需要帮助的水印PHP

Question

在水印PHP中获得黑线。我正在使用PHP版本7.2.19。

public function Watermark($input, $output, $watermark, $opacity = 50) {
    try {
        $image = $this->imagecreatefrom($input);
        $stamp = $this->imagecreatefrom($watermark);
        $watermark_width = imagesx($stamp);
        $watermark_height = imagesy($stamp);
        $percent = 0.5;
        $newwidth = $watermark_width * $percent;
        $newheight = $watermark_height * $percent;
        $stamp_new = imagecreatetruecolor($newwidth, $newheight);
        imagecolortransparent($stamp_new, imagecolorallocatealpha($stamp_new, 0, 0, 0, 127));
        imagealphablending($stamp_new, false);
        imagesavealpha($stamp_new, true);
        imagecopyresampled($stamp_new, $stamp, 0, 0, 0, 0, $newwidth, $newheight, imagesx($stamp), imagesy($stamp));
        $margin = ['right' => 20, 'bottom' => 20];
        imagecopymerge($image, $stamp_new, imagesx($image) - imagesx($stamp_new) - $margin['right'], imagesy($image) - imagesy($stamp_new) - $margin['bottom'], 0, 0, imagesx($stamp_new), imagesy($stamp_new), $opacity);
        imagejpeg($image, $output);
        ImageDestroy($image);
        ImageDestroy($stamp);
        return true;
    }
    catch(\Exception $e) {
        print_r($e->getMessage());
        die;
        Yii::$app->api->sendFailedResponse("Something went wrong please try again later");
    }
}
private function imagecreatefrom($input) {
    $size = getimagesize($input);
    if ($size) {
        switch ($size['mime']) {
            case 'image/jpeg':
                $base = imagecreatefromjpeg($input);
                imagealphablending($base, false);
                imagesavealpha($base, true);
                return $base;
            break;
            case 'image/png':
                $base = imagecreatefrompng($input);
                imagealphablending($base, false);
                imagesavealpha($base, true);
                return $base;
            break;
            case 'image/gif':
                $base = imagecreatefromgif($input);
                imagealphablending($base, false);
                imagesavealpha($base, true);
                return $base;
            break;
            case 'image/vnd.wap.wbmp':
                $base = imagecreatefromwbmp($input);
                imagealphablending($base, false);
                imagesavealpha($base, true);
                return $base;
            break;
            case '':
            default:
                return false;
            break;
        }
    }
    return false;
}

PHP版本7.2.19