为全宽页面调用不同的header.php

I am currently using

<?php if ( is_home() ) :
get_header( 'home' );
endif;
?>

To call 'header-home.php' on the homepage only.

I also want to call 'header-fullwidth.php' on our full width posts.

This is one of our full width posts: http://www.sickchirpse.com/photos-vatnajokull-glacier/

This is a normal post (it has a sidebar): http://www.sickchirpse.com/how-survive-european-squat-house-berlin/

What can I add to achieve this?

if(get_page_template() == 'your-full-width-template'):
get_header( 'full-width' );
endif;

You can alwasy check the current page template path with the get_page_template() function.