C语言实现BMP转换JPG的方法
发布时间:2020-12-16 03:30:01 所属栏目:百科 来源:网络整理
导读:本篇章节讲解C语言实现BMP转换JPG的方法。供大家参考研究。具体实现方法如下: /****************************************************************************名称: jpeg.c功能: linux下bmp转化为jpeg程序源代码日期: 2010.01.26注意: 编译时
本篇章节讲解C语言实现BMP转换JPG的方法。分享给大家供大家参考。具体实现方法如下: /**************************************************************************** 名称: jpeg.c 功能: linux下bmp转化为jpeg程序源代码 日期: 2010.01.26 注意: 编译时加“-ljpeg”(gcc -o bmp2jpg jpeg.c -ljpeg) *****************************************************************************/ #include <string.h> #include <sys/types.h> #include <sys/stat.h> #include <sys/ioctl.h> #include <sys/mman.h> #include <linux/videodev.h> #include <fcntl.h> #include <unistd.h> #include <stdio.h> #include <errno.h> #include <stdlib.h> #include <signal.h> #include <sys/timeb.h> #include <jpeglib.h> #define JPEG_QUALITY 95 //图片质量 int Bmp2Jpg(const char *bmp_file,const char *jeg_file,const int width,const int height) { FILE *fd; int ret; unsigned char *data; long sizeImage; int depth = 3; JSAMPROW * row_pointer; long rgb_index = 0; int i=0; struct jpeg_compress_struct cinfo; struct jpeg_error_mgr jerr; FILE *outfile; ; // Read bmp image data sizeImage = width*height*3; data = (unsigned char*)malloc(sizeImage); fd = fopen(bmp_file,"rb"); if(!fd) { printf("ERROR1: Can not open the image.n"); free(data); return -1; } fseek(fd,54,SEEK_SET); ret = fread(data,sizeof(unsigned char)*sizeImage,1,fd); if(ret == 0) { if(ferror(fd)) { printf("nERROR2: Can not read the pixel data.n"); free(data); fclose(fd); return -1; } } //Convert BMP to JPG cinfo.err = jpeg_std_error(&jerr); //* Now we can initialize the JPEG compression object. jpeg_create_compress(&cinfo); if ((outfile = fopen(jeg_file,"wb")) == NULL) { fprintf(stderr,"can't open %sn",jeg_file); return -1; } jpeg_stdio_dest(&cinfo,outfile); cinfo.image_width = width; //* image width and height,in pixels cinfo.image_height = height; cinfo.input_components = depth; //* # of color components per pixel cinfo.in_color_space = JCS_RGB; //* colorspace of input image jpeg_set_defaults(&cinfo); //Now you can set any non-default parameters you wish to. //Here we just illustrate the use of quality (quantization table) scaling: jpeg_set_quality(&cinfo,JPEG_QUALITY,TRUE ); //* limit to baseline-JPEG values jpeg_start_compress(&cinfo,TRUE); //一次写入 int j=0; row_pointer = malloc(height*width*3); char * line[300]; for(i=0;i<height;i++) { unsigned char * lineData = NULL; lineData = malloc(width*3); line[i]=lineData; for(j=0;j<width;j++) { lineData[j*3+2] = data[rgb_index]; rgb_index ++; lineData[j*3+1] = data[rgb_index]; rgb_index ++; lineData[j*3+0] = data[rgb_index]; rgb_index ++; } row_pointer[height-i-1] = lineData; } jpeg_write_scanlines(&cinfo,row_pointer,height); jpeg_finish_compress(&cinfo); jpeg_destroy_compress(&cinfo); for (i=0; i<height; i++) { free(line[i]); } free(row_pointer); free(data); fclose(fd); fclose(outfile); return 0; } 希望本文所述对大家的C语言程序设计有所帮助。 (编辑:李大同) 【声明】本站内容均来自网络,其相关言论仅代表作者个人观点,不代表本站立场。若无意侵犯到您的权利,请及时与联系站长删除相关内容! |