Is there a way to check if the page is set to be secure with code?

Slightly confusing title, but does this have a variable which can be checked to see if the page is meant to be being served as secure?

My use for this is to basically say if page isn’t secure, serve webfont from http (faster), if it is a secure page then serve it from htts.

https://www.ads-software.com/extend/plugins/wordpress-https/