>I think you are right. You know, when Bill Atkinson did QuickDraw for the 
>Mac, he came up with a useful insight: to have the coordinates be zero 
>width and be located between the pixels, instead of being on the pixels. 
>This has many felicitous properties and perhaps someday we should convert 
>over to this convention for Squeak ....

I think Squeak already works this way, at least under the Macintosh.  Try:

Display fill: (Rectangle origin: 1 at 1 corner: 2 at 2) fillColor: Color red.

which plots a single red pixel on my Mac.  Does it do something different 
(e.g. plot a 2x2 square of pixels) on other systems?  I would suspect 
that it doesn't, otherwise some of the UI (borders, etc.) might look 
strange.  If all systems plot the single pixel, then the various VMs must 
be handling the interface to the underlying display such that they are 
all treating it as a "zero width coordinate, between pixels" organization.



     -- tim