Php image verification code

[Php] & lt ;? Php/*** image verification code class * generates an image verification code. the verification code contains numbers and uppercase letters. the session stores the md5-encrypted verification code. ** usage: * $ captcha = newCatpcha (); * $ captcha-& gt; buildAndExportImage (); ** author... "/> <scr

[Php]
/**
* Image verification code
* An image verification code is generated. the verification code contains numbers and uppercase letters. the md5 encrypted verification code is stored in the session.
*
* Usage:
* $ Captcha = new Catpcha ();
* $ Captcha-> buildAndExportImage ();
*
* Author: luojing
* Creation Time: 11:42:12
*/
Class Captcha {

Private $ width; // width
Private $ height; // height
Private $ codeNum; // Number of characters in the verification code
Private $ image; // verification code image resource
Private $ sessionKey; // name saved in the session
Private $ captcha; // verification code string
Const charWidth = 10; // The width of a single character, which varies according to the size of the output character

/**
* Create a verification code class and initialize relevant parameters
* @ Param $ width: Image width
* @ Param $ height: Image height
* @ Param $ codeNum verification code character count
* @ Param $ Name saved in sessionKey session
*/
Function _ construct ($ width = 50, $ height = 20, $ codeNum = 4, $ sessionKey = 'captcha '){
$ This-> width = $ width;
$ This-> height = $ height;
$ This-> codeNum = $ codeNum;
$ This-> sessionKey = $ sessionKey;

// Minimum height and width
If ($ height <20 ){
$ This-> height = 20;
}
If ($ width <($ codeNum * self: charWidth + 10) {// Each left and right retain 5 pixel gaps
$ This-> width = $ codeNum * self: charWidth + 10;
}
}

/**
* Construct and output the verification code Image
*/
Public function buildAndExportImage (){
$ This-> createImage ();
$ This-> setDisturb ();
$ This-> setCaptcha ();
$ This-> exportImage ();
}

/**
* Construct an image and set the background color
*/
Private function createImage (){
// Create an image
$ This-> image = imagecreatetruecolor ($ this-> width, $ this-> height );
// Create a background color
$ Bg = imagecolorallocate ($ this-> image, mt_rand (220,255), mt_rand (220,255), mt_rand (220,255 ));
// Fill in the background color
Imagefilledrectangle ($ this-> image, 0, 0, $ this-> width-1, $ this-> height-1, $ bg );
}

/**
* Set interference elements
*/
Private function setDisturb (){

// Set interference points
For ($ I = 0; I I <150; $ I ++ ){
$ Color = imagecolorallocate ($ this-> image, mt_rand (150,200), mt_rand (150,200), mt_rand (150,200 ));
Imagesetpixel ($ this-> image, mt_rand (5, $ this-> width-10), mt_rand (5, $ this-> height-3), $ color );
}

// Set the interference line
For ($ I = 0; $ I <10; $ I ++ ){
$ Color = imagecolorallocate ($ this-> image, mt_rand (150,220), mt_rand (150,220), mt_rand (150,220 ));
Imagearc ($ this-> image, mt_rand (-10, $ this-> width), mt_rand (-10, $ this-> height), mt_rand (30,300 ), mt_rand (20,200), 55, 44, $ color );
}

// Create a border color
$ Border = imagecolorallocate ($ this-> image, mt_rand (0, 50), mt_rand (0, 50), mt_rand (0, 50 ));
// Draw a border
Imagerectangle ($ this-> image, 0, 0, $ this-> width-1, $ this-> height-1, $ border );
}

/**
* Generate and draw a verification code
*/
Private function setCaptcha (){
$ Str = '23456789abcdefghjklmnpqrstuvwxyz ';
// Generate verification code characters
For ($ I = 0; $ I <$ this-> codeNum; $ I ++ ){
$ This-> captcha. =$ str {mt_rand (0, strlen ($ str)-1 )};
}
// Draw the verification code
For ($ I = 0; $ I <strlen ($ this-> captcha); $ I ++ ){
$ Color = imagecolorallocate ($ this-> image, mt_rand (0,200), mt_rand (0,200), mt_rand (0,200 ));
$ X = floor ($ this-> width-10)/$ this-> codeNum );
$ X = $ x * $ I + floor ($ x-self: charWidth)/2) + 5;
$ Y = mt_rand (2, $ this-> height-20 );
Imagechar ($ this-> image, 5, $ x, $ y, $ this-> captcha {$ I}, $ color );
}
}

/*
* Output the image and save the verification code to the session.
*/
Private function exportImage (){
If (imagetypes () & IMG_GIF ){
Header ('content-type: image/gif ');
Imagegif ($ this-> image );
} Else if (imagetypes () & IMG_PNG ){
Header ('content-type: image/png ');
Imagepng ($ this-> iamge );
} Else if (imagetypes () & IMG_JPEG ){
Header ('content-type: image/jpeg ');
Imagepng ($ this-> iamge );
} Else {
Imagedestroy ($ this-> image );
Die ("Don't support image type! ");
}
// Save the verification code information to the session and encrypt it with md5.
If (! Isset ($ _ SESSION )){
Session_start ();
}
$ _ SESSION [$ this-> sessionKey] = md5 ($ this-> captcha );

