生成数字验证码的功能

把该文件  http://pan.baidu.com/s/1dFnO6nZ  放入www目录，然后新建一个test.php文件，复制以下代码，可以进行测试

<?php
/**
 * 简单的图片验证码
 */
class PictureCaptcha
{
    /**
     * @var int 图片像素宽度
     */
    protected $imageWidth;

    /**
     * @var int 图片像素高度
     */
    protected $imageHeight;


    /**
     * @var resource 图片句柄
     */
    protected $img;


    /**
     * @var string 字符集
     */
    protected $font;

    /**
     * @var string 字体文件路径
     */
    protected $fontDir;

    /**
     * @var int 字符尺寸大小
     */
    protected $fontSize;

    /**
     * @var string 验证码
     */
    protected $code;

    /**
     * @var int 验证码字符数
     */
    protected $codeCount;

    /**
     * @var array 颜色数组
     */
    protected $colorArr;

    /**
     * @var int 图片中线的数量
     */
    protected $lineCount;

    /**
     * @var int 图片中点的数量
     */
    protected $pixCount;
    /**
     * @var int 颜色的数量
     */
    protected $colorCount;

    /**
     * @var array 颜色值
     */
    protected $colorStyle;

    /**
     * @var array 配置参数
     */
    protected $config;

    /**
     * 生成图片验证码需GD库支持
     */
    public function __construct()
    {
        if (!function_exists('imagecreate')) {
            throw new RuntimeException('GD extension is not exist!');
        }

        $this->init();
    }


    public function init()
    {
        $this->config = $this->getConfig();

        $this->font = isset($this->config['font']) ? $this->config['font'] : '0123456789abcdefghijklmnopqrstuvwxyz0123456789';  //想要纯数字, 这边可以替换成0123456789
        $this->fontDir = dirname(__FILE__) . '/' . (isset($this->config['fontFile']) ? $this->config['fontFile'] : 'BELL.TTF');
        $this->imageWidth = isset($this->config['width']) ? $this->config['width'] : 100;
        $this->imageHeight = isset($this->config['height']) ? $this->config['height'] : 30;
        $this->codeCount = isset($this->config['codeCount']) ? $this->config['codeCount'] : 4;
        $this->fontSize = isset($this->config['fontSize']) ? $this->config['fontSize'] : 30;
        $this->lineCount = isset($this->config['lineCount']) ? $this->config['lineCount'] : 2;
        $this->pixCount = isset($this->config['pixCount']) ? $this->config['pixCount'] : 200;
        $this->colorCount = isset($this->config['colorCount']) ? $this->config['colorCount'] : 1;
        $this->colorStyle = isset($this->config['colorStyle']) ? $this->config['colorStyle'] : [];

    }


    /**
     * 载入配置参数
     * @return array
     */
    public function getConfig()
    {
        $fileDir = dirname(__FILE__) . '/config.php';

        if (file_exists($fileDir)) {
            return require $fileDir;
        }

        return [];
    }

    /**
     * 返回创建好的图像句柄，
     * 还需要进行头信息的设置与销毁
     *
     * @return resource $this->img
     */
    public function create()
    {
        $this->createImage();
        $this->createColor($this->colorCount);
        $this->createPix($this->pixCount);
        $this->createLine($this->lineCount);
        $this->createText();

        return $this->img;
    }


    /**
     * 创建字符所用颜色
     * 可以指定颜色的个数
     * 默认为4个颜色
     * @param int $colorCount
     * @return array
     */
    protected function createColor($colorCount = 0)
    {
        $this->colorArr = [];

        // 第一次调用该函数则 为画布创建背景色
        imagecolorallocate($this->img, 255, 255, 255);

        if ($colorCount > 0) {

            $i = 0;

            $styleIndex = 0;
            $styleCount = count($this->colorStyle) - 1;


            while ($i < $colorCount){

                if (isset($this->colorStyle[$styleIndex])) {
                    $color1 = $this->colorStyle[$styleIndex][0];
                    $color2 = $this->colorStyle[$styleIndex][1];
                    $color3 = $this->colorStyle[$styleIndex][2];

                    // 当设置的颜色不够时，循环赋值
                    if ($styleIndex == $styleCount) {
                        $styleIndex = 0;
                    } else {
                        $styleIndex++;
                    }
                } else {
                    $color1 = rand(0, 255);
                    $color2 = rand(0, 255);
                    $color3 = rand(0, 255);
                }

                $this->colorArr[] = imagecolorallocate($this->img, $color1, $color2, $color3);
                $i++;
            }

            return $this->colorArr;
        }

        $this->colorArr[] = imagecolorallocate($this->img, 0, 0, 0);
        $this->colorArr[] = imagecolorallocate($this->img, 0, 0, 0);
        $this->colorArr[] = imagecolorallocate($this->img, 0, 0, 0);
        $this->colorArr[] = imagecolorallocate($this->img, 0, 0, 0);

        return $this->colorArr;
    }


    /**
     * 创建基础画布
     */
    protected function createImage()
    {
        $this->img = imagecreate($this->imageWidth,$this->imageHeight);
    }

    /**
     * 在画布上生成若干点
     * （颜色随机，位置随机）
     * @param int $pixCount 生成点的数量
     */
    protected function createPix($pixCount = 400)
    {
        $i = 0;
        $colorIndex = count($this->colorArr) - 1;

        while ($i < $pixCount) {
            imagesetpixel($this->img, rand(0,$this->imageWidth), rand(0,$this->imageHeight), $this->colorArr[rand(0,$colorIndex)]);
            $i++;
        }
    }


    /**
     * 画线
     * @param int $lineCount 线的数量
     */
    protected function createLine($lineCount = 2)
    {
        $i = 0;
        imagesetstyle($this->img ,$this->colorArr);

        while ($i < $lineCount) {
            imageline($this->img, 0, rand(0, $this->imageHeight), $this->imageWidth, rand(0, $this->imageHeight), IMG_COLOR_STYLED);
            $i++;
        }
    }

    /**
     * 设置图片中文字
     */
    protected function createText()
    {
        $i = 0;
        $fontIndex = strlen($this->font) - 1;
        $colorIndex = count($this->colorArr) - 1;
        $codes = '';
        $x = 0;

        while ($i < $this->codeCount) {

            $code = $this->font{rand(0, $fontIndex)};
            $color = $this->colorArr[rand(0, $colorIndex)];

            imagettftext($this->img, $this->fontSize, 0, $x, rand($this->fontSize - 10, $this->fontSize * 2 - $this->imageHeight), $color, $this->fontDir, $code);
            $x += intval($this->imageWidth / $this->codeCount);

            $i++;
            $codes .= $code;
        }
        $this->code = $codes;
    }

    public function getCode()
    {
        return $this->code;
    }

}

$pictureCaptcha = new PictureCaptcha();

$image = $pictureCaptcha->create();
$code = $pictureCaptcha->getCode();

$imageFile = 'D:123' .  '.png';

imagepng($image, $imageFile);
imagedestroy($image);//显示和销毁是必需的

$base64Content = base64_encode(file_get_contents($imageFile));//base64编码

unlink($imageFile);  //本地测试的时候可以注释, 可以看见图片内容, 正式环境需要unlink，因为返回了base64码，会形成图片，图片占资源

$base64 = 'data:image/png;base64,'.$base64Content;

print <<<EOT
    <img src=$base64 />
EOT;

// 图片转换Base64在线工具[http://imgbase64.duoshitong.com]
?>