[racket-dev] Plot Contour Intervals Question (Bug?)

From: Neil Toronto (neil.toronto at gmail.com)
Date: Sat Aug 4 12:26:37 EDT 2012

On 08/03/2012 11:59 AM, Doug Williams wrote:
> Here is a simple contour-interval example that I don't understand.
> [We are changing out some uses of shade in older code when I came
> across something I simplified to this.]
> Consider the following simple program.
> (require plot)
> (plot (contour-intervals (lambda (x y) (define z (- x y)) (cond ((< z
> -1) -1) ((> z 1) 1) (else z))) -2 2 -2 2))
> Whose output is attached.
> Why is the lower white triangle not colored red - they definitely
> have a value of 1? It's like those points are completely ignored.

It's definitely an error. Thanks for reporting it and providing a small 
test case.

I'll fix it today and get it into the release, so if you're planning to 
upgrade, you can proceed as if it works.

Neil ⊥

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