[racket] Racket/gui : How to rotate a bitmap% ?

@noelWelsh : I tested your advice, but it not run.. I tested to rotate and translate then : The bitmap is turn around another point..I test to translate and rotate then, the result is the same. Thanks you anyway.
@Jay : I don't know how you can rotate bitmap with gl2d library.. I must draw with another thing ? 

> Date: Mon, 9 May 2011 08:21:49 -0600
> Subject: Re: [racket] Racket/gui : How to rotate a bitmap% ?
> From: jay.mccarthy at gmail.com
> To: noelwelsh at gmail.com
> CC: julien-0659 at hotmail.fr; users at racket-lang.org
> 
> And that's the exact same thing you do in OpenGL too. My gl2d code
> just packages those GL commands in a nice way. I have a new experiment
> with doing the same thing but with a functional packaging:
> 
> https://github.com/get-bonus/get-bonus/blob/master/exp/gl.rkt
> 
> Look at the contracts at the bottom. (This package, btw, can very
> easily get very high frame rates with very naive rendering, because it
> automatically compiles common draw sequences to the card.)
> 
> Jay
> 
> 2011/5/9 Noel Welsh <noelwelsh at gmail.com>:
> > 2011/5/9 Jyu 。 <julien-0659 at hotmail.fr>:
> >> I can rotate a bitmap% around the (0,0) coordinate point, but I cannot do
> >> the same for any other point..
> >
> > You probably need to call translate and then rotate. There is a
> > transformation matrix maintained by the dc% which allows for rotation,
> > translation, and scaling. If you first translate and then rotate you
> > should be able to rotate your bitmap around an arbitrary point. (I say
> > "should" because I haven't tested it myself.)
> >
> > HTH,
> > N.
> >
> > _________________________________________________
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> 
> 
> 
> -- 
> Jay McCarthy <jay at cs.byu.edu>
> Assistant Professor / Brigham Young University
> http://faculty.cs.byu.edu/~jay
> 
> "The glory of God is Intelligence" - D&C 93
 		 	   		  
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