Abstract:
A method, program and apparatus for rendering an image area in an electronic document are provided by means of a web browser having non-visual capabilities. The invention comprises parsing a web page and creating a document object model (DOM). The browser then determine if an image in the web page contains a “long description” attribute that names a URL address for a second web page. This second web page contains a long description of the image in the first web page. If the image does have this attribute, the browser creates a new subtree within the DOM of the first web page, and places the subtree adjacent to the image in the DOM. The subtree presents a visible and renderable hyperlink to the second web page containing the long description. The browser will then render the image and/or hyperlink. The image and hyperlink can be rendered audibly, tactilely, visually, or by a combination of these methods, depending on the needs of the user.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
       [0001]    The present application is related to co-pending U.S. patent application Ser. No. ______ (IBM Docket No. AUS920010102US1) entitled “METHOD FOR PRESENTATION OF HTML IMAGE-MAP ELEMENTS IN NON VISUAL WEB BROWSERS” filed even date herewith. The content of the above mentioned commonly assigned, co-pending U.S. patent applications are hereby incorporated herein by reference for all purposes. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Technical Field  
           [0003]    The present invention relates to computer network environments and more specifically to non-visual presentation of electronic documents.  
           [0004]    2. Description of Related Art  
           [0005]    Information on the World Wide Web is typically made available by structuring the information into a visual presentation. Hyper Text Markup Language (HTML) is used by web authors to define the visual structure. The end user is presented with this information by viewing the information on a computer display, after the information has been rendered into a visual format by a web browser (e.g. Netscape Navigator or MS Internet Explorer).  
           [0006]    Web sites of well established businesses and organizations make extensive use of visual images. A HTML MAP defines a set of sub-regions over the image area. Each region is called an AREA, and is defined by an AREA element within the MAP definition. Each AREA can be associated with an Internet Uniform Resource Locator (URL). When the end user performs a mouse click within an area defined by the MAP, the web browser will navigate the associated URL. This process works well for a sighted user who is accessing the web using a visual browser. However, this process is not accessible by people with vision impairments, nor is it accessible by users who do not have a visual display device available (e.g. while driving a car).  
           [0007]    A variety of software products are becoming available which enable non-visual access to HTML pages. These products capture the web page content and then present an audible rendering of the web page. This is generally accomplished by using a text-to-speech (TTS) technology to read the textual content.  
           [0008]    HTML, which is used to provide a visual structure to a web page, also provides a semantic structure to the page. Well known techniques exist for parsing an HTML source file into a parse tree, also known as a Document Object Model (DOM). The various structural elements and relationships among the elements are then apparent from the topology of the parse tree. The DOM is accessible as a component, and this component provides the foundation needed to build a non-visual browser.  
           [0009]    In an HTML page, a MAP-AREA definition is a non-visible element. Consequently, the web author is free to locate the MAP-AREA definition within the DOM wherever the author pleases. A cross referencing scheme is then used to associate the MAP-AREA definition with a corresponding IMAGE within the DOM. However, the physical separation of the IMAGE from the MAP-AREA definition introduces a fair amount of program complexity when the HTML page is being presented by a non-visual browser. Currently, non-visual browsers must maintain extensive internal records in order to keep track of the logical association between a MAP-AREA and an IMAGE in the DOM.  
           [0010]    Therefore, it would be desirable to have a method for maintaining the logical association between corresponding IMAGE-AREAs and IMAGEs in a DOM, while reducing program complexity and the need for extensive record keeping.  
         SUMMARY OF THE INVENTION  
         [0011]    The present invention provides a method, program and apparatus for the rendering an image area in an electronic document by means of a non-visual browser. The invention comprises parsing a web page and creating a document object model (DOM). The browser then determine if an image in the web page contains a “long description” attribute that names a URL address for a second web page. This second web page contains a long description of the image in the first web page. If the image does have this attribute, the browser creates a new subtree within the DOM of the first web page, and places the subtree adjacent to the image in the DOM. The subtree presents a visible and renderable hyperlink to the second web page containing the long description. The browser will then render the image and/or hyperlink. The image and hyperlink can be rendered audibly, tactilely, visually, or by a combination of these methods, depending on the needs of the user.  
