Conference tnpubs::i-exchange

2.0. " Converting WinHelp and MM Viewer to the Web " by VAXUUM::KILLELEA () Tue May 30 1995 12:21

From:	ORION::GENT "I'm acutely aware of being involved in something that ought to be making more of a difference -- Brian Eno  22-May-1995 1033" 22-MAY-1995 10:37:34.92
To:	@HLPTOHTML
CC:	
Subj:	Converting WinHelp and MM Viewer to the Web -- Summary

    This note provides a brief overview of the technology we (Shared
    Engineering Services) are currently testing for converting Windows Help
    and multimedia viewer documents to the web.

    Note: the technology described below is still under development and 
    is not ready for distribution either internally or externally. You are
    receiving this message because you expressed interest in the
    WinHelp-to-HTML project. 


    			Digital Internal Use Only



Converting WinHelp and Multimedia Viewer Sources for Dissemination
on the World-Wide Web
--------------------------------------------------------------

    There are several existing RTF-to-HTML converters (notably, the 
    Internet Assistant from Microsoft and rtftohtml from Chris Hector of
    Cray Computers). These converters are designed to handle standard
    Microsoft Word documents, not hyper-documents. Although the converters
    have private mechanisms for representing Web links within the RTF,
    these mechanisms are different than and incompatible with those used to
    represent WinHelp hotspots. 

    Since, the topic structure and hotspots are integral components of
    hypermedia and the existing converters ignore these elements, none of
    the current converters are sufficient for converting Winhelp and the
    Multimedia Viewer documents out of the box. However the converters do
    an adequate job of converting the content. 

    Rather than build a new converter from scratch, the goal of this
    project was to:

    -	Take advantage of existing converters for content conversion
	(rtftohtml was the target converter for testing, but the 
    	preprocessor can be modified to support additional converters)

    -	Provide pre- and post-processors to convert hotspots, topic
	identifiers and other WinHelp features (such as sequence numbers,
    	keywords, etc.)

    -   In addition, support "hot" graphics (known as segmented or SHED 
	graphics) through a separate conversion process

    At the moment, the pre- and post-processors successfully handle 
    hotspots and topic ids. Sequence numbers, keywords, and topic macros
    are recorded by the preprocessor but ignored by the postprocessor at
    this time. 


    			Digital Internal Use Only



Conversion Process
--------------------------------------------------------------

    The following are the steps for converting a set of WinHelp source
    files. (Notes in square brackets identify the tools used during the
    initial tests.)

    1.	Create a list of RTF source files.

    2.	Process each RTF source file through the preprocessor, creating
    	a modified source file.

    3.	Process each of the new RTF files through the RTF converter.
    	[For testing, the rtftohtml converter was used on an OSF/1
    	machine. This converter will create one HTML file for each input
    	file, plus separate files for any embedded graphics.]

    4.	Process the HTML files through the postprocessor. This process
    	creates separate HTML files for each help topic. The postprocessor 
	will also provide a list of BMP and SHG files that are included 
	by reference.

    5.  Use the list of SHG files from step #4 to determine what SHG
    	files need to processed, then:

    	5A.  Process each SHG file through SHG2MAP to create an imagemap
    	     map file.

    	5B.  Use the SHED graphics editor to export the graphic content
    	     to a BMP file.

    6.	Use one or more graphics converters to convert the BMP and WMF
    	files created by the RTF conversion (Step #3), listed during
    	postprocessing (step #4), or exported from SHG files (step #5B)
    	to GIF files. [For testing, two converters were used: Convert
    	on Windows for converting WMFs to BMP and GraphicConverter on 
    	Macintosh for converting BMP to GIF. These converters were chosen
    	because they were available and have the ability to batch process 
	large numbers of files.]


    			Digital Internal Use Only



Conversion Model
--------------------------------------------------------------

    The following is a picture of the conversion process:

    +---                  +---      +-------+    +---                   +---
    |  |\     +======+    |  |\     | RTF   |    |  |\     +=======+    |  |\
    |  +-| -> |wppre | -> |  +-| -> |convrtr| -> |  +-| -> |wppost | -> |  +-|
    |    |    +======+    |    |    |       |    |    |    +=======+    |    |
    +----+                +----+    +-------+    +----+                 +----+
     RTF                    RTF       \           HTML                   HTML
                                       \
    +---                                \    +---        +--------+     +---
    |  |\                                \   |  |\       |graphic |     |  |\
    |  +-|                                -> |  +-| ---> |convrtrs| --> |  +-|
    |    | --------------------              |    |  --> |        |     |    |
    +----+                     \             +----+ / -> +--------+     +----+
      BMP                       \           BMP|WMF/ /                    GIF
                                 ------------------ /
    +---                         ------------------/
    |  |\                       /                                       +---   
    |  +-| --------------------/    +=======+                           |  |\  
    |    | -----------------------> |shg2map| ------------------------> |  +-| 
    +----+                          +=======+                           |    | 
      SHG                                                               +----+ 
                                                                       IMAGEMAP
                                                                           
    			Digital Internal Use Only



Current Status (May 21, 1995)
--------------------------------------------------------------

    The preprocessor, postprocessor, and shg2map applications are
    working (with a few known bugs). However, it is clear that the
    conversion process is complex and contains several manual steps.

    At the moment, all three applications are separate and operate on
    a single file at a time. The goal of the following wishlist of 
    possible new features is to reduce the complexity of the process
    by integrating the separate tools and removing manual activities.

    Wishlist
    -------------

    -	Have the pre- and post-processors process the project file to
    	determine the appropriate input files and process all files in
    	a single pass. (This would reduce the number of unrecognized
    	link messages and would be the first step towards supporting
    	sequence numbers.)

    -	Have the post-processor invoke shg2map directly, passing it a
    	default URL. (Today, the map files from shg2map must be edited
    	manually to include a default URL.)

    -   Support sequence numbers in the post-processor, adding the
	appropriate previous and next as <META> tags and possibly
    	URL links on the page.

    -	Add support in the post-processor for prefixes and suffixes to 
    	provide "canned text" for every page (such as a copyright message).

    -   Support POPID and JUMPIP macros.

    -	Port rtftohtml to VMS. (Currently, rtftohtml is supported for UNIX
    	and Macintosh only.)



    			Digital Internal Use Only



Contact List
--------------------------------------------------------------

    Author:	Andrew Gent
    		[email protected]
    		DTN 381-2417