如何从imagettftext()中创建的图像中获取文本的顶点？

<?php
// 创建一个空白图像
$image = imagecreatetruecolor(400, 200);

// 定义文本颜色
$textColor = imagecolorallocate($image, 255, 255, 255);

// 定义字体文件路径
$fontFile = 'path/to/font.ttf';

// 定义文本字符串
$text = 'Hello, World!';

// 在图像上绘制文本
imagettftext($image, 24, 0, 50, 100, $textColor, $fontFile, $text);

// 获取文本的边界框
$bbox = imagettfbbox(24, 0, $fontFile, $text);

// 提取顶点坐标
$topLeftX = $bbox[0];
$topLeftY = $bbox[1];
$topRightX = $bbox[2];
$topRightY = $bbox[3];
$bottomRightX = $bbox[4];
$bottomRightY = $bbox[5];
$bottomLeftX = $bbox[6];
$bottomLeftY = $bbox[7];

// 打印顶点坐标
echo "Top Left: ($topLeftX, $topLeftY)\n";
echo "Top Right: ($topRightX, $topRightY)\n";
echo "Bottom Right: ($bottomRightX, $bottomRightY)\n";
echo "Bottom Left: ($bottomLeftX, $bottomLeftY)\n";

// 输出图像
header('Content-Type: image/png');
imagepng($image);
imagedestroy($image);
?>