Method to_lower

modules/gui/gui/src/backend/text_server/ustring.cpp:1701–1716

}

String String::to_lower() const
{
    String lower = *this;

    for (int i = 0; i < lower.size(); i++)
    {
        const char32_t s = lower[i];
        const char32_t t = _find_lower(s);
        if (s != t)
        { // avoid copy on write
            lower[i] = t;
        }
    }

    return lower;
}

String String::chr(char32_t p_char)
{