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]    The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:  
         [0013]    [0013]FIG. 1 depicts a pictorial representation of a network of data processing systems in which the present invention may be implemented;  
         [0014]    [0014]FIG. 2 depicts a block diagram of a data processing system that may be implemented as a server in accordance with a preferred embodiment of the present invention;  
         [0015]    [0015]FIG. 3 depicts a block diagram illustrating a data processing system in which the present invention may be implemented;  
         [0016]    [0016]FIG. 4 depicts a block diagram of a browser program in accordance with a preferred embodiment of the present invention;  
         [0017]    [0017]FIG. 5 depicts a diagram illustrating a Document Object Model in accordance with the prior art;  
         [0018]    [0018]FIG. 6 depicts a diagram illustrating an edited DOM in accordance with the present invention;  
         [0019]    [0019]FIG. 7 depicts a flowchart illustrating the process of editing a DOM in accordance with the present invention; and  
         [0020]    [0020]FIG. 8 depicts a flowchart illustrating the process of creating a new subtree within a DOM in accordance with the present invention.  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0021]    With reference now to the figures, FIG. 1 depicts a pictorial representation of a network of data processing systems in which the present invention may be implemented. Network data processing system  100  is a network of computers in which the present invention may be implemented. Network data processing system  100  contains a network  102 , which is the medium used to provide communications links between various devices and computers connected together within network data processing system  100 . Network  102  may include connections, such as wire, wireless communication links, or fiber optic cables.  
         [0022]    In the depicted example, a server  104  is connected to network  102  along with storage unit  106 . In addition, clients  108 ,  110 , and  112  also are connected to network  102 . These clients  108 ,  110 , and  112  may be, for example, personal computers or network computers. In the depicted example, server  104  provides data, such as boot files, operating system images, and applications to clients  108 - 112 . Clients  108 ,  110 , and  112  are clients to server  104 . Network data processing system  100  may include additional servers, clients, and other devices not shown.  
         [0023]    In the depicted example, network data processing system  100  is the Internet with network  102  representing a worldwide collection of networks and gateways that use the TCP/IP suite of protocols to communicate with one another. At the heart of the Internet is a backbone of high-speed data communication lines between major nodes or host computers, consisting of thousands of commercial, government, educational and other computer systems that route data and messages. Of course, network data processing system  100  also may be implemented as a number of different types of networks, such as for example, an intranet, a local area network (LAN), or a wide area network (WAN). FIG. 1 is intended as an example, and not as an architectural limitation for the present invention.  
         [0024]    Referring to FIG. 2, a block diagram of a data processing system that may be implemented as a server, such as server  104  in FIG. 1, is depicted in accordance with a preferred embodiment of the present invention. Data processing system  200  may be a symmetric multiprocessor (SMP) system including a plurality of processors  202  and  204  connected to system bus  206 . Alternatively, a single processor system may be employed. Also connected to system bus  206  is memory controller/cache  208 , which provides an interface to local memory  209 . I/O bus bridge  210  is connected to system bus  206  and provides an interface to I/O bus  212 . Memory controller/cache  208  and I/O bus bridge  210  may be integrated as depicted.  
         [0025]    Peripheral component interconnect (PCI) bus bridge  214  connected to I/O bus  212  provides an interface to PCI local bus  216 . A number of modems may be connected to PCI bus  216 . Typical PCI bus implementations will support four PCI expansion slots or add-in connectors. Communications links to network computers  108 - 112  in FIG. 1 may be provided through modem  218  and network adapter  220  connected to PCI local bus  216  through add-in boards.  
         [0026]    Additional PCI bus bridges  222  and  224  provide interfaces for additional PCI buses  226  and  228 , from which additional modems or network adapters may be supported. In this manner, data processing system  200  allows connections to multiple network computers. A memory-mapped graphics adapter  230  and hard disk  232  may also be connected to I/O bus  212  as depicted, either directly or indirectly.  
         [0027]    Those of ordinary skill in the art will appreciate that the hardware depicted in FIG. 2 may vary. For example, other peripheral devices, such as optical disk drives and the like, also may be used in addition to or in place of the hardware depicted. The depicted example is not meant to imply architectural limitations with respect to the present invention.  
