Add html class to body
The Context API allow to pass a variable from view.tpl to template.php file

Example:

In view.tpl file :

context_set('slider_settings', 'slider_class', 'fixed_position');

In theme template file :

function MYTHEME_preprocess_html(&amp;$variables) { 

$slider_class = context_get('slider_settings', 'slider_class');
if ($slider_class == 'fixed_position'){
    $variables['classes_array'][] = 'slider_fixed';
}


}

It is an aswer for my own question, because I found a solution by myself, and it might be useful for someone I think..