[plt-scheme] Got problems with gif transparency!

the mask bitmap we get with get-loaded-mask seems to
be ok ( monochrome with white were the gif is
transparent and black were it's not )
but when we send the method draw-bitmap to the dc with
: 

(send dc draw-bitmap a-gif x y 'solid (make-object
color% black) (send a-gif get-loaded-mask))

with dc being the dc%; and a-gif being a bitmap%

nothing apears on the canvas.
we must be wrong somewhere, but can't find out where
... 


>Matthew Flatt  wrote:
>
>There's not really any such thing as a transparent
>bitmap% in MrEd.Instead, the `draw-bitmap' method of
>dc accepts an optional maskbitmap in addition to the
>main bitmap.So, after obtaining a mask bitmap with
>`get-loaded-mask', did you supply it as the mask
>argument to dc? (If so, do you know whetherthe bitmap
>returned by `get-loaded-mask' is right? Or is it that
>the bitmap and its mask seem to be ok, but
`draw->bitmap' doesn't seem to do the right thing?)
>
>Matthew

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