Commit 0bfb343

square

triangle

(define-proto Polygon

#:init

(λ (vertices mode pen-or-color)

(define xs (map posn-x vertices))

(define ys (map posn-y vertices))

(define width (- (apply max xs) (apply min xs)))

(define height (- (apply max ys) (apply min xs)))

(set-object! #js*.this

[type "polygon"]

[vertices vertices]

[width width]

[height height]

[mode mode]

[pen pen-or-color]))

#:prototype-fields

[render

(λ (ctx x y)

(define first-point (car #js*.this.vertices))

(define rest-points (cdr #js*.this.vertices))

(define radius #js*.this.radius)

(with-origin ctx [x y]

(with-path ctx {#js*.this.mode #js*.this.pen}

(#js.ctx.moveTo (posn-x first-point) (posn-y first-point))

(let loop ([points rest-points])

(unless (null? points)

(define pt (car points))

(#js.ctx.lineTo (posn-x pt) (posn-y pt))

(loop (cdr points)))))))])

(define (square s m p)

(new (Rectangle s s m p)))

(define (triangle side mode color)

;; height = side * sin(45)

(define height (* side (/ (sqrt 3) 2)))

(new (Polygon (list (posn (- (/ side 2)) (/ height 2))

(posn 0 (- (/ height 2)))

(posn (/ side 2) (/ height 2)))

mode

color)))

;;

[("right") (- x (half #js.image.width))]

[("bottom") (- y (half #js.image.height))]