posn in graphics/graphics

[Jos Koot]

Hi

posn-s of graphics/graphics are structs with two reals. They are used to locate objects in a viewport. I would expect locations to be identified by two exact nonnegative integers pointing to a pixel. We don't have fractions of pixels, do we? Where  for example is (make-posn 3.4 5.6)? Does it identify the same position as (make-posn 3 6)? Maybe there is a reason posn has reals, but I do not see why. If there is such a reason, please tell me.

Racket is great!!!

Jos

[George Neuner]

Hi Jos,

I don't think the coordinates are  /meant/  to be real valued ... I think somebody just used  real?  as the check function.  Or possibly the docs all are wrong: if you look at  racket/draw you'll see that all the functions specify coordinates as real values.   It certainly doesn't make any other sense.

Also, if you haven't already, you should ask in the discourse.

George

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