racket/collects/graphics/turtle-unit.ss
2005-05-27 18:56:37 +00:00

467 lines
18 KiB
Scheme

(module turtle-unit mzscheme
(require (lib "unitsig.ss")
(lib "mred-sig.ss" "mred")
(lib "class.ss")
(lib "class100.ss")
(lib "list.ss")
(lib "etc.ss")
"turtle-sig.ss")
(provide turtle@)
(define turtle@
(unit/sig turtle^
(import [mred : mred^])
(define turtles:window #f)
(define turtles:shown? #f)
(define pi 3.141592653589793)
(define pi/2 (/ pi 2))
(define icon-pen (send mred:the-pen-list find-or-create-pen "SALMON" 1 'xor))
(define icon-brush (send mred:the-brush-list find-or-create-brush "SALMON" 'xor))
(define blank-pen (send mred:the-pen-list find-or-create-pen "BLACK" 1 'transparent))
(define w-pen (send mred:the-pen-list find-or-create-pen "white" 1 'solid))
(define b-pen (send mred:the-pen-list find-or-create-pen "black" 1 'solid))
(define show-turtle-icons? #t)
;; turtle-style : (union 'triangle 'line 'empty)
(define turtle-style 'triangle)
(define plot-window%
(class100 mred:frame% (name width height)
(private-field
[bitmap (make-object mred:bitmap% width height #t)])
(inherit show)
(private-field
[memory-dc (make-object mred:bitmap-dc%)]
[pl (make-object mred:point% 0 0)]
[pr (make-object mred:point% 0 0)]
[ph (make-object mred:point% 0 0)]
[points (list pl pr ph)])
(public
[get-canvas
(lambda ()
canvas)]
[flip-icons
(lambda ()
(case turtle-style
[(triangle line)
(flatten (lambda (x) x))
(let* ([dc (send canvas get-dc)]
[proc
(if (eq? turtle-style 'line)
(lambda (turtle)
(let ([x (turtle-x turtle)]
[y (turtle-y turtle)]
[theta (turtle-angle turtle)]
[size 2])
(send dc draw-line
x y
(+ x (* size (cos theta)))
(+ y (* size (sin theta))))))
(lambda (turtle)
(let* ([x (turtle-x turtle)]
[y (turtle-y turtle)]
[theta (turtle-angle turtle)]
[long-size 20]
[short-size 7]
[l-theta (+ theta pi/2)]
[r-theta (- theta pi/2)])
(send ph set-x (+ x (* long-size (cos theta))))
(send ph set-y (+ y (* long-size (sin theta))))
(send pl set-x (+ x (* short-size (cos l-theta))))
(send pl set-y (+ y (* short-size (sin l-theta))))
(send pr set-x (+ x (* short-size (cos r-theta))))
(send pr set-y (+ y (* short-size (sin r-theta))))
(send dc draw-polygon points))))])
(if (eq? turtle-style 'line)
(send dc set-pen icon-pen)
(begin
(send dc set-pen blank-pen)
(send dc set-brush icon-brush)))
(for-each proc turtles-state)
(send dc set-pen b-pen))]
[else
(void)]))]
[clear
(lambda ()
(send memory-dc clear)
(send canvas on-paint))])
(sequence
(send memory-dc set-bitmap bitmap)
(send memory-dc clear)
(super-init name #f width height))
(public
[on-menu-command (lambda (op) (turtles #f))])
(private-field
[menu-bar (make-object mred:menu-bar% this)]
[file-menu (make-object mred:menu% "File" menu-bar)])
(sequence
(make-object mred:menu-item%
"Print"
file-menu
(lambda (_1 _2)
(print)))
(make-object mred:menu-item%
"Close"
file-menu
(lambda (_1 _2)
(turtles #f))))
(public
[save-turtle-bitmap
(lambda (fn type)
(send bitmap save-file fn type))])
(private-field
[canvas%
(class100 mred:canvas% args
(inherit get-dc)
(override
[on-paint
(lambda ()
(let ([dc (get-dc)])
(send dc clear)
(send dc draw-bitmap (send memory-dc get-bitmap) 0 0)
(flip-icons)))])
(sequence (apply super-init args)))]
[canvas (make-object canvas% this)]
[dc (send canvas get-dc)])
(public
[wipe-line (lambda (a b c d)
(send memory-dc set-pen w-pen)
(send dc set-pen w-pen)
(send memory-dc draw-line a b c d)
(send dc draw-line a b c d)
(send memory-dc set-pen b-pen)
(send dc set-pen b-pen))]
[draw-line (lambda (a b c d)
(send memory-dc draw-line a b c d)
(send dc draw-line a b c d))])
(sequence
(send canvas min-width width)
(send canvas min-height height)
(send this clear))))
(define turtle-window-size
(let-values ([(w h) (mred:get-display-size)]
[(user/client-offset) 65]
[(default-size) 800])
(min default-size
(- w user/client-offset)
(- h user/client-offset))))
(define-struct turtle (x y angle))
; x : int
; y: int
; angle : int
(define-struct cached (turtles cache))
; turtles : (list-of turtle)
; cache : turtle -> turtle
(define-struct tree (children))
; children : (list-of cached)
(define clear-turtle (make-turtle (/ turtle-window-size 2)
(/ turtle-window-size 2) 0))
;; turtles-state is either a
;; - (list-of turtle) or
;; - tree
(define turtles-state (list clear-turtle))
;; the cache contains a turtle-offset, which is represented
;; by a turtle -- but it is a delta not an absolute.
