nodejs产生图片验证码
基于html5 canvas
1、ubuntu 下安装
sudo apt-get install libcairo2-dev
1、ubuntu 下安装
sudo apt-get install libcairo2-dev
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1
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sudo npm install canvas
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2、nodejs代码
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var Canvas = require(
'./Common/canvas'
);
var getRandom = function(start,end){
return
start+Math.random()*(end-start);
};
var canvas =
new
Canvas(
50
,
20
);
var ctx = canvas.getContext(
'2d'
);
var s =
'ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789'
;
var code =
''
;
for
(var i=
0
;i<
4
;i++){
code+= s.substr(parseInt(Math.random()*
36
),
1
);
}
var font=
'bold {FONTSIZE}px Impact'
;
//"Bold Italic {FONTSIZE}px arial,sans-serif";//"13px sans-serif";
var start =
3
;
var colors = [
"rgb(255,165,0)"
,
"rgb(16,78,139)"
,
"rgb(0,139,0)"
,
"rgb(255,0,0)"
];
var trans = {c:[-
0.108
,
0.108
],b:[-
0.05
,
0.05
]};
var fontsizes = [
11
,
12
,
13
,
14
,
15
,
16
];
for
(var i in code){
ctx.font = font.replace(
'{FONTSIZE}'
,fontsizes[Math.round(Math.random()*
10
)%
6
]);
ctx.fillStyle = colors[Math.round(Math.random()*
10
)%
4
];
//"rgba(0, 0, 200, 0.5)";
ctx.fillText(code[i], start,
15
,
50
);
ctx.fillRect();
//con.translate(start,15);
//ctx.transform(a,b, c, d, e, f);
//参考：
//a:水平缩放，default：1 ,取值：0.89,1.32,-0.56等,
//b:y轴斜切，default：0 ,取值：-0.89,1.32等,
//c:x轴斜切，default：0 ,取值：-0.89,1.32等,
//d:垂直缩放，default：1 ,取值：-0.89，0.88,1.32等,
//e:平移，default：0 ,取值：-53,52等,
//f:纵称，default：0 ,取值：-53,52等,
var c = getRandom(trans[
'c'
][
0
],trans[
'c'
][
1
]);
var b = getRandom(trans[
'b'
][
0
],trans[
'b'
][
1
]);
//alert(c+','+b);
//ctx.transform(1,b, c, 1, 0, 0);
start+=
11
;
}
//参考下面链接；可发送给客户端
console.log(
'code:'
+code);
console.log('//输出文件到out.png.可方便使用
var buf = canvas.toDataURL();
var base64Data = buf.replace(/^data:image\/\w+;base64,/,
""
);
var dataBuffer =
new
Buffer(base64Data,
'base64'
);
var fs = require(
"fs"
);
fs.writeFile(
"out.png"
, dataBuffer, function(err) {
if
(err){
console.log(
"errro！"
);
}
else
{
console.log(
"保存成功！"
);
}
});
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