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Minor tweaks to documentation and rotating-triangle test.

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This commit is contained in:
Stephen Bloch 2010-12-30 10:29:12 -05:00
parent 7069a267a6
commit f3352794d8
2 changed files with 9 additions and 2 deletions
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2
collects/picturing-programs/picturing-programs.scrbl
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@ -211,7 +211,7 @@ produces a copy of @racket[my-picture] with all the red leached out,
leaving only the blue and green components.
Since @racket[make-color] with three arguments defaults alpha to 255,
this function discards any alpha information (including edge-dithering)
this definition of @racket[lose-red] discards any alpha information (including edge-dithering)
that was in the original image. To preserve this information, one could write
@racketblock[
(define (lose-red-but-not-alpha x y old-color)

9
collects/picturing-programs/tests/rotating-triangle.rkt
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@ -18,7 +18,14 @@
(define (rotate-1 pic)
(rotate 1 pic))
(big-bang badtricirc
"Triangle rotating around its center:"
(big-bang tricirc
(on-tick rotate-1 .05)
(check-with image?)
(on-draw show-it))
"Triangle rotating around the center of its bounding box:"
(big-bang badtricirc
(on-tick rotate-1 .05)
(check-with image?)
(on-draw show-it))