公司项目需要在jpeg图片里面添加exif信息，同事完成了这部分代码；但是有些手机兼容性有问题；

libexif 地址：http://libexif.sourceforge.net/

注意相关资料来之：

http://blog.csdn.net/fioletfly/article/details/53605959

注意使用的工具为：PowerExif.exe，因为项目太多了，需要对比添加～有工具可以比较好的参考.

手机兼容有问题，注意是因为一些项目没按照exif标准来添加；按标准来添加，添加后用PowerExif.exe解析，如果每项都正常了，基本手机解析不会有问题;

 

代码如下：

1.前面代码来至src sample下面的；

2.添加了一些必要的exif信息；

3.添加到结果如最后.

static const unsigned char exif_header[] = {  0xff, 0xd8, 0xff, 0xe1,};/* length of data in exif_header */static const unsigned int exif_header_len = sizeof(exif_header);/* length of data in image_jpg */static const unsigned int image_jpg_len ;//= sizeof(image_jpg);/* start of JPEG image data section */static const unsigned int image_data_offset = 20;#define image_data_len (image_jpg_len - image_data_offset)const char *pucMaker = "xx公司";const char *pucModel = "拍照设备";/* Create a brand-new tag with a data field of the given length, in the * given IFD. This is needed when exif_entry_initialize() isn't able to create * this type of tag itself, or the default data length it creates isn't the * correct length. */static ExifEntry *create_tag(ExifData *exif, ExifIfd ifd, ExifTag tag, size_t len){    void *buf;    ExifEntry *entry;        /* Create a memory allocator to manage this ExifEntry */    ExifMem *mem = exif_mem_new_default();    assert(mem != NULL); /* catch an out of memory condition */    /* Create a new ExifEntry using our allocator */    entry = exif_entry_new_mem (mem);    assert(entry != NULL);    /* Allocate memory to use for holding the tag data */    buf = exif_mem_alloc(mem, len);    assert(buf != NULL);    /* Fill in the entry */    entry->data = buf;    entry->size = len;    entry->tag = tag;    entry->components = len;    entry->format = EXIF_FORMAT_UNDEFINED;    /* Attach the ExifEntry to an IFD */    exif_content_add_entry (exif->ifd[ifd], entry);    /* The ExifMem and ExifEntry are now owned elsewhere */    exif_mem_unref(mem);    exif_entry_unref(entry);    return entry;}//需要参考PowerExif.exe软件打开图片//添加对应的只需要对应的代码ID,exifname、数据类型、和数据长度;int cdr_write_exif_to_jpg(char *pSrcFileName, GPS_INFO sGpsInfo){        int rc = 1;    char GPSversionid[5]={
   0x02,0x02,0x00,0x00,0x00};    FILE *f = NULL;        unsigned char *exif_data;    unsigned int exif_data_len;    FILE *f2 = fopen(pSrcFileName, "r");    if (!f2) {        fprintf(stderr, "Error creating file \n");        return -1;    }    fseek (f2, 0, SEEK_END);   ///将文件指针移动文件结尾    int iFileSize = ftell (f2); ///求出当前文件指针距离文件开始的字节数    fseek (f2, 0, SEEK_SET);         char *buf = calloc(iFileSize,sizeof(char));    if(buf == NULL){       printf("calloc fails!\n");       fclose(f2);       return -1;    }    int i = 0;    int pos = 0;    char temp = 0;    for(i=0; i
     
