把从framebuffer抓出来的数据转换成jpg图像
把从framebuffer抓出来的数据转换成为jpg图象
2008-07-10 14:15
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//gcc -o grab grab.c -ljpeg
//The source code of grab.c //cat /dev/fb/0 >tmp //./grab -i tmp -o grab.jpg #include <setjmp.h> #include <stdio.h> #include <getopt.h> #include <jpeglib.h> #define W 800 #define H 480 /*The name of this program.*/ const char *program_name; /* Prints usage information for this program to STREAM,and exit the program with EXIT_CODE. */ void print_usage(FILE* stream,int exit_code) { fprintf(stream,"Usage: %s options [inputfile outputfile...]\n",program_name); fprintf(stream, " -h --help Display this usage information\n" " -i --input filename Read from file\n" " -o --output filename Write output to file\n" ); exit(exit_code); } void convert_line( char *src, char *dst, int line,int weight,int height ); int main(int argc,char **argv) { int next_option; unsigned int image_height = 0; unsigned int image_width = 0; const char* const short_opti; const struct option long_options[] = { {"help", 0, NULL, 'h'}, {"input",1, NULL, 'i'}, {"output",1, NULL, 'o'}, {NULL, 0, NULL,0 } }; const char *output_filename = NULL; char *input_filename = NULL; program_name = argv[0]; do{ next_option = getopt_long(argc,argv,short_options,long_options,NULL); switch(next_option) { case 'h': print_usage(stdout,0); case 'o': output_filename = optarg; break; case 'i': input_filename = optarg; break; case '?': print_usage(stdout,1); case -1: break; default: abort(); } } while(next_option != -1); if(!output_filename){ output_filename = "grab.jpg"; } if(!input_filename) { input_filename = "tmp"; } printf("outputfile = %s,inputfile = %s\n",output_filename,input_filename); struct jpeg_compress_struct cinfo; struct jpeg_error_mgr jerr; JSAMPLE *buffer; JSAMPLE *image_buffer; buffer = malloc(W*H*3); image_buffer = malloc(W*3); FILE *in; int ret = 0; in = fopen(input_filename,"r"); if(!in){ printf("please provide the rgb source\n"); exit(0); } ret = fread(buffer, 1,W*H*2, in ); if( ret == 0 ){ printf("read image buffer error\n"); exit(0); } int height = H; int width = W; FILE *outfile; JSAMPROW row_pointer[1];//points to JSAMPLE row[s] //setp 1:allocate and initialize JPEG compression object cinfo.err = jpeg_std_error(&jerr); jpeg_create_compress(&cinfo); //step 2:specify data destination //char *filename="grab1.jpg"; if((outfile = fopen(output_filename,"wb")) == NULL){ printf("cannot open file to write\n"); exit(0); } jpeg_stdio_dest( &cinfo, outfile ); //step 3:set parameters for compression cinfo.image_width = width; cinfo.image_height = height; cinfo.input_components = 3; cinfo.in_color_space = JCS_RGB; jpeg_set_defaults(&cinfo); jpeg_set_quality(&cinfo, 100, TRUE ); //step 4:start compresor jpeg_start_compress(&cinfo, TRUE); //step 5: while(cinfo.next_scanline < cinfo.image_height ){ convert_line( buffer,image_buffer,cinfo.next_scanline,height,width); //printf("%d======end",cinfo.next_scanline); row_pointer[0] = image_buffer; (void)jpeg_write_scanlines( &cinfo, row_pointer, 1); } jpeg_finish_compress(&cinfo); fclose( outfile ); jpeg_destroy_compress(&cinfo); free(buffer); free(image_buffer); } void convert_line(char* src,char* dst,int line,int width,int height){ int NUM1 = W*2; int NUM2 = W*3; char *p = src + line*NUM1; int i = 0; while( i < NUM2 ){ dst[i] = (p[1]&0xf8 ); dst[i+1] = ((p[1]&0x7)<<5) | ((p[0] & 0xe0)>>3); dst[i+2] = (p[0]&0x1f)<<3; i += 3; p += 2; } } |