Magic Pages Providing Added Value to Electronic Documents

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1 Magic Pages Providing Added Value to Electronic Documents Marcel Götze, Stefan Schlechtweg Department of Simulation and Graphics, University of Magdeburg Universitätsplatz 2, D Magdeburg, Germany {goetze Abstract Most electronic documents have a predefined structure, and a visualization of a document is adjusted to this structure. In many cases, however, it is desirable to have different visual representations of the document. This becomes especially important if there is additional information available, for instance, annotations. This paper introduces Magic Pages, a user interface technique that supports different views onto an electronic document. Support in this case means to provide an intuitive way of handling the visualization of textual content as well as additional information. Magic Pages are designed based on the user's experience with the handling of paper documents and treat different views as transparent pages set atop the original text. 1 Introduction Electronic documents are replacing their traditional paper counterparts as a medium for information exchange. Hence, it is of vital importance to provide tools and techniques to work with the information given in electronic documents. This pertains not only to the textual content but also to additional information being attached to the document. Providing added value and offering means to handle this added value is the key to the acceptance of electronic documents over their paper equivalents. Electronic documents can be adaptively visualized and personalized. Personalization in this case is the process of adding information and changing the view onto a document. Hence, it goes hand in hand with an adaptive visualization of the textual content and the additional information. A user (or even multiple users) can add and edit information (e.g., annotations) that is not part of the original document. The text in connection with the annotations should then be visualized based on the user's needs, his or her reading goals (O'Hara, 1996), or the type of reading (Adler & van Doren, 1972). Altogether, personalization enables to deliver the right information to the appropriate place at the desired time and in a form that supports the user's task at hand. The user interface to handle electronic documents should adopt the well known environment from paper documents. One of our main concerns is therefore to provide a familiar environment to the user by exploiting pen-based input as well as paper document metaphors wherever possible to raise the acceptance of electronic documents even more. In this paper we will present M a g i c P a g e s, a user interface technique for visualization of and interaction with electronic documents that are enriched with additional information. A Magic Page is a transparent page that is placed on top of a document's text, that performs a certain function such as keyword search, annotation selection, or marking selection, and that finally visualizes the results of these function in the context of the document itself. The proposed user interface is based on the metaphor of a stack of transparent pages and thus handling the Magic Pages resembles handling a stack of sheets of paper. 2 Related Work The idea presented in this paper draws on research work from quite different areas. In (Erwig, 2000) is stated that there is a very strong need for a user-friendly query interface to XML

2 documents. This is not only the case for structured documents but also for documents that contain rather unstructured, textual data. In order to prevent the user from needing to learn and exploit query languages or difficult query interfaces, a graphical way of specifying and visualizing query results is called for. Magic Lenses as introduced by (Bier, Stone, Pier, Buxton & DeRose, 1993) provide an intuitive way of automatically querying (or transforming) a document and visualizing the result on a per-region basis. A Toolglass widget contains a function that is performed on the objects viewed in a region. The result of this function is directly visualized overlaying the region in question. For textual documents, this technique has been applied in (Phelps & Wilensky, 1998) as part of the Multivalent Document architecture. In both cases, the Toolglass widgets and lenses have to be positioned and resized by the user, adding interaction tasks that are uncommon for paper documents. Detail-in-context presentations, like Fluid Documents (Chang, Mackinlay, Zellweger & Igarashi, 1998), and focus+context techniques (Document Lense (Robertson & Mackinlay, 1993), Fisheye Views (Furnas, 1986) and Semantic Depth of Field (Kosara, Miksch & Hauser, 2002)) are another source of inspiration. The problem with these techniques is that they visualize information within the document which is not possible when working with paper documents. The mentioned visualization techniques change the document content in a way that the additional information becomes part of the document itself. In contrast to this, the approach presented in this paper supports the visualization of information separately from the document it belongs to. 3 Magic Pages Adopting the terminology from (Bier et al., 1993), we define a M a g i c P a g e as a display page together with a filter function on a document and together with a second function that visualizes the result of the filtering. More formally, a Magic Page is a triple M=( D, f, v) where D is (part of) the document model that is displayed on the page, f is a function that returns a selected part of the document model based on some criteria, and v is a function that displays the result of the filter function in a certain way. 3.1 The Document Model The Magic Pages interface is designed to work on an information enriched textual document. The original electronic document is given as an XML file so that while parsing this file an internal representation can be built that supports the search for specific information. We have decided to use the W3C Document Object Model (DOM) as basis for our work. The Document Object Model defines the logical structure of documents and the way a document is accessed and manipulated (W3C, 2002). Using a DOM parser, the structure of the document is represented as a tree that can be traversed to search for specific elements (nodes) or attributes. In order to enrich a document with additional information such as annotations or markings, we use the technique presented in (Goetze, Schlechtweg & Strothotte, 2002). Here, the user works with a pen-based interface to mark up an electronic document just as he or she would do on paper. Different kinds of pens can be simulated and different types of markings and annotations are supported. All these annotations and markings are stored within the document's XML file and hence become part of the DOM tree. Together with the actual annotation data, information are given that identify the user who added the annotation and the pen type that was used. This is especially useful since readers over time develop a more or less consistent scheme of markings that delivers information which parts of a text are, for example, important, questionable, or unclear. Also, this information enables a distinctive visualization based on different users. The additional information in the form of annotations and markings may or may not be present in the document. The standard DOM tree, which is built from any HTML or XML document, already contains all necessary information to use the Magic Pages interface. The more additional

