Created
November 22, 2020 21:22
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#lang racket/gui | |
(define (maybe-set-box! b v) | |
(when b | |
(set-box! b v))) | |
(define rect-snip-class% | |
(class snip-class% | |
(inherit set-classname) | |
(super-new) | |
(set-classname "rect-snip-class%") | |
)) | |
(define rect-snip-class (new rect-snip-class%)) | |
(define rect-snip% | |
(class snip% | |
(inherit set-snipclass | |
set-flags get-flags | |
get-admin) | |
(init w h) | |
(super-new) | |
(set-snipclass rect-snip-class) | |
(define height h) | |
(define width w) | |
(define/override (get-extent dc x y [w #f] [h #f] . _) | |
(maybe-set-box! w width) | |
(maybe-set-box! h height)) | |
(define/override (draw dc x y left top right bottom . _) | |
(send dc draw-rectangle x y width height)) | |
)) | |
(define pb | |
(new | |
(class pasteboard% | |
(super-new) | |
(inherit insert) | |
(define start-pos #f) | |
(define/override (on-default-event event) | |
(super on-default-event event) | |
(define x (send event get-x)) | |
(define y (send event get-y)) | |
(cond | |
[(and (equal? (send event get-event-type) 'left-down) | |
(send event button-down? 'left) | |
(not (send event dragging?))) | |
(set! start-pos (cons x y))] | |
[(and (equal? (send event get-event-type) 'left-up) | |
start-pos) | |
(let ([dx (- (car start-pos) x)] | |
[dy (- (cdr start-pos) y)]) | |
(define-values (nx nw) | |
(if (> dx 0) | |
(values x dx) | |
(values (+ x dx) (abs dx)))) | |
(define-values (ny nh) | |
(if (> dy 0) | |
(values y dy) | |
(values (+ y dy) (abs dy)))) | |
(define sn (new rect-snip% | |
[w nw] | |
[h nh])) | |
(insert sn nx ny) | |
(set! start-pos #f))])) | |
))) | |
(define f-main (new frame% [label "wireframe"])) | |
(define cnv-main (new editor-canvas% | |
[editor pb] | |
[parent f-main])) | |
(send f-main show #t) |
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