CGM Open BHO Project

BHO Information/FAQ

Copyright©2000 CGM Open Consortium, Inc. All Rights Reserved.

What is it?

BHO IS NOT A CGM VIEWER! (If you need a CGM viewer, please have a look at our members' websites.)

CGM Open has developed a Browser Helper Object (BHO) that allows software vendors to build WebCGM viewers that can handle object-level WebCGM addressing when running inside Microsoft Internet Explorer.

WebCGM product suppliers. Only software developers who want to develop a WebCGM viewer need this BHO, to be able to provide full support for WebCGM addressing.

End users. The BHO must not be installed directly on a computer. This will be handled by the installers that install the WebCGM viewer.

W3C standards prescribe an extension associated with URLs - the "URL fragment" - which enables specifications such as WebCGM (and SVG) to address individual graphical objects within Web documents or pages. It was discovered that Microsoft Internet Explorer (IE, 5.0 and 5.5 at least) did not correctly handle URL fragments in all necessary situations. The WebCGM BHO solves the problem for WebCGM applications running with IE.

An example is http://www.cgmopen.org/sample.cgm#myObj. This URL points to the graphical object "myObj" inside the file "sample.cgm" on the CGM Open server. The fragment is the portion of the URL address that follows the "#" character. It is specific to and should be handled by browser plugins or controls for the associated data type. All major browsers do not handle the fragment after the #-character correctly in all cases. This leads to a situation that either the MIME type was not recognized, or the CGM viewer would not get the full URL including the fragment.

In collaboration with Microsoft, CGM Open developed a solution that examines all CGM URLs that are processed by Internet Explorer. If it encounters a URL that contains a WebCGM fragment it will store this fragment in a safe place so that the WebCGM viewer will be able to access it. WebCGM viewers will have to check this location to find out whether there was a fragment, and then act accordingly.

Microsoft will change the behavior of Microsoft Internet Explorer in the future. Once this will happen the BHO will no longer be needed.

No. This BHO component works only with Microsoft Internet Explorer (IE) -- it is of no use with other browsers, because it is tailored to fit with IE software interfaces. Initial CGM Open results seemed to indicate that Netscape Navigator (NN) did not have the problem. However, more careful testing indicates that NN does indeed suffer from the "#" fragment bug. CGM Open will try to work with Netscape, as we did with Microsoft, to find an equivalent workaround for NN.

By the nature of the BHO, serious interference and software problems for WebCGM viewers could result from installation of a WebCGM BHO which differs from the CGM Open standard release. CGM Open's BHO license restrictions are aimed at preventing such scenarios.

Distribution & Ordering

Object-code distribution.

The WebCGM BHO is freely available in object code form, to any builders and distributors of WebCGM viewers, and includes sufficient implementors' documentation. Please read the license agreement and follow the instructions below, if you wish to obtain the BHO.

Source code distribution.

Source code for the WebCGM BHO is available to CGM Open members, under an additional source code license. Qualified recipients should please send an email request to bho-request@cgmopen.org.

Technology transfer.

CGM Open will share the technology of the WebCGM BHO with non-CGM Web graphics applications (such as SVG), under a separate Technology License. The BHO will be shared free of charge with qualified recipients under the following license terms and conditions.

CGM OPEN BHO DISTRIBUTION LICENSE Copyright © 2000 CGM Open Consortium, Inc. All Rights Reserved. The CGM Open Browser Helper Object (the "BHO") in its object code form is provided by CGM Open Consortium, Inc. (together with its successors and assigns, the "Licensor") to you subject to the following terms and conditions: Permission to use, copy, and distribute the BHO, in any medium for any purpose and without fee or royalty is hereby granted to you, provided that you comply with each of the following: 1. The BHO may be installed and used only in conjunction with a WebCGM viewer. 2. Installation of the BHO must be conducted in accordance with the technical guidelines from CGM Open. 3. If you distribute the BHO, you may do so only in conjunction with a WebCGM viewer. 4. If you distribute the BHO, you will inform CGM Open of the start of the distribution prior to first shipment. 5. If you distribute the BHO, you must require all recipients of the BHO to agree and be subject to the terms of this license, except that no such recipient shall have any right or permission to distribute the BHO. 6. You shall include the following copyright notice in the "About" dialog and the documentation of the WebCGM viewer: "CGM Open WebCGM BHO © 2000 CGM Open Consortium, Inc.". No right to create modifications or derivatives of the BHO is granted pursuant to this license. THE BHO IS PROVIDED "AS IS," AND NEITHER LICENSOR NOR ANY OTHER PERSON MAKES ANY REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, NON-INFRINGEMENT, OR TITLE; THAT THE BHO IS SUITABLE FOR ANY PURPOSE. NEITHER LICENSOR NOR ANY OTHER PERSON WILL BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF ANY USE OF THE BHO OR THE PERFORMANCE OR IMPLEMENTATION OF THE CONTENTS THEREOF. The name and trademarks of Licensor may NOT be used in advertising or publicity pertaining to the BHO without specific, prior written permission. Title to copyright in the BHO will at all times remain with Licensor.

If you wish to obtain the BHO, please send an email request for to bho-request@cgmopen.org. Include all of the following in your request:

Name
Company
Mail address
Phone
Email address
Product with which BHO will be used

Please include the following sentence in your email request, "I have read the CGM OPEN BHO DISTRIBUTION LICENSE at http://www.cgmopen.org/technical/bho/index.html#distribution, and I accept and agree to abide by its terms."

BHO IS NOT A CGM VIEWER!
(If you need a CGM viewer, please have a look at our members' websites.)