Here comes the Sun

recaptcha的验证码新增了alpha composite的新机制取代干扰线，今天用了一些时间在YAN上也实现了这种绘图机制。 使用Java2D的AlphaComposite实现，选用的Rule为alpha 1.0的SrcOut，即通过公式 Ar = As * (1 – Ad ) Cr = Cs * (1 – Ad ) 用语言描述就是叠加区域的透明度为0. 使用这种机制必须采用BufferedImage.TYPE_INT_ARGB的图像，并且输出支持alpha通道的格式。

I am glad to release the Yan 0.4 at the last night of 2009. It’s an important release which witnesses the improvement on both code and the project itself. We have great changes in all modules.  Packages have been rearranged and renamed to be more comprehensible. Let’s dive into the changeset: Changeset ApiKey database derby [...]

今天新增的拼图验证码的可配置性非常强，你只要替换资源文件，在配置文件中修改提问的模版，指定图片的大小、行数、列数，就可以创造一套全新的验证码。他的简单程度实在超出你的想象。

Yan 新增了一种验证码类型，Web 2.0 图标验证码。用户根据图标的内容和提示的信息，提交验证码。验证码图片如下： 提示文字： Please figure out twitter icons. 用户输入Twitter图标左上角上的字母，即可进行验证。在Yan的测试界面上使用如图： Web2.0 Icon实际上是Yan中新增的拼图验证码的一个实例，利用拼图验证码可以生成相似的更有创意的验证码。在我的开发环境中生成这样一张图片大约需要80ms。 项目中使用的图标均从互联网收集，遵循CC等协议或经作者授权，详情参考项目中README文件。 祝DAF同学生日快乐。

给Yan的验证码图片服务做了压力测试。测试环境： Intel Xeon 3.00GHz 4核 内存2G Red Hat Enterprise Linux AS release 4 (Nahant Update 7) Jetty 6 / JDK 6 Jetty采用默认配置 maxThreads 200。 测试工具：ab (Apache Bench) 分别用10/50/100/200/500/1000并发用户，每个用户请求100次进行测试。结果如下： 10 50 100 200 500 1000 Requests per second 487.11 472.09 442.74 421.63 408.11 326.12 Time per request 2.05 2.12 2.26 2.37 2.45 3.07 Transfer rate 987.91 [...]

I will show you the usage of Yan captcha service. In this tutorial, it’s based on a simple ruby web application of the Sinatra web framework. Before we start to use the service, it is necesary to get Yan running. Download the code from the project page, then build and run it with maven: mvn [...]

经过一周的重构和开发，我的开源项目，验证码服务，打上了0.3的tag，算是一个release吧。 This release has been focusing on support for different types captcha generators. Now Yan is not only able to provide image/jpeg captcha, but also text/plain and any others. Changeset: Internal API Changes: Cache API improved: new CacheItemIdentity and CacheIdStrategy were introduced in to provide convertion between cache item name and captcha info model; Captcha [...]

I’d like to announce my recent works, a project called Yan Captcha Service written in Java which is aimed to provide whole solutions of captcha for your websites. It will be very easy to use the service because 1. interfaces are based on plain http url; 2. different kinds of usage are supported to fit [...]