使用libjpeg把iplImage转jpeg

static bool ipl2jpeg(IplImage *img, unsigned char **outbuffer, unsigned long*outlen)
{
    unsigned char *outdata = (uchar *)img->imageData;
    struct jpeg_compress_struct cinfo = { 0 };
    struct jpeg_error_mgr jerr;
    JSAMPROW row_ptr[1];
    int row_stride;

    *outbuffer = NULL;
    *outlen = 0;

    cinfo.err = jpeg_std_error(&jerr);
    jpeg_create_compress(&cinfo);
    

    cinfo.image_width = img->width;
    cinfo.image_height = img->height;
    cinfo.input_components = img->nChannels;
    cinfo.in_color_space = JCS_RGB;

    jpeg_mem_dest(&cinfo, outbuffer, outlen);

    jpeg_set_defaults(&cinfo);
    jpeg_start_compress(&cinfo, TRUE);
    row_stride = img->width * img->nChannels;


    while (cinfo.next_scanline < cinfo.image_height)
    {
        row_ptr[0] = &outdata[cinfo.next_scanline * row_stride];
        jpeg_write_scanlines(&cinfo, row_ptr, 1);
    }

    jpeg_finish_compress(&cinfo);
    jpeg_destroy_compress(&cinfo);

    return true;
}

static bool jpegSave(const char* filename, unsigned char *outbuffer, unsigned long outlen)
{
    FILE *f;
    fopen_s(&f, filename, "wb");
    if (!f)
        return false;

    size_t size = fwrite(outbuffer, (size_t)outlen, 1, f);
    fclose(f);


    if (size == 1)
        return true;

    return false;
}