一、交叉编译libjepg编译

tar xzf libjpeg-turbo-1.2.1.tar.gz

./configure –help

./configure --prefix=/work/project/first_project/13libjepg/libjpeg-turbo-1.2.1/tmp/  --host=arm-linux

make

make install

二、交叉编译jepg2rgb.c

arm-linux-gcc -o jpg2rgb jpg2rgb.c  -I /work/project/first_project/13libjepg/libjpeg-turbo-1.2.1/tmp/include/ -L /work/project/first_project/13libjepg/libjpeg-turbo-1.2.1/tmp/lib/ –ljpeg

把库考到开发板上

cp ../libjpeg-turbo-1.2.1/tmp/lib/*so* /work/nfs_root/fs_mini_mdev/lib/

 

编译出来的头文件应该放入：
cd /work/project/first_project/13libjepg/libjpeg-turbo-1.2.1/tmp/include

cp *  /work/tools/gcc-3.4.5-glibc-2.3.6/arm-linux/include  -rf

 

编译出来的库文件应该放入：
cd /work/project/first_project/13libjepg/libjpeg-turbo-1.2.1/tmp/lib

sudo cp * /work/tools/gcc-3.4.5-glibc-2.3.6/arm-linux/lib -d –rf

 

现在不需要指定目录

arm-linux-gcc -o jpg2rgb jpg2rgb.c –ljpeg

 

1th输出源文件信息，及解压后信息

#include <stdio.h>
#include "jpeglib.h"
#include <setjmp.h>


/*
Allocate and initialize a JPEG decompression object    // 分配和初始化一个decompression结构体
Specify the source of the compressed data (eg, a file) // 指定源文件
Call jpeg_read_header() to obtain image info           // 用jpeg_read_header获得jpg信息
Set parameters for decompression                       // 设置解压参数,比如放大、缩小
jpeg_start_decompress(...);                            // 启动解压：jpeg_start_decompress
while (scan lines remain to be read)
    jpeg_read_scanlines(...);                           // 循环调用jpeg_read_scanlines
jpeg_finish_decompress(...);                           // jpeg_finish_decompress
Release the JPEG decompression object                   // 释放decompression结构体
*/

/* Uage: jpg2rgb <jpg_file>
 */

int main(int argc, char **argv)
{
    struct jpeg_decompress_struct cinfo;
    struct jpeg_error_mgr jerr;
    FILE * infile;

     // 分配和初始化一个decompression结构体
    cinfo.err = jpeg_std_error(&jerr);
    jpeg_create_decompress(&cinfo);

     // 指定源文件
    if ((infile = fopen(argv[1], "rb")) == NULL) {
        fprintf(stderr, "can't open %s\n", argv[1]);
        return -1;
    }
    jpeg_stdio_src(&cinfo, infile);

     // 用jpeg_read_header获得jpg信息
    jpeg_read_header(&cinfo, TRUE);
    /* 源信息 */
    printf("image_width    = %d\n", cinfo.image_width);
    printf("image_height   = %d\n", cinfo.image_height);
    printf("num_components = %d\n", cinfo.num_components);


      // 设置解压参数,比如放大、缩小

    // 启动解压：jpeg_start_decompress
    jpeg_start_decompress(&cinfo);

    /* 输出的图像信息 */
    printf("output_width   = %d\n", cinfo.output_width);
    printf("output_height  = %d\n", cinfo.output_height);
    printf("output_components = %d\n", cinfo.output_components);
      
     // 循环调用jpeg_read_scanlines一行一行的获得解压数据

    jpeg_finish_decompress(&cinfo);

    jpeg_destroy_decompress(&cinfo);
      
     return 0;
}

 

使用LCD输出

#include <stdio.h>
#include "jpeglib.h"
#include <setjmp.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <linux/fb.h>
#include <string.h>

#define FB_DEVICE_NAME "/dev/fb0"
#define DBG_PRINTF     printf




static int g_fd;

static struct fb_var_screeninfo g_tFBVar;
static struct fb_fix_screeninf