Re: [racket-users] Bitmaps and Canvas sizes

[silverfire675]

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,  > 
> 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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[racket-users] Bitmaps and Canvas sizes

[silverfire675]

(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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[racket-users] Windows Foreign Libraries

[silverfire675]

Really silly question but I was using the rsvg package with racket/gui on 
Linux and everything was working fine.   I moved the code over to windows 
to try it out (after installing the rsvg package there) and it's 
complaining that librsvg-2.2.dll is missing.   I've now tried two separate 
.dll files in my code directory (one that was from the official gnome ftp) 
and racket throws an error that ($1 is not a valid Win32 application) when 
trying to call (ffi-lib) on it.

Now I'm going to try building the .dll myself,  but I'm wondering if it's 
possible after I've got a .dll that works if you can somehow connect it 
with the rsvg package so when I compile for distribution in DrRacket it 
automatically includes the .dll I have.  It pretty much already does this 
for all the other gnome libraries racket/gui uses, and it'd be much easier 
than having to manually add it to the libs after it's done compiling.


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