problem obtaining screen coords from visad coordinates using MouseBehaviour

[Stuart Maclean]

Given the standard visad 'box' whose lower left has value -1,-1 in the 
visad coordinate system, and upper right of 1,1, I need to obtain the 
screen coordinates of the points.

In offscreen mode, this works.  The visadCanvasJ2D has an 
affineTransform which takes account of the (Swing/awt) component's 
physical width and height, and the MouseBehaviour object on which I call 
getScreenCoords() uses the canvas's AffineTransform (I have been through 
the source code).

But in onscreen mode, the canvas has no 'size' when its AffineTransform 
is built, so width and height default to 1.  So then MouseBehaviour's 
getScreenCoords returns x' = (0.33,0,0.5) y' = (0,-0.33,0.5) which is wrong.

I see that ProjectionControl's setAspect call affects the 
DisplayRenderer's AffineTransform, but this does appear to update the AT 
in the canvas, as used by the MouseBehaviour.

So, how do I get screen coords in onscreen mode?  I suspect that I am 
overlooking something very simple here.

My app is actually an offscreen one, but I am intrigued as to how 
MouseBehaviour.getScreenCoords would/should work in the general case.

Any help appreciated

Stuart Maclean

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