使用qrencode库生成指定信息二维码图片

qrencode源码下载地址：https://fukuchi.org/works/qrencode/

windows下编译方式，新建visual studio工程，将源码目录下所有*.c/*.h文件加入工程中(除了qrenc.c，此为测试例子)，然后把config.h.in重命名为config.h然后修改内容为如下

/* config.h.  Generated from config.h.in by configure.  */
/* config.h.in.  Generated from configure.ac by autoheader.  */
/* Define to 1 if you have the <inttypes.h> header file. */
#define HAVE_INTTYPES_H 1  
/* Define to 1 if using pthread is enabled. */
#undef HAVE_LIBPTHREAD  
/* Define to 1 if you have the <memory.h> header file. */
#define HAVE_MEMORY_H 1  
/* Define to 1 if you have the <stdint.h> header file. */
#define HAVE_STDINT_H 1  
/* Define to 1 if you have the <stdlib.h> header file. */
#define HAVE_STDLIB_H 1  
/* Define to 1 if you have the <strings.h> header file. */
#define HAVE_STRINGS_H 1  
/* Define to 1 if you have the <string.h> header file. */
#define HAVE_STRING_H 1  
/* Define to 1 if you have the `strdup' function. */
//#define HAVE_STRDUP 1  
#undef  HAVE_STRDUP
/* Define to 1 if you have the <sys/stat.h> header file. */
#define HAVE_SYS_STAT_H 1  
/* Define to 1 if you have the <sys/types.h> header file. */
#define HAVE_SYS_TYPES_H 1  
/* Define to 1 if you have the <unistd.h> header file. */
#define HAVE_UNISTD_H 1  
/* Major version number */
#define MAJOR_VERSION 3  
/* Micro version number */
#define MICRO_VERSION 4  
/* Minor version number */
#define MINOR_VERSION 4  
/* Name of package */
#define PACKAGE "qrencode"  
/* Define to the address where bug reports for this package should be sent. */
#define PACKAGE_BUGREPORT ""  
/* Define to the full name of this package. */
#define PACKAGE_NAME "QRencode"  
/* Define to the full name and version of this package. */
#define PACKAGE_STRING "QRencode 3.4.4"  
/* Define to the one symbol short name of this package. */
#define PACKAGE_TARNAME "qrencode"  
/* Define to the home page for this package. */
#define PACKAGE_URL ""  
/* Define to the version of this package. */
#define PACKAGE_VERSION "3.4.4"  
/* Define to 1 if you have the ANSI C header files. */
#define STDC_HEADERS 1  
/* Version number of package */
#define VERSION "3.4.4"  
#define inline  
/* Define to 'static' if no test programs will be compiled. */
#define __STATIC static  
/* #undef WITH_TESTS */

编译过程中会提示strdup函数错误，可重命名函数(因为编译时会跟c++中的strdup冲突)，预处理宏中添加HAVE_CONFIG_H

编译为静态库，项目中直接引用。

下面是二维码图片生成代码（bmp图片）

#include "stdafx.h"
#include <Windows.h>
#include <iostream>
#include <fstream>
#include <string>
#include "qrcode/include/config.h"
#include "qrcode/include/qrencode.h"

using namespace std;

#ifdef _M_IX86
	#pragma comment(lib,"qrcode/lib/libQR32.lib")
#else
	#pragma comment(lib,"qrcode/lib/libQR64.lib")
#endif

int _tmain(int argc, _TCHAR* argv[])
{
	string data("192.168.1.1 aa-bb-cc-dd-ee-ff administrator asfnsdugnerhgernihdmakfa");
	QRcode* qrData = QRcode_encodeString(data.c_str(), 1, QR_ECLEVEL_L, QR_MODE_8, 1);
	if (NULL == qrData)
	{
		cout << "QRcode_encodeString error" << endl;
		return -1;
	}
	unsigned int width = qrData->width;
	cout << "width: " << width << endl;
	unsigned int widthAdjusted = width * 8 * 3;
	if (widthAdjusted % 4)
		widthAdjusted = (widthAdjusted / 4 + 1) * 4;
	unsigned int bytesOfData = widthAdjusted * width * 8;
	unsigned char* pixelData = new unsigned char[bytesOfData];
	memset(pixelData, 0xff, bytesOfData);
	
	BITMAPFILEHEADER fileHeader;
	ZeroMemory(&fileHeader, sizeof(fileHeader));
	fileHeader.bfType = 0x4d42; // BM
	fileHeader.bfSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + bytesOfData;
	fileHeader.bfReserved1 = 0;
	fileHeader.bfReserved2 = 0;
	fileHeader.bfOffBits = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);

	BITMAPINFOHEADER infoHeader;
	ZeroMemory(&infoHeader, sizeof(infoHeader));
	infoHeader.biSize = sizeof(BITMAPINFOHEADER);
	infoHeader.biWidth = width * 8;
	infoHeader.biHeight = -((int)width * 8);
	infoHeader.biPlanes = 1;
	infoHeader.biBitCount = 24;
	infoHeader.biCompression = BI_RGB;
	infoHeader.biSizeImage = 0;
	infoHeader.biXPelsPerMeter = 0;
	infoHeader.biYPelsPerMeter = 0;
	infoHeader.biClrUsed = 0;
	infoHeader.biClrImportant = 0;
	
	unsigned char* source = qrData->data;
	for (int j=0; j<width; ++j)
	{
		unsigned char* dest = pixelData + widthAdjusted * j * 8;
		for (int i=0; i<width; ++i)
		{
			if (*source & 1)
			{
				for (int k=0; k<8; ++k)
					memset(dest + widthAdjusted * k, 0, 24);
			}
			dest += 3 * 8;
			++source;
		}
	}
	QRcode_free(qrData);

	ofstream ofs(L"qrcode.bmp", ios::binary);
	if (ofs.is_open())
	{
		ofs.write(reinterpret_cast<const char*>(&fileHeader), sizeof(fileHeader));
		ofs.write(reinterpret_cast<const char*>(&infoHeader), sizeof(infoHeader));
		ofs.write(reinterpret_cast<const char*>(pixelData), bytesOfData);
		ofs.close();
	}
	delete[] pixelData;

	return 0;
}

参考：https://www.zhaokeli.com/article/8311.html