zw_captpng

#Captcha PNG generator
A numeric captcha generator for Node.js

##Features
* Only generate numeric captcha PNG image
* Build-in fonts
* Characters up and down, left and right limits, random displacement
* Full JavaScript

##Examples
``javascript
/**
* Captcha PNG img generator
* @Author: George Chan
* @Email: gchan@21cn.com
* @Version: 1.0
* @Date: 2013-08-18
* @license http://www.opensource.org/licenses/bsd-license.php BSD License
*/

var http = require('http');
var captchapng = require('captchapng');

http.createServer(function (request, response) {
if(request.url == '/captcha.png') {
var p = new captchapng(80,30,parseInt(Math.random()*9000+1000)); // width,height,numeric captcha
p.color(0, 0, 0, 0); // First color: background (red, green, blue, alpha)
p.color(80, 80, 80, 255); // Second color: paint (red, green, blue, alpha)

var img = p.getBase64();
var imgbase64 = new Buffer(img,'base64');
response.writeHead(200, {
'Content-Type': 'image/png'
});
response.end(imgbase64);
} else response.end('');
}).listen(8181);

console.log('Web server started.\n http:\\\\127.0.0.1:8181\\captcha.png');
``