A practical _php technique for PHP verification code function

This example for you to share a few sections of PHP verification code functions, are very practical, the specific contents are as follows

Code Snippet One: Simple PHP Verification code function

<?php function code () {$im = Imagecreatetruecolor (100, 40);
 
 $black = imagecolorallocate ($im, 0, 0, 0);
 
 
 
 $white = Imagecolorallocate ($im, 255, 255, 255);
 
 Imagefill ($im, 0,0, $white);
 
 $strarr =array_merge (Range (0,9), Range (a,z), Range (a,z));
 
 Shuffle ($strarr);
 
 $str =join (Array_slice ($strarr, 0,4));
 
 $MM =rand (0,40);
 
 $AAA =rand (0,0);
 
 $BBB =rand (0,255);
 
 $CCC =rand (0,255);
 
 $color 1=imagecolorallocate ($im, $AAA, $BBB, $CCC);
 
 Imagestring ($im, 5, $mm, $str, $color 1);
 
   For ($i =0 $i <700; $i + +) {$aa =rand (0,255);
 
   $BB =rand (0,255);
 
 $CC =rand (0,255);
 
   $color =imagecolorallocate ($im, $aa, $BB, $CC);
 
   $a =rand (0,100);
 
   $b =rand (0,40);
 
 Imagesetpixel ($im, $a, $b, $color);
 
   For ($t =0 $t <3; $t + +) {$a 1=rand (0,255);
 
   $b 1=rand (0,255);
 
 $c 1=rand (0,255);
 
   $color 2=imagecolorallocate ($im, $a 1, $b 1, $c 1);
 
   $a 2=rand (0,100);
 
   $b 2=rand (0,40);
 
   $a 3=rand (0,100);
 
   $b 3=rand (0,40);
 
 Imageline ($im, $a 2, $b 2, $b 3, $b 3, $color 2);
 
} 
 
 Header ("Content-type:image/png");
 
 Imagepng ($im);
 
} code ();

 ?>

Code Snippet two: PHP validation code function

function _code ($_code_length = 4, $_width = +, $_height =) {for ($i =0; $i <$_code_length; $i + +) {$_nmsg. = Dechex (M
 T_rand (0,15));

 } $_session["Code" = $_nmsg;

 $_img = Imagecreatetruecolor ($_width, $_height);

 $_white = Imagecolorallocate ($_img, 250, 250, 250);

 Imagefill ($_img, 0, 0, $_white);

 $_gray = Imagecolorallocate ($_img, 196, 196, 196);

 Imagerectangle ($_img, 0, 0, $_width-1, $_height-1, $_gray); For ($i =0 $i < 6; $i + +) {$_md_color = Imagecolorallocate ($_img, Mt_rand (200,255), Mt_rand (200,255), Mt_rand (200,25
  5));
 Imageline ($_img, Mt_rand (0,$_width), Mt_rand (0, $_height), Mt_rand (0,$_width), Mt_rand (0, $_height), $_md_color); For ($i =0 $i < $i + +) {$_md_color = Imagecolorallocate ($_img, Mt_rand (200,255), Mt_rand (200,255), Mt_rand (2
  00,255));
 Imagestring ($_img, 1, Mt_rand (1,$_width-5), Mt_rand (1, $_height-5), "*", $_md_color); For ($i =0 $i < $_code_length $i + +) {$_md_color = Imagecolorallocate ($_img, Mt_rand (0,102), Mt_rand (0,102), Mt_rand (0,102)); Imagestring ($_img, 5, $i * $_width/$_code_length+ Mt_rand (1), Mt_rand (1, $_HEIGHT/2), $_session["code" [$i], $_md_
 color);

 Header ("Content-type:image/png");

 Imagepng ($_IMG);
Imagedestroy ($_IMG);

 }

Code Snippet three: PHP Picture Verification code function

function of the/*@ captcha () function: Generate Authenticode * @ Customizable parameters: * @ $width picture width, default $high height, default of * @ $num Verification code number, default 4 * @ $line _num randomly drawn lines Number, default x @ $snow _num random snowflakes, default/function Captcha ($width =80, $high =25, $num =4, $line _num=10, $snow _num=50) {header (' C
 Ontent-type:image/png ');
 Session_Start (); Generate a random number + letter for ($a = 0; $a < $num; $a + +) {$code. = Dechex (Mt_rand (0));//dechex-decimal to hexadecimal}//Save generated CAPTCHA in Sessio
 N Super Global Array $_session[' captcha ' = $code;
 Create Canvas $img = Imagecreatetruecolor ($width, $high);
 The fill background color is white $backcolor = imagecolorallocate ($img, ' 255 ', ' 255 ', ' 255 ');
 Imagefill ($img, ' 0 ', ' 0 ', $backcolor);
 Add a black border $bordercolor = imagecolorallocate ($img, 0, 0, 0);
 Imagerectangle ($img, 0, 0, $width-1, $high-1, $bordercolor); Random draw lines for ($i =0; $i < $line _num; $i + +) {imageline ($img, Mt_rand (0, $width *0.1), Mt_rand (0, $high), Mt_rand ($width *0.9
 , $width), Mt_rand (0, $high), Imagecolorallocate ($img, Mt_rand (255), Mt_rand (255), Mt_rand (150, 255)); ///randomly hit snowflake for ($i =0; $i < $snow _num $i + +) {Imagechar ($img, 1, mt_rand (0, $width), Mt_rand (0, $high), ' * ', imagecolorallocate ($img, Mt_rand (200
 , 255), Mt_rand (MB, 255), Mt_rand (200, 255)); //Draw Verification code for ($b = 0; $b < strlen ($_session[' captcha ')) $b + +) {Imagechar ($img, 5, $b * $width/$num +mt_rand (5,10), Mt_ra nd (2, $high/2), $_session[' Captcha '] [$b], Imagecolorallocate ($img, Mt_rand, Mt_rand (0, 100))
 );
 Ob_clean ();//Empty output buffer imagepng ($img);
Imagedestroy ($IMG);

 }

Above is a three-paragraph reference to the higher PHP verification code function, I hope to learn from the PHP program to help.