PHP使用GD庫生成簽名圖片png圖片

需求：根據輸入的名字，自動計算名字字符的長度，來生成相應的簽名png圖片

難點： 自動計算輸入文本的長度

    public static function generateSignImage($sign_name){
        if(empty($sign_name)){
            return ['status' => false];
        }
        $height = 95;

        $ttfPath = __DIR__.'/yizhiqingshu.ttf';

        $w = static ::charwidth(56,0,$ttfPath,$sign_name);
        $width = $w + 80 + 80;

        $image = imagecreatetruecolor($width, $height);

        //2.上色
        $color=imagecolorallocate($image,255,255,255);

        //3.設置透明
        imagecolortransparent($image,$color);

        imagefill($image,0,0,$color);

        $text_color = imagecolorallocate($image, 26, 26, 26);

        imagettftext($image, 56, 0, 80 , 76, $text_color, $ttfPath, $sign_name);

        ob_start();   //啓用輸出緩衝
        imagepng($image);    //輸出圖像
        $imagebin=ob_get_contents();    //將緩衝的數據存入變量
        ob_end_clean();    //結束並清空輸出緩存

        imagedestroy($image);



        $res = UploadFromServerHelper::uploadImageFromStream($imagebin);

        //var_dump($res);
        return $res;

    }


    static function charwidth($fontsize,$fontangle,$ttfpath,$char){
        $box = imagettfbbox($fontsize,$fontangle,$ttfpath,$char);
        $width = abs(max($box[2], $box[4]) - min($box[0], $box[6]));
        return $width;
    }