[plt-scheme] Save image file from canvas

I can't work it out either, but oyu may be able to use the following
techique to draw straight to a bitmap-dc which you can save.

- I can't remember where I found this;
#lang scheme/gui
(let
    ((bitmap (make-object bitmap% 255 255))
     (dc (make-object bitmap-dc%))
     (red-amount 150)
     (image-file "test.jpg"))

 (send dc set-bitmap bitmap)

;; do some drawing
(do ((x 0 (+ x 1)))
    ((>= x 255))
    (do ((y 0 (+ y 1)))
      ((>= y 255))
      (send dc set-pixel x y
            (make-object color% x y 50)
            ))
    )
;;
(when (file-exists? image-file)
    (delete-file image-file))
  ;; this bit saves the canvas
  (send bitmap save-file image-file 'jpeg 100)

  (display image-file)
  (display (current-directory))
  )


2009/5/14 Scott Brown <sukottoburaun at yahoo.co.jp>

> I have created a turtle module which draws pictures using
> a canvas% object and the draw-line method of dc from the
> PLT Graphics Toolkit.
> Is there some way to save pictures drawn to canvas% as
> image files?
>
>
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Stephen De Gabrielle
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