      format = EXIF_FORMAT_BYTE;    entry->components = 4;    exif_set_sshort(entry->data,   FILE_BYTE_ORDER, GPSversionid[0]);    exif_set_sshort(entry->data+1, FILE_BYTE_ORDER, GPSversionid[1]);    exif_set_sshort(entry->data+2, FILE_BYTE_ORDER, GPSversionid[2]);    exif_set_sshort(entry->data+3, FILE_BYTE_ORDER, GPSversionid[3]);    entry = create_tag(exif, EXIF_IFD_GPS, EXIF_TAG_GPS_LATITUDE_REF,2);    entry->format = EXIF_FORMAT_ASCII;    memcpy(entry->data, "N", 2);    ExifRational a;    ExifRational b;    ExifRational c;    a.numerator = sGpsInfo.latitude_Degree;//纬度    a.denominator = 1;    b.numerator = sGpsInfo.latitude_Cent;    b.denominator = 1;    c.numerator = sGpsInfo.latitude_Second;    c.denominator = 1;    entry = create_tag(exif, EXIF_IFD_GPS, EXIF_TAG_GPS_LATITUDE,24);    entry->format = EXIF_FORMAT_RATIONAL;    entry->components = 3;    exif_set_rational(entry->data,FILE_BYTE_ORDER,a);    exif_set_rational(entry->data+8,FILE_BYTE_ORDER,b);    exif_set_rational(entry->data+16,FILE_BYTE_ORDER,c);    entry = create_tag(exif, EXIF_IFD_GPS, EXIF_TAG_GPS_LONGITUDE_REF,2);    entry->format = EXIF_FORMAT_ASCII;    entry->components = 2;    memcpy(entry->data, "E", 2);    a.numerator = sGpsInfo.longitude_Degree;    a.denominator = 1;    b.numerator = sGpsInfo.longitude_Cent;    b.denominator = 1;    c.numerator = sGpsInfo.longitude_Second;    c.denominator = 1;    entry = create_tag(exif, EXIF_IFD_GPS, EXIF_TAG_GPS_LONGITUDE,24);    entry->format = EXIF_FORMAT_RATIONAL;    entry->components = 3;    exif_set_rational(entry->data,FILE_BYTE_ORDER,a);    exif_set_rational(entry->data+8,FILE_BYTE_ORDER,b);    exif_set_rational(entry->data+16,FILE_BYTE_ORDER,c);            //GPS速度单位K KM/H    entry = create_tag(exif, EXIF_IFD_GPS, EXIF_TAG_GPS_SPEED_REF,2);    entry->format = EXIF_FORMAT_ASCII;    //entry->components = 1;    memcpy(entry->data, "K", 2);        //GPS速度值.    entry = create_tag(exif, EXIF_IFD_GPS, EXIF_TAG_GPS_SPEED,8);    entry->format = EXIF_FORMAT_RATIONAL;    entry->components = 1;    a.numerator = sGpsInfo.speed;    a.denominator = 1;    exif_set_rational(entry->data,FILE_BYTE_ORDER,a);        /*date time*/    entry = create_tag(exif, EXIF_IFD_EXIF, EXIF_TAG_DATE_TIME_ORIGINAL,20);    entry->format = EXIF_FORMAT_ASCII;    //entry->components = 20;    char pDataTime[21] = {
   0};    sprintf(pDataTime,"%04d-%02d-%02d %02d:%02d:%02d",sGpsInfo.D.year,sGpsInfo.D.month,sGpsInfo.D.day,        sGpsInfo.D.hour,sGpsInfo.D.minute,sGpsInfo.D.second);    memcpy(entry->data,pDataTime,20);    //厂商信息和设备信息    entry = create_tag(exif, EXIF_IFD_0, EXIF_TAG_MAKE,strlen(pucMaker)+1);    entry->format = EXIF_FORMAT_ASCII;    memcpy(entry->data,pucMaker,strlen(pucMaker));    entry = create_tag(exif, EXIF_IFD_0, EXIF_TAG_MODEL,strlen(pucModel)+1);    entry->format = EXIF_FORMAT_ASCII;    memcpy(entry->data,pucModel,strlen(pucModel));    exif_data_save_data(exif, &exif_data, &exif_data_len);    assert(exif_data != NULL);            f = fopen(pSrcFileName, "wb");//write exif to this file pSrcFileName    if (!f) {       exif_data_unref(exif);       free(buf);       buf=NULL;       return rc;    }    /* Write EXIF header */    if (fwrite(exif_header, exif_header_len, 1, f) != 1) {goto errout;    }    /* Write EXIF block length in big-endian order */    if (fputc((exif_data_len+2) >> 8, f) < 0) {goto errout;    }    if (fputc((exif_data_len+2) & 0xff, f) < 0) {goto errout;    }    /* Write EXIF data block */    if (fwrite(exif_data, exif_data_len, 1, f) != 1) {goto errout;    }    int image_data_len2 =  iFileSize - image_data_offset;    /* Write JPEG image data, skipping the non-EXIF header */    if (fwrite(buf+image_data_offset, image_data_len2, 1, f) != 1) {goto errout;    }    rc = 0;    free(buf);    buf = NULL;    fflush(f);errout:    if (fclose(f)) {        fprintf(stderr, "Error writing to file %s\n", FILE_NAME);        rc = 1;    }    /* The allocator we're using for ExifData is the standard one, so use     * it directly to free this pointer.     */    free(exif_data);    exif_data_unref(exif);    return rc;}
     

 

添加后的图片效果如下：