php生成gif动态验证码图片

发一个真正能运行的通过php生成的动态验证码图片的示例。网上下载的好多都报错的，于是自己综合各方面的见解，终于完成了这么一个效果。

下面是php生成动态验证码需要用到的相关类和函数。

<p><?php</p>/**<br />*ImageCode 生成包含验证码的GIF图片的函数<br />*@param $string 字符串<br />*@param $width 宽度<br />*@param $height 高度<br />**/<br />function ImageCode($string='',$width=75,$height=25){<br />	$authstr=$string?$string:((time()%2==0)?mt_rand(1000,9999):mt_rand(10000,99999));<br />	$board_width=$width;<br />	$board_height=$height;<br />	// 生成一个32帧的GIF动画<br />	for($i=0;$i<32;$i++){<br />		ob_start();<br />	    $image=imagecreate($board_width,$board_height);<br />	    imagecolorallocate($image,0,0,0);<br />	    // 设定文字颜色数组 <br />	 	$colorList[]=ImageColorAllocate($image,15,73,210);<br />	 	$colorList[]=ImageColorAllocate($image,0,64,0);<br />	 	$colorList[]=ImageColorAllocate($image,0,0,64);<br />	 	$colorList[]=ImageColorAllocate($image,0,128,128);<br />	 	$colorList[]=ImageColorAllocate($image,27,52,47);<br />	 	$colorList[]=ImageColorAllocate($image,51,0,102);<br />	 	$colorList[]=ImageColorAllocate($image,0,0,145);<br />	 	$colorList[]=ImageColorAllocate($image,0,0,113);<br />	 	$colorList[]=ImageColorAllocate($image,0,51,51);<br />	 	$colorList[]=ImageColorAllocate($image,158,180,35);<br />	 	$colorList[]=ImageColorAllocate($image,59,59,59);<br />	 	$colorList[]=ImageColorAllocate($image,0,0,0);<br />	 	$colorList[]=ImageColorAllocate($image,1,128,180);<br />	 	$colorList[]=ImageColorAllocate($image,0,153,51);<br />	 	$colorList[]=ImageColorAllocate($image,60,131,1);<br />	 	$colorList[]=ImageColorAllocate($image,0,0,0);<br />	 	$fontcolor=ImageColorAllocate($image,0,0,0);<br />	 	$gray=ImageColorAllocate($image,245,245,245);<br />	    $color=imagecolorallocate($image,255,255,255);<br />	    $color2=imagecolorallocate($image,255,0,0);<br />	    imagefill($image,0,0,$gray);<br />	    $space=15;// 字符间距<br />	    if($i>0){// 屏蔽第一帧<br />			$top=0;<br />		    for($k=0;$k<strlen($authstr);$k++){ <br />				$colorRandom=mt_rand(0,sizeof($colorList)-1);<br />				$float_top=rand(0,4);<br />				$float_left=rand(0,3);<br />				imagestring($image,6,$space*$k,$top+$float_top,substr($authstr,$k,1),$colorList[$colorRandom]);<br />			}<br />	   }<br />		for($k=0;$k<20;$k++){ <br />			$colorRandom=mt_rand(0,sizeof($colorList)-1);<br />	 		imagesetpixel($image,rand()%70,rand()%15,$colorList[$colorRandom]);<br />	<br />		}<br />		// 添加干扰线<br />		for($k=0;$k<3;$k++){<br />			$colorRandom=mt_rand(0,sizeof($colorList)-1);<br />			$todrawline=1;<br />			if($todrawline){<br />				imageline($image,mt_rand(0,$board_width),mt_rand(0,$board_height),mt_rand(0,$board_width),mt_rand(0,$board_height),$colorList[$colorRandom]);<br />			}else{<br />				$w=mt_rand(0,$board_width);<br />				$h=mt_rand(0,$board_width);<br />				imagearc($image,$board_width-floor($w / 2),floor($h / 2),$w,$h, rand(90,180),rand(180,270),$colorList[$colorRandom]);<br />			}<br />		}<br />	    imagegif($image);<br />	    imagedestroy($image);<br />	    $imagedata[]=ob_get_contents();<br />	    ob_clean();<br />	    ++$i;<br />	}<br />	$gif=new GIFEncoder($imagedata);<br />	Header('Content-type:image/gif');<br />	echo $gif->GetAnimation();<br />}<br /><br /><br />/**<br />*GIFEncoder类<br />**/<br />Class GIFEncoder{<br />    var $GIF="GIF89a";              /* GIF