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Re: Weiler Atherton Clipping Algorithm [message #62444 is a reply to message #62443]

Tue, 09 September 2008 10:10

wlandsman
Messages: 743
Registered: June 2000

Senior Member

On Sep 9, 12:39 pm, David Fanning <n...@dfanning.com> wrote:

> I'm always a little surprised to find scientists annoyed
> when research problems present themselves. (My middle son
> is experiencing similar problems with fire ants.) I would
> have thought this kind of thing is sort of the *point*
> of scientific research. At least it was in my day. :-)

I think I agree more with Chris here. An extreme analogy might be
the one's reaction if IDL did not have an built-in FFT. Now
developing one's own FFT might be an interesting research problem, but
one would expect a commercial image processing package to have one
built-in and to be annoyed if it does not. Similarly one would
expect an image processing package to have a built-in polygon clipping
algorithm, and to be annoyed if it does not.

Having said that, my need for polygon-clipping has always been to
render onto square pixels, and the Sutherland-Hodgman algorithm has
sufficed.

The documentation included in JD's code polyclip.c describes how to
make use of the IDL MAKE_DLL function to create a shareable library,
and then use CALL_EXTERNAL to call the C polyclip program from
IDL. Since you probably want the your Weiler-Atherton code in C
anyway, and the algorithm is (supposedly) not that complicated, this
is probably the way to go. --Wayne

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[Message index]

		Re: Weiler Atherton Clipping Algorithm By: rogass on Tue, 09 September 2008 11:59
		Re: Weiler Atherton Clipping Algorithm By: David Fanning on Tue, 09 September 2008 10:26
		Re: Weiler Atherton Clipping Algorithm By: wlandsman on Tue, 09 September 2008 10:10
		Re: Weiler Atherton Clipping Algorithm By: David Fanning on Tue, 09 September 2008 09:39
		Re: Weiler Atherton Clipping Algorithm By: rogass on Tue, 09 September 2008 09:03
		Re: Weiler Atherton Clipping Algorithm By: wlandsman on Tue, 09 September 2008 06:40
		Re: Weiler Atherton Clipping Algorithm By: rogass on Tue, 09 September 2008 05:32
		Re: Weiler Atherton Clipping Algorithm By: Wox on Tue, 09 September 2008 04:35

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