Restrict/allow schemes
By default, only http:// and https:// URLs are allowed. URLs that use a difference scheme are rejected but they might still appear as plain text.
In the following example, we remove http from the list of allowed schemes and add ftps.
$configurator = new s9e\TextFormatter\Configurator;
$configurator->urlConfig->allowScheme('ftps');
$configurator->urlConfig->disallowScheme('http');
print_r($configurator->urlConfig->getAllowedSchemes());
Array
(
[0] => https
[1] => ftps
)