PHP使用GD库生成签名图片png图片

需求：根据输入的名字，自动计算名字字符的长度，来生成相应的签名png图片

难点： 自动计算输入文本的长度

    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($image,255,255,255);//3.设置透明imagecolortransparent($image,$color);imagefill($image,0,0,$color);$text_color = imagecolorallocate($image, 26, 26, 26);imagettftext($image, 56, 0, 80 , 76, $text_color, $ttfPath, $sign_name);ob_start();   //启用输出缓冲imagepng($image);    //输出图像$imagebin=ob_get_contents();    //将缓冲的数据存入变量ob_end_clean();    //结束并清空输出缓存imagedestroy($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;}