如何用C代碼生成二維碼

本文轉載自查看原文 2016-10-16 20:48 13244 C&C++

如何用C代碼生成二維碼

　　當下因微信和支付寶等手機應用廣泛使用，而基於二維碼/一維條碼的移動支付，也借助手機移動端席卷全國，使得越來越多的人知道有“二維碼”這么一種東西。

　　對於普通用戶而來，一般只知道將自己的二維碼展示給別人，別人使用軟件識別這個二維碼即可完成一定的功能。比如，掃碼二維碼付款、掃碼二維碼加微信好友、掃碼二維碼訪問網頁、掃碼二維碼下載app等等。這些個功能，在日常行為中，已經很常見了，但作為程序猿的我們，我們怎么能不知道二維碼是如何生成的呢？或者說，我要自己生成一個二維碼，除了去網頁上找二維碼生成工具來生成，我可以自己編碼來實現么？

　　答案，當然是，必須可以。不然這文章不用寫了。

　　在介紹如何用代碼生成二維碼之前，就不得不先介紹一個開源庫叫zint。這個開源可謂牛叉的很，幾乎平時見過的“碼”，各式各樣的一維條碼、各式各樣的二維碼條碼都難不倒它，重要的是，它還是開源的，幾乎包含了所有常見“碼”的生成。以下是摘自官方用戶使用手冊的介紹片段。（筆者上一篇博文介紹zint的安裝時簡單介紹了一下zint庫，http://www.cnblogs.com/Recan/p/5967378.html ，它的開源項目網頁為https://sourceforge.net/projects/zint/）

The Zint project aims to provide a complete cross-platform open source barcode generating solution. The package currently consists of a Qt based GUI, a command line executable and a library with an API to allow developers access to the capabilities of Zint. It is hoped that Zint provides a solution which is flexible enough for professional users while at the same time takes care of as much of the processing as possible to allow easy translation from input data to barcode image.

-----------------------------------------------------華麗麗的分割線-----------------------------------------------------

　　言歸正傳，說回如何使用zint庫生成二維碼。主要使用到以下幾個函數：可以從zint.h中得到api的聲明（主要是C語言的接口）。

ZINT_EXTERN struct zint_symbol* ZBarcode_Create(void);

ZINT_EXTERN void ZBarcode_Clear(struct zint_symbol *symbol);

ZINT_EXTERN void ZBarcode_Delete(struct zint_symbol *symbol);

ZINT_EXTERN int ZBarcode_Encode_and_Print(struct zint_symbol *symbol, unsigned char *input, int length, int rotate_angle);

　　以下是個人封裝的生成二維碼的自定義接口函數：

/****************************************************************************

Descpribe: Create Qrcode API with C Code by calling zint lib.

Input : pQrCodeData, the qrcode data buf

QrcodeLen, the len of qrcode data, but it can be 0

pQrCodeFile, the output file name of qrcode, it can be NULL

Output : pZintRet, to store the ret code from linzint.

Return : 0 is ok, and other values are fail. See the meanings in enum ZINT_RET_CODE

Notes : pQrCodeFile, Must end in .png, .eps or .svg. when isn,t NULL string.

****************************************************************************/

ZINT_RET_CODE Zint_Create_QrCode(uint8_t *pQrCodeData, int QrcodeLen, char *pQrCodeFile, int *pZintRet);

　　這個接口定義比較簡單，上面也簡單說了各個參數的意義，其他中特別需要注意的是，如果傳入生成二維碼圖片名字不使用默認值時（pQrCodeFile ！= NULL），也務必保證pQrCodeFile必須是以.png, .eps or .svg.結尾的文件名。

　　以下是zint_code.c 和 zint_code.h的內容，里面將zint中生成二維碼的幾個函數封裝在一塊了，使用者只需關注上面定義的Zint_Create_QrCode函數，即可生成漂亮的二維碼圖片文件。