3 information is included, however, the more possibilities for filtering and visualizing the documents become available and, hence, the more powerful becomes the Magic Pages interface. 3.2 The Filter Function The most important part of each Magic Page is the filter function, i.e., the operation on the document model that is performed by the respective page. These functions are implemented by means of the DOM API and here especially using methods that traverse the DOM tree and return a list of all those nodes that are of a certain type, contain a certain text or have a certain attribute. To describe the various functions more formally, we introduce the following terminology. The set text(d) contains all nodes of the document model that actually contain textual content. The set attr( D) contains all those nodes that hold attribute values which are attached to textual elements. We can immediately identify several types of functions that yield usable results for the application at hand. These include: d o c u m e n t c o n t e n t s s e l e c t i o n : f(d) = text( D) This function returns all characters of the document, i.e., the text contents. k e y w o r d s e a r c h : f(d) = {n n text( D); n contains the keyword as substring} This function returns all those text nodes that contain the given keyword. a t t r i b u t e s e a r c h : f(d) = {n n attr( D); n contains the given attribute value} This function returns the attribute nodes that contain a specified attribute value. The functions themselves are relatively straightforward and hence their power depends on the parameter values that are given and on the combination of several filter functions. A combination of two filter functions f and h can be performed in two ways. Either we apply h to the result of g which yields h( g(d)), i.e., h filters the a l r e a d y f i l t e r e d s e t o f n o d e s o r we apply h to the same domain (document model) as g which yields g ( D ) h(d). 3.3 The Visualization Function The second function that is part of each Magic Page works on the results of the filter function and is responsible for presenting the results to the user. Such a presentation dependents heavily on the type of information to be displayed as well as on user preferences. Hence, the visualization function is freely programmable. Some examples include d o c u m e n t r e n d e r i n g to display all of a document's text content by applying either standard formatting instructions or by f o l l o w i n g a s t y l e s h e e t, h i g h l i g h t i n g k e y w o r d s after a keyword search in the context of the whole document by color coding them or by applying other visualization techniques (e.g., Semantic Depth of Field (Kosara et al., 2002)), s h o w i n g a n n o t a t i o n s as they were drawn/written by the user when he or she annotated the document using the pen type and color that was chosen by the user at that time Even though the visualization is rather specific we can supply some standard Magic Pages where a filter function is coupled with a matching visualization. These pages provide a standard functionality that can be extended by the user. 4 The User Interface A Magic Page acts as a filter on a page of the document or on other Magic Pages. The document itself and all additional information therefore has to be represented in a way that filtering different information is possible. To add annotations, we built upon the idea of the I n t e l l i g e n t P e n described in (Götze et al., 2002). A Magic Page placed on top of a document filters the document page and displays only the information that passes the respective filter. Adding a new Magic Page adds a new filter whose results are displayed on this new page. Depending on the chosen combination rule, it is applied to the document page and all other Magic Pages below and either filters the

