Image 水印图片 和 缩略图

<?php
class Image
{
    //路径
    public $path = './';
    //初始化路径

    public function __construct($path = './')
    {
        $this->path = rtrim($path , '/') . '/';
    }

    //判断路径是否存在
    //获取文件信息
    //判断目标图片大小是否大于水印图片大小
    //获取位置 1-9  非0-9的就是随机
    //打开图片
    //合并图片
    //保存图片
    //销毁图片
    public function water($dst , $src , $isRand = true , $prefix = 'water_' , $opacity =100 , $position = 110)
    {
        //目标图片路径
        $dst = $this->path . $dst;
        //水印图片路径
        $src = $this->path . $src;

        if (!file_exists($dst)) {
            exit('目标图片不存在');
        }
        if (!file_exists($src)) {
            exit('水印图片不存在');
        }
        //开始比较大小（获取所有的图片信息）
        $dstInfo = self::getImageInfo($dst);
        $srcInfo = self::getImageInfo($src);

        //比较
        if (!$this->checkSize($dstInfo , $srcInfo)) {
            exit('水印图片太大');
        }
        ////获取位置 1-9  非0-9的就是随机

        $position = self::getPosition($dstInfo , $srcInfo , $position);

        //打开图片
        $dstRes = self::openImg($dst , $dstInfo);
        $srcRes = self::openImg($src , $srcInfo); // mime
        //开始合并
        $newRes = self::mergeImg($dstRes , $srcRes , $srcInfo , $position , $opacity);

        //处理随机
        if ($isRand) {
            $newPath = $this->path . $prefix . uniqid() . $dstInfo['name'];
        } else {
            $newPath = $this->path . $prefix . $dstInfo['name'];
        }

        //保存图片
        self::saveImg($newPath , $newRes , $dstInfo);

        //销毁资源
        imagedestroy($dstRes);
        imagedestroy($srcRes);
    }


    //缩略图
    public function thumb($img, $width, $height, $prefix = 'thumb_')
    {
        if (!file_exists($img)) {
            exit('文件路径不正在');
        }

        $info = self::getImageInfo($img);
        $newSize = self::getNewSize($width,$height,$info);
        $res = self::openImg($img, $info);
        $newRes = self::kidOfImage($res,$newSize,$info);
        $newPath = $this->path.$prefix.$info['name'];
        self::saveImg($newPath,$newRes,$info);
        imagedestroy($newRes);
        return $newPath;
    }


    private static function kidOfImage($srcImg, $size, $imgInfo)
    {
        $newImg = imagecreatetruecolor($size["width"], $size["height"]);       
        $otsc = imagecolortransparent($srcImg);
        if ( $otsc >= 0 && $otsc < imagecolorstotal($srcImg)) {
             $transparentcolor = imagecolorsforindex( $srcImg, $otsc );
                 $newtransparentcolor = imagecolorallocate(
                 $newImg,
                 $transparentcolor['red'],
                     $transparentcolor['green'],
                 $transparentcolor['blue']
             );

             imagefill( $newImg, 0, 0, $newtransparentcolor );
             imagecolortransparent( $newImg, $newtransparentcolor );
        }


        imagecopyresized( $newImg, $srcImg, 0, 0, 0, 0, $size["width"], $size["height"], $imgInfo["width"], $imgInfo["height"] );
        imagedestroy($srcImg);
        return $newImg;
    }

    private static function getNewSize($width, $height, $imgInfo)
    {   
        //将原图片的宽度给数组中的$size["width"]
        $size["width"] = $imgInfo["width"];   
        //将原图片的高度给数组中的$size["height"]
        $size["height"] = $imgInfo["height"]; 

        if($width < $imgInfo["width"]) {
            //缩放的宽度如果比原图小才重新设置宽度
            $size["width"] = $width;             
        }

        if ($width < $imgInfo["height"]) {
            //缩放的高度如果比原图小才重新设置高度
            $size["height"] = $height;       
        }

        if($imgInfo["width"]*$size["width"] > $imgInfo["height"] * $size["height"]) {
            $size["height"] = round($imgInfo["height"] * $size["width"] / $imgInfo["width"]);
        } else {
            $size["width"] = round($imgInfo["width"] * $size["height"] / $imgInfo["height"]);
        }

