: jpgname:name of input jpg file.eg:*jpgname="lena.jpg" bmpname:name of output bmp file.eg:*bmpname="lena.bmp"
output parameters: return Error Code(see more in No.6)
1.function:decode jpeg image(lena.jpg),translate and output lena.bmp. 2.input:lena.jpg 3.output:lena.bmp 4.function: (if not listed,see libjpeg document for more information) int analyse_jpeg() :analyse jpegfile,decompress jpegfile,write data to buffer(src_buff),using write_bmp_header(),write_bmp_data() to write bmp file int write_bmp_header(j_decompress_ptr cinfo) :write bmpfile header,using jpegfile info(cinfo),should used after decompress jpegfile int write_bmp_data(j_decompress_ptr cinfo,unsigned char *src_buff) :write bmpfile data,using jpegfile info(cinfo),write data from buffer(src_buff) to bmpfile
5.static vars: FILE *input_file; :pointer of input jpeg file FILE *output_file; :pointer of output bmp file enum ERROR_CODE{PASS,ERROR_JPGREAD,ERROR_BMPWRITE}; :error code,see No.6 for more
6.Error Code: PASS :pass ERROR_JPGREAD :cannot open jpg file or cannot read from jpg file ERROR_BMPWRITE :cannot open bmp file or cannot write into it