         [0028]    The data processing system depicted in FIG. 2 may be, for example, an IBM RISC/System 6000 system, a product of International Business Machines Corporation in Armonk, N.Y., running the Advanced Interactive Executive (AIX) operating system.  
         [0029]    With reference now to FIG. 3, a block diagram illustrating a data processing system is depicted in which the present invention may be implemented. Data processing system  300  is an example of a client computer. Data processing system  300  employs a peripheral component interconnect (PCI) local bus architecture. Although the depicted example employs a PCI bus, other bus architectures such as Accelerated Graphics Port (AGP) and Industry Standard Architecture (ISA) may be used. Processor  302  and main memory  304  are connected to PCI local bus  306  through PCI bridge  308 . PCI bridge  308  also may include an integrated memory controller and cache memory for processor  302 . Additional connections to PCI local bus  306  may be made through direct component interconnection or through add-in boards. In the depicted example, local area network (LAN) adapter  310 , SCSI host bus adapter  312 , and expansion bus interface  314  are connected to PCI local bus  306  by direct component connection. In contrast, audio adapter  316 , graphics adapter  318 , and audio/video adapter  319  are connected to PCI local bus  306  by add-in boards inserted into expansion slots. Expansion bus interface  314  provides a connection for a keyboard and mouse adapter  320 , modem  322 , and additional memory  324 . Small computer system interface (SCSI) host bus adapter  312  provides a connection for hard disk drive  326 , tape drive  328 , and CD-ROM drive  330 . Typical PCI local bus implementations will support three or four PCI expansion slots or add-in connectors.  
         [0030]    An operating system runs on processor  302  and is used to coordinate and provide control of various components within data processing system  300  in FIG. 3. The operating system may be a commercially available operating system, such as Windows 2000, which is available from Microsoft Corporation. An object oriented programming system such as Java may run in conjunction with the operating system and provide calls to the operating system from Java programs or applications executing on data processing system  300 . “Java” is a trademark of Sun Microsystems, Inc. Instructions for the operating system, the object-oriented operating system, and applications or programs are located on storage devices, such as hard disk drive  326 , and may be loaded into main memory  304  for execution by processor  302 .  
         [0031]    Those of ordinary skill in the art will appreciate that the hardware in FIG. 3 may vary depending on the implementation. Other internal hardware or peripheral devices, such as flash ROM (or equivalent nonvolatile memory) or optical disk drives and the like, may be used in addition to or in place of the hardware depicted in FIG. 3. Also, the processes of the present invention may be applied to a multiprocessor data processing system.  
         [0032]    As another example, data processing system  300  may be a stand-alone system configured to be bootable without relying on some type of network communication interface, whether or not data processing system  300  comprises some type of network communication interface. As a further example, data processing system  300  may be a Personal Digital Assistant (PDA) device, which is configured with ROM and/or flash ROM in order to provide non-volatile memory for storing operating system files and/or user-generated data.  
         [0033]    The depicted example in FIG. 3 and above-described examples are not meant to imply architectural limitations. For example, data processing system  300  also may be a notebook computer or hand held computer in addition to taking the form of a PDA. Data processing system  300  also may be a kiosk or a Web appliance.  
         [0034]    Turning next to FIG. 4, a block diagram of a browser program is depicted in accordance with a preferred embodiment of the present invention. Browser  400  includes a user interface  402 , which is a graphical user interface (GUI) that allows the user to interface or communicate with browser  400 . This interface provides for selection of various functions through menus  404  and allows for navigation through the navigation input  410 . For example, menu  404  may allow a user to perform various functions, such as saving a file, opening a new window, displaying a history, and entering a URL. Navigation  410  allows for a user to navigate various pages and to select web sites for viewing. For example, navigation  410  may allow a user to see a previous page or a subsequent page relative to the present page. Navigation  410  may also have voice recognition capabilities. Preferences may be set through preferences  406 . Browser  400  also contains text-to-speech (TTS)  408 , which converts text data into auditory signals.  
