现在好多网站使用的验证码非常容易被软件自动识别到，本文介绍了一种PHP生成复杂验证码加入倾斜,弦干扰线,黏贴,旋转等效果
常见的软件不容易自动识别的验证码做法有以下3种：
1、字体变型 （一般通过算法，进行扭曲）
2、字体黏贴 （这里面以qq验证码为代表了，目前网上还是很难找到，破解qq验证码的)
3、干扰线，噪点 (这种识别起来相当容易，很容易被程序自动化识别）
对于上面提到，第1,2 二种方法，在识别时候，是比较困难的。
具体实现代码：
rush:PHP;">
var $TFonts = array("font.ttf");
var $TFontSize=array(17,20); //字体大小范围
var $TFontAngle=array(-20,20); //旋转角度
var $Chars = "0123456789"; //验证码范围（字母数字）
var $Code = array(); //验证码
var $Image = ""; //图形对象
var $FontColors=array('#f36161','#6bc146','#5368bd'); //字体颜色,红绿蓝
var $TPadden = 0.75;///字符间距,多少个字符
var $Txbase = 5;///x轴两边距离
var $Tybase =5 ;///y轴两边距离
var $TLine =true; ///画干扰线
public function RandRSI() ///生成验证码
{
$this->TFontAngle=range($this->TFontAngle[0],$this->TFontAngle[1]);
$this->TFontSize=range($this->TFontSize[0],$this->TFontSize[1]);
$arr=array();
$Chars=$this->Chars;
$TFontAngle=$this->TFontAngle;
$TFontSize=$this->TFontSize;
$FontColors=$this->FontColors;
$code="";
$font=dirname(__FILE__)."/font/".$this->TFonts[0];
$charlen=strlen($Chars)-1;
$anglelen=count($TFontAngle)-1; // 角度范围
$fontsizelen=count($TFontSize)-1; // 角度范围
$fontcolorlen=count($FontColors)-1; // 角度范围
for($i=0;$i<$this->Length;$i++) ///得到字符与颜色
{
$char=$Chars[rand(0,$charlen)]; ///得到字符
$angle=$TFontAngle[rand(0,$anglelen)]; ///旋转角度
$fontsize=$TFontSize[rand(0,$fontsizelen)]; ///字体大小
$fontcolor=$FontColors[rand(0,$fontcolorlen)]; ///字体大小
$bound=$this->_cal<a href="https://www.jb51.cc/tag/cula/" target="_blank" class="keywords">cula</a>teText<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>($fontsize,$angle,$font,$char); ///得到范围
$arr[]=array($fontsize,$fontcolor,$char,$bound); ///得到矩形框
$code.=$char;
}
$this->Code=$arr; //验证码
return $code;
}
public function Draw() ///画图
{
if(empty($this->Code)) $this->RandRSI();
$codes=$this->Code; ///<a href="https://www.jb51.cc/tag/yonghu/" target="_blank" class="keywords">用户</a>验证码
$wh=$this->_ge<a href="https://www.jb51.cc/tag/timage/" target="_blank" class="keywords">timage</a>WH($codes);
$width=$wh[0];
$height=$wh[1]; ///高度
$this->Width=$width;
$this->Height=$height;
$this->Image = imageCreate( $width,$height );
$image=$this->Image;
$back = $this->_getColor2($this->_getColor( $this->BgColor)); ///背景颜色
imageFilledRectangle($image,$width,$height,$back); ///填充背景
$TPadden=$this->TPadden;
$basex=$this->Txbase;
$color=null;
foreach ($codes as $v) ///逐个画字符
{
$bound=$v[5];
$color=$this->_getColor2($this->_getColor($v[2]));
imagettftext($image,$v[0],$v[1],$basex,$bound['height'],$color,$v[4],$v[3]);
$basex=$basex+$bound['width']*$TPadden-$bound['left'];///计算下<a href="https://www.jb51.cc/tag/yige/" target="_blank" class="keywords">一个</a>左边距
}
$this->TLine?$this->_wirteSinLine($color,$basex):null; ///画干扰线
header("Content-type: image/png");
imagepng( $image);
imagedestroy($image);
}
/**
*通过字体角度得到字体矩形宽度*
*
* @p<a href="https://www.jb51.cc/tag/ara/" target="_blank" class="keywords">ara</a>m int $font_size 字体尺寸
* @p<a href="https://www.jb51.cc/tag/ara/" target="_blank" class="keywords">ara</a>m float $font_angle 旋转角度
* @p<a href="https://www.jb51.cc/tag/ara/" target="_blank" class="keywords">ara</a>m string $font_file 字体<a href="https://www.jb51.cc/tag/wenjian/" target="_blank" class="keywords">文件</a>路径
* @p<a href="https://www.jb51.cc/tag/ara/" target="_blank" class="keywords">ara</a>m string $text 写入字符
* @return array 返回长宽高
*/
private function _cal<a href="https://www.jb51.cc/tag/cula/" target="_blank" class="keywords">cula</a>teText<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>($font_size,$font_angle,$font_file,$text) {
$<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a> = imagettfb<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>($font_size,$text);
$min_x = min(array($<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>[0],$<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>[2],$<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>[4],$<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>[6]));
$max_x = max(array($<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>[0],$<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>[6]));
$min_y = min(array($<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>[1],$<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>[3],$<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>[5],$<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>[7]));
$max_y = max(array($<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>[1],$<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>[7]));
return array(
'left' => ($min_x >= -1) ? -abs($min_x + 1) : abs($min_x + 2),'top' => abs($min_y),'width' => $max_x - $min_x,'height' => $max_y - $min_y,'<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>' => $<a href="https://www.jb51.cc/tag/Box/" target="_blank" class="keywords">Box</a>
);
}
private function _getColor( $color ) //#ffffff
{
return array(hexdec($color[1].$color[2]),hexdec($color[3].$color[4]),hexdec($color[5].$color[6]));
}
private function _getColor2( $color ) //#ffffff
{
return imagecolorallocate ($this->Image,$color[0],$color[1],$color[2]);
}
private function _ge<a href="https://www.jb51.cc/tag/timage/" target="_blank" class="keywords">timage</a>WH($data)
{
$TPadden=$this->TPadden;
$w=$this->Txbase;
$h=0;
foreach ($data as $v)
{
$w=$w+$v[5]['width']*$TPadden-$v[5]['left'];
$h=$h>$v[5]['height']?$h:$v[5]['height'];
}
return array(max($w,$this->Width),max($h,$this->Height));
}
//画正弦干扰线
private function _wirteSinLine($color,$w)
{
$img=$this->Image;
$h=$this->Height;
$h1=rand(-5,5);
$h2=rand(-1,1);
$w2=rand(10,15);
$h3=rand(4,6);
for($i=-$w/2;$i<$w/2;$i=$i+0.1)
{
$y=$h/$h3*sin($i/$w2)+$h/2+$h1;
<a href="https://www.jb51.cc/tag/imageset/" target="_blank" class="keywords">imageset</a>pixel($img,$i+$w/2,$y,$color);
$h2!=0?<a href="https://www.jb51.cc/tag/imageset/" target="_blank" class="keywords">imageset</a>pixel($img,$y+$h2,$color):null;
}
}
}
DEMO代码：
TFontSize=array(15,17);
$rsi->Width=50;
$rsi->Height=25;
$code = $rsi->RandRSI();
session_start();
$_SESSION["CHECKCODE"] = $code;
$rsi->Draw();
运行效果：