header 6 bytes       */  <br />    var $VER="GIFEncoder V2.06";      /* Encoder version            */  <br />    var $BUF=Array();<br />    var $LOP=0;<br />    var $DIS=2;<br />    var $COL=-1;<br />    var $IMG=-1;<br />    var $ERR=Array(<br />        'ERR00'=>"Does not supported function for only one image!", <br />        'ERR01'=>"Source is not a GIF image!", <br />        'ERR02'=>"Unintelligible flag ", <br />        'ERR03'=>"Could not make animation from animated GIF source", <br />   );<br />    function GIFEncoder($GIF_src,$GIF_dly=100,$GIF_lop=0,$GIF_dis=0, $GIF_red=0,$GIF_grn=0,$GIF_blu=0,$GIF_mod='bin'){<br />        if(!is_array($GIF_src)&&!is_array($GIF_tim)){<br />            printf("%s: %s",$this->VER,$this->ERR['ERR00']);<br />            exit(0);<br />        }  <br />        $this->LOP=($GIF_lop>-1)?$GIF_lop:0;<br />        $this->DIS=($GIF_dis>-1)?(($GIF_dis<3)?$GIF_dis:3):2;<br />        $this->COL=($GIF_red>-1&&$GIF_grn>-1&&$GIF_blu>-1)?($GIF_red |($GIF_grn<<8)|($GIF_blu<<16)):-1;<br /><br />        for($i=0,$src_count=count($GIF_src);$i<$src_count;$i++){<br />            if(strToLower($GIF_mod)=="url"){<br />            	$this->BUF[]=fread(fopen($GIF_src [$i],"rb"),filesize($GIF_src [$i]));<br />           }elseif(strToLower($GIF_mod)=="bin"){<br />                $this->BUF [ ]=$GIF_src [ $i ];<br />           }else{<br />                printf("%s: %s(%s)!",$this->VER,$this->ERR [ 'ERR02' ],$GIF_mod);<br />                exit(0);<br />           }  <br />            if(substr($this->BUF[$i],0,6)!="GIF87a"&&substr($this->BUF [$i],0,6)!="GIF89a"){<br />                printf("%s: %d %s",$this->VER,$i,$this->ERR ['ERR01']);<br />                exit(0);<br />           }  <br />            for($j=(13+3*(2<<(ord($this->BUF[$i]{10})&0x07))),$k=TRUE;$k;$j++){<br />                switch($this->BUF [$i]{$j}){<br />                    case "!":  <br />                        if((substr($this->BUF[$i],($j+3),8))=="NETSCAPE"){<br />                                printf("%s: %s(%s source)!",$this->VER,$this->ERR ['ERR03'],($i+1));<br />                                exit(0);<br />                       }  <br />                        break;<br />                    case ";":  <br />                        $k=FALSE;<br />                    break;<br />               }  <br />           }  <br />        }  <br />        GIFEncoder::GIFAddHeader();<br />        for($i=0,$count_buf=count($this->BUF);$i<$count_buf;$i++){<br />        	GIFEncoder::GIFAddFrames($i,$GIF_dly[$i]);<br />       }  <br />        GIFEncoder::GIFAddFooter();<br />    }  <br />    function GIFAddHeader(){<br />		$cmap=0;<br />		if(ord($this->BUF[0]{10})&0x80){<br />			$cmap=3*(2<<(ord($this->BUF [0]{10})&0x07));<br />			$this->GIF.=substr($this->BUF [0],6,7);<br />			$this->GIF.=substr($this->BUF [0],13,$cmap);<br />			$this->GIF.="!\377\13NETSCAPE2.0\3\1".GIFEncoder::GIFWord($this->LOP)."\0";<br />		}  <br />    }  <br />    function GIFAddFrames($i,$d){<br />        $Locals_str=13+3*(2 <<(ord($this->BUF[$i]{10})&0x07));<br />        $Locals_end=strlen($this->BUF[$i])-$Locals_str-1;<br />        $Locals_tmp=substr($this->BUF[$i],$Locals_str,$Locals_end);<br />        $Global_len=2<<(ord($this->BUF [0]{10})&0x07);<br />        $Locals_len=2<<(ord($this->BUF[$i]{10})&0x07);<br />        $Global_rgb=substr($this->BUF[0],13,3*(2<<(ord($this->BUF[0]{10})&0x07)));<br />        $Locals_rgb=substr($this->BUF[$i],13,3*(2<<(ord($this->BUF[$i]{10})&0x07)));<br />        $Locals_ext="!