arm下编译并运行zbar实现图片二维码解析_zbar识别模糊二维码 assert

1. 在linux开发板上实现jpg图片二维码的解析功能

1. 生成指定内容的二维码图片
2. 利用djpeg将jpg图片解析成rgb数据
3. 将rgb数据输入到zbar进行内容识别

1. 很多网页版可以直接根据输入内容生成二维码图片
2. 
3. 下载图片，另存为jpg格式 hello.jpg

1. 下载源码Directory Listing of /files (ijg.org)
2. 编译
   1. ./configure --host=arm-linux-gnueabihf --target=arm-linux-gnueabihf --prefix=/home/xxx/linux/nfs/rootfs2/bin/jpg
   2. make install
3. 开发板上面运行测试
   1. cd /bin/jpg
   2. ./djpeg hello.jpg > hw.ppm

1. ppm头部为P6. 图像长度 图像宽度. 最大像素.
   1. P6代表格式为pixelmap binary 
2. 后面接着的就是长宽对应的各个pixel的rgb数据

1. 下载源码ZBar bar code reader - Download (sourceforge.net)
2. 编译lib

   1. ./configure --prefix=/home/xxx/linux/nfs/rootfs2/bin/zbar --disable-video --without-imagemagick --without-gtk --without-qt --without-python CFLAGS=""  --host=arm-linux-gnueabihf --target=arm-linux-gnueabihf

   2. make install

   3. 注意：配置里面加了很多--without项，是为了编译通过，免得去折腾那些环境；向zbar本身也是支持直接解析img的，但是编译会报错，因此采取曲线救国方式，通过直接调用zbar的lib来实现解析；本质上大同小异

调用zbar库的应用程序

1. 程序主要分为两部分

   1. 一部分是将djpeg生成的ppm文件转换成y800数据

   2. 另一部分是将y800数据输入到zbar的库去解析，这部分主要是参考zbarimg.c

2. code：头文件

   #include <stdio.h>
   #include <stdlib.h>
   #include <string.h>
    
   typedef struct{
       char *filename;
       int w;
       int h;
       char *buf;
   }ppm_t;
    
   int ppm2y800(ppm_t *ppm);
   

3. code：part1

   #include "ppm.h"
    
   int ppm2y800(ppm_t *ppm)
   {
       FILE *fd = fopen(ppm->filename, "rb");
       if (NULL == fd){
           printf("open %s failed.\n", ppm->filename);
           return -1;
       }
    
       fseek(fd, 0, SEEK_END);
       int len = ftell(fd);
       printf("%s len:%d\n", ppm->filename, len);
       fseek(fd, 0, SEEK_SET);
    
       unsigned char *pbuf = malloc(len);
    
       int ret = fread(pbuf, 1, len, fd);
    
       if (ret != len){
           printf("read %s failed.\n", ppm->filename);
           return -2;
       }
    
       if (0x50 != pbuf[0] || 0x36 != pbuf[1] || 0x0a != pbuf[2]){
           printf("head:%c %c is not P6. \n", pbuf[0], pbuf[1]);
           return -3;
       }
    
       // find width
       int idx = 3;
       while(pbuf[idx] != 0x20){
           idx++;
       }
       char str[10] = {0};
       memcpy(str, pbuf+3, idx-3);
       ppm->w = strtol(str, NULL, 10);
       printf("ppm->w:%d\n", ppm->w);
    
       // find height
       idx++;
       int idxe = idx;
       while(pbuf[idxe] != 0x0a){
           idxe++;
       }
       memcpy(str, pbuf+idx, idxe-idx);
       str[idxe-idx] = 0;
       ppm->h = strtol(str, NULL, 10);
       printf("ppm->h:%d\n", ppm->h);
    
       // find head tail
       idxe++;
       while(pbuf[idxe] != 0x0a){
           idxe++;
       }
       
       // check len is valid or not
       int explen = idxe + 1 + ppm->w * ppm->h * 3;
       if (len != explen){
           printf("ppm w:%d h:%d idxe:%d explen:%d is not fit len:%d. \n", ppm->w, ppm->h, idxe, explen, len);
           return -3;
       }
    
       // malloc and set y buf
       unsigned char *ybuf = malloc(ppm->w * ppm->h);
       unsigned char r, g, b;
       for (int i = 0; i < ppm->w * ppm->h; i++){
           r = pbuf[idxe + 1 + i * 3];
           g = pbuf[idxe + 2 + i * 3];
           b = pbuf[idxe + 3 + i * 3];
           ybuf[i] = (char)(0.257 * r + 0.504 * g + 0.098 * b + 16);
       }
    
       ppm->buf = ybuf;
    
       printf("ybuf[0]:%x rgb:%x %x %x\n", ybuf[0], r, g, b);
    
       free(pbuf);
       fclose(fd);
    
       return 0;
   }
   

4. code：part2

    
    
   #include <assert.h>
    
   #include <zbar.h>
   #include "ppm.h"
    
   ppm_t ppm = {0};
   static zbar_processor_t *processor = NULL;
   static int notfound = 0, exit_code = 0;
   static int num_images = 0, num_symbols = 0;
   static int xmllvl = 0;
    
   char *xmlbuf = NULL;
   unsigned xmlbuflen = 0;
    
   int main(char argc, char **argv){
       int found = 0;
    
       for (int i = 0; i < argc; i++){
           printf("%s ", argv[i]);
       }
       if (argc < 2){
           printf("argc:%d is less than 2.\n", argc);
           return -1;
       }
    
       ppm.filename = argv[1];
       ppm2y800(&ppm);
    
       // FILE *fd = fopen("400x400_y800.yuv", "wb");
       // fwrite(ppm.buf, 1, ppm.h*ppm.w, fd);
       // fclose(fd);
    
       processor = zbar_processor_create(0);
       assert(processor);
       if(zbar_processor_init(processor, NULL, 0)) {
           zbar_processor_error_spew(processor, 0);
           return(1);
       }
    
       zbar_image_t *zimage = zbar_image_create();
       assert(zimage);
       zbar_image_set_format(zimage, *(unsigned long*)"Y800");
       zbar_image_set_size(zimage, ppm.w, ppm.h);
       zbar_image_set_data(zimage, ppm.buf, ppm.h*ppm.w, zbar_image_free_data);
    
       zbar_process_image(processor, zimage);
    
       // output result data
       const zbar_symbol_t *sym = zbar_image_first_symbol(zimage);
       for(; sym; sym = zbar_symbol_next(sym)) {
           zbar_symbol_type_t typ = zbar_symbol_get_type(sym);
           if(typ == ZBAR_PARTIAL)
               continue;
           else if(!xmllvl)
               printf("%s%s:%s\n",
                       zbar_get_symbol_name(typ),
                       zbar_get_addon_name(typ),
                       zbar_symbol_get_data(sym));
           else if(xmllvl < 0)
               printf("%s\n", zbar_symbol_get_data(sym));
           else {
               if(xmllvl < 3) {
                   xmllvl++;
                   // printf("<index num='%u'>\n", seq);
               }
               zbar_symbol_xml(sym, &xmlbuf, &xmlbuflen);
               printf("%s\n", xmlbuf);
           }
           found++;
           num_symbols++;
       }
       if(xmllvl > 2) {
           xmllvl--;
           printf("</index>\n");
       }
       fflush(stdout);
    
       zbar_image_destroy(zimage);
       zbar_processor_destroy(processor);
    
       return 0;
   }
   

5. 编译：

   1. arm-linux-gnueabihf-gcc $^ $(CFLAGS) $(LDFLAGS)  -lzbar -o zbar

运行测试