 1 /****************************************************************************
 2  * File       : zint_code.c
 3  * 
 4  * Copyright (c) 2011 by Li.Recan < 721317716@qq.com >
 5  * 
 6  * DESCRIPTION: Demo for creating qrcode by C code.
 7  * 
 8  * Modification history
 9  * --------------------------------------------------------------------------
10  * Date         Version  Author       History
11  * --------------------------------------------------------------------------
12  * 2016-10-15   1.0.0    Li.Recan     written
13  ***************************************************************************/
14  
15 // Standard Library
16 #include <string.h>
17 #include <stdio.h>
18 
19 // so Library
20 #include "zint.h"
21 
22 // Project Header
23 #include "zint_code.h"
24 
25 
26 /****************************************************************************
27 Descpribe: Create Qrcode API with C Code by calling zint lib.
28 Input    : pQrCodeData, the qrcode data buf
29            QrcodeLen, the len of qrcode data, but it can be 0
30            pQrCodeFile, the output file name of qrcode, it can be NULL           
31 Output   : pZintRet, to store the ret code from linzint. 
32 Return   : 0 is ok, and other values are fail. See the meanings in enum ZINT_RET_CODE
33 Notes    : pQrCodeFile, Must end in .png, .eps or .svg. when isn,t NULL string.
34 ****************************************************************************/
35 ZINT_RET_CODE Zint_Create_QrCode(uint8_t *pQrCodeData, int QrcodeLen, char *pQrCodeFile, int *pZintRet)
36 {
37     struct zint_symbol *pMySymbol     = NULL;
38     int RetCode                     = 0;    
39     
40     if(!pQrCodeData) //check input pointer
41     {
42         return ZINT_ERR_INV_DATA;
43     }
44 
45     if(QrcodeLen == 0)
46     {
47         QrcodeLen = strlen((char *)pQrCodeData);
48     }
49     if(QrcodeLen > QRCODE_MAX_LEN)//len is too long
50     {        
51         return ZINT_ERR_TOO_LONG;
52     }
53 
54     if(0 == ZBarcode_ValidID(BARCODE_QRCODE))
55     {
56         return ZINT_ERR_INV_CODE_ID;
57     }
58     
59     pMySymbol = ZBarcode_Create();
60     if(pMySymbol == NULL)
61     {
62         return ZINT_ERR_MEMORY;
63     }
64 
65     if(pQrCodeFile)//when it's NULL, outfile will be "out.png"
66     {
67         if(strstr(pQrCodeFile, "png") || (strstr(pQrCodeFile, "eps")) || (strstr(pQrCodeFile, "svg")))
68         {
69             strcpy(pMySymbol->outfile, pQrCodeFile);
70         }
71         else
72         {
73             ZBarcode_Clear(pMySymbol);
74             ZBarcode_Delete(pMySymbol); //release memory in zint lib
75             return ZINT_ERR_FILE_NAME;
76         }
77     }
78     pMySymbol->symbology     = BARCODE_QRCODE;  
79     pMySymbol->option_1     = 3; //ECC Level.It can be large when ECC Level is larger.(value:1-4)  
80     pMySymbol->scale         = 4; //contorl qrcode file size, default is 1, used to be 4   
81     pMySymbol->border_width = 2; //set white space width around your qrcode and 0 is for nothing 
82     
83     RetCode = ZBarcode_Encode_and_Print(pMySymbol, pQrCodeData, QrcodeLen, 0);    
84     ZBarcode_Clear(pMySymbol);
85     ZBarcode_Delete(pMySymbol); //release memory in zint lib
86 
87     if(pZintRet)
88     {
89         *pZintRet = RetCode; //save ret code from zint lib
90     }
91     
92     return ((0 == RetCode) ? (ZINT_OK) : (ZINT_ERR_LIB_RET));
93 }

