(define Basic-Shapes (unit (import) (export Shape Rectangle Circle Translated) (define Shape (interface () draw)) (define Rectangle (class* object% (Shape) (width height) (public [draw (lambda (dc x y) (send dc draw-rectangle x y width height))]) (sequence (super-init)))) (define Circle (class* object% (Shape) (radius) (public [draw (lambda (dc x y) (send dc draw-ellipse (- x radius) (- y radius) (* 2 radius) (* 2 radius)))]) (sequence (super-init)))) (define Translated (class* object% (Shape) (orig-shape dx dy) (public [draw (lambda (dc x y) (send orig-shape draw dc (+ x dx) (+ y dy)))]) (sequence (super-init)))))) (define Union-Shape (unit (import Shape) (export Union) (define Union (class* object% (Shape) (left right) (public [draw (lambda (dc x y) (send left draw dc x y) (send right draw dc x y))]) (sequence (super-init)))))) (define Basic+Union-Shapes (compound-unit (import) (link [S (Basic-Shapes)] [US (Union-Shape (S Shape))]) (export(S Shape) (S Rectangle) (S Circle) (S Translated) (US Union)))) (define BB-Shapes (unit (import Shape Rectangle Circle Translated Union) (export BB-Shape BB-Rectangle BB-Circle BB-Translated BB-Union make-BB BB-left BB-top BB-right BB-bottom) (define BB-Shape (interface (Shape) bounding-box)) (define-struct BB (left top right bottom)) (define BB-Rectangle (class* Rectangle (BB-Shape) (width height) (public [bounding-box (lambda () (make-BB 0 0 width height))]) (sequence (super-init width height)))) (define BB-Circle (class* Circle (BB-Shape) (r) (public [bounding-box (lambda () (make-BB (- r) (- r) r r))]) (sequence (super-init r)))) (define BB-Translated (class* Translated (BB-Shape) (shape dx dy) (public [bounding-box (lambda () (let ([pre-bb (send shape bounding-box)]) (make-BB (+ (BB-left pre-bb) dx) (+ (BB-top pre-bb) dy) (+ (BB-right pre-bb) dx) (+ (BB-bottom pre-bb) dy))))]) (sequence (super-init shape dx dy)))) (define BB-Union (class* Union (BB-Shape) (left right) (public [bounding-box (lambda () (let ([left-bb (send left bounding-box)] [right-bb (send right bounding-box)]) (make-BB (min (BB-left left-bb) (BB-left right-bb)) (min (BB-top left-bb) (BB-top right-bb)) (max (BB-right left-bb) (BB-right right-bb)) (max (BB-bottom left-bb) (BB-bottom right-bb)))))]) (sequence (super-init left right)))))) (define Basic+Union+BB-Shapes (compound-unit (import) (link [S (Basic+Union-Shapes)] [BS (BB-Shapes (S Shape) (S Rectangle) (S Circle) (S Translated) (S Union))]) (export (S Shape) (BS BB-Shape) ;rename BS's BB-Rectangle to Rectangle, etc.: (BS (BB-Rectangle Rectangle)) (BS (BB-Circle Circle)) (BS (BB-Translated Translated)) (BS (BB-Union Union)) (BS make-BB) (BS BB-left) (BS BB-top) (BS BB-right) (BS BB-bottom)))) (define Picture (unit (import Rectangle Circle Translated display-shape) (export shape1 shape2) (define shape1 (make-object Rectangle 40 30)) (define shape2 (make-object Translated (make-object Circle 20) 30 30)) (display-shape shape1) (display-shape shape2))) (define Union-Picture (unit (import Rectangle Circle Translated Union shape1 shape2 display-shape) (export) (define shape3 (make-object Union shape1 shape2)) (display-shape shape3))) ;; the graphics library (mred@) is defaultly a signed unit. ;; see mzscheme manual for details of signed units. (define MrEd-Toolkit (unit/sig->unit mred@)) (define BB-Gui (unit (import BB-Shape BB-left BB-top BB-right BB-bottom canvas% frame%) (export display-shape) (define shape-canvas% (class canvas% (parent shape) (inherit get-dc get-client-size) (override [on-paint (lambda () (let-values ([(win-width win-height) (get-client-size)]) (let* ([bb (send shape bounding-box)] [size (lambda (left1 right1 left2 right2) (- (/ (- (- right2 left2) (- right1 left1)) 2) left1))] [x (size (BB-left bb) (BB-right bb) 0 win-width)] [y (size (BB-top bb) (BB-bottom bb) 0 win-height)]) (send shape draw (get-dc) x y))))]) (sequence (super-init parent)))) (define display-shape (lambda (a-shape) (unless (is-a? a-shape BB-Shape) (error 'display-shape "expected a BB-Shape, got: ~e" a-shape)) (let* ([frame (make-object frame% "Centered Shapes" #F 150 150)] [canvas (make-object shape-canvas% frame a-shape)]) (send frame show #t)))))) (define BB-Program (compound-unit (import) (link [S (Basic+Union+BB-Shapes)] [M (MrEd-Toolkit)] [BG (BB-Gui (S BB-Shape) (S BB-left) (S BB-top) (S BB-right) (S BB-bottom) (M canvas%) (M frame%))] [P (Picture (S Rectangle) (S Circle) (S Translated) (BG display-shape))] [UP (Union-Picture (S Rectangle) (S Circle) (S Translated) (S Union) (P shape1) (P shape2) (BG display-shape))]) (export))) (invoke-unit BB-Program)
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