#lang scheme/gui

;; draw.ss
;; Lee Spector, lspector@hampshire.edu, 20091004
;; Simple code for drawing shapes in a separate window in DrScheme.
;;
;; User functions:
;; (make-window) -- creates the window
;; (clear) -- clears the drawing
;; (ellipse x y width height r g b a) -- draw ellipse; r g & b are 0-255, a is 0.0-1.0
;; (rectangle x y width height r g b a) -- draw ellipse; r g & b are 0-255, a is 0.0-1.0

(define width 500)
(define height 500)

(define frame (new frame% (label "Drawing Window")
                   (width width)
                   (height height)))

(define bm (make-object bitmap% width height))

(define canvas
  (new canvas% [parent frame]
       [paint-callback (lambda (canvas dc)
                         (send dc draw-bitmap bm 0 0))]))

(define dc (make-object bitmap-dc% bm))
(send dc set-pen (make-object pen% "BLACK" 1 'transparent)) ;; No pen
(send dc set-smoothing 'smoothed)

(define make-window
  (lambda ()
    (send frame show #t)))

(define ellipse
  (lambda (x y width height r g b a)
    (send dc set-brush (make-object brush% (make-object color% r g b) 'solid))
    (send dc set-alpha a)
    (send dc draw-ellipse x y width height)))

(define rectangle
  (lambda (x y width height r g b a)
    (send dc set-brush (make-object brush% (make-object color% r g b) 'opaque))
    (send dc set-alpha a)
    (send dc draw-rectangle x y width height)))

(define clear
  (lambda ()
    (rectangle 0 0 width height 255 255 255 1.0)))

(define test 
  (lambda ()
    (clear)
    (rectangle 20 30 300 210 255 0 120 0.5)
    (ellipse 120 100 135 265 43 154 0 0.5)
    (make-window)))

(test)