What are the ways to generate complex verification codes in PHP?

This time I will bring you php to generate complex verification codeWhat are the methods, and what are the notesfor php to generate complex verification code. The following is a practical case. Let’s take a look. .

There are three common verification code methods that are not easily recognized by software:

1. Font variation (generally distorted through algorithms)

2. Paste fonts (the qq verification code is represented here, it is still difficult to find online, crack the qq verification code)

3 , interference lines, noise (this kind of identification is quite easy and can be automatically identified by the program)

As mentioned above, the first and second methods are more difficult to identify.

Specific implementation code:

<?php
/**
 *带文字旋转，倾斜，黏贴，加正弦干扰线验证码*
 */
class Utils_Caption
{
	var $Width   = 60;      //图片宽
	var $Height   = 30;      //图片高
	var $Length   = 4;      //验证码位数
	var $BgColor  = "#FFFFFF";  //背景色
	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(&#39;#f36161&#39;,&#39;#6bc146&#39;,&#39;#5368bd&#39;); //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->_calculateTextBox($fontsize,$angle,$font,$char); ///得到范围
			$arr[]=array($fontsize,$angle,$fontcolor,$char,$font,$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; ///用户验证码
		$wh=$this->_getImageWH($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, 0, 0, $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'];///计算下一个左边距
		}
		$this->TLine?$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*
	 *
	 * @param int $font_size 字体尺寸
	 * @param float $font_angle 旋转角度
	 * @param string $font_file 字体文件路径
	 * @param string $text 写入字符
	 * @return array 返回长宽高
	 */
	private function _calculateTextBox($font_size, $font_angle, $font_file, $text) {
		$box = imagettfbbox($font_size, $font_angle, $font_file, $text);
		$min_x = min(array($box[0], $box[2], $box[4], $box[6]));
		$max_x = max(array($box[0], $box[2], $box[4], $box[6]));
		$min_y = min(array($box[1], $box[3], $box[5], $box[7]));
		$max_y = max(array($box[1], $box[3], $box[5], $box[7]));
		return array(
		'left' => ($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,
		'box' => $box
		);
	}
	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], $color[2]);
	}
	private function _getImageWH($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+$h1;
			imagesetpixel($img,$i+$w/2,$y,$color);
			$h2!=0?imagesetpixel($img,$i+$w/2,$y+$h2,$color):null;
		}
	}
}

DEMO code:

$rsi = new Utils_Caption();
$rsi->TFontSize=array(15,17);
$rsi->Width=50;
$rsi->Height=25;
$code = $rsi->RandRSI();
session_start();
$_SESSION["CHECKCODE"] = $code;
$rsi->Draw();

Running effect:

Believe it or not After reading the case in this article, you have mastered the method. For more exciting information, please pay attention to other related articles on the PHP Chinese website!

Recommended reading:

Detailed explanation of the steps to generate promotional posters in PHP

Laravel framework implementation of search function code analysis

The above is the detailed content of What are the ways to generate complex verification codes in PHP?. For more information, please follow other related articles on the PHP Chinese website!