Re: [Vxl-users] Ellipse iterator border ...

[Ian S. <ian...@st...>]

Julio Pastrana wrote:
> Hi VXL users 
> just one simple question ..
> 
> how do I draw "just the border" of one ellipse 
> with the vgl_ellipse_scan_iterator
> 
> can some one give me some hints??

As a rule VXL is rubbish at "drawing". However, if you want a unfilled 
ellipsoid, you could use vgl_ellipse_scan_iterator to draw a filled 
ellipse, and then use a vil_binary_dilate, and find the difference 
between the original and dilated image.

It might be easier, and would certainly be faster, to write the code to 
draw an ellipsoid yourself. There should be plenty of examples on the 
web to draw a pixel-width axis-aligned ellipsoid, using a modified form 
of Bresenham's algorithm.

Ian.