php将文本生成图片

接收前端发送的文本，使用php内置函数实现文本转换图片

<?php
    header('Content-Type: text/html; charset=utf-8'); 
    $content = file_get_contents("php://input");
    $content = json_decode($content,true);
    $type = $content['type'];
    $errcode = 0;
    $errtext = "";
    $myJson = array();
    
    $greetingpath = 'static/greeting/';//合成图片目录
    $jsonfile = 'config.json';//语言合成config文件
    $fontttf = "./static/dist/fonts/xiekai.ttf"; //文本字体

    if(!$type)
        $errtext = "error param";

    if($errtext == ""){
        switch ($type) {

            case 'setgreeting':
                $greeting = $content['greeting'];
                $width = 1600;
                $height = 450;
                $fontsize = 50;
                $strlength = mb_strlen($greeting)*$fontsize;
                //imgx和imgy用于文本的垂直居中显示，目前只考虑单行文本
                $imgx = ($width-$strlength)/2;
                $imgy = $height/2;

                $myImage=imagecreatetruecolor($width,$height); //参数为宽度和高度
                $background = imagecolorallocate($myImage, 0, 0, 0);//背景颜色
                imagefill($myImage, 0, 0, $background);
                $red= ImageColorAllocate($myImage, 255, 0, 0);//字体颜色
                imagettftext($myImage, $fontsize, 0, $imgx, $imgy, $red, $fontttf, $greeting);
                $pathname = date('Ymd',time());
                $filename = time();
                $new_file = $greetingpath.$pathname."/";
                if(!file_exists($new_file)){
                    //检查是否有该文件夹，如果没有就创建，并给予最高权限
                    mkdir($new_file, 0700,true);
                }
                $new_file = $new_file.$filename.".jpg";
                imagepng($myImage,$new_file);
                imagedestroy($myImage);
                $myJson['picurl'] ='http://'.$_SERVER['HTTP_HOST'].'/'.$new_file;//返回生成图片的url地址
                break;
            
            default:
                $errtext = "unkonw type";
                break;
        }  
    }

    if($errtext !='')
        $errcode = 1;

    $myJson['errcode'] = $errcode;
    $myJson['errtext'] = $errtext;

   echo json_encode($myJson);

生成效果