I'm working in a custom module that displays date fields. I want to be able to change the date's timezone programmatically. 

I've tried implementing `hook_views_pre_render()`, but that doesn't allow me to format the field value. I'd really like to do the theming inside my module code since that's where the logic is regarding my timezone. 

As a total hack, I could use `hook_views_post_render()`, but then I'd be doing search/replace on the text and that seems like a poor solution. 

What other hooks inside my module are available?