PHP验证码

来源：互联网发布：网络常用端口号大全编辑：程序博客网时间：2024/04/24 14:19

网上有不少用php写验证码的代码，不过效果都不太喜欢，了解了一下原理就自己写了一个,字体采用的是Consolas.ttf

<?phpif(!isset($_SESSION)) session_start();$png_width=88;$png_height=31;$captcha_length=4;$captcha_content=captcha_content($captcha_length);$_SESSION['captcha']=$captcha_content;$img=imagecreate($png_width,$png_height);$png_bgcolor=imagecolorallocate($img,165,178,170);imagerectangle($img,0,0,$width,$height,$png_bgcolor);for($i=0;$i<$captcha_length;$i++){ $char_color=imagecolorallocate($img,mt_rand(50,200),mt_rand(50,150),mt_rand(50,200)); $char_angle=mt_rand(-30,30); $char_x=$i*17+mt_rand(-1,8); $char_y=mt_rand(25,31); imagettftext($img,25,$char_angle,$char_x,$char_y,$char_color,'Consola.ttf',$captcha_content[$i]);}for($i=0;$i<100;$i++){$pixel_color=imagecolorallocate($img,mt_rand(50,200),mt_rand(50,150),mt_rand(50,200));imagesetpixel($img,mt_rand(1,$png_width-1),mt_rand(1,$png_height-1),$pixel_color);}for($i=0;$i<30;$i++){$line_color=imagecolorallocate($img,mt_rand(0,250),mt_rand(0,250),mt_rand(0,250));$line_x=mt_rand(1,$png_width-1);$line_y=mt_rand(1,$png_height-1);imageline($img,$line_x,$line_y,$line_x+mt_rand(0,4)-2,$line_y+mt_rand(0,4)-2,$line_color);}function captcha_content($captcha_length){  $char_source="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghiklmnopqrstuvwxyz"; for($i=0;$i<$captcha_length;$i++){    $num=mt_rand(0,61);    $captcha_content.=$char_source[$num];  }  return $captcha_content;}ob_clean();header('Content-type:image/png');imagepng($img);imagedestroy($img);?>

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