That works perfectly, thanks David!
(define (resize-draw canvas0 bm)
(let* ((dc (send canvas0 get-dc))
(t (send dc get-transformation)))
(send dc scale
(/ (send canvas0 get-width) (send bm get-width))
(/ (send canvas0 get-height) (send bm get-height)))
(send dc draw-bitmap bm 0 0)
(send dc set-transformation t)))
On Saturday, August 11, 2018 at 10:36:16 PM UTC-4, david.vanderson wrote:
>
> Usually you adjust the drawing context's scale. Something like
> (untested):
>
> (define bm (read-bitmap ...))
> (define dc (send image-box get-dc))
> (define t (send dc get-transformation)) ; save old scale
> (send dc scale
> (/ (send image-box get-width) (send bm get-width))
> (/ (send image-box get-height) (send bm get-height)))
> (send dc draw-bitmap bm 0 0)
> (send dc set-transformation t) ; restore old scale
>
> If you want to create a new bitmap with the exact size you want, then
> you create a new bitmap and use the same strategy:
> (define new-bm (make-bitmap w h))
> (define dc (send new-bm get-dc))
> ; same as above
>
> Does that help?
> Dave
>
> On Sat, Aug 11, 2018 at 9:48 PM, <silver...@gmail.com <javascript:>>
> wrote:
> > (define image-box
> > (new canvas% [parent frame]
> > [min-width 300]
> > [min-height 300]))
> >
> > I'm still trying to figure out how the racket/gui library works but I'm
> > having some difficulty understanding how to have an image fill a canvas.
> >
> > I'd like for instance to have a canvas in my gui that is 300x300 and
> have
> > any image I load resized to fit those dimensions.
> >
> > (send (send image-box get-dc)
> > draw-bitmap
> > (read-bitmap (string->path (send list-box
> get-string
> > select)))
> > 0 0))))))
> >
> > Here I have some quickly thrown together code for selecting a list of
> > pathnames to images from a list-box. The images are all different sizes
> and
> > usually end up exceeding the canvas size.
> >
> > I've looked around the documentation, especially in the racket/draw
> module
> > but I can't find anything beyond a "scale" which doesn't really seem all
> > that helpful. If anyone knows how to change images to certain sizes
> that'd
> > be helpful. I tried looking at racket/pict too but that doesn't seem to
> > have anyway to absolutely set a image's dimensions.
> >
> > Thanks!
> >
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