什么是 QR Code？
QR 码（ QR Code ）是二维条码的一种，1994 年由日本 Denso-Wave 公司发明。QR 来自英文“Quick Response”的缩写，即快速反应的意思。QR 码比普通条码可储存更多资料，亦无需像普通条码般在扫描时需直线对准扫描器。
QR 码呈正方形，只有黑白两色。在3个角落，印有较小，像“回”字的的正方图案。这 3 个是帮助解码软件定位的图案，使用者不需要对准，无论以任何角度扫描，资料仍可正确被读取。via 维基百科
如何生成 QR Code？
最方便的当然是在线服务：
推荐 QRStuff，它除了能生成常见的条形码之外，还能生成联系人信息（Contact Details (VCARD)）、日历事件（Event (VCALENDAR)）、Wifi 登陆信息（Wifi Login (Android Only)）备选服务：QR Code Generator 。
把当前网址转换成 QR Code
Firefox 扩展 Mobile Barcode 和 Chrome 扩展 QR-Code Tag 可以轻松地把当前网站转化成 QR Code。
怎么识别 QR Code
可以用 ZXing Decoder Online识别，它能识别网络上的 QR Code图片，也可以从电脑上上传一张图片进行识别。Android 用户可以试试 Barcode Scanner App（免费），iOS 平台有 QR Reader for iPhone （免费）。
跨系统平台识别软件 – Desktop QR Code Reader 该软件需要安装 Adobe AIR，然后就可以用电脑摄像头识别 QR Code 了。
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Note：
ZXing是一个开源项目，对QR Code解码感兴趣的可以学习一下！
http://code.google.com/p/zxing/
ZXing ("Zebra Crossing")
ZXing (pronounced "zebra crossing") is an open-source, multi-format 1D/2D barcode image processing library implemented in Java, with ports to other languages. Our focus is on using the built-in camera on mobile phones to scan and decode barcodes on the device, without communicating with a server. However the project can be used to encode and decode barcodes on desktops and servers as well. We currently support these formats:
- UPC-A and UPC-E
- EAN-8 and EAN-13
- Code 39
- Code 93
- Code 128
- QR Code
- ITF
- Codabar
- RSS-14 (all variants)
- Data Matrix
- PDF 417 ('alpha' quality)
- Aztec ('alpha' quality)
This library is divided into several main components which are actively supported:
- core: The core image decoding library, and test code
- javase: J2SE-specific client code
- android: Android client, called Barcode Scanner
- androidtest: Android test app
- android-integration: Supports integration with our Barcode Scanner app via Intent
- zxingorg: The source behind zxing.org/w
There are also additional modules which are contributed and/or intermittently maintained:
- zxing.appspot.com: The source behind our web-based barcode generator
- csharp: Partial C# port
- cpp: Partial C++ port
- iphone: iPhone client + port to Objective C / C++ (QR code only)
- jruby: Ruby wrapper
- actionscript: partial port to Actionscript
There are, finally, some modules no longer maintained but that are available from earlier releases:
- javame: JavaME client
- rim: RIM/Blackberry-specific client build
- bug: Client for BugLabs's BUG
To complement our decoding software, we have created a web-based QR Code generator which supports contact information, calendar events, URLs, and much more.