(define empty-cache (make-turtle 0 0 0))
(define turtles-cache empty-cache)
(define init-error (lambda _ (error 'turtles "Turtles not initialized. Evaluate (turtles).")))
(define inner-line init-error)
(define inner-wipe-line init-error)
(define inner-clear-window init-error)
(define inner-flip-icons init-error)
(define inner-save-turtle-bitmap init-error)
(define line
(lambda (a b c d)
(set! lines-in-drawing (cons (make-draw-line a b c d) lines-in-drawing))
(inner-line a b c d)))
(define do-wipe-line
(lambda (a b c d)
(set! lines-in-drawing (cons (make-wipe-line a b c d) lines-in-drawing))
(inner-wipe-line a b c d)))
(define (flip-icons) (inner-flip-icons))
(define clear-window (lambda () (inner-clear-window)))
(define save-turtle-bitmap (lambda (x y) (inner-save-turtle-bitmap x y)))
(define turtles
(case-lambda
[() (turtles #t)]
[(x)
(set! turtles:shown? x)
(unless turtles:window
(set! turtles:window
(make-object plot-window%
"Turtles"
turtle-window-size
turtle-window-size))
(set! inner-line (lambda x (send turtles:window draw-line . x)))
(set! inner-wipe-line (lambda x (send turtles:window wipe-line . x)))
(set! inner-clear-window (lambda x (send turtles:window clear . x)))
(set! inner-save-turtle-bitmap (lambda x (send turtles:window save-turtle-bitmap . x)))
(set! flip-icons (lambda x (send turtles:window flip-icons . x))))
(send turtles:window show x)
(send turtles:window get-canvas)]))
(define clear
(lambda ()
(set! turtles-cache empty-cache)
(set! turtles-state (list clear-turtle))
(set! lines-in-drawing null)
(clear-window)))
;; cache elements:
(define-struct c-forward (distance))
(define-struct c-turn (angle))
(define-struct c-draw (distance))
(define-struct c-offset (x y))
;; combines a cache-element and a turtle-offset.
;; turtle-offsets are represented as turtles,
;; however they are deltas, not absolutes.
(define combine
(lambda (entry cache)
(cond
[(c-forward? entry)
(let* ([n (c-forward-distance entry)]
[angle (turtle-angle cache)]
[x (turtle-x cache)]
[y (turtle-y cache)]
[newx (+ x (* n (cos angle)))]
[newy (+ y (* n (sin angle)))])
(make-turtle newx newy angle))]
[(c-offset? entry)
(let* ([tx (turtle-x cache)]
[ty (turtle-y cache)]
[newx (+ tx (c-offset-x entry))]
[newy (+ ty (c-offset-y entry))])
(make-turtle newx newy
(turtle-angle cache)))]
[(c-turn? entry)
(make-turtle (turtle-x cache)
(turtle-y cache)
(- (turtle-angle cache)
(c-turn-angle entry)))]
[else
(error 'turtles-cache "illegal entry in cache: ~a" entry)])))
;; this applies an offset to a turtle.
;; an offset is a turtle, representing what would happen
;; if the turtle had started at zero.
