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<?php
/**
* Generate Validation Code
*
* Copyright 2008 Goodjobs.cn
* @author andy <lvqingan@yahoo.com.cn>
*
*/
 
class ValidationCode
{
    // Length of Validation Code
    private $mValidationCodeLength   = 4;
 
    // Validation Code Candidate
    private $mValidationCodeCandidate = '3456789abcdefghjkmnpqrstuvwxy';
     
    // Final Validation Code
    private $mValidationCode    = '';
 
    // Image for Validatio Code
    private $mValidationImage   = '';
 
    // Disturb Color
    private $mDisturbColor   = '';
     
    // Number of Disturb Pix
    private $mDisturbLevel   = 128;    
 
    // Width of Image
    private $mValidationImageWidth = '90';
 
    // Height of Image
    private $mValidationImageHeight   = '25';
 
    // 算术验证码第一个数字
    private $firstNumber = '';
 
    // 算术验证码第二个数字
    private $secondNumber = '';
 
    // 算术验证码符号
    private $symbol = '';
 
    // 算术验证码符号数组
    private $symbolMap = ['+','×'];
 
 
    /**
     * Output Header
     *
     */
    private function OutFileHeader()
    {
        header ("Content-type: image/png");
    }
 
    /**
     * Get Font
     */
    private function getFont()
    {
        return dirname(__FILE__).'/../data/fonts/Arial_Bold.ttf';
    }
 
    /**
     * Create Validation Code
     *
     */
    private function CreateValidationCode()
    {
        for ($i = 0; $i < $this->mValidationCodeLength; $i++) {
            $pos = mt_rand(0, strlen($this->mValidationCodeCandidate) - 1);
            $this->mValidationCode .= strtoupper(substr($this->mValidationCodeCandidate, $pos, 1));
        }  
        return $this->mValidationCode;
    }
    /**
     * Create Math Validation Code
     *
     */
    private function CreateMathValidationCode()
    {
        $this->firstNumber = rand(0,9);
        $this->secondNumber = rand(0,9);
        $this->symbol = $this->symbolMap[array_rand($this->$symbolMap)];
        switch ($this->symbol) {
            case '+':
                $this->mValidationCode = $this->firstNumber + $this->secondNumber;
                break;
            case '×':
                $this->mValidationCode = $this->firstNumber * $this->secondNumber;
                break;
            default:
                # code...
                break;
        }
        return $this->mValidationCode;
    }
 
    /**
     * Create Validation Image
     *
     */
    private function CreateValidationImage()
    {
        $this->mValidationImage = @imagecreate($this->mValidationImageWidth, $this->mValidationImageHeight);
        imagecolorallocate($this->mValidationImage, 192, 192, 192);
        return $this->mValidationImage;
    }
 
    /**
     * Set Disturb Color
     *
     */
    private function SetDisturbColor()
    {
        for ($i = 0; $i <= $this->mDisturbLevel; $i++)
        {
            // Random Color
            $this->mDisturbColor = imagecolorallocate($this->mValidationImage, rand(0, 255), rand(0, 255), rand(0, 255));
            imagesetpixel($this->mValidationImage, rand(0, $this->mValidationImageWidth), rand(0, $this->mValidationImageHeight), $this->mDisturbColor);
        }
    }
 
    /**
     * Set Width and Height of Validation Image
     *
     * @param $width
     * @param $height
     *
     */
    public function SetValidationImageSize($width, $height)
    {
        if($width == '' || $height == '') {
            return false;
        }
        $this->mValidationImageWidth  = $width;
        $this->mValidationImageHeight = $height;
        return true;
    }
 
    /**
     * Draw Validation Code to Image
     *
     */
    private function DrawValidationCodeToImage()
    {
        for ($i=0; $i <= $this->mValidationCodeLength; $i++)
        {
            $backgroundColor = imagecolorallocate($this->mValidationImage, rand(0,255), rand(0,128), rand(0,255));
            $charX = floor($this->mValidationImageWidth / $this->mValidationCodeLength) * $i + 5;
            $charY = rand($this->mValidationImageHeight - 6, $this->mValidationImageHeight - 2);
            $angle = rand(-25, 25);
            imagettftext ($this->mValidationImage, 14, $angle, $charX, $charY, $backgroundColor, $this->getFont, $this->mValidationCode[$i]);
        }
    }
 
    /**
     * Draw Math Validsation Code to Image
     *
     */
    private function DrawMathValidationCodeToImage()
    {
        $mathArr = [$this->firstNumber, $this->Symbol, $this->secondNumber, '='];
        foreach($mathArr as $key=>$value){
            $backgroundColor = imagecolorallocate($this->mValidationImage, rand(0,255), rand(0,128), rand(0,255));
            $charX = floor($this->mValidationImageWidth / count($mathArr) ) * $key + 5;
            $charY = rand($this->mValidationImageHeight - 6, $this->mValidationImageHeight - 2);
            $angle = rand(-25, 25);
            imagettftext ($this->mValidationImage, 14, $angle, $charX, $charY, $backgroundColor, $this->getFont, $value);
        }
    }
 
    /**
     * Output Image
     *
     */
    public function OutputValidationImage()
    {
        $this->OutFileHeader();
        $outPutfunc = ['OutputCode','OutputMathCode'];
        $func = $outPutfunc[array_rand($outPutfunc)];
        $this->$func();
        imagepng($this->mValidationImage);
        imagedestroy($this->mValidationImage);
    }
 
    /**
     * Output Normal Code
     */
    private function OutputCode()
    {
        $this->CreateValidationCode();
        $this->CreateValidationImage();
        $this->SetDisturbColor();
        $this->DrawValidationCodeToImage();
    }
 
    /**
     * Output Math Code
     */
    private function OutputMathCode()
    {
        $this->CreateMathValidationCode();
        $this->CreateValidationImage();
        $this->SetDisturbColor();
        $this->DrawMathValidationCodeToImage();
 
    }
     
    /**
     * Get Validation Code
     *
     * @return string
     */
    public function getValidationCode() {
        return $this->mValidationCode;
    }
}