big-bang 02
You should be familiar with the importance of check-expects before doing the exercises.
Long Leg Triangle
The first animation code is below.
(define (left-mid img)
(overlay/align "left" "middle" img (empty-scene 350 250)))
(define initial-model
(right-triangle 200 100 "solid" "blue"))
(big-bang initial-model
(on-mouse ...to-write...)
(to-draw left-mid))
- Sketch the first image shown when the code is run. (Commit to your best guess before testing it.)
- What kind of “thing” is the initial model?
Mouse Handler 1
The purpose of the mouse handler my-mouse
is to create a triangle with width equal to the
x-coordinate of the mouse but with the height always 100.
-
Write a check-expect showing the result when the mouse moves to the point (150,75).
(check-expect (my-mouse initial-model 150 75 "move") ...)
-
Write another check-expect that has everything different from the one above. (Every single input, and the output.)
Mouse Handler 2
Now we write another, different mouse handler.
The purpose of this mouse handler, slide-handler
, is to make it seem
like there is a large triangle extending off the left side of the
screen that slides back and forth on the screen so that the tip of the
triangle is at the x-coordinate of the mouse.
- Write a check-expect for
slide-handler
. - Write a totally different check-expect for
slide-handler
.