         [0035]    Communications  412  is the mechanism with which browser  400  receives documents and other resources from a network such as the Internet. Further, communications  412  is used to send or upload documents and resources onto a network. In the depicted example, communication  412  uses HTTP. However, other protocols are possible. Documents that are received by browser  400  are processed by language interpretation  414 , which includes an HTML unit  416 , and a parser  418  which is capable of generating a parse tree associated with an electronic document, as discussed below in reference to FIG. 6. Language interpretation  414  will process a document for presentation on graphical display  420 . In particular, HTML statements are processed by HTML unit  416  for presentation.  
         [0036]    Graphical display  420  includes layout unit  422 , rendering unit  424 , and window management  426 . These units are involved in presenting web pages to a user based on results from language interpretation  414 .  
         [0037]    Browser  400  is presented as an example of a browser program in which the present invention may be embodied. Browser  400  is not meant to imply architectural limitations to the present invention. Presently available browsers may include additional functions not shown or may omit functions shown in browser  400 . As used herein, the term “browser” encompasses any software application used to view or navigate for information or data (e.g. something that assists a user to browse) in a distributed data base where the distributed database is typically the internet or World Wide Web.  
         [0038]    A variety of software products are becoming available which enable non-visual access to HTML pages. These products capture the web page content and then present an audible rendering of the web page. This is generally accomplished by using a text-to-speech (TTS) technology to read the textual content. However, TTS technology cannot directly render an image. Prior art approaches to the problem involve either ignoring the image or simply announcing the fact that there is an image that contains MAP-AREAs.  
         [0039]    HTML, which is used to provide a visual structure to a web page, also provides a semantic structure to the page. Well known techniques exist for parsing an HTML source file into a parse tree. The various structural elements and relationships among the elements are then apparent from the topology of the parse tree. The parse tree is also called a Document Object Model (DOM). The present invention relies on information contained within the DOM to provide a non-visual rendering of web page images.  
         [0040]    Referring to FIG. 5, a diagram illustrating a Document Object Model is depicted in accordance with the prior art. Current web browser component technology (i.e. MS IE 5.0+, or Mozilla) maintains a DOM for the web page currently displayed. The DOM is accessible as a component, and this component provides the foundation needed to build a non-visual browser.  
         [0041]    The MAP-AREA elements  531 - 533  in DOM  500  describe the subregions of the IMAGE  511 , and the hyperlinks associated with each subregion. However, the MAP-AREA  525  is normally not shown in a HTML page. Since the MAP-AREA  525  is not visible, web authors frequently put it at the bottom of the page, where it would be completely out of context with the visible, informational content around it. Because the IMAGE  511  and MAP-AREA  525  are separated in the web page (and DOM), a cross referencing scheme, “IMAGE usemap=map 1 ”  511  and “MAP name=map 1 ”  525 , is used to associate the separate parts of the document.  
         [0042]    However, the physical separation of the IMAGE  511  from the MAP-AREA definition  525  introduces a fair amount of program complexity when the HTML page is being presented by a web browser with non-visual capabilities. A non-visual browser must describe the map at the same time it describes the image. An object of the present invention is to provide an algorithm that makes this process easier to perform. Though prior art browsers can respect the logical association between a separated image and map by maintaining extensive internal records, the present invention provides a simpler approach.  
         [0043]    Referring now to FIG. 6, a diagram illustrating an edited DOM is depicted in accordance with the present invention. The present invention comprises modifying the DOM to move the MAP-AREA definition  621  to be adjacent to the IMAGE  611 . Logically, this is the same as dynamically rewriting the web page to eliminate the problem with its topology.  
         [0044]    Referring to FIG. 7, a flowchart illustrating the process of editing a DOM is depicted in accordance with the present invention. When a web page is first loaded, it is parsed, and a DOM is created which can be analyzed for IMAGE-MAPs (step  701 ). The browser then checks for any MAP-AREA references (step  702 ) and determines whether or not the MAP is adjacent to the IMAGE element (step  703 ). If the MAP is not adjacent to the IMAGE, a new subtree is created in the DOM which places the content of the MAP-AREA definition in proximity to the IMAGE (step  704 ). This provides a topology which requires no internal bookkeeping to deal with this issue of separated images and maps. The browser then checks if the MAP is referenced by more than one IMAGE (step  705 ). If the MAP is referenced by more than one IMAGE (which is unusual), duplicate copies of the MAP-AREA definition can be made so that the one MAP-AREA definition is directly adjacent to each IMAGE which references it (step  706 ).  
