imagettftext() does not properly render combining chars

Description

I'm forwarding this from the ancient https://bugs.php.net/34670; I had reported that a couple of years ago upstream (https://github.com/libgd/libgd/issues/758), where the ticket had been closed as WONTFIX; however, that was a week after libgd 2.3.3 had been released, which has optional support for libraqm, which solves the issue, as I found out while investigating on https://github.com/libgd/libgd/issues/861.

The following code:

<?php
$im = imagecreatetruecolor(64, 32);
imagefilledrectangle($im, 0, 0, imagesx($im) - 1, imagesy($im) - 1, 0x000000);
imagettftext($im, 16, 0, 10, 20, 0xffffff, "Arial", hex2bin("c3a461cc88"));
imagegif($im, __DIR__ . "/out.gif");

Resulted in this output (bundled libgd):

But I expected this output instead (libgd 2.3.3 with libraqm):

So to solve this for our bundled libgd, we would need to add support for libraqm (probably that wouldn't be a big deal, if especially gdft.c hadn't been diverged between bundled and external libgd, and I believe there are a couple of important fixes only in bundled libgd). For Windows users, we would also need to build and ship libraqm and its dependencies (at least harfbuzz in this case).

PHP Version

any

Operating System

any

从捆绑的 gdft.c 实现开始，使用组合字符复现所提供的 PHP 示例。将其输出与配置了 libraqm 的 libgd 2.3.3 进行比较，然后确定集成和 Windows 依赖项要求。当 imagettftext() 能够在所有受支持的构建中使用捆绑的 libgd 正确渲染组合字符时，即视为完成。