How to convert a string to small capitals in PHP?

I am trying to convert a strint composed of "standard" upper and lower case letters to small capitals, in PHP. There is no information about small caps in the php.net docs.

Small capitals are, in my understanding, this thing :

Hᴇʟʟᴏ ᴛʜᴇʀᴇ

(generated with this site : https://fsymbols.com/generators/smallcaps/)

For instance, here is the small cap version of a t : http://www.fileformat.info/info/unicode/char/1d1b/index.htm

I searched the web for a longtime and found nothin in PHP. I know that CSS let you do that by using

font-variant: small-caps;

But I need to do this on the server side for what I do. Is this possible in PHP ?

EDIT: To complete my question, I am trying to generate plain text. So no HTML, images or CSS is possible in my case.

EDIT 2: On the website linked, a Javascript function is used to convert the text

Here is the code :

function encool() {
    var _0xce74x20 = location[_0x804c[82]],
        _0xce74x21;
    if (_0xce74x20[_0x804c[84]](_0x804c[83]) == -1 && _0xce74x20[_0x804c[84]](_0x804c[85]) == -1 && _0xce74x20[_0x804c[84]](_0x804c[86]) == -1 && _0xce74x20[_0x804c[84]](_0x804c[87]) == -1 && _0xce74x20[_0x804c[84]](_0x804c[88]) == -1) {
        _0xce74x21 = document[_0x804c[91]][_0x804c[90]][_0x804c[89]]
    } else {
        _0xce74x21 = change(decomposeAString(document[_0x804c[91]][_0x804c[90]][_0x804c[89]]))
    };
    document[_0x804c[91]][_0x804c[92]][_0x804c[89]] = _0xce74x21
}

Pretty sure he is using a character mapping. I will look into that and post the solution if I find it.

Ok here is the solution I came up with, but it is not very complete because even if it fits my needs. I needed this to convert small text (category names) so it is ok for me.

function convertToSmallCaps($string) {
    // standar capitals
    $caps = array('A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z');
    // small capitals
    $smallCaps = array('ᴀ', 'ʙ', 'ᴄ', 'ᴅ', 'ᴇ', 'ꜰ', 'ɢ', 'ʜ', 'ɪ', 'ᴊ', 'ᴋ', 'ʟ', 'ᴍ', 'ɴ', 'ᴏ', 'ᴘ', 'ǫ', 'ʀ', 's', 'ᴛ', 'ᴜ', 'ᴠ', 'ᴡ', 'x', 'ʏ', 'ᴢ');

    // remove all chars except [a-z] and - (replacing dashes with spaces)
    $sanitized_string = str_replace('-',' ',sanitize_title($string));

    // convert to uppercase
    $sanitized_string = mb_strtoupper($string);

    $length = strlen($sanitized_string);
    $output_string='';
    for($i = 0; $i<$length; $i++){
        $char = $sanitized_string[$i];
        // If the letter exsist in small capitals
        $letter_position = array_search($char,$caps);
        if(is_numeric($letter_position) && isset($smallCaps[$letter_position])) {
            // We append it to the ouput string
            $output_string.=$smallCaps[$letter_position];

        } else {
            // or else we append the original char to the output string
            $output_string.=$char;
        }
    }
    // return the converted string
    return $output_string;
}

It basically maps all chars in the string from caps to small caps

Problems :

1. it is wordpress dependent. I used the sanitize_title function from wordpress, which "slugifies" the string (removing all chars except [a-z] and -)
2. If your text has a lot of diacritics or is a composed of numbers and non latin chars, or longer than a category name, the result may be a bit weird
3. some of the letters (the x or s or q) are not actual small caps (because they don't exist, I guess ?) so the result can be confusing on some display.

I will try to improve this in the future if my need change