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Principles for Use of VML Graphics

These are reminders for what we want to do next with VML graphics. As Adrian answers these questions, I'll revise this page.

Here's our first VML graphics display ("concept2"): Prejudice and Enlightenment .


  1. We'd like for the chart to scale to the user's screen. A concept map is easier to understand if it fits on the screen. Maybe we need to convert the VML graphic to a .pdf file so it will automatically scale to the screen.
  2. Suppose we already have a line drawing on paper. How do we create VML graphics?
    • scan it ?
    • pass cursor over its lines with software to trace the lines ?
    • ... ?

Here are messages from Adrian to be blended into the above outline.

What does PSB mean? I want to know so I can build it into my documentation.

Whatever you want it to mean! It was probably PostScript Builder but that is lost in the mists of the great cloud of whatever.

To explain ....

psb‘Box(500 50 mb 70 300)

all the psb utilities take a bounding box (xyxy) and I got bored adding up numbers so mb (makebox) just takes xy on the left and (width,height) on the right and does the adding for me!

All numbers are in points so divide by 72 to get inches. Should a higher-level utility set allow you to choose the units and scale for you? Should it let you choose to work 'top down' in the y-direction?? All my numbers are from an origin at the lower left.

Today somebody called me who is running IE5.0 saying her computer couldn't display vml graphics without downloading something and changing some settings, so we can anticipate some problems now and then.

As I remember it, in Orlando last year about 2 out of 3 had VML already enabled. It just depends which way the switches were set on the CD you installed IE5 from! Windows ME and 2000 installations get it 'out of the box' I am glad to say.

We could do an SVG alternative (this is a 2Mb plugin from Adobe but does work on Netscape) - if you want the text to behave as text (with links, ability for the user to copy/paste etc) then putting out a mapped image (like the Marsmap site) is not a good alternative. Can Fred's server discriminate on the basis of the incoming browser and switch page automatically?? Unfortunately there is no way of telling if an IE5 user has VML!

A fallback would be to make the boxes the jump-off points (so you associate an href with the psbBox call) then you just have dumb text and the entire rectangle is the link. Then I just render the entire map onto a big PNG image, link to it from the page and define the rectangles in an imagemap. This is hopw Marsmap is done.

Much harder to administer and a less flexible approach. Probably best to go with VML and let the world catch up!

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