这是一个通过PHP生成的动态验证码图片的示例，重点是可以运行哦！下面先发下效果图：
}
// <a href="https://www.jb51.cc/tag/tianjia/" target="_blank" class="keywords">添加</a>干扰线
for($k=0;$k<3;$k++){
$colorRandom=mt_rand(0,sizeof($colorList)-1);
$todrawline=1;
if($todrawline){
imageline($image,mt_rand(0,$board_width),$board_height),$colorList[$colorRandom]);
}else{
$w=mt_rand(0,$board_width);
$h=mt_rand(0,$board_width);
imagearc($image,$board_width-floor($w / 2),floor($h / 2),$w,$h,rand(90,180),rand(180,270),$colorList[$colorRandom]);
}
}
imagegif($image);
imagedestroy($image);
$imagedata[]=ob_get_contents();
ob_clean();
++$i;
}
$gif=new GIFEncoder($imagedata);
Header('Content-type:image/gif');
echo $gif->GetAnimation();
}
/*
GIFEncoder类
*/
Class GIFEncoder{
var $GIF="GIF89a"; / GIF header 6 bytes /
var $VER="GIFEncoder V2.06"; / Encoder version */
var $BUF=Array();
var $LOP=0;
var $DIS=2;
var $COL=-1;
var $IMG=-1;
var $ERR=Array(
'ERR00'=>"Does not supported function for only one image!",'ERR01'=>"Source is not a GIF image!",'ERR02'=>"Unintelligible flag ",'ERR03'=>"Could not make animation from animated GIF source",);
function GIFEncoder($GIF_src,$GIF_dly=100,$GIF_lop=0,$GIF_dis=0,$GIF_red=0,$GIF_grn=0,$GIF_blu=0,$GIF_mod='bin'){
if(!is_array($GIF_src)&&!is_array($GIF_tim)){
printf("%s: %s",$this->VER,$this->ERR['ERR00']);
exit(0);
}
$this->LOP=($GIF_lop>-1)?$GIF_lop:0;
$this->DIS=($GIF_dis>-1)?(($GIF_dis<3)?$GIF_dis:3):2;
$this->COL=($GIF_red>-1&&$GIF_grn>-1&&$GIF_blu>-1)?($GIF_red |($GIF_grn<<8)|($GIF_blu<<16)):-1;
for($i=0,$src_count=count($GIF_src);$i<$src_count;$i++){
if(strToLower($GIF_mod)=="url"){
$this->BUF[]=fread(fopen($GIF_src [$i],"rb"),filesize($GIF_src [$i]));
}elseif(strToLower($GIF_mod)=="bin"){
$this->BUF [ ]=$GIF_src [ $i ];
}else{
printf("%s: %s(%s)!",$this->ERR [ 'ERR02' ],$GIF_mod);
exit(0);
}
if(substr($this->BUF[$i],6)!="GIF87a"&&substr($this->BUF [$i],6)!="GIF89a"){
printf("%s: %d %s",$i,$this->ERR ['ERR01']);
exit(0);
}
for($j=(13+3*(2<<(ord($this->BUF[$i]{10})&0x07))),$k=TRUE;$k;$j++){
switch($this->BUF [$i]{$j}){
case "!":
if((substr($this->BUF[$i],($j+3),8))=="NETSCAPE"){
printf("%s: %s(%s source)!",$this->ERR ['ERR03'],($i+1));
exit(0);
}
break;
case ";":
$k=FALSE;
break;
}
}
}
GIFEncoder::GIFAddHeader();
for($i=0,$count_buf=count($this->BUF);$i<$count_buf;$i++){
GIFEncoder::GIFAddFrames($i,$GIF_dly[$i]);
}
GIFEncoder::GIFAddFooter(); }
function GIFAddHeader(){
$cmap=0;
if(ord($this->BUF[0]{10})&0x80){
$cmap=3(2<<(ord($this->BUF [0]{10})&0x07));
$this->GIF.=substr($this->BUF [0],7);
$this->GIF.=substr($this->BUF [0],13,$cmap);
$this->GIF.="!\377\13NETSCAPE2.0\3\1".GIFEncoder::GIFWord($this->LOP)."\0";
}
}
function GIFAddFrames($i,$d){
$Locals_str=13+3(2 <<(ord($this->BUF[$i]{10})&0x07));
$Locals_end=strlen($this->BUF[$i])-$Locals_str-1;
$Locals_tmp=substr($this->BUF[$i],$Locals_str,$Locals_end);
$Global_len=2<<(ord($this->BUF [0]{10})&0x07);
$Locals_len=2<<(ord($this->BUF[$i]{10})&0x07);
$Global_rgb=substr($this->BUF[0],3(2<<(ord($this->BUF[0]{10})&0x07)));
$Locals_rgb=substr($this->BUF[$i],3(2<<(ord($this->BUF[$i]{10})&0x07)));
$Locals_ext="!\xF9\x04".chr(($this->DIS<<2)+0).chr(($d>>0)&0xFF).chr(($d>>8)&0xFF)."\x0\x0";
if($this->COL>-1&&ord($this->BUF[$i]{10})&0x80){
for($j=0;$j<(2<<(ord($this->BUF[$i]{10})&0x07));$j++){
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){
$Locals_ext="!\xF9\x04".chr(($this->DIS<<2)+1).chr(($d>>0)&0xFF).chr(($d>>8)&0xFF).chr($j)."\x0";
break;
}
}
}
switch($Locals_tmp{0}){
case "!":
$Locals_img=substr($Locals_tmp,8,10);
$Locals_tmp=substr($Locals_tmp,18,strlen($Locals_tmp)-18);
break;
case ",":
$Locals_img=substr($Locals_tmp,10,strlen($Locals_tmp)-10);
break;
}
if(ord($this->BUF[$i]{10})&0x80&&$this->IMG>-1){
if($Global_len==$Locals_len){
if(GIFEncoder::GIFBlockCompare($Global_rgb,$Locals_rgb,$Global_len)){
$this->GIF.=($Locals_ext.$Locals_img.$Locals_tmp);
}else{
$byte=ord($Locals_img{9});
$byte|=0x80;
$byte&=0xF8;
$byte|=(ord($this->BUF [0]{10})&0x07);
$Locals_img{9}=chr($byte);
$this->GIF.=($Locals_ext.$Locals_img.$Locals_rgb.$Locals_tmp);
}
}else{
$byte=ord($Locals_img{9});
$byte|=0x80;
$byte&=0xF8;
$byte|=(ord($this->BUF[$i]{10})&0x07);
$Locals_img {9}=chr($byte);
$this->GIF.=($Locals_ext.$Locals_img.$Locals_rgb.$Locals_tmp);
}
}else{
$this->GIF.=($Locals_ext.$Locals_img.$Locals_tmp);
}
$this->IMG=1;
}
function GIFAddFooter(){
$this->GIF.=";";
}
function GIFBlockCompare($GlobalBlock,$LocalBlock,$Len){
for($i=0;$i<$Len;$i++){
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}){
return(0);
}
}
return(1);
}
function GIFWord($int){
return(chr($int&0xFF).chr(($int>>8)&0xFF));
}
function GetAnimation(){
return($this->GIF);
}
}
