php滑动验证码类

<?php
class SliderCaptcha {
    private $image;
    private $sliderPos;
    private $correctPos;

    public function __construct($width = 200, $height = 50) {
        $this->image = imagecreatetruecolor($width, $height);
        $this->sliderPos = rand(20, $width - 40);
        $this->correctPos = rand(20, $width - 40);
        $this->generateCaptcha();
    }

    private function generateCaptcha() {
        $bgColor = imagecolorallocate($this->image, 255, 255, 255);
        $fgColor = imagecolorallocate($this->image, 0, 0, 0);
        $sliderColor = imagecolorallocate($this->image, 128, 128, 128);

        imagefilledrectangle($this->image, 0, 0, $this->width, $this->height, $bgColor);

        // Draw slider track
        imagerectangle($this->image, 20, $this->height / 2 - 5, $this->width - 20, $this->height / 2 + 5, $fgColor);

        // Draw slider
        imagefilledrectangle($this->image, $this->sliderPos, $this->height / 2 - 10, $this->sliderPos + 20, $this->height / 2 + 10, $sliderColor);

        // Draw correct position indicator (for debugging purposes)
        imagerectangle($this->image, $this->correctPos, $this->height / 2 - 5, $this->correctPos + 2, $this->height / 2 + 5, $fgColor);
    }

    public function getImage() {
        header('Content-Type: image/png');
        imagepng($this->image);
        imagedestroy($this->image);
    }

    public function verifyPosition($userPos) {
        return $userPos == $this->correctPos;
    }
}

$captcha = new SliderCaptcha();
$captcha->getImage();
?>