An Authoring Environment on the Web

by Vincent Quint, Irène Vatton et Daniel Veillard

The main objective of Tamaya is to create new HTML documents on the Web, however Tamaya also allows users to browse existing pages. Browsing is a complementary functionality that is useful for editing hypertext links in a simple way, by simply clicking the target document, or for copying information from remote documents. Users can update existing Web pages and create new ones at the same time and with the same tool.

WYSIWYG editing

Documents are handled with an intuitive user interface. Web pages are formatted on the screen and edited in a WYSIWYG mode. Several documents can be manipulated simultaneously. In addition, several views of the same document may be presented, each one showing a different aspect of the document:

• the main view shows a formatted document, which looks like a page displayed by a browser
• the source view presents the HTML code
• the anchor view displays all links and anchors, with all their attributes, but only links and anchors
• the table of contents allows the user to see the whole structure of a document at a glance
• the alternate view displays the document with the lay out it would have when displayed by a simple line browser.

All these views can be used for editing; any change made in one view is immediately reflected in all other views. A view can be opened or closed at any time.

Editing is structure driven: the user is guided by the editor, which proposes only the elements that can be created in the current context (via context sensitive menus). The documents created by Tamaya are guaranteed to be consistent with the HTML DTD.

Links are handled in a very simple way. The user selects a character string, invokes the command "create anchor" and clicks the target.

The usual commands of word processors are available as well as a multilingual spelling checker.

HTML document model

HTML has been designed as a markup language that represents the structure of documents, but it is often considered by authors as presentation-oriented. In many WWW documents, markup is clearly used for obtaining a specific graphical form. Authors just test the appearance of documents with their preferred browser. The result is that very few documents on the Web strictly conform to the HTML DTD and many documents are rejected by a standard SGML parser. For the sake of flexibility and tolerance, Tamaya includes a specific parser that accepts the most frequent mistakes and highlights dubious parts of documents in order to allow authors to correct them.

Tamaya supports the whole HTML2.0 DTD specification and the most innovative HTML3.0 features:

• editing of tables in WYSIWYG mode
• creating active pictures where hotzones are processed by the client and scripts on the server side are no longer necessary. Picture overlays are also experimented with
• editing of math formulae in WYSIWYG mode
• creating division elements and their class attribute which allows a better structuring of HTML documents.

Tamaya has been conceived as a platform for experimenting extensions to HTML.

Style sheets

A part of the Cascading Style Sheets (http://www.w3.org/hypertext/WWW/Style/) proposal is currently being implemented. Tamaya does not present the user with complex dialogue boxes. It does not require either the description of style sheets in any language. It is simply based on the concept of programming by example. The user selects a given element in a document, changes its style with the usual commands of a word processor, and when this element has the required style, a simple command generates a new style from that element.

The goal is to allow a user to control the graphical aspect of the documents being edited as simply as in a desktop publishing system, with a direct manipulation style of interface. The authoring tool converts these manipulations in terms of the style sheet language.

The styles currently available are color, font and character size. Other styles are being added.

Software architecture

Tamaya is entirely written in C and runs on several Unix systems (Sun OS, Solaris, Linux, AIX). The user interface is based on OSF/Motif.

Tamaya includes three main parts:

• the Thot editing tool kit constitutes the kernel of the authoring tool. It is an open-ended version of the editor previously known as Grif, that allows document-centered applications to be developed in a very short time
• the W3C Reference Library is used to fetch documents on the Web and to provide the parser with remote documents. This allows the user to load and edit not only local files, but also remote Web pages
• the main application module controls two other components and implements the Tamaya specific commands, which extend and specialize the editing functionality provided by the Thot tool kit. This component accesses the editing functions provided by the Thot tool kit through a well defined API.

Information on the web: http://opera.inrialpes.fr/OPERA/Tamaya.en.html