View Code： zint_code.c

 1 /****************************************************************************
 2  * File       : zint_code.h
 3  * 
 4  * Copyright (c) 2011 by Li.Recan < 721317716@qq.com >
 5  * 
 6  * DESCRIPTION: API for creating qrcode by C code.
 7  * 
 8  * Modification history
 9  * --------------------------------------------------------------------------
10  * Date         Version  Author       History
11  * --------------------------------------------------------------------------
12  * 2016-10-15   1.0.0    Li.Recan     written
13  ***************************************************************************/
14  
15 #ifndef __ZINT_CODE__
16 #define __ZINT_CODE__
17 
18 #ifdef __cplusplus
19 extern "C"
20 {
21 #endif
22 
23 #include <stdint.h>
24 
25 #define QRCODE_MAX_LEN        500 //max string len for creating qrcode
26 
27 typedef enum 
28 {
29     ZINT_OK                 = 0,
30     ZINT_ERR_INV_DATA         = -1, //input invalid data
31     ZINT_ERR_TOO_LONG         = -2, //len for input data is too long    
32     ZINT_ERR_INV_CODE_ID     = -3,//the code type is not supported by zint
33     ZINT_ERR_MEMORY         = -4, //malloc memory error in zint lib
34     ZINT_ERR_FILE_NAME        = -5, //qrcode file isn'y end in .png, .eps or .svg.
35     ZINT_ERR_LIB_RET         = -6, //zint lib ret error, real ret code should be zint api ret code
36 }ZINT_RET_CODE;
37 
38 /****************************************************************************
39 Descpribe: Create Qrcode API with C Code by calling zint lib.
40 Input    : pQrCodeData, the qrcode data buf
41            QrcodeLen, the len of qrcode data, but it can be 0
42            pQrCodeFile, the output file name of qrcode, it can be NULL           
43 Output   : pZintRet, to store the ret code from linzint. 
44 Return   : 0 is ok, and other values are fail. See the meanings in enum ZINT_RET_CODE
45 Notes    : pQrCodeFile, Must end in .png, .eps or .svg. when isn,t NULL string.
46 ****************************************************************************/
47 ZINT_RET_CODE Zint_Create_QrCode(uint8_t *pQrCodeData, int QrcodeLen, char *pQrCodeFile, int *pZintRet);
48 
49 #define Debuging(fmt, arg...)       printf("[%20s, %4d] "fmt, __FILE__, __LINE__, ##arg)
50 
51 #ifdef __cplusplus
52 }
53 #endif
54 
55 #endif /* __ZINT_CODE__ */

View Code: zint_code.h

　　在工程實踐中，只需要將這兩個文件添加到工程中，並讓他們參與工程編譯，即可完美使用zint生成二維碼了。

　　下面是一個簡單的demo，將會展示如何使用這個接口函數，見qrcode_test.c

 1 /****************************************************************************
 2  * File       : qrcode_test.c
 3  * 
 4  * Copyright (c) 2011 by Li.Recan < 721317716@qq.com >
 5  * 
 6  * DESCRIPTION: Demo for creating qrcode by C code.
 7  * 
 8  * Modification history
 9  * --------------------------------------------------------------------------
10  * Date         Version  Author       History
11  * --------------------------------------------------------------------------
12  * 2016-10-15   1.0.0    Li.Recan     written
13  ***************************************************************************/
14  
15 // Standard Library
16 #include <stdio.h>
17 
18 // Project Header
19 #include "zint_code.h"
20 
21 int main(int argc, char *argv[])
22 {
23     int ZintLibRet             = 0; //ret code from zint lib
24     ZINT_RET_CODE ZintRet     = 0; //ret code from zint_code api
25     char QrcodeData[]         = "I love zint lib. 測試一下gbk編碼 ...";
26     char QrcodeDataDef[]     = "This's default qrcode file name : out.png ";
27     char QrcodeFile[]         = "MyQrcode.png"; // Must end in .png, .eps or .svg. //zint lib ask !
28     
29     //test with inputing qrcode_file name
30     ZintRet = Zint_Create_QrCode((uint8_t*)QrcodeData, 0, QrcodeFile, &ZintLibRet);
31     if(ZINT_OK != ZintRet)
32     {
33         Debuging("Create qrcode err, ZintRet = %d, ZintLibRet = %d\n", ZintRet, ZintLibRet);
34     }
35     else
36     {
37         Debuging("Create qrcode OK ! View qrcode file : %s in cur path. ZintRet = %d, ZintLibRet = %d\n", QrcodeFile, ZintRet, ZintLibRet);
38     }
39     
40     //test without inputing qrcode_file name
41     ZintRet = Zint_Create_QrCode((uint8_t*)QrcodeDataDef, 0, NULL, &ZintLibRet);
42     if(ZINT_OK != ZintRet)
43     {
44         Debuging("Create qrcode err, ZintRet = %d, ZintLibRet = %d\n", ZintRet, ZintLibRet);
45     }
46     else
47     {
48         Debuging("Create qrcode OK ! View qrcode file : out.png in cur path. ZintRet = %d, ZintLibRet = %d\n", ZintRet, ZintLibRet);
49     }
50     
51     return 0;
52 }