The Art of Programming: Encapsulating a Verification Code Class (php)_PHP Tutorial

Encapsulate a verification code class
validationcode.class.php
class ValidationCode {
private $width;
private $height;
private $codeNum;
private $image; //Image resource
private $disturbColorNum;
private $checkCode;
function __construct($width=80, $height=20, $codeNum=4){
$this->width=$width;
$this->height=$height;
$this->codeNum=$codeNum;
$this->checkCode=$this->createCheckCode();
$number=floor($width*$height/15);

If($number > 240-$codeNum){
$this->disturbColorNum= 240-$codeNum;
}else{
$this->disturbColorNum=$number;
}

}
//Output the image to the browser by accessing this method
function showImage($fontFace=""){
//Step one: Create image background
$this->createImage();
//Step 2: Set up interference elements
$this->setDisturbColor();
//Step 3: Draw random text into the image
$this->outputText($fontFace);
//Step 4: Output image
$this->outputImage();
}

//Get the randomly created verification code string by calling this method
function getCheckCode(){
Return $this->checkCode;
}
private function createImage(){
//Create image resource
$this->image=imagecreatetruecolor($this->width, $this->height);
//Random background color
$backColor=imagecolorallocate($this->image, rand(225, 255), rand(225,255), rand(225, 255));
//Add color to the background
Imagefill($this->image, 0, 0, $backColor);
//Set border color
$border=imagecolorallocate($this->image, 0, 0, 0);
//Draw a rectangular border
Imagerectangle($this->image, 0, 0, $this->width-1, $this->height-1, $border);
}
private function setDisturbColor(){
for($i=0; $i<$this->disturbColorNum; $i++){
$color=imagecolorallocate($this->image, rand(0, 255), rand(0, 255), rand(0, 255));
imagesetpixel($this->image, rand(1, $this->width-2), rand(1, $this->height-2), $color);
}
for($i=0; $i<10; $i++){
$color=imagecolorallocate($this->image, rand(200, 255), rand(200, 255), rand(200, 255));
imagearc($this->image, rand(-10, $this->width), rand(-10, $this->height), rand(30, 300), rand(20, 200), 55 , 44, $color);
}
}
private function createCheckCode(){
$code="23456789abcdefghijkmnpqrstuvwxyzABCDEFGHIJKMNPQRSTUVWXYZ";
$string='';
for($i=0; $i < $this->codeNum; $i++){
$char=$code{rand(0, strlen($code)-1)};
$string.=$char;
}
Return $string;
}
private function outputText($fontFace=""){
for($i=0; $i<$this->codeNum; $i++){
$fontcolor=imagecolorallocate($this->image, rand(0, 128), rand(0, 128), rand(0, 128));
If($fontFace==""){
$fontsize=rand(3, 5);
$x=floor($this->width/$this->codeNum)*$i+3;
$y=rand(0, $this->height-15);
Imagechar($this->image,$fontsize, $x, $y, $this->checkCode{$i},$fontcolor);
}else{
$fontsize=rand(12, 16);
$x=floor(($this->width-8)/$this->codeNum)*$i+8;
$y=rand($fontSize+5, $this->height);
Imagettftext($this->image,$fontsize,rand(-30, 30),$x,$y ,$fontcolor, $fontFace, $this->checkCode{$i});
}
}
}
private function outputImage() {
If(imagetypes() & IMG_GIF){
header("Content-Type:image/gif");
Imagepng($this->image);
}else if(imagetypes() & IMG_JPG){
header("Content-Type:image/jpeg");
Imagepng($this->image);
}else if(imagetypes() & IMG_PNG){
header("Content-Type:image/png");
Imagepng($this->image);
}else if(imagetypes() & IMG_WBMP){
header("Content-Type:image/vnd.wap.wbmp");
Imagepng($this->image);
}else{
Die("PHP does not support image creation");
}
}
function __destruct(){
Imagedestroy($this->image);
}
}

Call the verification code class
code.php
session_start();
include "validationcode.class.php";
$code=new ValidationCode(80, 20, 4);
$code->showImage(); //Output to the page for registration or login
$_SESSION["code"]=$code->getCheckCode(); //Save the verification code to the server