Consider moving post-filter phase before html-to-text phase to allow better plain text messages

Many websites need an multipart/alternative outgoing email for most of their emails.

Many of these emails consist of an explanatory wrapper which contains user-generated content (Think contact module or private message notifications)

The way htmlmail currently works, the html message is generated, then the text version of it is formatted, then the post-format filter is applied.

That means that the text-format message *cannot* be derived from the finished html-format message. For example, it would be natural for filtered_html to be applied as a post-format. It works nicely for almost-plain-text messages like the user messages, the contact message, pm notifications, etc. However, it's impossible to use it and still have decent plain text messages, because the filter is applied after the plain-text message is derived.

I know that this can be solved with theming... but it's not that pretty there either, and requires applying a filter in the tpl.php.

I'd provide a patch if you're open to this.