59 lines
2.8 KiB
Racket
59 lines
2.8 KiB
Racket
#lang racket ;; -*- racket -*-
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(require (only-in syndicate seal))
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(require syndicate/actor)
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(require syndicate/big-bang)
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(define (button #:background [background "grey"]
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#:foreground [foreground "white"]
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#:font-size [font-size 22]
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name x y label callback)
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(define label-image (text label font-size foreground))
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(actor (forever
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(on (message (mouse-event _ _ name "button-down") #:meta-level 1) (callback))
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(assert (window name x y 0
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(seal
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(overlay label-image
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(rectangle (+ (image-width label-image) 20)
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(+ (image-height label-image) 20)
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"solid"
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background))))
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#:meta-level 1))))
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(define (draggable-shape name orig-x orig-y image)
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(define (window-at x y) (window name x y 10 (seal image)))
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(define (mouse-left-event-type? t) (member t '("leave" "button-up")))
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(define (idle ticks x y)
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;; TODO: Once "tail-calls" between `state`s are fixed, remove the
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;; ugly returning-of-an-immediately-called-thunk-from-the-
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;; termination-handlers here and in `dragging`.
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((state [#:collect [(ticks ticks) (x x) (y y)]
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(assert (window-at x y) #:meta-level 1)
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(on (message (tick-event) #:meta-level 1)
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(define new-ticks (+ ticks 1))
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(define displacement (* (cos (* new-ticks 10 1/180 pi)) 4))
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(values new-ticks x (+ y displacement)))]
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[(message (mouse-event $mx $my name "button-down") #:meta-level 1)
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(lambda () (dragging mx my (- mx x) (- my y)))])))
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(define (dragging mx my dx dy)
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((state [#:collect [(mx mx) (my my)]
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(assert (window-at (- mx dx) (- my dy)) #:meta-level 1)
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(on (message (mouse-event $mx $my _ "drag") #:meta-level 1) (values mx my))]
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[(message (mouse-event $mx $my _ (? mouse-left-event-type? $t)) #:meta-level 1)
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(lambda () (idle 0 (- mx dx) (- my dy)))])))
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(actor (idle 0 orig-x orig-y)))
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(big-bang-dataspace #:width 640
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#:height 480
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(actor (forever
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(during (active-window $id) #:meta-level 1
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(assert (window 'active-window-label 300 0 0
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(seal (text (format "~v" id) 22 "black")))
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#:meta-level 1))))
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(button #:background "red" 'stop-button 0 0 "Exit"
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(lambda () (assert! 'stop #:meta-level 1)))
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(draggable-shape 'c1 50 50 (circle 30 "solid" "orange"))
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(draggable-shape 's1 100 100 (star 40 "solid" "firebrick")))
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(exit 0)
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