Re: [paragui-dev] Ellipse Function?

[Andrew Ford]

You'll have to add it yourself.  Hmm... ellipse
drawing algorithms...  I'm sure you can find some on
the web.  You may even be able to adapt an
anti-aliased line-drawing algorithm for the ellipse.

(x^2 / a) + (y^2 / b) = 1

the slope is dy/dx.

y ^ 2 = b - b/a x^2

2y dy/dx = -2bx/a

dy/dx = - bx/ay (if I didn't screw something up)

okay, so your slope at (x,y) is -bx/ay

Perhaps you could use this slope with bresenham's
algorithm, I think there's an anti-aliased bresenham
around somewhere...

Andrew

--- Mark Krosky <address@hidden> wrote:
> Is there an Ellipse function available anywhere, or
> do I have to add it 
> myself?  Does anybody know what's a good algorithm
> to use?
> 
> 
> _______________________________________________
> paragui-dev mailing list
> address@hidden
>
http://mail.freesoftware.fsf.org/mailman/listinfo/paragui-dev


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