(define apply-cache
(lambda (offset)
(let ([x (turtle-x offset)]
[y (turtle-y offset)]
[offset-angle (turtle-angle offset)])
(lambda (turtle)
(let* ([angle (turtle-angle turtle)])
(let* ([c (cos angle)]
[s (sin angle)]
[rx (- (* x c) (* y s))]
[ry (+ (* y c) (* x s))])
(make-turtle (+ rx (turtle-x turtle))
(+ ry (turtle-y turtle))
(+ offset-angle angle))))))))
(define flatten
(lambda (at-end)
(letrec ([walk-turtles
(lambda (turtles cache list)
(cond
[(tree? turtles)
(let ([children (tree-children turtles)]
[ac (apply-cache cache)])
(foldl (lambda (child list)
(walk-turtles (cached-turtles child)
(ac (cached-cache child))
list))
list
children))]
[else
(let ([f (compose at-end (apply-cache cache))])
(foldl (lambda (t l) (cons (f t) l)) list turtles))]))])
(set! turtles-state (walk-turtles turtles-state turtles-cache null))
(set! turtles-cache empty-cache))))
(define draw/erase
(lambda (doit)
(lambda (n)
(flip-icons)
(flatten
(lambda (turtle)
(let* ([x (turtle-x turtle)]
[y (turtle-y turtle)]
[angle (turtle-angle turtle)]
[d (if (zero? n) 0 (sub1 (abs n)))]
[res (if (< n 0) (- d) d)]
[c (cos angle)]
[s (sin angle)]
[drawx (+ x (* res c))]
[drawy (+ y (* res s))]
[newx (+ x (* n c))]
[newy (+ y (* n s))])
(unless (zero? n)
(doit x y drawx drawy))
(make-turtle newx newy angle))))
(flip-icons))))
(define draw (draw/erase (lambda (a b c d) (line a b c d))))
(define erase (draw/erase (lambda (a b c d) (do-wipe-line a b c d))))
(define move
(lambda (n)
(flip-icons)
(set! turtles-cache (combine (make-c-forward n) turtles-cache))
(flip-icons)))
(define turn/radians
(lambda (d)
(flip-icons)
(set! turtles-cache (combine (make-c-turn d) turtles-cache))
(flip-icons)))
(define turn
(lambda (c)
(turn/radians (* (/ c 360) 2 pi))))
(define move-offset
(lambda (x y)
(flip-icons)
(set! turtles-cache (combine (make-c-offset x y) turtles-cache))
(flip-icons)))
(define erase/draw-offset
(lambda (doit)
(lambda (x y)
(flip-icons)
(flatten
(lambda (turtle)
(let* ([tx (turtle-x turtle)]
[ty (turtle-y turtle)]
[newx (+ tx x)]
[newy (+ ty y)])
(doit tx ty newx newy)
(make-turtle newx newy (turtle-angle turtle)))))
(flip-icons))))
(define erase-offset (erase/draw-offset (lambda (a b c d) (do-wipe-line a b c d))))
(define draw-offset (erase/draw-offset (lambda (a b c d) (line a b c d))))
(define splitfn
(lambda (e)
(let ([t turtles-state]
[c turtles-cache])
(e)
(flip-icons)
(set! turtles-state
(make-tree (list (make-cached turtles-state turtles-cache)
(make-cached t c))))
(set! turtles-cache empty-cache)
(flip-icons))))
(define split*fn
(lambda (es)
(let ([t turtles-state]
[c turtles-cache]
[l '()])
(for-each (lambda (x)
(x)
(set! l (cons (make-cached turtles-state turtles-cache) l))
(flip-icons)
(set! turtles-state t)
(set! turtles-cache c)
(flip-icons))
es)
(flip-icons)
(set! turtles-cache empty-cache)
(set! turtles-state (make-tree l))
(flip-icons))))
(define tpromptfn
(lambda (thunk)
(let ([save-turtles-cache #f]
[save-turtles-state #f])
(dynamic-wind
(lambda ()
(set! save-turtles-cache turtles-cache)
(set! save-turtles-state turtles-state))
(lambda ()
(thunk))
(lambda ()
(flip-icons)
(set! turtles-cache save-turtles-cache)
(set! turtles-state save-turtles-state)
(flip-icons))))))
(define-struct drawing-line (x1 y1 x2 y2))
(define-struct (wipe-line drawing-line) ())
(define-struct (draw-line drawing-line) ())
(define lines-in-drawing null)
(define (draw-lines-into-dc dc)
(for-each (lambda (line)
(cond
[(wipe-line? line) (send dc set-pen w-pen)]
[(draw-line? line) (send dc set-pen b-pen)])
(send dc draw-line
(drawing-line-x1 line)
(drawing-line-y1 line)
(drawing-line-x2 line)
(drawing-line-y2 line)))
lines-in-drawing))
;; used to test printing
(define (display-lines-in-drawing)
(let* ([lines-in-drawing-canvas%
(class100 mred:canvas% (frame)
(inherit get-dc)
(override
[on-paint
(lambda ()
(draw-lines-into-dc (get-dc)))])
(sequence
(super-init frame)))]
[frame (make-object mred:frame% "Lines in Drawing")]
[canvas (make-object lines-in-drawing-canvas% frame)])
(send frame show #t)))
(define (print)
(case (system-type)
[(macos macosx windows)
(let ([dc (make-object mred:printer-dc%)])
(send dc start-doc "Turtles")
(send dc start-page)
(draw-lines-into-dc dc)
(send dc end-page)
(send dc end-doc))]
[(unix)
(let ([dc (make-object mred:post-script-dc%)])
(send dc start-doc "Turtles")
(send dc start-page)
(draw-lines-into-dc dc)
(send dc end-page)
(send dc end-doc))]
[else
(mred:message-box "Turtles"
"Printing is not supported on this platform")])))))