        return $size;
    }


    //保存图片
    public static function saveImg($path , $res , $info)
    {
        //imagepng();
        switch ($info['mime']) {
            case 'image/jpeg':
            case 'image/jpg':
            case 'image/pjpeg':
                imagejpeg($res, $path);
                break;
            case 'image/bmp':
            case 'image/wbmp':
                imagewbmp($res, $path);
                break;
            case 'image/gif':
                imagegif($res, $path);
                break;
            case 'image/png':
            case 'image/x-png':
                imagepng($res, $path);
                break;
        }
    }
    //合并图片
    public static function mergeImg($dstRes , $srcRes , $srcInfo , $position , $opacity)
    {
        imagecopymerge($dstRes , $srcRes , $position['x'] , $position['y'] , 0 , 0 ,$srcInfo['width'] , $srcInfo['height'] , $opacity );

        return $dstRes;
    }
    //打开图片
    public static function openImg($path , $info)
    {

        switch ($info['mime']) {
            case 'image/jpeg':
            case 'image/jpg':
            case 'image/pjpeg':
                $res = imagecreatefromjpeg($path);
                break;
            case 'image/bmp':
            case 'image/wbmp':
                $res = imagecreatefromwbmp($path);
                break;
            case 'image/gif':
                $res = imagecreatefromgif($path);
                break;
            case 'image/png':
            case 'image/x-png':
                $res = imagecreatefrompng($path);
                break;
        }
        return $res;
    }
    //获取图片位置
    public static function getPosition($dstInfo , $srcInfo , $position)
    {
        switch($position) {
            case 1:
                $x = 0;
                $y = 0;
                break;
            case 2:
                $x = ($dstInfo['width'] - $srcInfo['width']) / 2;
                $y = 0;
                break;
            case 3:
                $x = $dstInfo['width'] - $srcInfo['width'];
                $y = 0;
                break;
            case 4:
                $x = 0;
                $y = ($dstInfo['height'] - $srcInfo['height']) / 2;
                break;
            case 5:
                $x = ($dstInfo['width'] - $srcInfo['width']) / 2;
                $y = ($dstInfo['height'] - $srcInfo['height']) / 2;
                break;
            case 6:
                $x = $dstInfo['width'] - $srcInfo['width'];
                $y = ($dstInfo['height'] - $srcInfo['height']) / 2;
                break;
            case 7:
                $x = 0;
                $y = $dstInfo['height'] - $srcInfo['height'];
                break;
            case 8:
                $x = ($dstInfo['width'] - $srcInfo['width']) / 2;
                $y = $dstInfo['height'] - $srcInfo['height'];
                break;
            case 9:
                $x = $dstInfo['width'] - $srcInfo['width'];
                $y = $dstInfo['height'] - $srcInfo['height'];
                break;
            default:
                $x = mt_rand(0 , $dstInfo['width'] - $srcInfo['width']);
                $y = mt_rand(0 , $dstInfo['height'] - $srcInfo['height']);
                break;
        }

        return [
            'x' => $x,
            'y' => $y
        ];
    }

    //比较大小的函数
    public function checkSize($dstInfo , $srcInfo)
    {
        if ($dstInfo['width'] < $srcInfo['width']) {
            return false;
        }
        if ($dstInfo['height'] < $srcInfo['height']) {
            return false;
        }
        return true;
    }
    //获取图片信息
    public static function getImageInfo($path)
    {
        //var_dump($path);
        $data = getimagesize($path);
        //var_dump($data);
        $info['width'] = $data[0];
        $info['height'] = $data[1];
        $info['mime'] = $data['mime'];
        $info['name'] = basename($path);
        return $info;
    }
}

$img = new Image();
//$img->water('原图名字.jpg' , '水印图片名字.jpg');
$img->thumb('原图名字 .jpg' , 100 , 100 , 'thumb1_'); //加上前缀
$img->thumb('原图名字 .jpg' , 200 , 200 , 'thumb2_');
$img->thumb('原图名字 .jpg' , 300 , 300 , 'thumb3_');