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a few more definitions to avoid re-typing for BSLers

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This commit is contained in:
Matthias Felleisen 2012-12-28 10:47:36 -05:00
parent dc7df5b9f1
commit e212c1c279
1 changed files with 16 additions and 19 deletions
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35
collects/teachpack/2htdp/scribblings/image-guide.scrbl
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@ -62,33 +62,30 @@ Instead, we can use @racket[beside/align] to line up the two triangles
along their bottoms instead of along the middles (which is what
@racket[beside] does).
@image-interaction[(above (beside/align "bottom"
(triangle 40 "solid" "red")
(triangle 30 "solid" "red"))
(rectangle 70 40 "solid" "black"))]
@image-interaction[
(define victorian
(above (beside/align "bottom"
(triangle 40 "solid" "red")
(triangle 30 "solid" "red"))
(rectangle 70 40 "solid" "black")))
victorian
]
To add a door to the house, we can overlay a brown @racket[rectangle],
aligning it with the center bottom of the rest of the house.
@image-interaction[(overlay/align "center" "bottom"
(rectangle 15 25 "solid" "brown")
(above (beside/align "bottom"
(triangle 40 "solid" "red")
(triangle 30 "solid" "red"))
(rectangle 70 40 "solid" "black")))]
@image-interaction[
(define door (rectangle 15 25 "solid" "brown"))
(overlay/align "center" "bottom" door victorian)]
We can use a similar technique to put a doorknob on the door, but instead of
overlaying the doorknob on the entire house, we can overlay it just on the
door.
@image-interaction[(overlay/align "center" "bottom"
(overlay/align "right" "center"
(circle 3 "solid" "yellow")
(rectangle 15 25 "solid" "brown"))
(above (beside/align "bottom"
(triangle 40 "solid" "red")
(triangle 30 "solid" "red"))
(rectangle 70 40 "solid" "black")))]
@image-interaction[
(define door-with-knob
(overlay/align "right" "center" (circle 3 "solid" "yellow") door))
(overlay/align "center" "bottom" door-with-knob victorian)]
@section{Recursive Image Functions}