PHP学习之图像处理-水印类

<?php
$image = new image();
$image->water('./upload/up_5cf0caca0565b.png','./upload/up_5cf0cb3a61fae.jpg',9);
class image
{
    //路径
    protected $path;
    //是否启用随机名字
    protected $israndname;
    //要保存的图像类型
    protected $type;

    //通过构造方法对成员属性进行初始化
    function __construct($path = './', $israndname = true, $type = 'png')
    {
        $this->path = $path;
        $this->israndname = $israndname;
        $this->type = $type;
    }

    /**
     * 对外公开的水印方法
     *
     * @param [type] $image 原图片
     * @param [type] $water 水印图片
     * @param [type] $postion 水印图片的位置
     * @param integer $tmd 水印图片的透明度
     * @param string $prefix 图片的前缀
     * @return void
     */
    function water($image, $water, $postion, $tmd = 100, $prefix = 'water_')
    {
        //1、判断这两个图片是否存在
        if ((!file_exists($image)) || (!file_exists($water))) {
            die('图片资源不存在');
        }
        //2、得到原图片的宽度和高度以及水印图片的宽带和高度
        $imageinfo = self::getimageinfo($image);
        $waterinfo = self::getimageinfo($water);
        //3、判断水印图片能否贴上来
        if (!$this->checkimage($imageinfo, $waterinfo)) {
            exit('水印图片太大');
        }
        //4、打开图片
        $imageres = self::openanyimage($image);
        $waterres = self::openanyimage($water);
        //5、根据水印图片的位置计算水印图片的坐标
        $pos = $this->getpostion($postion, $imageinfo, $waterinfo);
        //6、将水印图片贴过来
        imagecopymerge($imageres, $waterres, $pos['x'], $pos['y'], 0, 0, $waterinfo['width'], $waterinfo['height'], $tmd);
        //7、得到要保存图片的文件名
        $newname = $this->createnewname($image, $prefix);
        //8、得到保存图片的路径，也就是文件的全路径
        $newpath = rtrim($this->path, '/') . '/' . $newname;
        //9、保存图片
        $this->saveimage($imageres, $newpath);
        //10、销毁资源
        imagedestroy($imageres);
        imagedestroy($waterres);
        return $newpath;
    }

    /**
     * 保存图像资源函数
     *
     * @param [type] $imageres
     * @param [type] $newpath
     * @return void
     */
    protected function saveimage($imageres, $newpath)
    {
        //imagepng   imagegif   imagewbmp
        $func = 'image' . $this->type;
        //通过变量函数进行保存
        $func($imageres, $newpath);
    }

    /**
     * 得到文件名函数
     *
     * @param [type] $imagepath
     * @param [type] $prefix
     * @return void
     */
    protected function createnewname($imagepath, $prefix)
    {
        if ($this->israndname) {
            $name = $prefix . uniqid() . '.' . $this->type;
        } else {
            $name = $prefix . pathinfo($imagepath)['filename'] . '.' . $this->type;
        }
        return $name;
    }

    /**
     * 根据位置计算水印图片的坐标
     *
     * @param [type] $postion
     * @param [type] $imageinfo
     * @param [type] $waterinfo
     * @return void
     */
    protected function getpostion($postion, $imageinfo, $waterinfo)
    {
        switch ($postion) {
            case 1:
                $x = 0;
                $y = 0;
                break;
            case 2:
                $x = ($imageinfo['width'] - $waterinfo['width']) / 2;
                $y = 0;
                break;
            case 3:
                $x = $imageinfo['width'] - $waterinfo['width'];
                $y = 0;
                break;
            case 4:
                $x = 0;
                $y = ($imageinfo['height'] - $waterinfo['height']) / 2;;
                break;
            case 5:
                $x = ($imageinfo['width'] - $waterinfo['width']) / 2;
                $y = ($imageinfo['height'] - $waterinfo['height']) / 2;
                break;
            case 6:
                $x = $imageinfo['width'] - $waterinfo['width'];
                $y = ($imageinfo['height'] - $waterinfo['height']) / 2;
                break;
            case 7:
                $x = 0;
                $y = $imageinfo['height'] - $waterinfo['height'];
                break;
            case 8:
                $x = ($imageinfo['width'] - $waterinfo['width']) / 2;
                $y = $imageinfo['height'] - $waterinfo['height'];
                break;
            case 9:
                $x = $imageinfo['width'] - $waterinfo['width'];
                $y = $imageinfo['height'] - $waterinfo['height'];
                break;
            case 0:
                $x = mt_rand(0, ($imageinfo['width'] - $waterinfo['width']));
                $y = mt_rand(0, ($imageinfo['height'] - $waterinfo['height']));
                break;
        }
        return ['x' => $x, 'y' => $y];
    }

    /**
     * 判断水印图片是否大于原图片
     *
     * @param [type] $imageinfo
     * @param [type] $waterinfo
     * @return void
     */
    protected function checkimage($imageinfo, $waterinfo)
    {
        if (($waterinfo['width'] > $imageinfo['width']) || ($waterinfo['height'] > $imageinfo['height'])) {
            return false;
        }
        return true;
    }

    /**
     * 静态方法，根据图片的路径得到图片信息，宽度、高度、mime类型
     *
     * @param [type] $imagepath
     * @return void
     */
    static function getimageinfo($imagepath)
    {
        //得到图片信息
        $info = getimagesize($imagepath);
        //保存图片宽度
        $data['width'] = $info[0];
        //保存图片高度
        $data['height'] = $info[1];
        //保存图片mime类型
        $data['mime'] = $info['mime'];
        //将图片信息返回
        return $data;
    }

    /**
     * 根据图片类型打开任意图片
     *
     * @param [type] $imagepath
     * @return void
     */
    static function openanyimage($imagepath)
    {
        //得到图片的mime类型
        $mime = self::getimageinfo($imagepath)['mime'];
        //根据不同的mime类型来使用不同的函数进行打开图片
        switch ($mime) {
            case 'image/png':
                $image = imagecreatefrompng($imagepath);
                break;
            case 'image/gif':
                $image = imagecreatefromgif($imagepath);
                break;
            case 'image/jpeg':
                $image = imagecreatefromjpeg($imagepath);
                break;
            case 'image/wbmp':
                $image = imagecreatefromwbmp($imagepath);
                break;
        }
        return $image;
    }
}