Imagedestroy ($ this-> image );
}

Function _ destruct (){
Unset ($ this-> width, $ this-> height, $ this-> codeNum, $ this-> captcha );
}
}

/**
* Image verification code
* An image verification code is generated. the verification code contains numbers and uppercase letters. the md5 encrypted verification code is stored in the session.
*
* Usage:
* $ Captcha = new Catpcha ();
* $ Captcha-> buildAndExportImage ();
*
* Author: luojing
* Creation Time: 11:42:12
*/
Class Captcha {
 
Private $ width; // width
Private $ height; // height
Private $ codeNum; // Number of characters in the verification code
Private $ image; // verification code image resource
Private $ sessionKey; // name saved in the session
Private $ captcha; // verification code string
Const charWidth = 10; // The width of a single character, which varies according to the size of the output character
 
/**
* Create a verification code class and initialize relevant parameters
* @ Param $ width: Image width
* @ Param $ height: Image height
* @ Param $ codeNum verification code character count
* @ Param $ Name saved in sessionKey session
*/
Function _ construct ($ width = 50, $ height = 20, $ codeNum = 4, $ sessionKey = 'captcha '){
$ This-> width = $ width;
$ This-> height = $ height;
$ This-> codeNum = $ codeNum;
$ This-> sessionKey = $ sessionKey;

// Minimum height and width
If ($ height <20 ){
$ This-> height = 20;
}
If ($ width <($ codeNum * self: charWidth + 10) {// Each left and right retain 5 pixel gaps
$ This-> width = $ codeNum * self: charWidth + 10;
}
}
 
/**
* Construct and output the verification code Image
*/
Public function buildAndExportImage (){
$ This-> createImage ();
$ This-> setDisturb ();
$ This-> setCaptcha ();
$ This-> exportImage ();
}
 
/**
* Construct an image and set the background color
*/
Private function createImage (){
// Create an image
$ This-> image = imagecreatetruecolor ($ this-> width, $ this-> height );
// Create a background color
$ Bg = imagecolorallocate ($ this-> image, mt_rand (220,255), mt_rand (220,255), mt_rand (220,255 ));
// Fill in the background color
Imagefilledrectangle ($ this-> image, 0, 0, $ this-> width-1, $ this-> height-1, $ bg );
}
 
/**
* Set interference elements
*/
Private function setDisturb (){

// Set interference points
For ($ I = 0; I I <150; $ I ++ ){
$ Color = imagecolorallocate ($ this-> image, mt_rand (150,200), mt_rand (150,200), mt_rand (150,200 ));
Imagesetpixel ($ this-> image, mt_rand (5, $ this-> width-10), mt_rand (5, $ this-> height-3), $ color );
}

// Set the interference line
For ($ I = 0; $ I <10; $ I ++ ){
$ Color = imagecolorallocate ($ this-> image, mt_rand (150,220), mt_rand (150,220), mt_rand (150,220 ));
Imagearc ($ this-> image, mt_rand (-10, $ this-> width), mt_rand (-10, $ this-> height), mt_rand (30,300 ), mt_rand (20,200), 55, 44, $ color );
}

// Create a border color
$ Border = imagecolorallocate ($ this-> image, mt_rand (0, 50), mt_rand (0, 50), mt_rand (0, 50 ));
// Draw a border
Imagerectangle ($ this-> image, 0, 0, $ this-> width-1, $ this-> height-1, $ border );
}
 
/**
* Generate and draw a verification code
*/
Private function setCaptcha (){
$ Str = '23456789abcdefghjklmnpqrstuvwxyz ';
// Generate verification code characters
For ($ I = 0; $ I <$ this-> codeNum; $ I ++ ){
$ This-> captcha. =$ str {mt_rand (0, strlen ($ str)-1 )};
}
// Draw the verification code
For ($ I = 0; $ I <strlen ($ this-> captcha); $ I ++ ){
$ Color = imagecolorallocate ($ this-> image, mt_rand (0,200), mt_rand (0,200), mt_rand (0,200 ));
$ X = floor ($ this-> width-10)/$ this-> codeNum );
$ X = $ x * $ I + floor ($ x-self: charWidth)/2) + 5;
$ Y = mt_rand (2, $ this-> height-20 );
Imagechar ($ this-> image, 5, $ x, $ y, $ this-> captcha {$ I}, $ color );
}
}
 
/*
* Output the image and save the verification code to the session.
*/
Private function exportImage (){
If (imagetypes () & IMG_GIF ){
Header ('content-type: image/gif ');
Imagegif ($ this-> image );
} Else if (imagetypes () & IMG_PNG ){
Header ('content-type: image/png ');
Imagepng ($ this-> iamge );
} Else if (imagetypes () & IMG_JPEG ){
Header ('content-type: image/jpeg ');
Imagepng ($ this-> iamge );
} Else {
Imagedestroy ($ this-> image );
Die ("Don't support image type! ");
}
// Save the verification code information to the session and encrypt it with md5.
If (! Isset ($ _ SESSION )){
Session_start ();
}
$ _ SESSION [$ this-> sessionKey] = md5 ($ this-> captcha );

Imagedestroy ($ this-> image );
}
 
Function _ destruct (){
Unset ($ this-> width, $ this-> height, $ this-> codeNum, $ this-> captcha );
}
}