         [0045]    An image on a web page can have a “longdesc” (long description) attribute. A “longdesc” names the URL where a long description of an image can be found. This attribute was added to HTML by the industry standards group (the w3c) precisely for Accessibility needs. For example, a web page may have a “Welcome” image. The longdesc attribute associated with the image might reference another web page which says “This is an image which welcomes customers to this page. There are three hyperlinks on the image.” Currently, the major commercial web browsers (IE, Netscape, Mozilla) all ignore this attribute.  
         [0046]    Because non-visual technology cannot directly render a web page image, the present invention allows a user to access the longdesc attribute in order to obtain an indirect, non-visual rendering of image content. The present invention uses the long description associated with an image as a surrogate for the image itself.  
         [0047]    Referring to FIG. 8, a flowchart illustrating the process of creating a new subtree within a DOM is depicted in accordance with the present invention. After the browser loads a web page and analyzes the DOM (step  801 ), the browser proceeds to the first DOM node (step  802 ). The browser then checks for Image elements with long description attributes (step  803 ). If there are no such Image elements, the process ends. If there are Image elements with long descriptions, the browser moves to the next one in the DOM (step  804 ).  
         [0048]    A text node which reads “Image description” is created (step  805 ). Then, a new Anchor node is created and set up so that its hyperlink points to the long description URL (step  806 ). The new text node, which reads “Image description” is made a child of the new Anchor node, so that this text appears as the visible hyperlink (step  807 ). Finally, the new Anchor node is inserted into the DOM as the first sibling node following the Image element (step  808 ). From there, the browser returns to Step  803  to determine if there are any more Image elements in the DOM with long description attributes.  
         [0049]    Rather than relying on the addition of special code for the longdesc attribute, the present invention transforms the DOM so that existing algorithms render the Accessibility information. The DOM transformation of the present invention makes the long description visible and renderable to anyone using today&#39;s current commercial web browsers (e.g. Mozilla or Internet Explorer). Currently, these browsers do not support the long description, and the information is lost.  
         [0050]    After the DOM edits are performed, subsequent DOM traversal is much more straightforward. All navigation operations can be handled using simple tree walk order navigation algorithms. This process is the subject of typical undergraduate computer science education and such algorithms are available in most any computer science textbook on data structures. One such reference is  Introduction to Algorithms,  by Cormen, Leiserson, Rivest, 19th printing, ISBN 0-262-53091-0. See INORDER-TREE-WALK algorithm in section 13.1 on p. 245. The non-visual browser can now render the MAP-AREAS audibly with less extensive bookkeeping than that required by the prior art. In another embodiment, the non-visual browser renders the MAP-AREAs by means of a tactile feedback mechanism.  
         [0051]    It should be pointed out that the non-visual rendering techniques of the present invention are not exclusive of traditional visual rendering. Both visual and non-visual rendering techniques may be used in conjunction with each other, depending on the needs of the user.  
         [0052]    It is important to note that while the present invention has been described in the context of a fully functioning data processing system, those of ordinary skill in the art will appreciate that the processes of the present invention are capable of being distributed in the form of a computer readable medium of instructions in a variety of forms and that the present invention applies equally regardless of the particular type of signal bearing media actually used to carry out the distribution. Examples of computer readable media include recordable-type media, such as a floppy disk, a hard disk drive, a RAM, CD-ROMs, DVD-ROMs, and transmission-type media, such as digital and analog communications links, wired or wireless communications links using transmission forms, such as, for example, radio frequency and light wave transmissions. The computer readable media may take the form of coded formats that are decoded for actual use in a particular data processing system.  
         [0053]    The description of the present invention has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the invention in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. The embodiment was chosen and described in order to best explain the principles of the invention, the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated.