[racket] freeze and bounding boxes

From: David Van Horn (dvanhorn at ccs.neu.edu)
Date: Wed Jan 18 18:22:39 EST 2012

On 1/18/12 6:04 PM, Robby Findler wrote:
> Yes, that's the right behavior. See the end of the 2htdp/image docs
> about pixels and whatnot.

OK, it seems at odds with the note that freeze can "improve performance 
without changing how the image draws," but I get that a square draws 
larger than its bounding box so it gets cropped when frozen (or saved to 
a file).

By the way, I think you can see this phenomenon in the rendering of the 
2htdp/image docs.  So for example, the section you referred me to has 
this example:

    (let* ([s (rectangle 20 20 "outline" "black")]
           [r (beside s s s s s s)])
        (above r r r r r r))

which when run in DrRacket produces a grid, but in the docs crops the 
right and bottom lines.  That makes the discussion about cropping very 
confusing.  Also: it seems you cannot in general have Scribble examples 
that involve outlined shapes such that they look like they really appear 
in DrRacket.


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