4 already filtered results or adds filtered document contents. As an example, given a document that was annotated by goetze and stefans, a first Magic Page filters all annotations by goetze, and a second one filters all annotations done with a blue ballpen. In combination, all blue ballpen annotations by goetze are seen through both Magic Pages on top of the document. We can take this further and filter the document contents, for example, by search queries that might result in highlighting all terms matching the query. This aids the reader in seeking for special information. The Magic Pages can be configured to aid the reader having a certain reading goal like getting an overview of the document. This can be seen as a more complex query within the electronic document and can, on the hand result in hiding instead of highlighting (possibly large) parts of the document. On the other hand, this can provide additional information as there is the visualization of connections between parts of the document or instructions for further reading. Magic pages can also be configured by the author to provide views onto the document that might be helpful for the user. The transparency of a Magic Page ensures that the Figure 1: Magic Pages used as filter to guide attention document's text is always visible in and to add information. order to provide the context. A schematic overview of the technique can be seen in Figure 1. Besides the possibility to let the user change the order of the Magic Pages, the system itself can reorder them. This is especially necessary in a case where the user adds information that belongs to a special Magic Page, e.g., an annotation. In this case (when the user starts writing) the system will move the desired Magic Page to the top of the stack. The implementation shows an intuitive way of handling Magic Pages and hence visualizing information in the context of an electronic document. However, it is only a proof of concept, the presented technique offers a general way to structue (additional) information an visualize them in a page structured environment. Since the metaphor behind Magic Pages originally came from the use of paper documents we consequently implemented our prototype based on the paper document metaphor. Hence, the user interface consists of different Figure 2: Tabs, used as a handle. transparent slides laying on top of each other like pages on the desk. The user can add and remove Magic Pages as well as change their order using a simple interface. Each page contains a tab that tells the function of the page and acts as a handle (cf. Figure 2). To change the order the user can simply drag a page to the desired position within the stack. Currently unused Magic Pages can be placed behind the document page where they are inactivated. In most cases, no additional menu is needed for interaction tasks since some predefined pages are supplied. For defining new Magic Pages, i.e., combining filter and visualization functions, a dialogue interface is used so far. 5 Conclusion In this paper Magic Pages, a new technique for visualizing electronic documents is introduced. For the acceptance of new technologies three supporting principles can be found. The first is to

5 connect new techniques and exisiting (known) habits uf the user. Therefore, the Magic Pages are based on handling page based documents. The second principle is to develop suitable metaphors to simplify the use of new technologies. This is achieved by adopting known aspects of paper documents and transparent slides. The third principle is to adapt the user's behavior to the new technique in a way that he or she realizes that he or she controls the new technique. Obviously, the interaction with a computer application is not the same as interacting with a paper document. Nevertheless, reducing the interface to the known pen and paper interface based on the document metaphor allows it to control the system and, hence, the new technique in a way that complies with the third principle. With Magic Pages we have provided an intuitive and novel way of dealing with electronic documents containing additional information. An enhanced and selective visualization provides distinctive views and aids the user's understanding of the document. Following the paper document metaphor, the user interface becomes a familiar environment also for electronic documents. Nevertheless, a still pending user study needs to confirm these findings.there are some aspects for further improvement and development. It would be interesting to investigate the use of Magic Pages as an input filter. In the above described system every user input is automatically redirected to the appropriate Magic Page. In contrast to this a Magic Page could also act as a cover and, for instance, prevent a document's page from beeing annotated. Also, since Magic Pages are defined as a rather abstract concept, it should be investigated if different representations of the document itself help to even more improve the usefulness of this technique. References Adler, M., & van Doren, C. (1972). How to read a book. New York:Simon & Schuster. Bier, E.A., Stone, M.C., Pier, K., Buxton, W., & DeRose, T. D. (1993). Toolglass and Magic Lenses: The See-Through Interface. In Proceedings of SIGGRAPH 93 (pp ). New York:ACM Press. Chang, B., Mackinlay, J.D., Zellweger P.T., & Igarashi, T. (1998). A Negotiation Architecture for Fluid Documents. In P r o c e e d i n g s o f U I S T ' 9 8 (pp ). New York:ACM Press. Erwig, M. (2000). XML Queries and Transformations for End Users. In P r o c e e d i n g s o f X M L (pp ). Furnas, G.W. (1986). Generalized Fisheye Views. In P r o c e e d i n g s o f C H I ' 8 6 (pp ). New York:ACM Press. Götze, M., Schlechtweg, S., & Strothotte, T. (2002). The Intelligent Pen Towards a Uniform Treatment of Electronic Documents. In P r o c e e d i n g s o f t h e 2 n d I n t e r n a t i o n a l S y m p o s i u m o n S m a r t G r a p h i c s (pp ). New York:ACM Press. Kosara, R., Miksch, S., & Hauser, H. (2002). Focus + Context Taken Literally. I E E E C o m p u t e r G r a p h i c s a n d A p p l i c a t i o n s, 22(1), O Hara, K. (1996). Towards a Typology of Reading Goals. Technical Report EPC , Rank Xerox Research Centre. Phelps, T.A. & Wilensky, R. (1998). Multivalent Documents: A New Model for Digital Documents. Technical Report No. CSD , Division of Computer Science, University of California at Berkeley. Robertson, G.G., Mackinlay, J.D. (1993). The Document Lens. In P r o c e e d i n g s o f U I S T ' 9 3 (pp ). New York:ACM Press. W3C DOM Working Group (2002). Document Object Model (DOM) Level 3 Core Specification, Version 1.0. Technical report, World Wide Web Consortium,

The Intelligent Pen Toward a Uniform Treatment of Electronic Documents

The Intelligent Pen Toward a Uniform Treatment of Electronic Documents Marcel Götze, Stefan Schlechtweg, Thomas Strothotte Department of Simulation and Graphics Otto-von-Guericke University of Magdeburg