English with numbers
Header ("Content-type:image/png");
Define header, declare picture file, preferably PNG, no copyright disturbance;
Generate a new four-bit integer verification code
Session_Start ();//open session;
$authnum _session = ";
$str = ' abcdefghijkmnpqrstuvwxyz1234567890 ';
Define the numbers and letters used to display on the image;
$l = strlen ($STR); Get the length of the string;
The loop randomly extracts four-bit letters and numbers defined earlier;
for ($i =1; $i <=4; $i + +)
{
$num =rand (0, $l-1);
Randomly extracting one digit at a time, from the first word to the maximum length of the string,
Minus 1 is because the Intercept character starts from 0, so that 34 characters may be in the line;
$authnum _session.= $str [$num];
The number of words Fulianqi will be four bits;
}
Session_register ("Authnum_session");
Using the session to do the verification is also good; register the session, the name is Authnum_session,
Other pages are included as long as they contain this image
That can be called by $_session["Authnum_session").
Generate a Captcha picture,
Srand (Double) microtime () *1000000);
$im = Imagecreate (50,20);//Picture width and height;
The main use of black and white gray three colors;
$black = Imagecolorallocate ($im, 0,0,0);
$white = Imagecolorallocate ($im, 255,255,255);
$gray = Imagecolorallocate ($im, 200,200,200);
Drawing a four-bit integer verification code into a picture
Imagefill ($im, 68,30, $gray);
If you do not have to interfere with the line, the comment is OK;
$li = Imagecolorallocate ($im, 220,220,220);
for ($i =0; $i <3; $i + +)
{//Add 3 lines of interference, or do not; Depending on the circumstances, as it may affect user input;
Imageline ($im, Rand (0,30), Rand (0,21), Rand (20,40), Rand (0,21), $li);
}
The position of the character in the picture;
Imagestring ($im, 5, 8, 2, $authnum _session, $white);
for ($i =0; $i <90; $i + +)
{//Add interfering pixels
Imagesetpixel ($im, Rand ()%70, Rand ()%30, $gray);
}
Imagepng ($im);
Imagedestroy ($im);
?>
Chinese
/*
* File: code.php
* Function: Verification code generation
*/
Session_Start ();
Set Content-type
Header ("Content-type:image/png");
Create a picture
$im = Imagecreatetruecolor (120, 30);
$ChineseChar = Array ("Person", "out", "Come", "friend", "Learn", "filial piety", "benevolence", "righteousness", "propriety", "low", "loyalty", "Country", "middle", "easy", "white", "person", "Fire", "Earth", "gold", "Wood", "Thunder", "Wind", "Dragon" , "Tiger", "Day", "ground",
"Sheng", "halo", "dish", "bird", "Tian", "three", "Hundred", "money", "blessing", "Love", "affection", "Beast", "Worm", "fish", "nine", "net", "new", "degree", "ay", "Alas", "ah", "Oh", "Miriam", "old", "less", "Day",
"Month", "star");
Create color
$fontcolor = Imagecolorallocate ($im, 255, 255, 255);
$BG = imagecolorallocate ($im, 0, 0, 0);
Set text
for ($i =0; $i <4; $i + +) $text. = $ChineseChar [(Array_rand ($ChineseChar))];
$_session[' Code ' = $text;
Set font [Url]http://www.font.com.cn/downlist/s_12_3.html[/url] have _GBK series font download, General GD Library are supported!
$font = ' Gbk.ttf ';
Add text
Imagettftext ($im, 0, one, one, $fontcolor, $font, Iconv ("GB2312", "UTF-8", $text));
Output picture
Imagepng ($im);
Imagedestroy ($im);
?>
The above describes the 12306 verification code PHP Chinese alphanumeric Verification code implementation codes, including the content of the 12306 verification Code, I hope to be interested in PHP tutorial friends helpful.
