php根据图片主要颜色添加相近颜色的水印

            $color = $this->dominant_color($img); //获取图片颜色
            $water = $this->make_watermark_img('水印文字', $color); //生成水印图片
            $this->add_img_water($file_path, $water['url']); //图片打水印

   /**
     * 给图片添加水印
     * @param string $filename 需添加水印图
     * @param string $water 水印图
     * @param string $newname 图片新名称
     */
    public function add_img_water($filename, $water)
    {
        list($f_w, $f_h) = getimagesize($filename);
        list($w_w, $w_h) = getimagesize($water);
        //确定水印起始位置(水印居右下角)
        $pos_x = $f_w - $w_w;
        $pos_y = $f_h - $w_h;
        //创建背景图片的资源
        $back_img = imagecreatefromjpeg($filename);
        //创建水印图片的资源
        $water_img = imagecreatefrompng($water);
        //添加水印
        imagecopy($back_img, $water_img, $pos_x, $pos_y, 0, 0, $w_w, $w_h);
        //保存图片
        imagepng($back_img,$filename);
        return;
    }

    /**
     * 获取图片主要颜色
     * @param $image
     * @return array
     */
    public function dominant_color($image)
    {
        $rTotal = $gTotal = $bTotal = $total = 0;
        $type = getimagesize($image);//取得图片的大小，类型等
        if (isset($type['mime']) && $type['mime'] == 'image/webp') {
            $i = imagecreatefromwebp($image);
        }else{
            $i = imagecreatefromstring(file_get_contents($image));
        }
//        $i      = imagecreatefromjpeg($image);
        for ($x = 0; $x < imagesx($i); $x++) {
            for ($y = 0; $y < imagesy($i); $y++) {
                $rgb    = imagecolorat($i, $x, $y);
                $r      = ($rgb >> 16) & 0xFF;
                $g      = ($rgb >> 8) & 0xFF;
                $b      = $rgb & 0xFF;
                $rTotal += $r;
                $gTotal += $g;
                $bTotal += $b;
                $total++;
            }
        }
        $rAverage = round($rTotal / $total);
        $gAverage = round($gTotal / $total);
        $bAverage = round($bTotal / $total);
        return array(
            'r' => $rAverage,
            'g' => $gAverage,
            'b' => $bAverage,
        );
    }

    public function make_watermark_img($text, $color)
    {
        $blue = $color['b'];
        $red = $color['r'];
        $green = $color['g'];
        if (strtoupper(substr(PHP_OS,0,3))==='WIN')
        {
            $font = "c:/windows/fonts/SIMHEI.TTF";//字体类型，这里为黑体，
        }else{
            $font = "/usr/share/fonts/simhei.ttf";//字体类型，这里为黑体，
        }
        $text_len = strlen($text) / 3; //显示的文字
        $width = $text_len * 20; //1个字17

        $logo = 'uploads/sy.png'; //水印文字图片地址
        $size = 14; //字体大小
        $img = imagecreate($width,24);//创建一个长为x高为y的空白图片
        imagecolorallocate($img,$red,$green,$blue);//设置图片背景颜色，这里背景颜色为#ffffff，也就是白色
//        imagecolorallocate($img,0xff,0xff,0xff);//设置图片背景颜色，这里背景颜色为#ffffff，也就是白色
        $black=imagecolorallocate($img,100,0x00,0x00);//设置字体颜色，这里为#000000，也就是黑色
        imagettftext($img,$size,0,0,16, $black, $font , $text);//将ttf文字写到图片中
        $watermark_logo = imagepng($img, $logo);//输出图片，输出png使用imagepng方法，输出gif使用imagegif方法
        if (!$watermark_logo) {
            return ['status' => false, 'msg' => '生成水印失败'];
        }
        return ['status' => true, 'url' => $logo];
    }