\xF9\x04".chr(($this->DIS<<2)+0).chr(($d>>0)&0xFF).chr(($d>>8)&0xFF)."\x0\x0";<br />        if($this->COL>-1&&ord($this->BUF[$i]{10})&0x80){<br />            for($j=0;$j<(2<<(ord($this->BUF[$i]{10})&0x07));$j++){<br />                if(ord($Locals_rgb{3*$j+0})==($this->COL>> 0)&0xFF&&ord($Locals_rgb{3*$j+1})==($this->COL>> 8)&0xFF&&ord($Locals_rgb{3*$j+2})==($this->COL>>16)&0xFF){<br />                    $Locals_ext="!\xF9\x04".chr(($this->DIS<<2)+1).chr(($d>>0)&0xFF).chr(($d>>8)&0xFF).chr($j)."\x0";<br />                    break;<br />               }  <br />           }  <br />        }  <br />        switch($Locals_tmp{0}){<br />            case "!":  <br />                $Locals_img=substr($Locals_tmp,8,10);<br />                $Locals_tmp=substr($Locals_tmp,18,strlen($Locals_tmp)-18);<br />                break;<br />            case ",":  <br />                $Locals_img=substr($Locals_tmp,0,10);<br />                $Locals_tmp=substr($Locals_tmp,10,strlen($Locals_tmp)-10);<br />                break;<br />        }  <br />        if(ord($this->BUF[$i]{10})&0x80&&$this->IMG>-1){<br />            if($Global_len==$Locals_len){<br />				if(GIFEncoder::GIFBlockCompare($Global_rgb,$Locals_rgb,$Global_len)){<br />					$this->GIF.=($Locals_ext.$Locals_img.$Locals_tmp);<br />				}else{<br />					$byte=ord($Locals_img{9});<br />					$byte|=0x80;<br />					$byte&=0xF8;<br />					$byte|=(ord($this->BUF [0]{10})&0x07);<br />					$Locals_img{9}=chr($byte);<br />					$this->GIF.=($Locals_ext.$Locals_img.$Locals_rgb.$Locals_tmp);<br />				}  <br />            }else{<br />                $byte=ord($Locals_img{9});<br />                $byte|=0x80;<br />                $byte&=0xF8;<br />                $byte|=(ord($this->BUF[$i]{10})&0x07);<br />                $Locals_img {9}=chr($byte);<br />                $this->GIF.=($Locals_ext.$Locals_img.$Locals_rgb.$Locals_tmp);<br />            }  <br />        }else{<br />            $this->GIF.=($Locals_ext.$Locals_img.$Locals_tmp);<br />        }  <br />        $this->IMG=1;<br />    }  <br />    function GIFAddFooter(){<br />        $this->GIF.=";";<br />    }  <br />    function GIFBlockCompare($GlobalBlock,$LocalBlock,$Len){<br />        for($i=0;$i<$Len;$i++){<br />            if($GlobalBlock{3*$i+0}!=$LocalBlock{3*$i+0}||$GlobalBlock{3*$i+1}!=$LocalBlock{3*$i+1}||$GlobalBlock{3*$i+2}!=$LocalBlock{3*$i+2}){<br />                return(0);<br />           }  <br />       }  <br />        return(1);<br />    }  <br />    function GIFWord($int){<br />       return(chr($int&0xFF).chr(($int>>8)&0xFF));<br />    }  <br />    function GetAnimation(){<br />        return($this->GIF);<br />    }  <br /><p>}

php生成动态验证码用法示例：

/*调用示例*/

session_start();<br />$checkCode='';<br />$chars='abcdefghjkmnpqrstuvwxyzABCDEFGHJKLMNPRSTUVWXYZ23456789';<br />for($i=0;$i<4;$i++){<br />	$checkCode.=substr($chars,mt_rand(0,strlen($chars)-1),1);<br />}<br />$_SESSION['code']=strtoupper($checkCode);// 记录session<br />ImageCode($checkCode,60);// 显示GIF动画