<?php
$width?=?200;
$height?=?40;
$font_file?=?'fonts/mini.ttf';

$image?=?imagecreatetruecolor($width,$height);
$white?=?imagecolorallocate($image,255,255,255);
function?get_color($image){
????$rand_color?=?imagecolorallocate($image,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255));
????return?$rand_color;
}
imagefilledrectangle($image,0,0,$width,$height,$white);
$string?=?join('',array_merge(range(0,9),range('a','z'),range('A','Z')));
$length?=?4;
for($i?=?0;$i?<?$length;$i++){
????$angle?=?mt_rand(-15,15);
????$fontsize?=?mt_rand(20,28);
????$text?=?str_shuffle($string)[0];
????//get?font?width?and?font?height
????$font_width?=?imagefontwidth($fontsize);
????$font_height?=?imagefontheight($fontsize);
????$x?=?20?+?($width?-?20?*?2)?/?3?*?$i;
????$y?=?40?-?((40?-?$font_height)?/?2);
????$rand_color?=?get_color($image);
????imagettftext($image,$fontsize,$angle,$x,$y,$rand_color,$font_file,$text);
}
//add?interference?of?pixel
for($i?=?0;?$i?<?50;?$i++){
????imagesetpixel($image,?mt_rand(0,$width),mt_rand(0,$height),get_color($image));
}
//add?interference?of?line
for($i?=?0;?$i?<?3;?$i++){
????$x1?=?mt_rand(0,$width);
????$y1?=?mt_rand(0,$height);
????$x2?=?mt_rand(0,$width);
????$y2?=?mt_rand(0,$height);
????while(1){
????????if($x1?==?$x2?and?$y1?==?$y2){
????????????$x1?=?mt_rand(0,$width);
????????????$y1?=?mt_rand(0,$height);
????????????$x2?=?mt_rand(0,$width);
????????????$y2?=?mt_rand(0,$height);
????????}
????????else{
????????????break;
????????}
????}
????imageline($image,$x1,$y1,$x2,$y2,get_color($image));
}
//add?interference?of?arc
for($i?=?0;?$i?<?3;?$i++){
????$cx?=?mt_rand(0,?$width);
????$cy?=?mt_rand(0,?$height);
????$w?=?mt_rand(0,?min($cx,?$width?-?$cx));
????$h?=?mt_rand(0,?min($cy,?$height?-?$cy));
????$s?=?mt_rand(0,?160);
????$e?=?mt_rand(0,?160);
????imagearc($image,?$cx,?$cy,?$w,?$h,?$s,?$e,?get_color($image));
}
header('content-type:image/png');
imagepng($image);
imagedestroy($image);

<pre class="brush:php;toolbar:false">&lt;?php $width?=?200; $height?=?40; $font_file?=?'fonts/mini.ttf'; $image?=?imagecreatetruecolor($width,$height); $white?=?imagecolorallocate($image,255,255,255); function?get_color($image){ ????$rand_color?=?imagecolorallocate($image,mt_rand(0,255),mt_rand(0,255),mt_rand(0,255)); ????return?$rand_color; } imagefilledrectangle($image,0,0,$width,$height,$white); $string?=?join('',array_merge(range(0,9),range('a','z'),range('A','Z'))); $length?=?4; for($i?=?0;$i?&lt;?$length;$i++){ ????$angle?=?mt_rand(-15,15); ????$fontsize?=?mt_rand(20,28); ????$text?=?str_shuffle($string)[0]; ????//get?font?width?and?font?height ????$font_width?=?imagefontwidth($fontsize); ????$font_height?=?imagefontheight($fontsize); ????$x?=?20?+?($width?-?20?*?2)?/?3?*?$i; ????$y?=?40?-?((40?-?$font_height)?/?2); ????$rand_color?=?get_color($image); ????imagettftext($image,$fontsize,$angle,$x,$y,$rand_color,$font_file,$text); } //add?interference?of?pixel for($i?=?0;?$i?&lt;?50;?$i++){ ????imagesetpixel($image,?mt_rand(0,$width),mt_rand(0,$height),get_color($image)); } //add?interference?of?line for($i?=?0;?$i?&lt;?3;?$i++){ ????$x1?=?mt_rand(0,$width); ????$y1?=?mt_rand(0,$height); ????$x2?=?mt_rand(0,$width); ????$y2?=?mt_rand(0,$height); ????while(1){ ????????if($x1?==?$x2?and?$y1?==?$y2){ ????????????$x1?=?mt_rand(0,$width); ????????????$y1?=?mt_rand(0,$height); ????????????$x2?=?mt_rand(0,$width); ????????????$y2?=?mt_rand(0,$height); ????????} ????????else{ ????????????break; ????????} ????} ????imageline($image,$x1,$y1,$x2,$y2,get_color($image)); } //add?interference?of?arc for($i?=?0;?$i?&lt;?3;?$i++){ ????$cx?=?mt_rand(0,?$width); ????$cy?=?mt_rand(0,?$height); ????$w?=?mt_rand(0,?min($cx,?$width?-?$cx)); ????$h?=?mt_rand(0,?min($cy,?$height?-?$cy)); ????$s?=?mt_rand(0,?160); ????$e?=?mt_rand(0,?160); ????imagearc($image,?$cx,?$cy,?$w,?$h,?$s,?$e,?get_color($image)); } header('content-type:image/png'); imagepng($image); imagedestroy($image);</pre><p><br /></p>