Subject:
Vector Based Annotation and Whiteboard
From:
"James Poelke" <james@anabas.com>
Date:
Tue, 26 Jun 2001 08:42:45 -0700
To:
"'John Yin'" <johnyin@anabas.com>, <fox@anabas.com>, <alexho@ANABAS.COM>
CC:
<Kyle@anabas.com>

Fellas,

 

I spent some time last week looking into the possiblity of converting the whiteboard and annotation tool into a single system that uses an industry standard format.  The benefits of this are as follows:

            - Consistent interface between whiteboard and annotation

            - Saving and Loading of slides which provides for Meeting Summary functionality

            - Enables shared export of Powerpoint slides to greatly reduce bandwidth

 

The options I considered were SVG and WMF.

 

SVG is extremely powerful and seems to be standard format for any serious vector graphics work.  Adobe has a real nice ActiveX control viewer which we are currently using for our shared export demo.  Batik has a Java toolkit, and IBM and CSIRO have java viewers as well.  The problem I found in common with all the SVG viewers is that they are huge (> 1MB), also the Java implementations all require Java 2. 

 

WMF is Microsofts Windows Meta File format.  It has been around since the 16bit windows days and there is a 32bit version called EMF (Enhanced Meta File).  The main drawback to WMF is that is fairly limited.   However; WMF is more than adequete for supporting powerpoint slides, and Powerpoint can export directly to it.  Also, its commands convert directly into windows GDI calls.              

 

After looking at both formats, I think that long-term SVG is the way to go, but short term we can implement a native WMF viewer that gives us everyhting we want very quickly.   This would make the whiteboard renderer a native component which would mean that all of the core presentation technology would be packaged up into a  couple of small (<150k compressed) dlls.   Annotation on top of exported powerpoint slides would be especially nice as each client could scale the image to fit his screen.  Once we have the basic system running with our WMF viewer, we can swap in a basic SVG viewer starting with a basic subset of elements that we already support with the WMFviewer. 

 

-James