1. The design should support both display within a browser and within a standalone application.

    Supporting a browser well means being able to treat many separate dvi files as a single document, so that pages can be downloaded separately. On the other hand, the user of a standalone application will want the software to work well with dvi files containing many pages.

  2. The design should support several applet models.

    It should be easy to write a single-equation applet or an applet which merges all pages of a document into a single long scroll.

  3. The design should support flexible data formats.

    It should be easy to add support for a new html: special or for another font file format.